Automated conversion of % format specifiers

Using ruff. Does not change any translatable strings.
There are still several thousand usages of % left that ruff wont
auto-convert. Get to them someday.

icons/icns/make_iconsets.py

@@ -27,7 +27,7 @@ for name, src in sources.items():
     try:
         for sz in (16, 32, 128, 256, 512, 1024):
             iname = f'icon_{sz}x{sz}.png'
-            iname2x = 'icon_{0}x{0}@2x.png'.format(sz // 2)
+            iname2x = f'icon_{sz // 2}x{sz // 2}@2x.png'
             if src.endswith('.svg'):
                 subprocess.check_call(['rsvg-convert', src, '-w', str(sz), '-h', str(sz), '-o', iname])
             else:

setup/build.py

@@ -656,7 +656,7 @@ class Build(Command):
         os.chdir(bdir)
         try:
             self.check_call(cmd + ['-S', os.path.dirname(sources[0])])
-            self.check_call([self.env.make] + ['-j{}'.format(cpu_count or 1)])
+            self.check_call([self.env.make] + [f'-j{cpu_count or 1}'])
         finally:
             os.chdir(cwd)
         os.rename(self.j(bdir, 'libheadless.so'), target)
@@ -733,7 +733,7 @@ sip-file = {os.path.basename(sipf)!r}
             env = os.environ.copy()
             if is_macos_universal_build:
                 env['ARCHS'] = 'x86_64 arm64'
-            self.check_call([self.env.make] + ([] if iswindows else ['-j{}'.format(os.cpu_count() or 1)]), env=env)
+            self.check_call([self.env.make] + ([] if iswindows else [f'-j{os.cpu_count() or 1}']), env=env)
             e = 'pyd' if iswindows else 'so'
             m = glob.glob(f'{ext.name}/{ext.name}.*{e}')
             if not m:

setup/check.py

@@ -114,7 +114,7 @@ class Check(Command):
             for i, f in enumerate(dirty_files):
                 self.info('\tChecking', f)
                 if self.file_has_errors(f):
-                    self.info('{} files left to check'.format(len(dirty_files) - i - 1))
+                    self.info(f'{len(dirty_files) - i - 1} files left to check')
                     try:
                         edit_file(f)
                     except FileNotFoundError:

setup/hosting.py

@@ -56,16 +56,16 @@ class ReadFileWithProgressReporting:  # {{{
         eta = int((self._total - self.tell()) / bit_rate) + 1
         eta_m, eta_s = eta / 60, eta % 60
         sys.stdout.write(
-            '  {:.1f}%   {:.1f}/{:.1f}MB {:.1f} KB/sec    {} minutes, {} seconds left'
-            .format(frac * 100, mb_pos, mb_tot, kb_rate, eta_m, eta_s)
+            f'  {frac * 100:.1f}%   {mb_pos:.1f}/{mb_tot:.1f}MB {kb_rate:.1f} KB/sec    {eta_m} minutes, {eta_s} seconds left'
+
         )
         sys.stdout.write('\x1b[u')
         if self.tell() >= self._total:
             sys.stdout.write('\n')
             t = int(time.time() - self.start_time) + 1
             print(
-                'Upload took {} minutes and {} seconds at {:.1f} KB/sec'
-                .format(t/60, t % 60, kb_rate)
+                f'Upload took {t/60} minutes and {t % 60} seconds at {kb_rate:.1f} KB/sec'
+
             )
         sys.stdout.flush()
 

setup/install.py

@@ -388,7 +388,7 @@ class Bootstrap(Command):
             st = time.time()
             clone_cmd.insert(2, '--depth=1')
             subprocess.check_call(clone_cmd, cwd=self.d(self.SRC))
-            print('Downloaded translations in {} seconds'.format(int(time.time() - st)))
+            print(f'Downloaded translations in {int(time.time() - st)} seconds')
         else:
             if os.path.exists(tdir):
                 subprocess.check_call(['git', 'pull'], cwd=tdir)

setup/plugins_mirror.py

@@ -460,7 +460,7 @@ def plugin_to_index(plugin, count):
     released = datetime(*tuple(map(int, re.split(r'\D', plugin['last_modified'])))[:6]).strftime('%e %b, %Y').lstrip()
     details = [
         'Version: <b>{}</b>'.format(escape('.'.join(map(str, plugin['version'])))),
-        'Released: <b>{}</b>'.format(escape(released)),
+        f'Released: <b>{escape(released)}</b>',
         'Author: {}'.format(escape(plugin['author'])),
         'calibre: {}'.format(escape('.'.join(map(str, plugin['minimum_calibre_version'])))),
         'Platforms: {}'.format(escape(', '.join(sorted(plugin['supported_platforms']) or ['all']))),

setup/publish.py

@@ -50,9 +50,9 @@ class Stage2(Command):
         platforms = 'linux64', 'linuxarm64', 'osx', 'win'
         for x in platforms:
             cmd = (
-                '''{exe} -c "import subprocess; subprocess.Popen(['{exe}', './setup.py', '{x}']).wait() != 0 and'''
-                ''' input('Build of {x} failed, press Enter to exit');"'''
-            ).format(exe=sys.executable, x=x)
+                f'''{sys.executable} -c "import subprocess; subprocess.Popen(['{sys.executable}', './setup.py', '{x}']).wait() != 0 and'''
+                f''' input('Build of {x} failed, press Enter to exit');"'''
+            )
             session.append('title ' + x)
             session.append('launch ' + cmd)
 
@@ -220,8 +220,8 @@ class Manual(Command):
                 if x and not os.path.exists(x):
                     os.symlink('.', x)
             self.info(
-                'Built manual for {} languages in {} minutes'
-                .format(len(jobs), int((time.time() - st) / 60.))
+                f'Built manual for {len(jobs)} languages in {int((time.time() - st) / 60.)} minutes'
+
             )
         finally:
             os.chdir(cwd)
@@ -335,6 +335,6 @@ class TagRelease(Command):
     def run(self, opts):
         self.info('Tagging release')
         subprocess.check_call(
-            'git tag -s v{0} -m "version-{0}"'.format(__version__).split()
+            f'git tag -s v{__version__} -m "version-{__version__}"'.split()
         )
         subprocess.check_call(f'git push origin v{__version__}'.split())

setup/upload.py

@@ -361,12 +361,11 @@ class UploadDemo(Command):  # {{{
 
     def run(self, opts):
         check_call(
-            '''ebook-convert {}/demo.html /tmp/html2lrf.lrf '''
+            f'''ebook-convert {self.j(self.SRC, HTML2LRF)}/demo.html /tmp/html2lrf.lrf '''
             '''--title='Demonstration of html2lrf' --authors='Kovid Goyal' '''
             '''--header '''
             '''--serif-family "/usr/share/fonts/corefonts, Times New Roman" '''
-            '''--mono-family  "/usr/share/fonts/corefonts, Andale Mono" '''
-            ''''''.format(self.j(self.SRC, HTML2LRF)),
+            '''--mono-family  "/usr/share/fonts/corefonts, Andale Mono" ''',
             shell=True
         )
 

setup/win-ci.py

@@ -98,7 +98,7 @@ def main():
     else:
         if len(sys.argv) == 1:
             raise SystemExit('Usage: win-ci.py sw|build|test')
-        raise SystemExit('{!r} is not a valid action'.format(sys.argv[-1]))
+        raise SystemExit(f'{sys.argv[-1]!r} is not a valid action')
 
 
 if __name__ == '__main__':

src/calibre/__init__.py

@@ -292,7 +292,7 @@ def get_proxy_info(proxy_scheme, proxy_string):
     '''
     from polyglot.urllib import urlparse
     try:
-        proxy_url = '%s://%s'%(proxy_scheme, proxy_string)
+        proxy_url = f'{proxy_scheme}://{proxy_string}'
         urlinfo = urlparse(proxy_url)
         ans = {
             'scheme': urlinfo.scheme,

src/calibre/constants.py

@@ -146,7 +146,7 @@ def _get_cache_dir():
 
     if iswindows:
         try:
-            candidate = os.path.join(winutil.special_folder_path(winutil.CSIDL_LOCAL_APPDATA), '%s-cache'%__appname__)
+            candidate = os.path.join(winutil.special_folder_path(winutil.CSIDL_LOCAL_APPDATA), f'{__appname__}-cache')
         except ValueError:
             return confcache
     elif ismacos:
@@ -341,7 +341,7 @@ class Plugins(collections.abc.Mapping):
         try:
             return import_module('calibre_extensions.' + name), ''
         except ModuleNotFoundError:
-            raise KeyError('No plugin named %r'%name)
+            raise KeyError(f'No plugin named {name!r}')
         except Exception as err:
             return None, str(err)
 

src/calibre/customize/__init__.py

@@ -322,8 +322,7 @@ class Plugin:  # {{{
         interface. It is called when the user does: calibre-debug -r "Plugin
         Name". Any arguments passed are present in the args variable.
         '''
-        raise NotImplementedError('The %s plugin has no command line interface'
-                                  %self.name)
+        raise NotImplementedError(f'The {self.name} plugin has no command line interface')
 
 # }}}
 
@@ -540,7 +539,7 @@ class CatalogPlugin(Plugin):  # {{{
         Custom fields sort after standard fields
         '''
         if key.startswith('#'):
-            return '~%s' % key[1:]
+            return f'~{key[1:]}'
         else:
             return key
 
@@ -575,9 +574,8 @@ class CatalogPlugin(Plugin):  # {{{
             if requested_fields - all_fields:
                 from calibre.library import current_library_name
                 invalid_fields = sorted(requested_fields - all_fields)
-                print('invalid --fields specified: %s' % ', '.join(invalid_fields))
-                print("available fields in '%s': %s" %
-                      (current_library_name(), ', '.join(sorted(all_fields))))
+                print('invalid --fields specified: {}'.format(', '.join(invalid_fields)))
+                print("available fields in '{}': {}".format(current_library_name(), ', '.join(sorted(all_fields))))
                 raise ValueError('unable to generate catalog with specified fields')
 
             fields = [x for x in of if x in all_fields]

src/calibre/customize/conversion.py

@@ -78,10 +78,9 @@ class OptionRecommendation:
     def validate_parameters(self):
         if self.option.choices and self.recommended_value not in \
                                                     self.option.choices:
-            raise ValueError('OpRec: %s: Recommended value not in choices'%
-                             self.option.name)
+            raise ValueError(f'OpRec: {self.option.name}: Recommended value not in choices')
         if not (isinstance(self.recommended_value, (numbers.Number, bytes, str)) or self.recommended_value is None):
-            raise ValueError('OpRec: %s:'%self.option.name + repr(
+            raise ValueError(f'OpRec: {self.option.name}:' + repr(
                 self.recommended_value) + ' is not a string or a number')
 
 
@@ -229,7 +228,7 @@ class InputFormatPlugin(Plugin):
     def __call__(self, stream, options, file_ext, log,
                  accelerators, output_dir):
         try:
-            log('InputFormatPlugin: %s running'%self.name)
+            log(f'InputFormatPlugin: {self.name} running')
             if hasattr(stream, 'name'):
                 log('on', stream.name)
         except:

src/calibre/customize/ui.py

@@ -85,7 +85,7 @@ def disable_plugin(plugin_or_name):
     if plugin is None:
         raise ValueError(f'No plugin named: {x} found')
     if not plugin.can_be_disabled:
-        raise ValueError('Plugin %s cannot be disabled'%x)
+        raise ValueError(f'Plugin {x} cannot be disabled')
     dp = config['disabled_plugins']
     dp.add(x)
     config['disabled_plugins'] = dp
@@ -199,7 +199,7 @@ def _run_filetype_plugins(path_to_file, ft=None, occasion='preprocess'):
             try:
                 nfp = plugin.run(nfp) or nfp
             except:
-                print('Running file type plugin %s failed with traceback:'%plugin.name, file=oe)
+                print(f'Running file type plugin {plugin.name} failed with traceback:', file=oe)
                 traceback.print_exc(file=oe)
         sys.stdout, sys.stderr = oo, oe
     def x(j):
@@ -526,10 +526,10 @@ def add_plugin(path_to_zip_file):
     plugin = load_plugin(path_to_zip_file)
     if plugin.name in builtin_names:
         raise NameConflict(
-            'A builtin plugin with the name %r already exists' % plugin.name)
+            f'A builtin plugin with the name {plugin.name!r} already exists')
     if plugin.name in get_system_plugins():
         raise NameConflict(
-            'A system plugin with the name %r already exists' % plugin.name)
+            f'A system plugin with the name {plugin.name!r} already exists')
     plugin = initialize_plugin(plugin, path_to_zip_file, PluginInstallationType.EXTERNAL)
     plugins = config['plugins']
     zfp = os.path.join(plugin_dir, plugin.name+'.zip')
@@ -892,7 +892,7 @@ def main(args=sys.argv):
             name, custom = opts.customize_plugin, ''
         plugin = find_plugin(name.strip())
         if plugin is None:
-            print('No plugin with the name %s exists'%name)
+            print(f'No plugin with the name {name} exists')
             return 1
         customize_plugin(plugin, custom)
     if opts.enable_plugin is not None:

src/calibre/customize/zipplugin.py

@@ -296,14 +296,14 @@ class CalibrePluginFinder:
 
     def load(self, path_to_zip_file):
         if not os.access(path_to_zip_file, os.R_OK):
-            raise PluginNotFound('Cannot access %r'%path_to_zip_file)
+            raise PluginNotFound(f'Cannot access {path_to_zip_file!r}')
 
         with zipfile.ZipFile(path_to_zip_file) as zf:
             plugin_name = self._locate_code(zf, path_to_zip_file)
 
         try:
             ans = None
-            plugin_module = 'calibre_plugins.%s'%plugin_name
+            plugin_module = f'calibre_plugins.{plugin_name}'
             m = sys.modules.get(plugin_module, None)
             if m is not None:
                 reload(m)
@@ -315,8 +315,7 @@ class CalibrePluginFinder:
                         obj.name != 'Trivial Plugin':
                     plugin_classes.append(obj)
             if not plugin_classes:
-                raise InvalidPlugin('No plugin class found in %s:%s'%(
-                    as_unicode(path_to_zip_file), plugin_name))
+                raise InvalidPlugin(f'No plugin class found in {as_unicode(path_to_zip_file)}:{plugin_name}')
             if len(plugin_classes) > 1:
                 plugin_classes.sort(key=lambda c:(getattr(c, '__module__', None) or '').count('.'))
 
@@ -324,14 +323,12 @@ class CalibrePluginFinder:
 
             if ans.minimum_calibre_version > numeric_version:
                 raise InvalidPlugin(
-                    'The plugin at %s needs a version of calibre >= %s' %
-                    (as_unicode(path_to_zip_file), '.'.join(map(str,
+                    'The plugin at {} needs a version of calibre >= {}'.format(as_unicode(path_to_zip_file), '.'.join(map(str,
                         ans.minimum_calibre_version))))
 
             if platform not in ans.supported_platforms:
                 raise InvalidPlugin(
-                    'The plugin at %s cannot be used on %s' %
-                    (as_unicode(path_to_zip_file), platform))
+                    f'The plugin at {as_unicode(path_to_zip_file)} cannot be used on {platform}')
 
             return ans
         except:
@@ -359,8 +356,7 @@ class CalibrePluginFinder:
         else:
             if self._identifier_pat.match(plugin_name) is None:
                 raise InvalidPlugin(
-                    'The plugin at %r uses an invalid import name: %r' %
-                    (path_to_zip_file, plugin_name))
+                    f'The plugin at {path_to_zip_file!r} uses an invalid import name: {plugin_name!r}')
 
         pynames = [x for x in names if x.endswith('.py')]
 
@@ -394,9 +390,8 @@ class CalibrePluginFinder:
                     break
 
         if '__init__' not in names:
-            raise InvalidPlugin(('The plugin in %r is invalid. It does not '
+            raise InvalidPlugin(f'The plugin in {path_to_zip_file!r} is invalid. It does not '
                     'contain a top-level __init__.py file')
-                    % path_to_zip_file)
 
         with self._lock:
             self.loaded_plugins[plugin_name] = path_to_zip_file, names, tuple(all_names)

src/calibre/db/backend.py

@@ -163,7 +163,7 @@ class DBPrefs(dict):  # {{{
         self.__setitem__(key, val)
 
     def get_namespaced(self, namespace, key, default=None):
-        key = 'namespaced:%s:%s'%(namespace, key)
+        key = f'namespaced:{namespace}:{key}'
         try:
             return dict.__getitem__(self, key)
         except KeyError:
@@ -174,7 +174,7 @@ class DBPrefs(dict):  # {{{
             raise KeyError('Colons are not allowed in keys')
         if ':' in namespace:
             raise KeyError('Colons are not allowed in the namespace')
-        key = 'namespaced:%s:%s'%(namespace, key)
+        key = f'namespaced:{namespace}:{key}'
         self[key] = val
 
     def write_serialized(self, library_path):
@@ -273,7 +273,7 @@ def IdentifiersConcat():
     '''String concatenation aggregator for the identifiers map'''
 
     def step(ctxt, key, val):
-        ctxt.append('%s:%s'%(key, val))
+        ctxt.append(f'{key}:{val}')
 
     def finalize(ctxt):
         try:
@@ -684,7 +684,7 @@ class DB:
                 suffix = 1
                 while icu_lower(cat + str(suffix)) in catmap:
                     suffix += 1
-                prints('Renaming user category %s to %s'%(cat, cat+str(suffix)))
+                prints(f'Renaming user category {cat} to {cat+str(suffix)}')
                 user_cats[cat + str(suffix)] = user_cats[cat]
                 del user_cats[cat]
                 cats_changed = True
@@ -700,7 +700,7 @@ class DB:
             for num, label in self.conn.get(
                     'SELECT id,label FROM custom_columns WHERE mark_for_delete=1'):
                 table, lt = self.custom_table_names(num)
-                self.execute('''\
+                self.execute(f'''\
                         DROP INDEX   IF EXISTS {table}_idx;
                         DROP INDEX   IF EXISTS {lt}_aidx;
                         DROP INDEX   IF EXISTS {lt}_bidx;
@@ -714,7 +714,7 @@ class DB:
                         DROP VIEW    IF EXISTS tag_browser_filtered_{table};
                         DROP TABLE   IF EXISTS {table};
                         DROP TABLE   IF EXISTS {lt};
-                        '''.format(table=table, lt=lt)
+                        '''
                 )
                 self.prefs.set('update_all_last_mod_dates_on_start', True)
                 self.deleted_fields.append('#'+label)
@@ -764,16 +764,15 @@ class DB:
 
             # Create Foreign Key triggers
             if data['normalized']:
-                trigger = 'DELETE FROM %s WHERE book=OLD.id;'%lt
+                trigger = f'DELETE FROM {lt} WHERE book=OLD.id;'
             else:
-                trigger = 'DELETE FROM %s WHERE book=OLD.id;'%table
+                trigger = f'DELETE FROM {table} WHERE book=OLD.id;'
             triggers.append(trigger)
 
         if remove:
             with self.conn:
                 for data in remove:
-                    prints('WARNING: Custom column %r not found, removing.' %
-                            data['label'])
+                    prints('WARNING: Custom column {!r} not found, removing.'.format(data['label']))
                     self.execute('DELETE FROM custom_columns WHERE id=?',
                             (data['num'],))
 
@@ -783,9 +782,9 @@ class DB:
                     CREATE TEMP TRIGGER custom_books_delete_trg
                         AFTER DELETE ON books
                         BEGIN
-                        %s
+                        {}
                     END;
-                    '''%(' \n'.join(triggers)))
+                    '''.format(' \n'.join(triggers)))
 
         # Setup data adapters
         def adapt_text(x, d):
@@ -1212,7 +1211,7 @@ class DB:
         if re.match(r'^\w*$', label) is None or not label[0].isalpha() or label.lower() != label:
             raise ValueError(_('The label must contain only lower case letters, digits and underscores, and start with a letter'))
         if datatype not in CUSTOM_DATA_TYPES:
-            raise ValueError('%r is not a supported data type'%datatype)
+            raise ValueError(f'{datatype!r} is not a supported data type')
         normalized  = datatype not in ('datetime', 'comments', 'int', 'bool',
                 'float', 'composite')
         is_multiple = is_multiple and datatype in ('text', 'composite')
@@ -1241,29 +1240,29 @@ class DB:
             else:
                 s_index = ''
             lines = [
-                '''\
-                CREATE TABLE %s(
+                f'''\
+                CREATE TABLE {table}(
                     id    INTEGER PRIMARY KEY AUTOINCREMENT,
-                    value %s NOT NULL %s,
+                    value {dt} NOT NULL {collate},
                     link TEXT NOT NULL DEFAULT "",
                     UNIQUE(value));
-                '''%(table, dt, collate),
+                ''',
 
-                'CREATE INDEX %s_idx ON %s (value %s);'%(table, table, collate),
+                f'CREATE INDEX {table}_idx ON {table} (value {collate});',
 
-                '''\
-                CREATE TABLE %s(
+                f'''\
+                CREATE TABLE {lt}(
                     id INTEGER PRIMARY KEY AUTOINCREMENT,
                     book INTEGER NOT NULL,
                     value INTEGER NOT NULL,
-                    %s
+                    {s_index}
                     UNIQUE(book, value)
-                    );'''%(lt, s_index),
+                    );''',
 
-                'CREATE INDEX %s_aidx ON %s (value);'%(lt,lt),
-                'CREATE INDEX %s_bidx ON %s (book);'%(lt,lt),
+                f'CREATE INDEX {lt}_aidx ON {lt} (value);',
+                f'CREATE INDEX {lt}_bidx ON {lt} (book);',
 
-                '''\
+                f'''\
                 CREATE TRIGGER fkc_update_{lt}_a
                         BEFORE UPDATE OF book ON {lt}
                         BEGIN
@@ -1324,22 +1323,22 @@ class DB:
                     value AS sort
                 FROM {table};
 
-                '''.format(lt=lt, table=table),
+                ''',
 
             ]
         else:
             lines = [
-                '''\
-                CREATE TABLE %s(
+                f'''\
+                CREATE TABLE {table}(
                     id    INTEGER PRIMARY KEY AUTOINCREMENT,
                     book  INTEGER,
-                    value %s NOT NULL %s,
+                    value {dt} NOT NULL {collate},
                     UNIQUE(book));
-                '''%(table, dt, collate),
+                ''',
 
-                'CREATE INDEX %s_idx ON %s (book);'%(table, table),
+                f'CREATE INDEX {table}_idx ON {table} (book);',
 
-                '''\
+                f'''\
                 CREATE TRIGGER fkc_insert_{table}
                         BEFORE INSERT ON {table}
                         BEGIN
@@ -1356,7 +1355,7 @@ class DB:
                                 THEN RAISE(ABORT, 'Foreign key violation: book not in books')
                             END;
                         END;
-                '''.format(table=table),
+                ''',
             ]
         script = ' \n'.join(lines)
         self.execute(script)
@@ -2396,15 +2395,14 @@ class DB:
         data = []
         if highlight_start is not None and highlight_end is not None:
             if snippet_size is not None:
-                text = "snippet({fts_table}, 0, ?, ?, '…', {snippet_size})".format(
-                        fts_table=fts_table, snippet_size=max(1, min(snippet_size, 64)))
+                text = f"snippet({fts_table}, 0, ?, ?, '…', {max(1, min(snippet_size, 64))})"
             else:
                 text = f'highlight({fts_table}, 0, ?, ?)'
             data.append(highlight_start)
             data.append(highlight_end)
         query = 'SELECT {0}.id, {0}.book, {0}.format, {0}.user_type, {0}.user, {0}.annot_data, {1} FROM {0} '
         query = query.format('annotations', text)
-        query += ' JOIN {fts_table} ON annotations.id = {fts_table}.rowid'.format(fts_table=fts_table)
+        query += f' JOIN {fts_table} ON annotations.id = {fts_table}.rowid'
         query += f' WHERE {fts_table} MATCH ?'
         data.append(fts_engine_query)
         if restrict_to_user:

src/calibre/db/cache.py

@@ -916,7 +916,7 @@ class Cache:
         try:
             return frozenset(self.fields[field].table.id_map.values())
         except AttributeError:
-            raise ValueError('%s is not a many-one or many-many field' % field)
+            raise ValueError(f'{field} is not a many-one or many-many field')
 
     @read_api
     def get_usage_count_by_id(self, field):
@@ -925,7 +925,7 @@ class Cache:
         try:
             return {k:len(v) for k, v in iteritems(self.fields[field].table.col_book_map)}
         except AttributeError:
-            raise ValueError('%s is not a many-one or many-many field' % field)
+            raise ValueError(f'{field} is not a many-one or many-many field')
 
     @read_api
     def get_id_map(self, field):
@@ -937,7 +937,7 @@ class Cache:
         except AttributeError:
             if field == 'title':
                 return self.fields[field].table.book_col_map.copy()
-            raise ValueError('%s is not a many-one or many-many field' % field)
+            raise ValueError(f'{field} is not a many-one or many-many field')
 
     @read_api
     def get_item_name(self, field, item_id):
@@ -2319,7 +2319,7 @@ class Cache:
         try:
             func = f.table.rename_item
         except AttributeError:
-            raise ValueError('Cannot rename items for one-one fields: %s' % field)
+            raise ValueError(f'Cannot rename items for one-one fields: {field}')
         moved_books = set()
         id_map = {}
         for item_id, new_name in item_id_to_new_name_map.items():
@@ -2705,7 +2705,7 @@ class Cache:
         if mi.authors:
             try:
                 quathors = mi.authors[:20]  # Too many authors causes parsing of the search expression to fail
-                query = ' and '.join('authors:"=%s"'%(a.replace('"', '')) for a in quathors)
+                query = ' and '.join('authors:"={}"'.format(a.replace('"', '')) for a in quathors)
                 qauthors = mi.authors[20:]
             except ValueError:
                 return identical_book_ids

src/calibre/db/categories.py

@@ -60,8 +60,7 @@ class Tag:
 
     @property
     def string_representation(self):
-        return '%s:%s:%s:%s:%s:%s'%(self.name, self.count, self.id, self.state,
-                                    self.category, self.original_categories)
+        return f'{self.name}:{self.count}:{self.id}:{self.state}:{self.category}:{self.original_categories}'
 
     def __str__(self):
         return self.string_representation

src/calibre/db/cli/cmd_add.py

@@ -400,7 +400,7 @@ the folder related options below.
         try:
             getattr(parser.values, option.dest).append(compile_rule(rule))
         except Exception:
-            raise OptionValueError('%r is not a valid filename pattern' % value)
+            raise OptionValueError(f'{value!r} is not a valid filename pattern')
 
     g.add_option(
         '-1',

src/calibre/db/cli/cmd_add_custom_column.py

@@ -72,7 +72,7 @@ def do_add_custom_column(db, label, name, datatype, is_multiple, display):
     num = db.create_custom_column(
         label, name, datatype, is_multiple, display=display
     )
-    prints('Custom column created with id: %s' % num)
+    prints(f'Custom column created with id: {num}')
 
 
 def main(opts, args, dbctx):

src/calibre/db/cli/cmd_list_categories.py

@@ -156,7 +156,7 @@ def main(opts, args, dbctx):
 
     def fmtr(v):
         v = v or 0
-        ans = '%.1f' % v
+        ans = f'{v:.1f}'
         if ans.endswith('.0'):
             ans = ans[:-2]
         return ans

src/calibre/db/cli/cmd_remove_custom_column.py

@@ -61,7 +61,7 @@ def do_remove_custom_column(db, label, force):
                 ' Use calibredb custom_columns to get a list of labels.'
             ) % label
         )
-    prints('Column %r removed.' % label)
+    prints(f'Column {label!r} removed.')
 
 
 def main(opts, args, dbctx):

src/calibre/db/fields.py

@@ -89,7 +89,7 @@ class Field:
             if tweaks['sort_dates_using_visible_fields']:
                 fmt = None
                 if name in {'timestamp', 'pubdate', 'last_modified'}:
-                    fmt = tweaks['gui_%s_display_format' % name]
+                    fmt = tweaks[f'gui_{name}_display_format']
                 elif self.metadata['is_custom']:
                     fmt = self.metadata.get('display', {}).get('date_format', None)
                 self._sort_key = partial(clean_date_for_sort, fmt=fmt)
@@ -454,7 +454,7 @@ class OnDeviceField(OneToOneField):
                 loc.append(_('Card A'))
             if b is not None:
                 loc.append(_('Card B'))
-        return ', '.join(loc) + ((' (%s books)'%count) if count > 1 else '')
+        return ', '.join(loc) + ((f' ({count} books)') if count > 1 else '')
 
     def __iter__(self):
         return iter(())

src/calibre/db/lazy.py

@@ -263,7 +263,7 @@ def composite_getter(mi, field, dbref, book_id, cache, formatter, template_cache
         except Exception:
             import traceback
             traceback.print_exc()
-            return 'ERROR WHILE EVALUATING: %s' % field
+            return f'ERROR WHILE EVALUATING: {field}'
         return ret
 
 
@@ -365,7 +365,7 @@ class ProxyMetadata(Metadata):
         try:
             return ga(self, '_cache')[field]
         except KeyError:
-            raise AttributeError('Metadata object has no attribute named: %r' % field)
+            raise AttributeError(f'Metadata object has no attribute named: {field!r}')
 
     def __setattr__(self, field, val, extra=None):
         cache = ga(self, '_cache')

src/calibre/db/legacy.py

@@ -616,9 +616,9 @@ class LibraryDatabase:
     def set_custom_bulk_multiple(self, ids, add=[], remove=[], label=None, num=None, notify=False):
         data = self.backend.custom_field_metadata(label, num)
         if not data['editable']:
-            raise ValueError('Column %r is not editable'%data['label'])
+            raise ValueError('Column {!r} is not editable'.format(data['label']))
         if data['datatype'] != 'text' or not data['is_multiple']:
-            raise ValueError('Column %r is not text/multiple'%data['label'])
+            raise ValueError('Column {!r} is not text/multiple'.format(data['label']))
         field = self.custom_field_name(label, num)
         self._do_bulk_modify(field, ids, add, remove, notify)
 
@@ -756,7 +756,7 @@ class LibraryDatabase:
         if data['datatype'] == 'composite':
             return set()
         if not data['editable']:
-            raise ValueError('Column %r is not editable'%data['label'])
+            raise ValueError('Column {!r} is not editable'.format(data['label']))
         if data['datatype'] == 'enumeration' and (
                 val and val not in data['display']['enum_values']):
             return set()
@@ -789,7 +789,7 @@ class LibraryDatabase:
                 val and val not in data['display']['enum_values']):
             return
         if not data['editable']:
-            raise ValueError('Column %r is not editable'%data['label'])
+            raise ValueError('Column {!r} is not editable'.format(data['label']))
 
         if append:
             for book_id in ids:
@@ -826,7 +826,7 @@ class LibraryDatabase:
             self.notify('cover', [book_id])
 
     def original_fmt(self, book_id, fmt):
-        nfmt = ('ORIGINAL_%s'%fmt).upper()
+        nfmt = (f'ORIGINAL_{fmt}').upper()
         return nfmt if self.new_api.has_format(book_id, nfmt) else fmt
 
     def save_original_format(self, book_id, fmt, notify=True):
@@ -931,7 +931,7 @@ for field in (
                     self.notify([book_id])
                 return ret if field == 'languages' else retval
         return func
-    setattr(LibraryDatabase, 'set_%s' % field.replace('!', ''), setter(field))
+    setattr(LibraryDatabase, 'set_{}'.format(field.replace('!', '')), setter(field))
 
 for field in ('authors', 'tags', 'publisher'):
     def renamer(field):
@@ -941,7 +941,7 @@ for field in ('authors', 'tags', 'publisher'):
                 return id_map[old_id]
         return func
     fname = field[:-1] if field in {'tags', 'authors'} else field
-    setattr(LibraryDatabase, 'rename_%s' % fname, renamer(field))
+    setattr(LibraryDatabase, f'rename_{fname}', renamer(field))
 
 LibraryDatabase.update_last_modified = lambda self, book_ids, commit=False, now=None: self.new_api.update_last_modified(book_ids, now=now)
 
@@ -954,7 +954,7 @@ for field in ('authors', 'tags', 'publisher', 'series'):
             return self.new_api.all_field_names(field)
         return func
     name = field[:-1] if field in {'authors', 'tags'} else field
-    setattr(LibraryDatabase, 'all_%s_names' % name, getter(field))
+    setattr(LibraryDatabase, f'all_{name}_names', getter(field))
 LibraryDatabase.all_formats = lambda self: self.new_api.all_field_names('formats')
 LibraryDatabase.all_custom = lambda self, label=None, num=None:self.new_api.all_field_names(self.custom_field_name(label, num))
 
@@ -977,7 +977,7 @@ for field in ('tags', 'series', 'publishers', 'ratings', 'languages'):
         def func(self):
             return [[tid, tag] for tid, tag in iteritems(self.new_api.get_id_map(fname))]
         return func
-    setattr(LibraryDatabase, 'get_%s_with_ids' % field, getter(field))
+    setattr(LibraryDatabase, f'get_{field}_with_ids', getter(field))
 
 for field in ('author', 'tag', 'series'):
     def getter(field):
@@ -986,7 +986,7 @@ for field in ('author', 'tag', 'series'):
         def func(self, item_id):
             return self.new_api.get_item_name(field, item_id)
         return func
-    setattr(LibraryDatabase, '%s_name' % field, getter(field))
+    setattr(LibraryDatabase, f'{field}_name', getter(field))
 
 for field in ('publisher', 'series', 'tag'):
     def getter(field):
@@ -995,7 +995,7 @@ for field in ('publisher', 'series', 'tag'):
         def func(self, item_id):
             self.new_api.remove_items(fname, (item_id,))
         return func
-    setattr(LibraryDatabase, 'delete_%s_using_id' % field, getter(field))
+    setattr(LibraryDatabase, f'delete_{field}_using_id', getter(field))
 # }}}
 
 # Legacy field API {{{

src/calibre/db/restore.py

@@ -111,13 +111,9 @@ class Restore(Thread):
                     'and were not fully restored:\n')
             for x in self.conflicting_custom_cols:
                 ans += '\t#'+x+'\n'
-                ans += '\tused:\t%s, %s, %s, %s\n'%(self.custom_columns[x][1],
-                                                    self.custom_columns[x][2],
-                                                    self.custom_columns[x][3],
-                                                    self.custom_columns[x][5])
+                ans += f'\tused:\t{self.custom_columns[x][1]}, {self.custom_columns[x][2]}, {self.custom_columns[x][3]}, {self.custom_columns[x][5]}\n'
                 for coldef in self.conflicting_custom_cols[x]:
-                    ans += '\tother:\t%s, %s, %s, %s\n'%(coldef[1], coldef[2],
-                                                         coldef[3], coldef[5])
+                    ans += f'\tother:\t{coldef[1]}, {coldef[2]}, {coldef[3]}, {coldef[5]}\n'
 
         if self.mismatched_dirs:
             ans += '\n\n'

src/calibre/db/schema_upgrades.py

@@ -243,14 +243,14 @@ class SchemaUpgrade:
     def upgrade_version_8(self):
         'Add Tag Browser views'
         def create_tag_browser_view(table_name, column_name):
-            self.db.execute('''
-                DROP VIEW IF EXISTS tag_browser_{tn};
-                CREATE VIEW tag_browser_{tn} AS SELECT
+            self.db.execute(f'''
+                DROP VIEW IF EXISTS tag_browser_{table_name};
+                CREATE VIEW tag_browser_{table_name} AS SELECT
                     id,
                     name,
-                    (SELECT COUNT(id) FROM books_{tn}_link WHERE {cn}={tn}.id) count
-                FROM {tn};
-                '''.format(tn=table_name, cn=column_name))
+                    (SELECT COUNT(id) FROM books_{table_name}_link WHERE {column_name}={table_name}.id) count
+                FROM {table_name};
+                ''')
 
         for tn in ('authors', 'tags', 'publishers', 'series'):
             cn = tn[:-1]
@@ -280,28 +280,28 @@ class SchemaUpgrade:
     def upgrade_version_10(self):
         'Add restricted Tag Browser views'
         def create_tag_browser_view(table_name, column_name, view_column_name):
-            script = ('''
-                DROP VIEW IF EXISTS tag_browser_{tn};
-                CREATE VIEW tag_browser_{tn} AS SELECT
+            script = (f'''
+                DROP VIEW IF EXISTS tag_browser_{table_name};
+                CREATE VIEW tag_browser_{table_name} AS SELECT
                     id,
-                    {vcn},
-                    (SELECT COUNT(id) FROM books_{tn}_link WHERE {cn}={tn}.id) count
-                FROM {tn};
-                DROP VIEW IF EXISTS tag_browser_filtered_{tn};
-                CREATE VIEW tag_browser_filtered_{tn} AS SELECT
+                    {view_column_name},
+                    (SELECT COUNT(id) FROM books_{table_name}_link WHERE {column_name}={table_name}.id) count
+                FROM {table_name};
+                DROP VIEW IF EXISTS tag_browser_filtered_{table_name};
+                CREATE VIEW tag_browser_filtered_{table_name} AS SELECT
                     id,
-                    {vcn},
-                    (SELECT COUNT(books_{tn}_link.id) FROM books_{tn}_link WHERE
-                        {cn}={tn}.id AND books_list_filter(book)) count
-                FROM {tn};
-                '''.format(tn=table_name, cn=column_name, vcn=view_column_name))
+                    {view_column_name},
+                    (SELECT COUNT(books_{table_name}_link.id) FROM books_{table_name}_link WHERE
+                        {column_name}={table_name}.id AND books_list_filter(book)) count
+                FROM {table_name};
+                ''')
             self.db.execute(script)
 
         for field in itervalues(self.field_metadata):
             if field['is_category'] and not field['is_custom'] and 'link_column' in field:
                 table = self.db.get(
                     "SELECT name FROM sqlite_master WHERE type='table' AND name=?",
-                    ('books_%s_link'%field['table'],), all=False)
+                    ('books_{}_link'.format(field['table']),), all=False)
                 if table is not None:
                     create_tag_browser_view(field['table'], field['link_column'], field['column'])
 
@@ -309,75 +309,74 @@ class SchemaUpgrade:
         'Add average rating to tag browser views'
         def create_std_tag_browser_view(table_name, column_name,
                                         view_column_name, sort_column_name):
-            script = ('''
-                DROP VIEW IF EXISTS tag_browser_{tn};
-                CREATE VIEW tag_browser_{tn} AS SELECT
+            script = (f'''
+                DROP VIEW IF EXISTS tag_browser_{table_name};
+                CREATE VIEW tag_browser_{table_name} AS SELECT
                     id,
-                    {vcn},
-                    (SELECT COUNT(id) FROM books_{tn}_link WHERE {cn}={tn}.id) count,
+                    {view_column_name},
+                    (SELECT COUNT(id) FROM books_{table_name}_link WHERE {column_name}={table_name}.id) count,
                     (SELECT AVG(ratings.rating)
-                     FROM books_{tn}_link AS tl, books_ratings_link AS bl, ratings
-                     WHERE tl.{cn}={tn}.id AND bl.book=tl.book AND
+                     FROM books_{table_name}_link AS tl, books_ratings_link AS bl, ratings
+                     WHERE tl.{column_name}={table_name}.id AND bl.book=tl.book AND
                      ratings.id = bl.rating AND ratings.rating <> 0) avg_rating,
-                     {scn} AS sort
-                FROM {tn};
-                DROP VIEW IF EXISTS tag_browser_filtered_{tn};
-                CREATE VIEW tag_browser_filtered_{tn} AS SELECT
+                     {sort_column_name} AS sort
+                FROM {table_name};
+                DROP VIEW IF EXISTS tag_browser_filtered_{table_name};
+                CREATE VIEW tag_browser_filtered_{table_name} AS SELECT
                     id,
-                    {vcn},
-                    (SELECT COUNT(books_{tn}_link.id) FROM books_{tn}_link WHERE
-                        {cn}={tn}.id AND books_list_filter(book)) count,
+                    {view_column_name},
+                    (SELECT COUNT(books_{table_name}_link.id) FROM books_{table_name}_link WHERE
+                        {column_name}={table_name}.id AND books_list_filter(book)) count,
                     (SELECT AVG(ratings.rating)
-                     FROM books_{tn}_link AS tl, books_ratings_link AS bl, ratings
-                     WHERE tl.{cn}={tn}.id AND bl.book=tl.book AND
+                     FROM books_{table_name}_link AS tl, books_ratings_link AS bl, ratings
+                     WHERE tl.{column_name}={table_name}.id AND bl.book=tl.book AND
                      ratings.id = bl.rating AND ratings.rating <> 0 AND
                      books_list_filter(bl.book)) avg_rating,
-                     {scn} AS sort
-                FROM {tn};
+                     {sort_column_name} AS sort
+                FROM {table_name};
 
-                '''.format(tn=table_name, cn=column_name,
-                           vcn=view_column_name, scn=sort_column_name))
+                ''')
             self.db.execute(script)
 
         def create_cust_tag_browser_view(table_name, link_table_name):
-            script = '''
-                DROP VIEW IF EXISTS tag_browser_{table};
-                CREATE VIEW tag_browser_{table} AS SELECT
+            script = f'''
+                DROP VIEW IF EXISTS tag_browser_{table_name};
+                CREATE VIEW tag_browser_{table_name} AS SELECT
                     id,
                     value,
-                    (SELECT COUNT(id) FROM {lt} WHERE value={table}.id) count,
+                    (SELECT COUNT(id) FROM {link_table_name} WHERE value={table_name}.id) count,
                     (SELECT AVG(r.rating)
-                     FROM {lt},
+                     FROM {link_table_name},
                           books_ratings_link AS bl,
                           ratings AS r
-                     WHERE {lt}.value={table}.id AND bl.book={lt}.book AND
+                     WHERE {link_table_name}.value={table_name}.id AND bl.book={link_table_name}.book AND
                            r.id = bl.rating AND r.rating <> 0) avg_rating,
                      value AS sort
-                FROM {table};
+                FROM {table_name};
 
-                DROP VIEW IF EXISTS tag_browser_filtered_{table};
-                CREATE VIEW tag_browser_filtered_{table} AS SELECT
+                DROP VIEW IF EXISTS tag_browser_filtered_{table_name};
+                CREATE VIEW tag_browser_filtered_{table_name} AS SELECT
                     id,
                     value,
-                    (SELECT COUNT({lt}.id) FROM {lt} WHERE value={table}.id AND
+                    (SELECT COUNT({link_table_name}.id) FROM {link_table_name} WHERE value={table_name}.id AND
                     books_list_filter(book)) count,
                     (SELECT AVG(r.rating)
-                     FROM {lt},
+                     FROM {link_table_name},
                           books_ratings_link AS bl,
                           ratings AS r
-                     WHERE {lt}.value={table}.id AND bl.book={lt}.book AND
+                     WHERE {link_table_name}.value={table_name}.id AND bl.book={link_table_name}.book AND
                            r.id = bl.rating AND r.rating <> 0 AND
                            books_list_filter(bl.book)) avg_rating,
                      value AS sort
-                FROM {table};
-                '''.format(lt=link_table_name, table=table_name)
+                FROM {table_name};
+                '''
             self.db.execute(script)
 
         for field in itervalues(self.field_metadata):
             if field['is_category'] and not field['is_custom'] and 'link_column' in field:
                 table = self.db.get(
                     "SELECT name FROM sqlite_master WHERE type='table' AND name=?",
-                    ('books_%s_link'%field['table'],), all=False)
+                    ('books_{}_link'.format(field['table']),), all=False)
                 if table is not None:
                     create_std_tag_browser_view(field['table'], field['link_column'],
                                             field['column'], field['category_sort'])
@@ -389,7 +388,7 @@ class SchemaUpgrade:
         for (table,) in db_tables:
             tables.append(table)
         for table in tables:
-            link_table = 'books_%s_link'%table
+            link_table = f'books_{table}_link'
             if table.startswith('custom_column_') and link_table in tables:
                 create_cust_tag_browser_view(table, link_table)
 
@@ -580,9 +579,9 @@ class SchemaUpgrade:
 
         INSERT INTO identifiers (book, val) SELECT id,isbn FROM books WHERE isbn;
 
-        ALTER TABLE books ADD COLUMN last_modified TIMESTAMP NOT NULL DEFAULT "%s";
+        ALTER TABLE books ADD COLUMN last_modified TIMESTAMP NOT NULL DEFAULT "{}";
 
-        '''%isoformat(DEFAULT_DATE, sep=' ')
+        '''.format(isoformat(DEFAULT_DATE, sep=' '))
         # Sqlite does not support non constant default values in alter
         # statements
         self.db.execute(script)

src/calibre/db/search.py

@@ -108,7 +108,7 @@ class DateSearch:  # {{{
         self.local_today         = {'_today', 'today', icu_lower(_('today'))}
         self.local_yesterday     = {'_yesterday', 'yesterday', icu_lower(_('yesterday'))}
         self.local_thismonth     = {'_thismonth', 'thismonth', icu_lower(_('thismonth'))}
-        self.daysago_pat = regex.compile(r'(%s|daysago|_daysago)$'%_('daysago'), flags=regex.UNICODE | regex.VERSION1)
+        self.daysago_pat = regex.compile(r'({}|daysago|_daysago)$'.format(_('daysago')), flags=regex.UNICODE | regex.VERSION1)
 
     def eq(self, dbdate, query, field_count):
         if dbdate.year == query.year:

src/calibre/db/tables.py

@@ -72,7 +72,7 @@ class Table:
             self.unserialize = lambda x: x.replace('|', ',') if x else ''
             self.serialize = lambda x: x.replace(',', '|')
         self.link_table = (link_table if link_table else
-                'books_%s_link'%self.metadata['table'])
+                'books_{}_link'.format(self.metadata['table']))
         if self.supports_notes and dt == 'rating':  # custom ratings table
             self.supports_notes = False
 

src/calibre/db/tests/add_remove.py

@@ -248,7 +248,7 @@ class AddRemoveTest(BaseTest):
         item_id = {v:k for k, v in iteritems(cache.fields['#series'].table.id_map)}['My Series Two']
         cache.remove_books((1,), permanent=True)
         for x in (fmtpath, bookpath, authorpath):
-            af(os.path.exists(x), 'The file %s exists, when it should not' % x)
+            af(os.path.exists(x), f'The file {x} exists, when it should not')
         for c in (cache, self.init_cache()):
             table = c.fields['authors'].table
             self.assertNotIn(1, c.all_book_ids())
@@ -279,7 +279,7 @@ class AddRemoveTest(BaseTest):
         item_id = {v:k for k, v in iteritems(cache.fields['#series'].table.id_map)}['My Series Two']
         cache.remove_books((1,))
         for x in (fmtpath, bookpath, authorpath):
-            af(os.path.exists(x), 'The file %s exists, when it should not' % x)
+            af(os.path.exists(x), f'The file {x} exists, when it should not')
         b, f = cache.list_trash_entries()
         self.assertEqual(len(b), 1)
         self.assertEqual(len(f), 0)

src/calibre/db/tests/base.py

@@ -48,7 +48,7 @@ class BaseTest(unittest.TestCase):
     def create_db(self, library_path):
         from calibre.library.database2 import LibraryDatabase2
         if LibraryDatabase2.exists_at(library_path):
-            raise ValueError('A library already exists at %r'%library_path)
+            raise ValueError(f'A library already exists at {library_path!r}')
         src = os.path.join(os.path.dirname(__file__), 'metadata.db')
         dest = os.path.join(library_path, 'metadata.db')
         shutil.copyfile(src, dest)
@@ -114,8 +114,8 @@ class BaseTest(unittest.TestCase):
             if isinstance(attr1, (tuple, list)) and 'authors' not in attr and 'languages' not in attr:
                 attr1, attr2 = set(attr1), set(attr2)
             self.assertEqual(attr1, attr2,
-                    '%s not the same: %r != %r'%(attr, attr1, attr2))
+                    f'{attr} not the same: {attr1!r} != {attr2!r}')
             if attr.startswith('#') and attr + '_index' not in exclude:
                 attr1, attr2 = mi1.get_extra(attr), mi2.get_extra(attr)
                 self.assertEqual(attr1, attr2,
-                    '%s {#extra} not the same: %r != %r'%(attr, attr1, attr2))
+                    f'{attr} {{#extra}} not the same: {attr1!r} != {attr2!r}')

src/calibre/db/tests/legacy.py

@@ -32,8 +32,7 @@ class ET:
         legacy = self.legacy or test.init_legacy(test.cloned_library)
         oldres = getattr(old, self.func_name)(*self.args, **self.kwargs)
         newres = getattr(legacy, self.func_name)(*self.args, **self.kwargs)
-        test.assertEqual(oldres, newres, 'Equivalence test for {} with args: {} and kwargs: {} failed'.format(
-            self.func_name, reprlib.repr(self.args), reprlib.repr(self.kwargs)))
+        test.assertEqual(oldres, newres, f'Equivalence test for {self.func_name} with args: {reprlib.repr(self.args)} and kwargs: {reprlib.repr(self.kwargs)} failed')
         self.retval = newres
         return newres
 

src/calibre/db/tests/reading.py

@@ -165,10 +165,10 @@ class ReadingTest(BaseTest):
             x = list(reversed(order))
             ae(order, cache.multisort([(field, True)],
                 ids_to_sort=x),
-                    'Ascending sort of %s failed'%field)
+                    f'Ascending sort of {field} failed')
             ae(x, cache.multisort([(field, False)],
                 ids_to_sort=order),
-                    'Descending sort of %s failed'%field)
+                    f'Descending sort of {field} failed')
 
         # Test sorting of is_multiple fields.
 
@@ -337,8 +337,7 @@ class ReadingTest(BaseTest):
         for query, ans in iteritems(oldvals):
             nr = cache.search(query, '')
             self.assertEqual(ans, nr,
-                'Old result: %r != New result: %r for search: %s'%(
-                    ans, nr, query))
+                f'Old result: {ans!r} != New result: {nr!r} for search: {query}')
 
         # Test searching by id, which was introduced in the new backend
         self.assertEqual(cache.search('id:1', ''), {1})
@@ -414,13 +413,12 @@ class ReadingTest(BaseTest):
                 ):
                     continue
                 self.assertEqual(oval, nval,
-                    'The attribute %s for %s in category %s does not match. Old is %r, New is %r'
-                                %(attr, old.name, category, oval, nval))
+                    f'The attribute {attr} for {old.name} in category {category} does not match. Old is {oval!r}, New is {nval!r}')
 
         for category in old_categories:
             old, new = old_categories[category], new_categories[category]
             self.assertEqual(len(old), len(new),
-                'The number of items in the category %s is not the same'%category)
+                f'The number of items in the category {category} is not the same')
             for o, n in zip(old, new):
                 compare_category(category, o, n)
 
@@ -595,7 +593,7 @@ class ReadingTest(BaseTest):
         test(True, {3}, 'Unknown')
         c.limit = 5
         for i in range(6):
-            test(False, set(), 'nomatch_%s' % i)
+            test(False, set(), f'nomatch_{i}')
         test(False, {3}, 'Unknown')  # cached search expired
         test(False, {3}, '', 'unknown', num=1)
         test(True, {3}, '', 'unknown', num=1)
@@ -638,7 +636,7 @@ class ReadingTest(BaseTest):
                     v = pmi.get_standard_metadata(field)
                     self.assertTrue(v is None or isinstance(v, dict))
                     self.assertEqual(f(mi.get_standard_metadata(field, False)), f(v),
-                                     'get_standard_metadata() failed for field %s' % field)
+                                     f'get_standard_metadata() failed for field {field}')
             for field, meta in cache.field_metadata.custom_iteritems():
                 if meta['datatype'] != 'composite':
                     self.assertEqual(f(getattr(mi, field)), f(getattr(pmi, field)),

src/calibre/db/tests/writing.py

@@ -65,19 +65,16 @@ class WritingTest(BaseTest):
                 if test.name.endswith('_index'):
                     val = float(val) if val is not None else 1.0
                     self.assertEqual(sqlite_res, val,
-                        'Failed setting for %s with value %r, sqlite value not the same. val: %r != sqlite_val: %r'%(
-                            test.name, val, val, sqlite_res))
+                        f'Failed setting for {test.name} with value {val!r}, sqlite value not the same. val: {val!r} != sqlite_val: {sqlite_res!r}')
                 else:
                     test.setter(db)(1, val)
                     old_cached_res = getter(1)
                     self.assertEqual(old_cached_res, cached_res,
-                                    'Failed setting for %s with value %r, cached value not the same. Old: %r != New: %r'%(
-                            test.name, val, old_cached_res, cached_res))
+                                    f'Failed setting for {test.name} with value {val!r}, cached value not the same. Old: {old_cached_res!r} != New: {cached_res!r}')
                     db.refresh()
                     old_sqlite_res = getter(1)
                     self.assertEqual(old_sqlite_res, sqlite_res,
-                        'Failed setting for %s, sqlite value not the same: %r != %r'%(
-                            test.name, old_sqlite_res, sqlite_res))
+                        f'Failed setting for {test.name}, sqlite value not the same: {old_sqlite_res!r} != {sqlite_res!r}')
                 del db
     # }}}
 
@@ -755,7 +752,7 @@ class WritingTest(BaseTest):
             self.assertEqual(ldata, {aid:d['link'] for aid, d in iteritems(c.author_data())})
         self.assertEqual({3}, cache.set_link_for_authors({aid:'xxx' if aid == max(adata) else str(aid) for aid in adata}),
                          'Setting the author link to the same value as before, incorrectly marked some books as dirty')
-        sdata = {aid:'%s, changed' % aid for aid in adata}
+        sdata = {aid:f'{aid}, changed' for aid in adata}
         self.assertEqual({1,2,3}, cache.set_sort_for_authors(sdata))
         for bid in (1, 2, 3):
             self.assertIn(', changed', cache.field_for('author_sort', bid))

src/calibre/db/utils.py

@@ -294,7 +294,7 @@ class ThumbnailCache:
             if not hasattr(self, 'total_size'):
                 self._load_index()
             self._invalidate_sizes()
-            ts = ('%.2f' % timestamp).replace('.00', '')
+            ts = (f'{timestamp:.2f}').replace('.00', '')
             path = '%s%s%s%s%d-%s-%d-%dx%d' % (
                 self.group_id, os.sep, book_id % 100, os.sep,
                 book_id, ts, len(data), self.thumbnail_size[0], self.thumbnail_size[1])

src/calibre/db/view.py

@@ -95,7 +95,7 @@ def format_is_multiple(x, sep=',', repl=None):
 def format_identifiers(x):
     if not x:
         return None
-    return ','.join('%s:%s'%(k, v) for k, v in iteritems(x))
+    return ','.join(f'{k}:{v}' for k, v in iteritems(x))
 
 
 class View:
@@ -190,7 +190,7 @@ class View:
 
     def _get_id(self, idx, index_is_id=True):
         if index_is_id and not self.cache.has_id(idx):
-            raise IndexError('No book with id %s present'%idx)
+            raise IndexError(f'No book with id {idx} present')
         return idx if index_is_id else self.index_to_id(idx)
 
     def has_id(self, book_id):
@@ -242,7 +242,7 @@ class View:
     def _get(self, field, idx, index_is_id=True, default_value=None, fmt=lambda x:x):
         id_ = idx if index_is_id else self.index_to_id(idx)
         if index_is_id and not self.cache.has_id(id_):
-            raise IndexError('No book with id %s present'%idx)
+            raise IndexError(f'No book with id {idx} present')
         return fmt(self.cache.field_for(field, id_, default_value=default_value))
 
     def get_series_sort(self, idx, index_is_id=True, default_value=''):

src/calibre/db/write.py

@@ -204,7 +204,7 @@ def one_one_in_books(book_id_val_map, db, field, *args):
     if book_id_val_map:
         sequence = ((sqlite_datetime(v), k) for k, v in book_id_val_map.items())
         db.executemany(
-            'UPDATE books SET %s=? WHERE id=?'%field.metadata['column'], sequence)
+            'UPDATE books SET {}=? WHERE id=?'.format(field.metadata['column']), sequence)
         field.table.book_col_map.update(book_id_val_map)
     return set(book_id_val_map)
 
@@ -229,13 +229,13 @@ def one_one_in_other(book_id_val_map, db, field, *args):
     book_id_val_map = {k:v for k, v in iteritems(book_id_val_map) if v != g(k, missing)}
     deleted = tuple((k,) for k, v in iteritems(book_id_val_map) if v is None)
     if deleted:
-        db.executemany('DELETE FROM %s WHERE book=?'%field.metadata['table'],
+        db.executemany('DELETE FROM {} WHERE book=?'.format(field.metadata['table']),
                         deleted)
         for book_id in deleted:
             field.table.book_col_map.pop(book_id[0], None)
     updated = {k:v for k, v in iteritems(book_id_val_map) if v is not None}
     if updated:
-        db.executemany('INSERT OR REPLACE INTO %s(book,%s) VALUES (?,?)'%(
+        db.executemany('INSERT OR REPLACE INTO {}(book,{}) VALUES (?,?)'.format(
             field.metadata['table'], field.metadata['column']),
             ((k, sqlite_datetime(v)) for k, v in iteritems(updated)))
         field.table.book_col_map.update(updated)
@@ -260,7 +260,7 @@ def custom_series_index(book_id_val_map, db, field, *args):
             # sorts the same as other books with no series.
             field.table.remove_books((book_id,), db)
     if sequence:
-        db.executemany('UPDATE %s SET %s=? WHERE book=? AND value=?'%(
+        db.executemany('UPDATE {} SET {}=? WHERE book=? AND value=?'.format(
                 field.metadata['table'], field.metadata['column']), sequence)
     return {s[1] for s in sequence}
 # }}}
@@ -287,7 +287,7 @@ def get_db_id(val, db, m, table, kmap, rid_map, allow_case_change,
             db.execute('INSERT INTO authors(name,sort) VALUES (?,?)',
                             (val.replace(',', '|'), aus))
         else:
-            db.execute('INSERT INTO %s(%s) VALUES (?)'%(
+            db.execute('INSERT INTO {}({}) VALUES (?)'.format(
                 m['table'], m['column']), (val,))
         item_id = rid_map[kval] = db.last_insert_rowid()
         table.id_map[item_id] = val
@@ -310,7 +310,7 @@ def change_case(case_changes, dirtied, db, table, m, is_authors=False):
     else:
         vals = ((val, item_id) for item_id, val in iteritems(case_changes))
     db.executemany(
-        'UPDATE %s SET %s=? WHERE id=?'%(m['table'], m['column']), vals)
+        'UPDATE {} SET {}=? WHERE id=?'.format(m['table'], m['column']), vals)
     for item_id, val in iteritems(case_changes):
         table.id_map[item_id] = val
         dirtied.update(table.col_book_map[item_id])
@@ -366,7 +366,7 @@ def many_one(book_id_val_map, db, field, allow_case_change, *args):
 
     # Update the db link table
     if deleted:
-        db.executemany('DELETE FROM %s WHERE book=?'%table.link_table,
+        db.executemany(f'DELETE FROM {table.link_table} WHERE book=?',
                             ((k,) for k in deleted))
     if updated:
         sql = (
@@ -383,7 +383,7 @@ def many_one(book_id_val_map, db, field, allow_case_change, *args):
     if remove:
         if table.supports_notes:
             db.clear_notes_for_category_items(table.name, remove)
-        db.executemany('DELETE FROM %s WHERE id=?'%m['table'],
+        db.executemany('DELETE FROM {} WHERE id=?'.format(m['table']),
             ((item_id,) for item_id in remove))
         for item_id in remove:
             del table.id_map[item_id]
@@ -467,14 +467,14 @@ def many_many(book_id_val_map, db, field, allow_case_change, *args):
 
     # Update the db link table
     if deleted:
-        db.executemany('DELETE FROM %s WHERE book=?'%table.link_table,
+        db.executemany(f'DELETE FROM {table.link_table} WHERE book=?',
                             ((k,) for k in deleted))
     if updated:
         vals = (
             (book_id, val) for book_id, vals in iteritems(updated)
             for val in vals
         )
-        db.executemany('DELETE FROM %s WHERE book=?'%table.link_table,
+        db.executemany(f'DELETE FROM {table.link_table} WHERE book=?',
                             ((k,) for k in updated))
         db.executemany('INSERT INTO {}(book,{}) VALUES(?, ?)'.format(
             table.link_table, m['link_column']), vals)
@@ -488,7 +488,7 @@ def many_many(book_id_val_map, db, field, allow_case_change, *args):
     if remove:
         if table.supports_notes:
             db.clear_notes_for_category_items(table.name, remove)
-        db.executemany('DELETE FROM %s WHERE id=?'%m['table'],
+        db.executemany('DELETE FROM {} WHERE id=?'.format(m['table']),
             ((item_id,) for item_id in remove))
         for item_id in remove:
             del table.id_map[item_id]

src/calibre/debug.py

@@ -321,7 +321,7 @@ def main(args=sys.argv):
             elif ext in {'mobi', 'azw', 'azw3'}:
                 inspect_mobi(path)
             else:
-                print('Cannot dump unknown filetype: %s' % path)
+                print(f'Cannot dump unknown filetype: {path}')
     elif len(args) >= 2 and os.path.exists(os.path.join(args[1], '__main__.py')):
         sys.path.insert(0, args[1])
         run_script(os.path.join(args[1], '__main__.py'), args[2:])

src/calibre/devices/__init__.py

@@ -90,7 +90,7 @@ def debug(ioreg_to_tmp=False, buf=None, plugins=None,
             try:
                 d.startup()
             except:
-                out('Startup failed for device plugin: %s'%d)
+                out(f'Startup failed for device plugin: {d}')
 
     if disabled_plugins is None:
         disabled_plugins = list(disabled_device_plugins())

src/calibre/devices/cli.py

@@ -208,7 +208,7 @@ def main():
         try:
             d.startup()
         except:
-            print('Startup failed for device plugin: %s'%d)
+            print(f'Startup failed for device plugin: {d}')
         if d.MANAGES_DEVICE_PRESENCE:
             cd = d.detect_managed_devices(scanner.devices)
             if cd is not None:

src/calibre/devices/cybook/driver.py

@@ -49,7 +49,7 @@ class CYBOOK(USBMS):
             coverdata = coverdata[2]
         else:
             coverdata = None
-        with open('%s_6090.t2b' % os.path.join(path, filename), 'wb') as t2bfile:
+        with open(f'{os.path.join(path, filename)}_6090.t2b', 'wb') as t2bfile:
             t2b.write_t2b(t2bfile, coverdata)
             fsync(t2bfile)
 
@@ -89,7 +89,7 @@ class ORIZON(CYBOOK):
             coverdata = coverdata[2]
         else:
             coverdata = None
-        with open('%s.thn' % filepath, 'wb') as thnfile:
+        with open(f'{filepath}.thn', 'wb') as thnfile:
             t4b.write_t4b(thnfile, coverdata)
             fsync(thnfile)
 

src/calibre/devices/iriver/driver.py

@@ -28,9 +28,9 @@ class IRIVER_STORY(USBMS):
     VENDOR_NAME = 'IRIVER'
     WINDOWS_MAIN_MEM = ['STORY', 'STORY_EB05', 'STORY_WI-FI', 'STORY_EB07',
                         'STORY_EB12']
-    WINDOWS_MAIN_MEM = re.compile(r'(%s)&'%('|'.join(WINDOWS_MAIN_MEM)))
+    WINDOWS_MAIN_MEM = re.compile(r'({})&'.format('|'.join(WINDOWS_MAIN_MEM)))
     WINDOWS_CARD_A_MEM = ['STORY', 'STORY_SD', 'STORY_EB12_SD']
-    WINDOWS_CARD_A_MEM = re.compile(r'(%s)&'%('|'.join(WINDOWS_CARD_A_MEM)))
+    WINDOWS_CARD_A_MEM = re.compile(r'({})&'.format('|'.join(WINDOWS_CARD_A_MEM)))
 
     # OSX_MAIN_MEM = 'Kindle Internal Storage Media'
     # OSX_CARD_A_MEM = 'Kindle Card Storage Media'

src/calibre/devices/kindle/apnx.py

@@ -105,13 +105,13 @@ class APNXBuilder:
 
         # Updated header if we have a KF8 file...
         if apnx_meta['format'] == 'MOBI_8':
-            content_header = '{"contentGuid":"%(guid)s","asin":"%(asin)s","cdeType":"%(cdetype)s","format":"%(format)s","fileRevisionId":"1","acr":"%(acr)s"}' % apnx_meta  # noqa: E501
+            content_header = '{{"contentGuid":"{guid}","asin":"{asin}","cdeType":"{cdetype}","format":"{format}","fileRevisionId":"1","acr":"{acr}"}}'.format(**apnx_meta)  # noqa: E501
         else:
             # My 5.1.x Touch & 3.4 K3 seem to handle the 'extended' header fine for
             # legacy mobi files, too. But, since they still handle this one too, let's
             # try not to break old devices, and keep using the simple header ;).
-            content_header = '{"contentGuid":"%(guid)s","asin":"%(asin)s","cdeType":"%(cdetype)s","fileRevisionId":"1"}' % apnx_meta
-        page_header = '{"asin":"%(asin)s","pageMap":"' % apnx_meta
+            content_header = '{{"contentGuid":"{guid}","asin":"{asin}","cdeType":"{cdetype}","fileRevisionId":"1"}}'.format(**apnx_meta)
+        page_header = '{{"asin":"{asin}","pageMap":"'.format(**apnx_meta)
         page_header += pages.page_maps + '"}'
         if DEBUG:
             prints('APNX Content Header:', content_header)

src/calibre/devices/kindle/bookmark.py

@@ -33,7 +33,7 @@ class Bookmark:  # {{{
     def record(self, n):
         from calibre.ebooks.metadata.mobi import StreamSlicer
         if n >= self.nrecs:
-            raise ValueError('non-existent record %r' % n)
+            raise ValueError(f'non-existent record {n!r}')
         offoff = 78 + (8 * n)
         start, = unpack('>I', self.data[offoff + 0:offoff + 4])
         stop = None
@@ -141,7 +141,7 @@ class Bookmark:  # {{{
                 # Search looks for book title match, highlight match, and location match
                 # Author is not matched
                 # This will find the first instance of a clipping only
-                book_fs = self.path.replace('.%s' % self.bookmark_extension,'.%s' % self.book_format)
+                book_fs = self.path.replace(f'.{self.bookmark_extension}',f'.{self.book_format}')
                 with open(book_fs,'rb') as f2:
                     stream = io.BytesIO(f2.read())
                     mi = get_topaz_metadata(stream)
@@ -152,7 +152,7 @@ class Bookmark:  # {{{
                     with open(my_clippings, encoding='utf-8', errors='replace') as f2:
                         marker_found = 0
                         text = ''
-                        search_str1 = '%s' % (mi.title)
+                        search_str1 = f'{mi.title}'
                         search_str2 = '- Highlight Loc. %d' % (displayed_location)
                         for line in f2:
                             if marker_found == 0:
@@ -271,12 +271,12 @@ class Bookmark:  # {{{
                 self.last_read_location = self.last_read - self.pdf_page_offset
 
         else:
-            print('unsupported bookmark_extension: %s' % self.bookmark_extension)
+            print(f'unsupported bookmark_extension: {self.bookmark_extension}')
         self.user_notes = user_notes
 
     def get_book_length(self):
         from calibre.ebooks.metadata.mobi import StreamSlicer
-        book_fs = self.path.replace('.%s' % self.bookmark_extension,'.%s' % self.book_format)
+        book_fs = self.path.replace(f'.{self.bookmark_extension}',f'.{self.book_format}')
 
         self.book_length = 0
         if self.bookmark_extension == 'mbp':
@@ -300,6 +300,6 @@ class Bookmark:  # {{{
             except:
                 pass
         else:
-            print('unsupported bookmark_extension: %s' % self.bookmark_extension)
+            print(f'unsupported bookmark_extension: {self.bookmark_extension}')
 
 # }}}

src/calibre/devices/kindle/driver.py

@@ -294,7 +294,7 @@ class KINDLE(USBMS):
                                 typ=user_notes[location]['type'],
                                 text=(user_notes[location]['text'] if
                                       user_notes[location]['type'] == 'Note' else
-                                      '<i>%s</i>' % user_notes[location]['text'])))
+                                      '<i>{}</i>'.format(user_notes[location]['text']))))
                 else:
                     if bookmark.book_format == 'pdf':
                         annotations.append(
@@ -351,7 +351,7 @@ class KINDLE(USBMS):
                                             bm.value.path, index_is_id=True)
         elif bm.type == 'kindle_clippings':
             # Find 'My Clippings' author=Kindle in database, or add
-            last_update = 'Last modified %s' % strftime('%x %X',bm.value['timestamp'].timetuple())
+            last_update = 'Last modified {}'.format(strftime('%x %X',bm.value['timestamp'].timetuple()))
             mc_id = list(db.data.search_getting_ids('title:"My Clippings"', '', sort_results=False))
             if mc_id:
                 db.add_format_with_hooks(mc_id[0], 'TXT', bm.value['path'],
@@ -623,7 +623,7 @@ class KINDLE2(KINDLE):
             except:
                 pass
 
-        apnx_path = '%s.apnx' % os.path.join(path, filename)
+        apnx_path = f'{os.path.join(path, filename)}.apnx'
         apnx_builder = APNXBuilder()
         # Check to see if there is an existing apnx file on Kindle we should keep.
         if opts.extra_customization[self.OPT_APNX_OVERWRITE] or not os.path.exists(apnx_path):
@@ -636,7 +636,7 @@ class KINDLE2(KINDLE):
                         if temp in self.EXTRA_CUSTOMIZATION_CHOICES[self.OPT_APNX_METHOD]:
                             method = temp
                         else:
-                            print('Invalid method choice for this book (%r), ignoring.' % temp)
+                            print(f'Invalid method choice for this book ({temp!r}), ignoring.')
                     except:
                         print('Could not retrieve override method choice, using default.')
                 apnx_builder.write_apnx(filepath, apnx_path, method=method, page_count=custom_page_count)

src/calibre/devices/kobo/books.py

@@ -106,7 +106,7 @@ class Book(Book_):
         if self.contentID:
             fmt('Content ID', self.contentID)
         if self.kobo_series:
-            fmt('Kobo Series', self.kobo_series + ' #%s'%self.kobo_series_number)
+            fmt('Kobo Series', self.kobo_series + f' #{self.kobo_series_number}')
         if self.kobo_series_id:
             fmt('Kobo Series ID', self.kobo_series_id)
         if self.kobo_subtitle:
@@ -203,7 +203,7 @@ class KTCollectionsBookList(CollectionsBookList):
                 fm = None
                 attr = attr.strip()
                 if show_debug:
-                    debug_print("KTCollectionsBookList:get_collections - attr='%s'"%attr)
+                    debug_print(f"KTCollectionsBookList:get_collections - attr='{attr}'")
 
                 # If attr is device_collections, then we cannot use
                 # format_field, because we don't know the fields where the

src/calibre/devices/kobo/driver.py

@@ -384,25 +384,25 @@ class KOBO(USBMS):
             if self.dbversion >= 33:
                 query= ('select Title, Attribution, DateCreated, ContentID, MimeType, ContentType, '
                     'ImageID, ReadStatus, ___ExpirationStatus, FavouritesIndex, Accessibility, IsDownloaded from content where '
-                    'BookID is Null %(previews)s %(recommendations)s and not ((___ExpirationStatus=3 or ___ExpirationStatus is Null) %(expiry)s') % dict(
+                    'BookID is Null {previews} {recommendations} and not ((___ExpirationStatus=3 or ___ExpirationStatus is Null) {expiry}').format(**dict(
                         expiry=' and ContentType = 6)' if opts.extra_customization[self.OPT_SHOW_EXPIRED_BOOK_RECORDS] else ')',
                     previews=' and Accessibility <> 6' if not self.show_previews else '',
-                    recommendations=" and IsDownloaded in ('true', 1)" if opts.extra_customization[self.OPT_SHOW_RECOMMENDATIONS] is False else '')
+                    recommendations=" and IsDownloaded in ('true', 1)" if opts.extra_customization[self.OPT_SHOW_RECOMMENDATIONS] is False else ''))
             elif self.dbversion >= 16 and self.dbversion < 33:
                 query= ('select Title, Attribution, DateCreated, ContentID, MimeType, ContentType, '
                     'ImageID, ReadStatus, ___ExpirationStatus, FavouritesIndex, Accessibility, "1" as IsDownloaded from content where '
-                    'BookID is Null and not ((___ExpirationStatus=3 or ___ExpirationStatus is Null) %(expiry)s') % dict(expiry=' and ContentType = 6)'
-                    if opts.extra_customization[self.OPT_SHOW_EXPIRED_BOOK_RECORDS] else ')')
+                    'BookID is Null and not ((___ExpirationStatus=3 or ___ExpirationStatus is Null) {expiry}').format(**dict(expiry=' and ContentType = 6)'
+                    if opts.extra_customization[self.OPT_SHOW_EXPIRED_BOOK_RECORDS] else ')'))
             elif self.dbversion < 16 and self.dbversion >= 14:
                 query= ('select Title, Attribution, DateCreated, ContentID, MimeType, ContentType, '
                     'ImageID, ReadStatus, ___ExpirationStatus, FavouritesIndex, "-1" as Accessibility, "1" as IsDownloaded from content where '
-                    'BookID is Null and not ((___ExpirationStatus=3 or ___ExpirationStatus is Null) %(expiry)s') % dict(expiry=' and ContentType = 6)'
-                    if opts.extra_customization[self.OPT_SHOW_EXPIRED_BOOK_RECORDS] else ')')
+                    'BookID is Null and not ((___ExpirationStatus=3 or ___ExpirationStatus is Null) {expiry}').format(**dict(expiry=' and ContentType = 6)'
+                    if opts.extra_customization[self.OPT_SHOW_EXPIRED_BOOK_RECORDS] else ')'))
             elif self.dbversion < 14 and self.dbversion >= 8:
                 query= ('select Title, Attribution, DateCreated, ContentID, MimeType, ContentType, '
                     'ImageID, ReadStatus, ___ExpirationStatus, "-1" as FavouritesIndex, "-1" as Accessibility, "1" as IsDownloaded from content where '
-                    'BookID is Null and not ((___ExpirationStatus=3 or ___ExpirationStatus is Null) %(expiry)s') % dict(expiry=' and ContentType = 6)'
-                    if opts.extra_customization[self.OPT_SHOW_EXPIRED_BOOK_RECORDS] else ')')
+                    'BookID is Null and not ((___ExpirationStatus=3 or ___ExpirationStatus is Null) {expiry}').format(**dict(expiry=' and ContentType = 6)'
+                    if opts.extra_customization[self.OPT_SHOW_EXPIRED_BOOK_RECORDS] else ')'))
             else:
                 query = ('select Title, Attribution, DateCreated, ContentID, MimeType, ContentType, '
                          'ImageID, ReadStatus, "-1" as ___ExpirationStatus, "-1" as FavouritesIndex, '
@@ -608,12 +608,12 @@ class KOBO(USBMS):
         self.report_progress(1.0, _('Removing books from device metadata listing...'))
 
     def add_books_to_metadata(self, locations, metadata, booklists):
-        debug_print('KoboTouch::add_books_to_metadata - start. metadata=%s' % metadata[0])
+        debug_print(f'KoboTouch::add_books_to_metadata - start. metadata={metadata[0]}')
         metadata = iter(metadata)
         for i, location in enumerate(locations):
             self.report_progress((i+1) / float(len(locations)), _('Adding books to device metadata listing...'))
             info = next(metadata)
-            debug_print('KoboTouch::add_books_to_metadata - info=%s' % info)
+            debug_print(f'KoboTouch::add_books_to_metadata - info={info}')
             blist = 2 if location[1] == 'cardb' else 1 if location[1] == 'carda' else 0
 
             # Extract the correct prefix from the pathname. To do this correctly,
@@ -645,7 +645,7 @@ class KOBO(USBMS):
                 book.size = os.stat(self.normalize_path(path)).st_size
             b = booklists[blist].add_book(book, replace_metadata=True)
             if b:
-                debug_print('KoboTouch::add_books_to_metadata - have a new book - book=%s' % book)
+                debug_print(f'KoboTouch::add_books_to_metadata - have a new book - book={book}')
                 b._new_book = True
         self.report_progress(1.0, _('Adding books to device metadata listing...'))
 
@@ -755,9 +755,9 @@ class KOBO(USBMS):
                     ' selecting "Configure this device" and then the '
                     ' "Attempt to support newer firmware" option.'
                     ' Doing so may require you to perform a Factory reset of'
-                    ' your Kobo.') + ((
-                    '\nDevice database version: %s.'
-                    '\nDevice firmware version: %s') % (self.dbversion, self.display_fwversion))
+                    ' your Kobo.') + (
+                    f'\nDevice database version: {self.dbversion}.'
+                    f'\nDevice firmware version: {self.display_fwversion}')
                     , UserFeedback.WARN)
 
                 return False
@@ -807,7 +807,7 @@ class KOBO(USBMS):
                 ('card_a', 'metadata.calibre', 1),
                 ('card_b', 'metadata.calibre', 2)
                 ]:
-            prefix = getattr(self, '_%s_prefix'%prefix)
+            prefix = getattr(self, f'_{prefix}_prefix')
             if prefix is not None and os.path.exists(prefix):
                 paths[source_id] = os.path.join(prefix, *(path.split('/')))
         return paths
@@ -891,7 +891,7 @@ class KOBO(USBMS):
             cursor.close()
 
     def update_device_database_collections(self, booklists, collections_attributes, oncard):
-        debug_print("Kobo:update_device_database_collections - oncard='%s'"%oncard)
+        debug_print(f"Kobo:update_device_database_collections - oncard='{oncard}'")
         if self.modify_database_check('update_device_database_collections') is False:
             return
 
@@ -1678,7 +1678,7 @@ class KOBOTOUCH(KOBO):
         return "'true'" if x else "'false'"
 
     def books(self, oncard=None, end_session=True):
-        debug_print("KoboTouch:books - oncard='%s'"%oncard)
+        debug_print(f"KoboTouch:books - oncard='{oncard}'")
         self.debugging_title = self.get_debugging_title()
 
         dummy_bl = self.booklist_class(None, None, None)
@@ -1699,11 +1699,11 @@ class KOBOTOUCH(KOBO):
         prefix = self._card_a_prefix if oncard == 'carda' else \
                  self._card_b_prefix if oncard == 'cardb' \
                  else self._main_prefix
-        debug_print("KoboTouch:books - oncard='%s', prefix='%s'"%(oncard, prefix))
+        debug_print(f"KoboTouch:books - oncard='{oncard}', prefix='{prefix}'")
 
         self.fwversion = self.get_firmware_version()
 
-        debug_print('Kobo device: %s' % self.gui_name)
+        debug_print(f'Kobo device: {self.gui_name}')
         debug_print('Version of driver:', self.version, 'Has kepubs:', self.has_kepubs)
         debug_print('Version of firmware:', self.fwversion, 'Has kepubs:', self.has_kepubs)
         debug_print('Firmware supports cover image tree:', self.fwversion >= self.min_fwversion_images_tree)
@@ -1718,7 +1718,7 @@ class KOBOTOUCH(KOBO):
         debug_print('KoboTouch:books - driver options=', self)
         debug_print("KoboTouch:books - prefs['manage_device_metadata']=", prefs['manage_device_metadata'])
         debugging_title = self.debugging_title
-        debug_print("KoboTouch:books - set_debugging_title to '%s'" % debugging_title)
+        debug_print(f"KoboTouch:books - set_debugging_title to '{debugging_title}'")
         bl.set_debugging_title(debugging_title)
         debug_print('KoboTouch:books - length bl=%d'%len(bl))
         need_sync = self.parse_metadata_cache(bl, prefix, self.METADATA_CACHE)
@@ -1739,7 +1739,7 @@ class KOBOTOUCH(KOBO):
             show_debug = self.is_debugging_title(title)
             # show_debug = authors == 'L. Frank Baum'
             if show_debug:
-                debug_print("KoboTouch:update_booklist - title='%s'"%title, 'ContentType=%s'%ContentType, 'isdownloaded=', isdownloaded)
+                debug_print(f"KoboTouch:update_booklist - title='{title}'", f'ContentType={ContentType}', 'isdownloaded=', isdownloaded)
                 debug_print(
                     '         prefix=%s, DateCreated=%s, readstatus=%d, MimeType=%s, expired=%d, favouritesindex=%d, accessibility=%d, isdownloaded=%s'%
                 (prefix, DateCreated, readstatus, MimeType, expired, favouritesindex, accessibility, isdownloaded,))
@@ -1838,19 +1838,19 @@ class KOBOTOUCH(KOBO):
                         try:
                             kobo_metadata.pubdate = datetime.strptime(DateCreated, '%Y-%m-%dT%H:%M:%S.%fZ')
                         except:
-                            debug_print("KoboTouch:update_booklist - Cannot convert date - DateCreated='%s'"%DateCreated)
+                            debug_print(f"KoboTouch:update_booklist - Cannot convert date - DateCreated='{DateCreated}'")
 
                 idx = bl_cache.get(lpath, None)
                 if idx is not None:  # and not (accessibility == 1 and isdownloaded == 'false'):
                     if show_debug:
                         self.debug_index = idx
                         debug_print('KoboTouch:update_booklist - idx=%d'%idx)
-                        debug_print('KoboTouch:update_booklist - lpath=%s'%lpath)
+                        debug_print(f'KoboTouch:update_booklist - lpath={lpath}')
                         debug_print('KoboTouch:update_booklist - bl[idx].device_collections=', bl[idx].device_collections)
                         debug_print('KoboTouch:update_booklist - playlist_map=', playlist_map)
                         debug_print('KoboTouch:update_booklist - bookshelves=', bookshelves)
                         debug_print('KoboTouch:update_booklist - kobo_collections=', kobo_collections)
-                        debug_print('KoboTouch:update_booklist - series="%s"' % bl[idx].series)
+                        debug_print(f'KoboTouch:update_booklist - series="{bl[idx].series}"')
                         debug_print('KoboTouch:update_booklist - the book=', bl[idx])
                         debug_print('KoboTouch:update_booklist - the authors=', bl[idx].authors)
                         debug_print('KoboTouch:update_booklist - application_id=', bl[idx].application_id)
@@ -1871,7 +1871,7 @@ class KOBOTOUCH(KOBO):
                             debug_print('KoboTouch:update_booklist - book size=', bl[idx].size)
 
                     if show_debug:
-                        debug_print("KoboTouch:update_booklist - ContentID='%s'"%ContentID)
+                        debug_print(f"KoboTouch:update_booklist - ContentID='{ContentID}'")
                     bl[idx].contentID           = ContentID
                     bl[idx].kobo_metadata       = kobo_metadata
                     bl[idx].kobo_series         = series
@@ -1897,8 +1897,8 @@ class KOBOTOUCH(KOBO):
                         debug_print('KoboTouch:update_booklist - updated bl[idx].device_collections=', bl[idx].device_collections)
                         debug_print('KoboTouch:update_booklist - playlist_map=', playlist_map, 'changed=', changed)
                         # debug_print('KoboTouch:update_booklist - book=', bl[idx])
-                        debug_print('KoboTouch:update_booklist - book class=%s'%bl[idx].__class__)
-                        debug_print('KoboTouch:update_booklist - book title=%s'%bl[idx].title)
+                        debug_print(f'KoboTouch:update_booklist - book class={bl[idx].__class__}')
+                        debug_print(f'KoboTouch:update_booklist - book title={bl[idx].title}')
                 else:
                     if show_debug:
                         debug_print('KoboTouch:update_booklist - idx is none')
@@ -1911,10 +1911,10 @@ class KOBOTOUCH(KOBO):
                                 title = 'FILE MISSING: ' + title
                             book = self.book_class(prefix, lpath, title, authors, MimeType, DateCreated, ContentType, ImageID, size=0)
                             if show_debug:
-                                debug_print('KoboTouch:update_booklist - book file does not exist. ContentID="%s"'%ContentID)
+                                debug_print(f'KoboTouch:update_booklist - book file does not exist. ContentID="{ContentID}"')
 
                     except Exception as e:
-                        debug_print("KoboTouch:update_booklist - exception creating book: '%s'"%str(e))
+                        debug_print(f"KoboTouch:update_booklist - exception creating book: '{e!s}'")
                         debug_print('        prefix: ', prefix, 'lpath: ', lpath, 'title: ', title, 'authors: ', authors,
                                     'MimeType: ', MimeType, 'DateCreated: ', DateCreated, 'ContentType: ', ContentType, 'ImageID: ', ImageID)
                         raise
@@ -1922,10 +1922,10 @@ class KOBOTOUCH(KOBO):
                     if show_debug:
                         debug_print('KoboTouch:update_booklist - class:', book.__class__)
                         # debug_print('    resolution:', book.__class__.__mro__)
-                        debug_print("    contentid: '%s'"%book.contentID)
-                        debug_print("    title:'%s'"%book.title)
+                        debug_print(f"    contentid: '{book.contentID}'")
+                        debug_print(f"    title:'{book.title}'")
                         debug_print('    the book:', book)
-                        debug_print("    author_sort:'%s'"%book.author_sort)
+                        debug_print(f"    author_sort:'{book.author_sort}'")
                         debug_print('    bookshelves:', bookshelves)
                         debug_print('    kobo_collections:', kobo_collections)
 
@@ -2021,39 +2021,35 @@ class KOBOTOUCH(KOBO):
             if self.supports_kobo_archive() or self.supports_overdrive():
                 where_clause = (" WHERE BookID IS NULL "
                         " AND ((Accessibility = -1 AND IsDownloaded in ('true', 1 )) "              # Sideloaded books
-                        "      OR (Accessibility IN (%(downloaded_accessibility)s) %(expiry)s) "    # Purchased books
-                        "      %(previews)s %(recommendations)s ) "                                  # Previews or Recommendations
-                    ) % \
-                    dict(
+                        "      OR (Accessibility IN ({downloaded_accessibility}) {expiry}) "    # Purchased books
+                        "      {previews} {recommendations} ) "                                  # Previews or Recommendations
+                    ).format(**dict(
                          expiry='' if self.show_archived_books else "and IsDownloaded in ('true', 1)",
                          previews=" OR (Accessibility in (6) AND ___UserID <> '')" if self.show_previews else '',
                          recommendations=" OR (Accessibility IN (-1, 4, 6) AND ___UserId = '')" if self.show_recommendations else '',
                          downloaded_accessibility='1,2,8,9' if self.supports_overdrive() else '1,2'
-                         )
+                         ))
             elif self.supports_series():
                 where_clause = (" WHERE BookID IS NULL "
-                    " AND ((Accessibility = -1 AND IsDownloaded IN ('true', 1)) or (Accessibility IN (1,2)) %(previews)s %(recommendations)s )"
-                    " AND NOT ((___ExpirationStatus=3 OR ___ExpirationStatus is Null) %(expiry)s)"
-                    ) % \
-                    dict(
+                    " AND ((Accessibility = -1 AND IsDownloaded IN ('true', 1)) or (Accessibility IN (1,2)) {previews} {recommendations} )"
+                    " AND NOT ((___ExpirationStatus=3 OR ___ExpirationStatus is Null) {expiry})"
+                    ).format(**dict(
                          expiry=' AND ContentType = 6' if self.show_archived_books else '',
                          previews=" or (Accessibility IN (6) AND ___UserID <> '')" if self.show_previews else '',
                          recommendations=" or (Accessibility in (-1, 4, 6) AND ___UserId = '')" if self.show_recommendations else ''
-                         )
+                         ))
             elif self.dbversion >= 33:
-                where_clause = (' WHERE BookID IS NULL %(previews)s %(recommendations)s AND NOT'
-                    ' ((___ExpirationStatus=3 or ___ExpirationStatus IS NULL) %(expiry)s)'
-                    ) % \
-                    dict(
+                where_clause = (' WHERE BookID IS NULL {previews} {recommendations} AND NOT'
+                    ' ((___ExpirationStatus=3 or ___ExpirationStatus IS NULL) {expiry})'
+                    ).format(**dict(
                          expiry=' AND ContentType = 6' if self.show_archived_books else '',
                          previews=' AND Accessibility <> 6' if not self.show_previews else '',
                          recommendations=" AND IsDownloaded IN ('true', 1)" if not self.show_recommendations else ''
-                         )
+                         ))
             elif self.dbversion >= 16:
                 where_clause = (' WHERE BookID IS NULL '
-                    'AND NOT ((___ExpirationStatus=3 OR ___ExpirationStatus IS Null) %(expiry)s)'
-                    ) % \
-                    dict(expiry=' and ContentType = 6' if self.show_archived_books else '')
+                    'AND NOT ((___ExpirationStatus=3 OR ___ExpirationStatus IS Null) {expiry})'
+                    ).format(**dict(expiry=' and ContentType = 6' if self.show_archived_books else ''))
             else:
                 where_clause = ' WHERE BookID IS NULL'
 
@@ -2094,7 +2090,7 @@ class KOBOTOUCH(KOBO):
                 show_debug = self.is_debugging_title(row['Title'])
                 if show_debug:
                     debug_print('KoboTouch:books - looping on database - row=%d' % i)
-                    debug_print("KoboTouch:books - title='%s'"%row['Title'], 'authors=', row['Attribution'])
+                    debug_print("KoboTouch:books - title='{}'".format(row['Title']), 'authors=', row['Attribution'])
                     debug_print('KoboTouch:books - row=', row)
                 if not hasattr(row['ContentID'], 'startswith') or row['ContentID'].lower().startswith(
                         'file:///usr/local/kobo/help/') or row['ContentID'].lower().startswith('/usr/local/kobo/help/'):
@@ -2103,7 +2099,7 @@ class KOBOTOUCH(KOBO):
                 externalId = None if row['ExternalId'] and len(row['ExternalId']) == 0 else row['ExternalId']
                 path = self.path_from_contentid(row['ContentID'], row['ContentType'], row['MimeType'], oncard, externalId)
                 if show_debug:
-                    debug_print("KoboTouch:books - path='%s'"%path, "  ContentID='%s'"%row['ContentID'], ' externalId=%s' % externalId)
+                    debug_print(f"KoboTouch:books - path='{path}'", "  ContentID='{}'".format(row['ContentID']), f' externalId={externalId}')
 
                 bookshelves = get_bookshelvesforbook(connection, row['ContentID'])
 
@@ -2142,7 +2138,7 @@ class KOBOTOUCH(KOBO):
                     need_sync = True
                     del bl[idx]
                 else:
-                    debug_print("KoboTouch:books - Book in mtadata.calibre, on file system but not database - bl[idx].title:'%s'"%bl[idx].title)
+                    debug_print(f"KoboTouch:books - Book in mtadata.calibre, on file system but not database - bl[idx].title:'{bl[idx].title}'")
 
         # print('count found in cache: %d, count of files in metadata: %d, need_sync: %s' % \
         #      (len(bl_cache), len(bl), need_sync))
@@ -2159,12 +2155,12 @@ class KOBOTOUCH(KOBO):
             debug_print('KoboTouch:books - have done sync_booklists')
 
         self.report_progress(1.0, _('Getting list of books on device...'))
-        debug_print("KoboTouch:books - end - oncard='%s'"%oncard)
+        debug_print(f"KoboTouch:books - end - oncard='{oncard}'")
         return bl
 
     @classmethod
     def book_from_path(cls, prefix, lpath, title, authors, mime, date, ContentType, ImageID):
-        debug_print('KoboTouch:book_from_path - title=%s'%title)
+        debug_print(f'KoboTouch:book_from_path - title={title}')
         book = super().book_from_path(prefix, lpath, title, authors, mime, date, ContentType, ImageID)
 
         # Kobo Audiobooks are directories with files in them.
@@ -2222,11 +2218,11 @@ class KOBOTOUCH(KOBO):
                 fpath = path + ending
                 if os.path.exists(fpath):
                     if show_debug:
-                        debug_print('KoboTouch:imagefilename_from_imageID - have cover image fpath=%s' % (fpath))
+                        debug_print(f'KoboTouch:imagefilename_from_imageID - have cover image fpath={fpath}')
                     return fpath
 
             if show_debug:
-                debug_print('KoboTouch:imagefilename_from_imageID - no cover image found - ImageID=%s' % (ImageID))
+                debug_print(f'KoboTouch:imagefilename_from_imageID - no cover image found - ImageID={ImageID}')
         return None
 
     def get_extra_css(self):
@@ -2313,7 +2309,7 @@ class KOBOTOUCH(KOBO):
 
                     cursor.close()
             except Exception as e:
-                debug_print('KoboTouch:upload_books - Exception:  %s'%str(e))
+                debug_print(f'KoboTouch:upload_books - Exception:  {e!s}')
 
         return result
 
@@ -2419,7 +2415,7 @@ class KOBOTOUCH(KOBO):
         imageId = super().delete_via_sql(ContentID, ContentType)
 
         if self.dbversion >= 53:
-            debug_print('KoboTouch:delete_via_sql: ContentID="%s"'%ContentID, 'ContentType="%s"'%ContentType)
+            debug_print(f'KoboTouch:delete_via_sql: ContentID="{ContentID}"', f'ContentType="{ContentType}"')
             try:
                 with closing(self.device_database_connection()) as connection:
                     debug_print('KoboTouch:delete_via_sql: have database connection')
@@ -2457,9 +2453,9 @@ class KOBOTOUCH(KOBO):
                     debug_print('KoboTouch:delete_via_sql: finished SQL')
                 debug_print('KoboTouch:delete_via_sql: After SQL, no exception')
             except Exception as e:
-                debug_print('KoboTouch:delete_via_sql - Database Exception:  %s'%str(e))
+                debug_print(f'KoboTouch:delete_via_sql - Database Exception:  {e!s}')
 
-        debug_print('KoboTouch:delete_via_sql: imageId="%s"'%imageId)
+        debug_print(f'KoboTouch:delete_via_sql: imageId="{imageId}"')
         if imageId is None:
             imageId = self.imageid_from_contentid(ContentID)
 
@@ -2469,12 +2465,12 @@ class KOBOTOUCH(KOBO):
         debug_print('KoboTouch:delete_images - ImageID=', ImageID)
         if ImageID is not None:
             path = self.images_path(book_path, ImageID)
-            debug_print('KoboTouch:delete_images - path=%s' % path)
+            debug_print(f'KoboTouch:delete_images - path={path}')
 
             for ending in self.cover_file_endings().keys():
                 fpath = path + ending
                 fpath = self.normalize_path(fpath)
-                debug_print('KoboTouch:delete_images - fpath=%s' % fpath)
+                debug_print(f'KoboTouch:delete_images - fpath={fpath}')
 
                 if os.path.exists(fpath):
                     debug_print('KoboTouch:delete_images - Image File Exists')
@@ -2488,8 +2484,8 @@ class KOBOTOUCH(KOBO):
     def contentid_from_path(self, path, ContentType):
         show_debug = self.is_debugging_title(path) and True
         if show_debug:
-            debug_print("KoboTouch:contentid_from_path - path='%s'"%path, "ContentType='%s'"%ContentType)
-            debug_print("KoboTouch:contentid_from_path - self._main_prefix='%s'"%self._main_prefix, "self._card_a_prefix='%s'"%self._card_a_prefix)
+            debug_print(f"KoboTouch:contentid_from_path - path='{path}'", f"ContentType='{ContentType}'")
+            debug_print(f"KoboTouch:contentid_from_path - self._main_prefix='{self._main_prefix}'", f"self._card_a_prefix='{self._card_a_prefix}'")
         if ContentType == 6:
             extension = os.path.splitext(path)[1]
             if extension == '.kobo':
@@ -2504,19 +2500,19 @@ class KOBOTOUCH(KOBO):
                 ContentID = ContentID.replace(self._main_prefix, 'file:///mnt/onboard/')
 
             if show_debug:
-                debug_print("KoboTouch:contentid_from_path - 1 ContentID='%s'"%ContentID)
+                debug_print(f"KoboTouch:contentid_from_path - 1 ContentID='{ContentID}'")
 
             if self._card_a_prefix is not None:
                 ContentID = ContentID.replace(self._card_a_prefix, 'file:///mnt/sd/')
         else:  # ContentType = 16
-            debug_print("KoboTouch:contentid_from_path ContentType other than 6 - ContentType='%d'"%ContentType, "path='%s'"%path)
+            debug_print("KoboTouch:contentid_from_path ContentType other than 6 - ContentType='%d'"%ContentType, f"path='{path}'")
             ContentID = path
             ContentID = ContentID.replace(self._main_prefix, 'file:///mnt/onboard/')
             if self._card_a_prefix is not None:
                 ContentID = ContentID.replace(self._card_a_prefix, 'file:///mnt/sd/')
         ContentID = ContentID.replace('\\', '/')
         if show_debug:
-            debug_print("KoboTouch:contentid_from_path - end - ContentID='%s'"%ContentID)
+            debug_print(f"KoboTouch:contentid_from_path - end - ContentID='{ContentID}'")
         return ContentID
 
     def get_content_type_from_path(self, path):
@@ -2538,8 +2534,8 @@ class KOBOTOUCH(KOBO):
         self.plugboard_func = pb_func
 
     def update_device_database_collections(self, booklists, collections_attributes, oncard):
-        debug_print("KoboTouch:update_device_database_collections - oncard='%s'"%oncard)
-        debug_print("KoboTouch:update_device_database_collections - device='%s'" % self)
+        debug_print(f"KoboTouch:update_device_database_collections - oncard='{oncard}'")
+        debug_print(f"KoboTouch:update_device_database_collections - device='{self}'")
         if self.modify_database_check('update_device_database_collections') is False:
             return
 
@@ -2573,7 +2569,7 @@ class KOBOTOUCH(KOBO):
         update_core_metadata     = self.update_core_metadata
         update_purchased_kepubs  = self.update_purchased_kepubs
         debugging_title          = self.get_debugging_title()
-        debug_print("KoboTouch:update_device_database_collections - set_debugging_title to '%s'" % debugging_title)
+        debug_print(f"KoboTouch:update_device_database_collections - set_debugging_title to '{debugging_title}'")
         booklists.set_debugging_title(debugging_title)
         booklists.set_device_managed_collections(self.ignore_collections_names)
 
@@ -2623,11 +2619,11 @@ class KOBOTOUCH(KOBO):
                             # debug_print('    Title:', book.title, 'category: ', category)
                             show_debug = self.is_debugging_title(book.title)
                             if show_debug:
-                                debug_print('    Title="%s"'%book.title, 'category="%s"'%category)
+                                debug_print(f'    Title="{book.title}"', f'category="{category}"')
                                 # debug_print(book)
-                                debug_print('    class=%s'%book.__class__)
-                                debug_print('    book.contentID="%s"'%book.contentID)
-                                debug_print('    book.application_id="%s"'%book.application_id)
+                                debug_print(f'    class={book.__class__}')
+                                debug_print(f'    book.contentID="{book.contentID}"')
+                                debug_print(f'    book.application_id="{book.application_id}"')
 
                             if book.application_id is None:
                                 continue
@@ -2635,13 +2631,13 @@ class KOBOTOUCH(KOBO):
                             category_added = False
 
                             if book.contentID is None:
-                                debug_print('    Do not know ContentID - Title="%s", Authors="%s", path="%s"'%(book.title, book.author, book.path))
+                                debug_print(f'    Do not know ContentID - Title="{book.title}", Authors="{book.author}", path="{book.path}"')
                                 extension = os.path.splitext(book.path)[1]
                                 ContentType = self.get_content_type_from_extension(extension) if extension else self.get_content_type_from_path(book.path)
                                 book.contentID = self.contentid_from_path(book.path, ContentType)
 
                             if category in self.ignore_collections_names:
-                                debug_print('        Ignoring collection=%s' % category)
+                                debug_print(f'        Ignoring collection={category}')
                                 category_added = True
                             elif category in self.bookshelvelist and self.supports_bookshelves:
                                 if show_debug:
@@ -2652,18 +2648,18 @@ class KOBOTOUCH(KOBO):
                                     self.set_bookshelf(connection, book, category)
                                     category_added = True
                             elif category in readstatuslist:
-                                debug_print("KoboTouch:update_device_database_collections - about to set_readstatus - category='%s'"%(category, ))
+                                debug_print(f"KoboTouch:update_device_database_collections - about to set_readstatus - category='{category}'")
                                 # Manage ReadStatus
                                 self.set_readstatus(connection, book.contentID, readstatuslist.get(category))
                                 category_added = True
 
                             elif category == 'Shortlist' and self.dbversion >= 14:
                                 if show_debug:
-                                    debug_print('        Have an older version shortlist - %s'%book.title)
+                                    debug_print(f'        Have an older version shortlist - {book.title}')
                                 # Manage FavouritesIndex/Shortlist
                                 if not self.supports_bookshelves:
                                     if show_debug:
-                                        debug_print('            and about to set it - %s'%book.title)
+                                        debug_print(f'            and about to set it - {book.title}')
                                     self.set_favouritesindex(connection, book.contentID)
                                     category_added = True
                             elif category in accessibilitylist:
@@ -2677,7 +2673,7 @@ class KOBOTOUCH(KOBO):
                             else:
                                 if show_debug:
                                     debug_print('            category not added to book.device_collections', book.device_collections)
-                        debug_print("KoboTouch:update_device_database_collections - end for category='%s'"%category)
+                        debug_print(f"KoboTouch:update_device_database_collections - end for category='{category}'")
 
                 elif have_bookshelf_attributes:  # No collections but have set the shelf option
                     # Since no collections exist the ReadStatus needs to be reset to 0 (Unread)
@@ -2702,11 +2698,10 @@ class KOBOTOUCH(KOBO):
                         books_in_library += 1
                         show_debug = self.is_debugging_title(book.title)
                         if show_debug:
-                            debug_print('KoboTouch:update_device_database_collections - book.title=%s' % book.title)
+                            debug_print(f'KoboTouch:update_device_database_collections - book.title={book.title}')
                             debug_print(
-                                'KoboTouch:update_device_database_collections - contentId=%s,'
-                                'update_core_metadata=%s,update_purchased_kepubs=%s, book.is_sideloaded=%s' % (
-                                book.contentID, update_core_metadata, update_purchased_kepubs, book.is_sideloaded))
+                                f'KoboTouch:update_device_database_collections - contentId={book.contentID},'
+                                f'update_core_metadata={update_core_metadata},update_purchased_kepubs={update_purchased_kepubs}, book.is_sideloaded={book.is_sideloaded}')
                         if update_core_metadata and (update_purchased_kepubs or book.is_sideloaded):
                             if show_debug:
                                 debug_print('KoboTouch:update_device_database_collections - calling set_core_metadata')
@@ -2717,7 +2712,7 @@ class KOBOTOUCH(KOBO):
                             self.set_core_metadata(connection, book, series_only=True)
                         if self.manage_collections and have_bookshelf_attributes:
                             if show_debug:
-                                debug_print('KoboTouch:update_device_database_collections - about to remove a book from shelves book.title=%s' % book.title)
+                                debug_print(f'KoboTouch:update_device_database_collections - about to remove a book from shelves book.title={book.title}')
                             self.remove_book_from_device_bookshelves(connection, book)
                             book.device_collections.extend(book.kobo_collections)
                 if not prefs['manage_device_metadata'] == 'manual' and delete_empty_collections:
@@ -2749,8 +2744,8 @@ class KOBOTOUCH(KOBO):
         :param filepath: The full path to the ebook file
 
         '''
-        debug_print("KoboTouch:upload_cover - path='%s' filename='%s' "%(path, filename))
-        debug_print("        filepath='%s' "%(filepath))
+        debug_print(f"KoboTouch:upload_cover - path='{path}' filename='{filename}' ")
+        debug_print(f"        filepath='{filepath}' ")
 
         if not self.upload_covers:
             # Building thumbnails disabled
@@ -2769,7 +2764,7 @@ class KOBOTOUCH(KOBO):
                 self.keep_cover_aspect, self.letterbox_fs_covers, self.png_covers,
                 letterbox_color=self.letterbox_fs_covers_color)
         except Exception as e:
-            debug_print('KoboTouch: FAILED to upload cover=%s Exception=%s'%(filepath, str(e)))
+            debug_print(f'KoboTouch: FAILED to upload cover={filepath} Exception={e!s}')
 
     def imageid_from_contentid(self, ContentID):
         ImageID = ContentID.replace('/', '_')
@@ -2793,7 +2788,7 @@ class KOBOTOUCH(KOBO):
             hash1 = qhash(imageId)
             dir1  = hash1 & (0xff * 1)
             dir2  = (hash1 & (0xff00 * 1)) >> 8
-            path = os.path.join(path, '%s' % dir1, '%s' % dir2)
+            path = os.path.join(path, f'{dir1}', f'{dir2}')
 
         if imageId:
             path = os.path.join(path, imageId)
@@ -2864,15 +2859,15 @@ class KOBOTOUCH(KOBO):
             ):
         from calibre.utils.img import optimize_png
         from calibre.utils.imghdr import identify
-        debug_print("KoboTouch:_upload_cover - filename='%s' upload_grayscale='%s' dithered_covers='%s' "%(filename, upload_grayscale, dithered_covers))
+        debug_print(f"KoboTouch:_upload_cover - filename='{filename}' upload_grayscale='{upload_grayscale}' dithered_covers='{dithered_covers}' ")
 
         if not metadata.cover:
             return
 
         show_debug = self.is_debugging_title(filename)
         if show_debug:
-            debug_print("KoboTouch:_upload_cover - path='%s'"%path, "filename='%s'"%filename)
-            debug_print("        filepath='%s'"%filepath)
+            debug_print(f"KoboTouch:_upload_cover - path='{path}'", f"filename='{filename}'")
+            debug_print(f"        filepath='{filepath}'")
         cover = self.normalize_path(metadata.cover.replace('/', os.sep))
 
         if not os.path.exists(cover):
@@ -2895,7 +2890,7 @@ class KOBOTOUCH(KOBO):
                     ImageID = result[0]
                 except StopIteration:
                     ImageID = self.imageid_from_contentid(ContentID)
-                    debug_print("KoboTouch:_upload_cover - No rows exist in the database - generated ImageID='%s'" % ImageID)
+                    debug_print(f"KoboTouch:_upload_cover - No rows exist in the database - generated ImageID='{ImageID}'")
 
                 cursor.close()
 
@@ -2907,7 +2902,7 @@ class KOBOTOUCH(KOBO):
 
                 image_dir = os.path.dirname(os.path.abspath(path))
                 if not os.path.exists(image_dir):
-                    debug_print("KoboTouch:_upload_cover - Image folder does not exist. Creating path='%s'" % (image_dir))
+                    debug_print(f"KoboTouch:_upload_cover - Image folder does not exist. Creating path='{image_dir}'")
                     os.makedirs(image_dir)
 
                 with open(cover, 'rb') as f:
@@ -2924,7 +2919,7 @@ class KOBOTOUCH(KOBO):
 
                     if self.dbversion >= min_dbversion and self.dbversion <= max_dbversion:
                         if show_debug:
-                            debug_print("KoboTouch:_upload_cover - creating cover for ending='%s'"%ending)  # , "library_cover_size'%s'"%library_cover_size)
+                            debug_print(f"KoboTouch:_upload_cover - creating cover for ending='{ending}'")  # , "library_cover_size'%s'"%library_cover_size)
                         fpath = path + ending
                         fpath = self.normalize_path(fpath.replace('/', os.sep))
 
@@ -2943,9 +2938,8 @@ class KOBOTOUCH(KOBO):
                         resize_to, expand_to = self._calculate_kobo_cover_size(library_cover_size, kobo_size, not is_full_size, keep_cover_aspect, letterbox)
                         if show_debug:
                             debug_print(
-                                'KoboTouch:_calculate_kobo_cover_size - expand_to=%s'
-                                ' (vs. kobo_size=%s) & resize_to=%s, keep_cover_aspect=%s & letterbox_fs_covers=%s, png_covers=%s' % (
-                                 expand_to, kobo_size, resize_to, keep_cover_aspect, letterbox_fs_covers, png_covers))
+                                f'KoboTouch:_calculate_kobo_cover_size - expand_to={expand_to}'
+                                f' (vs. kobo_size={kobo_size}) & resize_to={resize_to}, keep_cover_aspect={keep_cover_aspect} & letterbox_fs_covers={letterbox_fs_covers}, png_covers={png_covers}')
 
                         # NOTE: To speed things up, we enforce a lower
                         # compression level for png_covers, as the final
@@ -2983,7 +2977,7 @@ class KOBOTOUCH(KOBO):
                                 fsync(f)
         except Exception as e:
             err = str(e)
-            debug_print('KoboTouch:_upload_cover - Exception string: %s'%err)
+            debug_print(f'KoboTouch:_upload_cover - Exception string: {err}')
             raise
 
     def remove_book_from_device_bookshelves(self, connection, book):
@@ -2993,8 +2987,8 @@ class KOBOTOUCH(KOBO):
         remove_shelf_list = remove_shelf_list - set(self.ignore_collections_names)
 
         if show_debug:
-            debug_print('KoboTouch:remove_book_from_device_bookshelves - book.application_id="%s"'%book.application_id)
-            debug_print('KoboTouch:remove_book_from_device_bookshelves - book.contentID="%s"'%book.contentID)
+            debug_print(f'KoboTouch:remove_book_from_device_bookshelves - book.application_id="{book.application_id}"')
+            debug_print(f'KoboTouch:remove_book_from_device_bookshelves - book.contentID="{book.contentID}"')
             debug_print('KoboTouch:remove_book_from_device_bookshelves - book.device_collections=', book.device_collections)
             debug_print('KoboTouch:remove_book_from_device_bookshelves - book.current_shelves=', book.current_shelves)
             debug_print('KoboTouch:remove_book_from_device_bookshelves - remove_shelf_list=', remove_shelf_list)
@@ -3009,12 +3003,12 @@ class KOBOTOUCH(KOBO):
         if book.device_collections:
             placeholder = '?'
             placeholders = ','.join(placeholder for unused in book.device_collections)
-            query += ' and ShelfName not in (%s)' % placeholders
+            query += f' and ShelfName not in ({placeholders})'
             values.extend(book.device_collections)
 
         if show_debug:
-            debug_print('KoboTouch:remove_book_from_device_bookshelves query="%s"'%query)
-            debug_print('KoboTouch:remove_book_from_device_bookshelves values="%s"'%values)
+            debug_print(f'KoboTouch:remove_book_from_device_bookshelves query="{query}"')
+            debug_print(f'KoboTouch:remove_book_from_device_bookshelves values="{values}"')
 
         cursor = connection.cursor()
         cursor.execute(query, values)
@@ -3023,7 +3017,7 @@ class KOBOTOUCH(KOBO):
     def set_filesize_in_device_database(self, connection, contentID, fpath):
         show_debug = self.is_debugging_title(fpath)
         if show_debug:
-            debug_print('KoboTouch:set_filesize_in_device_database contentID="%s"'%contentID)
+            debug_print(f'KoboTouch:set_filesize_in_device_database contentID="{contentID}"')
 
         test_query = ('SELECT ___FileSize '
                         'FROM content '
@@ -3136,8 +3130,8 @@ class KOBOTOUCH(KOBO):
     def set_bookshelf(self, connection, book, shelfName):
         show_debug = self.is_debugging_title(book.title)
         if show_debug:
-            debug_print('KoboTouch:set_bookshelf book.ContentID="%s"'%book.contentID)
-            debug_print('KoboTouch:set_bookshelf book.current_shelves="%s"'%book.current_shelves)
+            debug_print(f'KoboTouch:set_bookshelf book.ContentID="{book.contentID}"')
+            debug_print(f'KoboTouch:set_bookshelf book.current_shelves="{book.current_shelves}"')
 
         if shelfName in book.current_shelves:
             if show_debug:
@@ -3175,7 +3169,7 @@ class KOBOTOUCH(KOBO):
     def check_for_bookshelf(self, connection, bookshelf_name):
         show_debug = self.is_debugging_title(bookshelf_name)
         if show_debug:
-            debug_print('KoboTouch:check_for_bookshelf bookshelf_name="%s"'%bookshelf_name)
+            debug_print(f'KoboTouch:check_for_bookshelf bookshelf_name="{bookshelf_name}"')
         test_query = 'SELECT InternalName, Name, _IsDeleted FROM Shelf WHERE Name = ?'
         test_values = (bookshelf_name, )
         addquery = 'INSERT INTO "main"."Shelf"'
@@ -3220,7 +3214,7 @@ class KOBOTOUCH(KOBO):
 
         if result is None:
             if show_debug:
-                debug_print('        Did not find a record - adding shelf "%s"' % bookshelf_name)
+                debug_print(f'        Did not find a record - adding shelf "{bookshelf_name}"')
             cursor.execute(addquery, add_values)
         elif self.is_true_value(result['_IsDeleted']):
             debug_print("KoboTouch:check_for_bookshelf - Shelf '{}' is deleted - undeleting. result['_IsDeleted']='{}'".format(
@@ -3253,7 +3247,7 @@ class KOBOTOUCH(KOBO):
         if bookshelves:
             placeholder = '?'
             placeholders = ','.join(placeholder for unused in bookshelves)
-            query += ' and ShelfName in (%s)' % placeholders
+            query += f' and ShelfName in ({placeholders})'
             values.append(bookshelves)
         debug_print('KoboTouch:remove_from_bookshelf query=', query)
         debug_print('KoboTouch:remove_from_bookshelf values=', values)
@@ -3267,8 +3261,8 @@ class KOBOTOUCH(KOBO):
     def set_series(self, connection, book):
         show_debug = self.is_debugging_title(book.title)
         if show_debug:
-            debug_print('KoboTouch:set_series book.kobo_series="%s"'%book.kobo_series)
-            debug_print('KoboTouch:set_series book.series="%s"'%book.series)
+            debug_print(f'KoboTouch:set_series book.kobo_series="{book.kobo_series}"')
+            debug_print(f'KoboTouch:set_series book.series="{book.series}"')
             debug_print('KoboTouch:set_series book.series_index=', book.series_index)
 
         if book.series == book.kobo_series:
@@ -3289,7 +3283,7 @@ class KOBOTOUCH(KOBO):
         elif book.series_index is None:         # This should never happen, but...
             update_values = (book.series, None, book.contentID, )
         else:
-            update_values = (book.series, '%g'%book.series_index, book.contentID, )
+            update_values = (book.series, f'{book.series_index:g}', book.contentID, )
 
         cursor = connection.cursor()
         try:
@@ -3320,7 +3314,7 @@ class KOBOTOUCH(KOBO):
             else:
                 new_value = new_value if len(new_value.strip()) else None
                 if new_value is not None and new_value.startswith('PLUGBOARD TEMPLATE ERROR'):
-                    debug_print("KoboTouch:generate_update_from_template  template error - template='%s'" % template)
+                    debug_print(f"KoboTouch:generate_update_from_template  template error - template='{template}'")
                     debug_print('KoboTouch:generate_update_from_template - new_value=', new_value)
 
             # debug_print(
@@ -3366,7 +3360,7 @@ class KOBOTOUCH(KOBO):
         if newmi.series is not None:
             new_series = newmi.series
             try:
-                new_series_number = '%g' % newmi.series_index
+                new_series_number = f'{newmi.series_index:g}'
             except:
                 new_series_number = None
         else:
@@ -3463,7 +3457,7 @@ class KOBOTOUCH(KOBO):
                 else:
                     new_subtitle = book.subtitle if len(book.subtitle.strip()) else None
                     if new_subtitle is not None and new_subtitle.startswith('PLUGBOARD TEMPLATE ERROR'):
-                        debug_print("KoboTouch:set_core_metadata subtitle template error - self.subtitle_template='%s'" % self.subtitle_template)
+                        debug_print(f"KoboTouch:set_core_metadata subtitle template error - self.subtitle_template='{self.subtitle_template}'")
                         debug_print('KoboTouch:set_core_metadata - new_subtitle=', new_subtitle)
 
                 if (new_subtitle is not None and (book.kobo_subtitle is None or book.subtitle != book.kobo_subtitle)) or \
@@ -3509,9 +3503,9 @@ class KOBOTOUCH(KOBO):
             update_query += ', '.join([col_name + ' = ?' for col_name in set_clause])
             changes_found = True
             if show_debug:
-                debug_print('KoboTouch:set_core_metadata set_clause="%s"' % set_clause)
-                debug_print('KoboTouch:set_core_metadata update_values="%s"' % update_values)
-                debug_print('KoboTouch:set_core_metadata update_values="%s"' % update_query)
+                debug_print(f'KoboTouch:set_core_metadata set_clause="{set_clause}"')
+                debug_print(f'KoboTouch:set_core_metadata update_values="{update_values}"')
+                debug_print(f'KoboTouch:set_core_metadata update_values="{update_query}"')
         if changes_found:
             update_query += ' WHERE ContentID = ? AND BookID IS NULL'
             update_values.append(book.contentID)
@@ -4087,9 +4081,9 @@ class KOBOTOUCH(KOBO):
                       ' Kobo forum at MobileRead. This is at %s.'
                       ) % 'https://www.mobileread.com/forums/forumdisplay.php?f=223' + '\n' +
                     (
-                    '\nDevice database version: %s.'
-                    '\nDevice firmware version: %s'
-                     ) % (self.dbversion, self.display_fwversion),
+                    f'\nDevice database version: {self.dbversion}.'
+                    f'\nDevice firmware version: {self.display_fwversion}'
+                     ),
                     UserFeedback.WARN
                     )
 
@@ -4206,7 +4200,7 @@ class KOBOTOUCH(KOBO):
         try:
             is_debugging = (len(self.debugging_title) > 0 and title.lower().find(self.debugging_title.lower()) >= 0) or len(title) == 0
         except:
-            debug_print(("KoboTouch::is_debugging_title - Exception checking debugging title for title '{}'.").format(title))
+            debug_print(f"KoboTouch::is_debugging_title - Exception checking debugging title for title '{title}'.")
             is_debugging = False
 
         return is_debugging

src/calibre/devices/misc.py

@@ -98,7 +98,7 @@ class PDNOVEL(USBMS):
     def upload_cover(self, path, filename, metadata, filepath):
         coverdata = getattr(metadata, 'thumbnail', None)
         if coverdata and coverdata[2]:
-            with open('%s.jpg' % os.path.join(path, filename), 'wb') as coverfile:
+            with open(f'{os.path.join(path, filename)}.jpg', 'wb') as coverfile:
                 coverfile.write(coverdata[2])
                 fsync(coverfile)
 

src/calibre/devices/mtp/driver.py

@@ -35,7 +35,7 @@ DEFAULT_THUMBNAIL_HEIGHT = 320
 class MTPInvalidSendPathError(PathError):
 
     def __init__(self, folder):
-        PathError.__init__(self, 'Trying to send to ignored folder: %s'%folder)
+        PathError.__init__(self, f'Trying to send to ignored folder: {folder}')
         self.folder = folder
 
 
@@ -405,7 +405,7 @@ class MTP_DEVICE(BASE):
             except Exception as e:
                 ans.append((path, e, traceback.format_exc()))
                 continue
-            base = os.path.join(tdir, '%s'%f.object_id)
+            base = os.path.join(tdir, f'{f.object_id}')
             os.mkdir(base)
             name = f.name
             if iswindows:
@@ -628,8 +628,7 @@ class MTP_DEVICE(BASE):
             try:
                 self.recursive_delete(parent)
             except:
-                prints('Failed to delete parent: %s, ignoring'%(
-                    '/'.join(parent.full_path)))
+                prints('Failed to delete parent: {}, ignoring'.format('/'.join(parent.full_path)))
 
     def delete_books(self, paths, end_session=True):
         self.report_progress(0, _('Deleting books from device...'))
@@ -673,7 +672,7 @@ class MTP_DEVICE(BASE):
         If that is not found looks for a device default and if that is not
         found uses the global default.'''
         dd = self.current_device_defaults if self.is_mtp_device_connected else {}
-        dev_settings = self.prefs.get('device-%s'%self.current_serial_num, {})
+        dev_settings = self.prefs.get(f'device-{self.current_serial_num}', {})
         default_value = dd.get(key, self.prefs[key])
         return dev_settings.get(key, default_value)
 

src/calibre/devices/mtp/filesystem_cache.py

@@ -69,8 +69,7 @@ class FileOrFolder:
         self.last_modified = as_utc(self.last_modified)
 
         if self.storage_id not in fs_cache.all_storage_ids:
-            raise ValueError('Storage id %s not valid for %s, valid values: %s'%(self.storage_id,
-                entry, fs_cache.all_storage_ids))
+            raise ValueError(f'Storage id {self.storage_id} not valid for {entry}, valid values: {fs_cache.all_storage_ids}')
 
         self.is_hidden = entry.get('is_hidden', False)
         self.is_system = entry.get('is_system', False)
@@ -92,7 +91,7 @@ class FileOrFolder:
         self.deleted = False
 
         if self.is_storage:
-            self.storage_prefix = 'mtp:::%s:::'%self.persistent_id
+            self.storage_prefix = f'mtp:::{self.persistent_id}:::'
 
         # Ignore non ebook files and AppleDouble files
         self.is_ebook = (not self.is_folder and not self.is_storage and
@@ -107,11 +106,10 @@ class FileOrFolder:
             path = str(self.full_path)
         except Exception:
             path = ''
-        datum = 'size=%s'%(self.size)
+        datum = f'size={self.size}'
         if self.is_folder or self.is_storage:
             datum = 'children=%s'%(len(self.files) + len(self.folders))
-        return '%s(id=%s, storage_id=%s, %s, path=%s, modified=%s)'%(name, self.object_id,
-                self.storage_id, datum, path, self.last_mod_string)
+        return f'{name}(id={self.object_id}, storage_id={self.storage_id}, {datum}, path={path}, modified={self.last_mod_string})'
 
     __str__ = __repr__
     __unicode__ = __repr__
@@ -171,10 +169,10 @@ class FileOrFolder:
 
     def dump(self, prefix='', out=sys.stdout):
         c = '+' if self.is_folder else '-'
-        data = ('%s children'%(sum(map(len, (self.files, self.folders))))
+        data = (f'{sum(map(len, (self.files, self.folders)))} children'
             if self.is_folder else human_readable(self.size))
-        data += ' modified=%s'%self.last_mod_string
-        line = '%s%s %s [id:%s %s]'%(prefix, c, self.name, self.object_id, data)
+        data += f' modified={self.last_mod_string}'
+        line = f'{prefix}{c} {self.name} [id:{self.object_id} {data}]'
         prints(line, file=out)
         for c in (self.folders, self.files):
             for e in sorted(c, key=lambda x: sort_key(x.name)):
@@ -290,14 +288,14 @@ class FilesystemCache:
 
     def resolve_mtp_id_path(self, path):
         if not path.startswith('mtp:::'):
-            raise ValueError('%s is not a valid MTP path'%path)
+            raise ValueError(f'{path} is not a valid MTP path')
         parts = path.split(':::', 2)
         if len(parts) < 3:
-            raise ValueError('%s is not a valid MTP path'%path)
+            raise ValueError(f'{path} is not a valid MTP path')
         try:
             object_id = json.loads(parts[1])
         except Exception:
-            raise ValueError('%s is not a valid MTP path'%path)
+            raise ValueError(f'{path} is not a valid MTP path')
         id_map = {}
         path = parts[2]
         storage_name = path.partition('/')[0]
@@ -308,4 +306,4 @@ class FilesystemCache:
         try:
             return id_map[object_id]
         except KeyError:
-            raise ValueError('No object found with MTP path: %s'%path)
+            raise ValueError(f'No object found with MTP path: {path}')

src/calibre/devices/mtp/test.py

@@ -182,7 +182,7 @@ class TestDeviceInteraction(unittest.TestCase):
         return end_mem - start_mem
 
     def check_memory(self, once, many, msg, factor=2):
-        msg += ' for once: %g for many: %g'%(once, many)
+        msg += f' for once: {once:g} for many: {many:g}'
         if once > 0:
             self.assertTrue(many <= once*factor, msg=msg)
         else:

src/calibre/devices/mtp/unix/driver.py

@@ -228,8 +228,7 @@ class MTP_DEVICE(MTPDeviceBase):
             self.dev = self.create_device(connected_device)
         except Exception as e:
             self.blacklisted_devices.add(connected_device)
-            raise OpenFailed('Failed to open %s: Error: %s'%(
-                    connected_device, as_unicode(e)))
+            raise OpenFailed(f'Failed to open {connected_device}: Error: {as_unicode(e)}')
 
         try:
             storage = sorted_storage(self.dev.storage_info)
@@ -259,13 +258,13 @@ class MTP_DEVICE(MTPDeviceBase):
         storage = [x for x in storage if x.get('rw', False)]
         if not storage:
             self.blacklisted_devices.add(connected_device)
-            raise OpenFailed('No storage found for device %s'%(connected_device,))
+            raise OpenFailed(f'No storage found for device {connected_device}')
         snum = self.dev.serial_number
         if snum in self.prefs.get('blacklist', []):
             self.blacklisted_devices.add(connected_device)
             self.dev = None
             raise BlacklistedDevice(
-                'The %s device has been blacklisted by the user'%(connected_device,))
+                f'The {connected_device} device has been blacklisted by the user')
         self._main_id = storage[0]['id']
         self._carda_id = self._cardb_id = None
         if len(storage) > 1:
@@ -281,11 +280,11 @@ class MTP_DEVICE(MTPDeviceBase):
     @synchronous
     def device_debug_info(self):
         ans = self.get_gui_name()
-        ans += '\nSerial number: %s'%self.current_serial_num
-        ans += '\nManufacturer: %s'%self.dev.manufacturer_name
-        ans += '\nModel: %s'%self.dev.model_name
-        ans += '\nids: %s'%(self.dev.ids,)
-        ans += '\nDevice version: %s'%self.dev.device_version
+        ans += f'\nSerial number: {self.current_serial_num}'
+        ans += f'\nManufacturer: {self.dev.manufacturer_name}'
+        ans += f'\nModel: {self.dev.model_name}'
+        ans += f'\nids: {self.dev.ids}'
+        ans += f'\nDevice version: {self.dev.device_version}'
         ans += '\nStorage:\n'
         storage = sorted_storage(self.dev.storage_info)
         ans += pprint.pformat(storage)
@@ -306,7 +305,7 @@ class MTP_DEVICE(MTPDeviceBase):
         path = tuple(reversed(path))
         ok = not self.is_folder_ignored(self._currently_getting_sid, path)
         if not ok:
-            debug('Ignored object: %s' % '/'.join(path))
+            debug('Ignored object: {}'.format('/'.join(path)))
         return ok
 
     @property
@@ -335,14 +334,10 @@ class MTP_DEVICE(MTPDeviceBase):
                     all_items.extend(items), all_errs.extend(errs)
                 if not all_items and all_errs:
                     raise DeviceError(
-                            'Failed to read filesystem from %s with errors: %s'
-                            %(self.current_friendly_name,
-                                self.format_errorstack(all_errs)))
+                            f'Failed to read filesystem from {self.current_friendly_name} with errors: {self.format_errorstack(all_errs)}')
                 if all_errs:
                     prints('There were some errors while getting the '
-                            ' filesystem from %s: %s'%(
-                                self.current_friendly_name,
-                                self.format_errorstack(all_errs)))
+                            f' filesystem from {self.current_friendly_name}: {self.format_errorstack(all_errs)}')
                 self._filesystem_cache = FilesystemCache(storage, all_items)
             debug('Filesystem metadata loaded in %g seconds (%d objects)'%(
                 time.time()-st, len(self._filesystem_cache)))
@@ -377,7 +372,7 @@ class MTP_DEVICE(MTPDeviceBase):
     @synchronous
     def create_folder(self, parent, name):
         if not parent.is_folder:
-            raise ValueError('%s is not a folder'%(parent.full_path,))
+            raise ValueError(f'{parent.full_path} is not a folder')
         e = parent.folder_named(name)
         if e is not None:
             return e
@@ -387,21 +382,18 @@ class MTP_DEVICE(MTPDeviceBase):
         ans, errs = self.dev.create_folder(sid, pid, name)
         if ans is None:
             raise DeviceError(
-                    'Failed to create folder named %s in %s with error: %s'%
-                    (name, parent.full_path, self.format_errorstack(errs)))
+                    f'Failed to create folder named {name} in {parent.full_path} with error: {self.format_errorstack(errs)}')
         return parent.add_child(ans)
 
     @synchronous
     def put_file(self, parent, name, stream, size, callback=None, replace=True):
         e = parent.folder_named(name)
         if e is not None:
-            raise ValueError('Cannot upload file, %s already has a folder named: %s'%(
-                parent.full_path, e.name))
+            raise ValueError(f'Cannot upload file, {parent.full_path} already has a folder named: {e.name}')
         e = parent.file_named(name)
         if e is not None:
             if not replace:
-                raise ValueError('Cannot upload file %s, it already exists'%(
-                    e.full_path,))
+                raise ValueError(f'Cannot upload file {e.full_path}, it already exists')
             self.delete_file_or_folder(e)
         sid, pid = parent.storage_id, parent.object_id
         if pid == sid:
@@ -409,21 +401,19 @@ class MTP_DEVICE(MTPDeviceBase):
 
         ans, errs = self.dev.put_file(sid, pid, name, stream, size, callback)
         if ans is None:
-            raise DeviceError('Failed to upload file named: %s to %s: %s'
-                    %(name, parent.full_path, self.format_errorstack(errs)))
+            raise DeviceError(f'Failed to upload file named: {name} to {parent.full_path}: {self.format_errorstack(errs)}')
         return parent.add_child(ans)
 
     @synchronous
     def get_mtp_file(self, f, stream=None, callback=None):
         if f.is_folder:
-            raise ValueError('%s if a folder'%(f.full_path,))
+            raise ValueError(f'{f.full_path} if a folder')
         set_name = stream is None
         if stream is None:
             stream = SpooledTemporaryFile(5*1024*1024, '_wpd_receive_file.dat')
         ok, errs = self.dev.get_file(f.object_id, stream, callback)
         if not ok:
-            raise DeviceError('Failed to get file: %s with errors: %s'%(
-                f.full_path, self.format_errorstack(errs)))
+            raise DeviceError(f'Failed to get file: {f.full_path} with errors: {self.format_errorstack(errs)}')
         stream.seek(0)
         if set_name:
             stream.name = f.name
@@ -476,18 +466,14 @@ class MTP_DEVICE(MTPDeviceBase):
         if obj.deleted:
             return
         if not obj.can_delete:
-            raise ValueError('Cannot delete %s as deletion not allowed'%
-                    (obj.full_path,))
+            raise ValueError(f'Cannot delete {obj.full_path} as deletion not allowed')
         if obj.is_system:
-            raise ValueError('Cannot delete %s as it is a system object'%
-                    (obj.full_path,))
+            raise ValueError(f'Cannot delete {obj.full_path} as it is a system object')
         if obj.files or obj.folders:
-            raise ValueError('Cannot delete %s as it is not empty'%
-                    (obj.full_path,))
+            raise ValueError(f'Cannot delete {obj.full_path} as it is not empty')
         parent = obj.parent
         ok, errs = self.dev.delete_object(obj.object_id)
         if not ok:
-            raise DeviceError('Failed to delete %s with error: %s'%
-                (obj.full_path, self.format_errorstack(errs)))
+            raise DeviceError(f'Failed to delete {obj.full_path} with error: {self.format_errorstack(errs)}')
         parent.remove_child(obj)
         return parent

src/calibre/devices/mtp/unix/sysfs.py

@@ -34,7 +34,7 @@ class MTPDetect:
             except OSError:
                 pass
 
-        ipath = os.path.join(self.base, '{0}-*/{0}-*/interface'.format(dev.busnum))
+        ipath = os.path.join(self.base, f'{dev.busnum}-*/{dev.busnum}-*/interface')
         for x in glob.glob(ipath):
             raw = read(x)
             if not raw or raw.strip() != b'MTP':
@@ -44,8 +44,8 @@ class MTPDetect:
             try:
                 if raw and int(raw) == dev.devnum:
                     if debug is not None:
-                        debug('Unknown device {} claims to be an MTP device'
-                              .format(dev))
+                        debug(f'Unknown device {dev} claims to be an MTP device'
+                              )
                     return True
             except (ValueError, TypeError):
                 continue

src/calibre/devices/mtp/windows/driver.py

@@ -258,7 +258,7 @@ class MTP_DEVICE(MTPDeviceBase):
         path = tuple(reversed(path))
         ok = not self.is_folder_ignored(self._currently_getting_sid, path)
         if not ok:
-            debug('Ignored object: %s' % '/'.join(path))
+            debug('Ignored object: {}'.format('/'.join(path)))
         return ok
 
     @property
@@ -330,19 +330,18 @@ class MTP_DEVICE(MTPDeviceBase):
                 self.dev = self.wpd.Device(connected_device)
             except self.wpd.WPDError as e:
                 self.blacklisted_devices.add(connected_device)
-                raise OpenFailed('Failed to open %s with error: %s'%(
-                    connected_device, as_unicode(e)))
+                raise OpenFailed(f'Failed to open {connected_device} with error: {as_unicode(e)}')
         devdata = self.dev.data
         storage = [s for s in devdata.get('storage', []) if s.get('rw', False)]
         if not storage:
             self.blacklisted_devices.add(connected_device)
-            raise OpenFailed('No storage found for device %s'%(connected_device,))
+            raise OpenFailed(f'No storage found for device {connected_device}')
         snum = devdata.get('serial_number', None)
         if snum in self.prefs.get('blacklist', []):
             self.blacklisted_devices.add(connected_device)
             self.dev = None
             raise BlacklistedDevice(
-                'The %s device has been blacklisted by the user'%(connected_device,))
+                f'The {connected_device} device has been blacklisted by the user')
 
         storage = sorted_storage(storage)
 
@@ -435,7 +434,7 @@ class MTP_DEVICE(MTPDeviceBase):
     @same_thread
     def get_mtp_file(self, f, stream=None, callback=None):
         if f.is_folder:
-            raise ValueError('%s if a folder'%(f.full_path,))
+            raise ValueError(f'{f.full_path} if a folder')
         set_name = stream is None
         if stream is None:
             stream = SpooledTemporaryFile(5*1024*1024, '_wpd_receive_file.dat')
@@ -446,8 +445,7 @@ class MTP_DEVICE(MTPDeviceBase):
                 time.sleep(2)
                 self.dev.get_file(f.object_id, stream, callback)
         except Exception as e:
-            raise DeviceError('Failed to fetch the file %s with error: %s'%
-                    (f.full_path, as_unicode(e)))
+            raise DeviceError(f'Failed to fetch the file {f.full_path} with error: {as_unicode(e)}')
         stream.seek(0)
         if set_name:
             stream.name = f.name
@@ -456,7 +454,7 @@ class MTP_DEVICE(MTPDeviceBase):
     @same_thread
     def create_folder(self, parent, name):
         if not parent.is_folder:
-            raise ValueError('%s is not a folder'%(parent.full_path,))
+            raise ValueError(f'{parent.full_path} is not a folder')
         e = parent.folder_named(name)
         if e is not None:
             return e
@@ -472,14 +470,11 @@ class MTP_DEVICE(MTPDeviceBase):
         if obj.deleted:
             return
         if not obj.can_delete:
-            raise ValueError('Cannot delete %s as deletion not allowed'%
-                    (obj.full_path,))
+            raise ValueError(f'Cannot delete {obj.full_path} as deletion not allowed')
         if obj.is_system:
-            raise ValueError('Cannot delete %s as it is a system object'%
-                    (obj.full_path,))
+            raise ValueError(f'Cannot delete {obj.full_path} as it is a system object')
         if obj.files or obj.folders:
-            raise ValueError('Cannot delete %s as it is not empty'%
-                    (obj.full_path,))
+            raise ValueError(f'Cannot delete {obj.full_path} as it is not empty')
         parent = obj.parent
         self.dev.delete_object(obj.object_id)
         parent.remove_child(obj)
@@ -489,13 +484,11 @@ class MTP_DEVICE(MTPDeviceBase):
     def put_file(self, parent, name, stream, size, callback=None, replace=True):
         e = parent.folder_named(name)
         if e is not None:
-            raise ValueError('Cannot upload file, %s already has a folder named: %s'%(
-                parent.full_path, e.name))
+            raise ValueError(f'Cannot upload file, {parent.full_path} already has a folder named: {e.name}')
         e = parent.file_named(name)
         if e is not None:
             if not replace:
-                raise ValueError('Cannot upload file %s, it already exists'%(
-                    e.full_path,))
+                raise ValueError(f'Cannot upload file {e.full_path}, it already exists')
             self.delete_file_or_folder(e)
         sid, pid = parent.storage_id, parent.object_id
         ans = self.dev.put_file(pid, name, stream, size, callback)

src/calibre/devices/nook/driver.py

@@ -70,7 +70,7 @@ class NOOK(USBMS):
         cover.save(data, 'JPEG')
         coverdata = data.getvalue()
 
-        with open('%s.jpg' % os.path.join(path, filename), 'wb') as coverfile:
+        with open(f'{os.path.join(path, filename)}.jpg', 'wb') as coverfile:
             coverfile.write(coverdata)
             fsync(coverfile)
 

src/calibre/devices/paladin/driver.py

@@ -214,11 +214,11 @@ class PALADIN(USBMS):
             import traceback
             tb = traceback.format_exc()
             raise DeviceError((('The Paladin database is corrupted. '
-                    ' Delete the file %s on your reader and then disconnect '
+                    f' Delete the file {dbpath} on your reader and then disconnect '
                     ' reconnect it. If you are using an SD card, you '
                     ' should delete the file on the card as well. Note that '
                     ' deleting this file will cause your reader to forget '
-                    ' any notes/highlights, etc.')%dbpath)+' Underlying error:'
+                    ' any notes/highlights, etc.'))+' Underlying error:'
                     '\n'+tb)
 
     def get_database_min_id(self, source_id):
@@ -261,11 +261,11 @@ class PALADIN(USBMS):
             import traceback
             tb = traceback.format_exc()
             raise DeviceError((('The Paladin database is corrupted. '
-                    ' Delete the file %s on your reader and then disconnect '
+                    f' Delete the file {dbpath} on your reader and then disconnect '
                     ' reconnect it. If you are using an SD card, you '
                     ' should delete the file on the card as well. Note that '
                     ' deleting this file will cause your reader to forget '
-                    ' any notes/highlights, etc.')%dbpath)+' Underlying error:'
+                    ' any notes/highlights, etc.'))+' Underlying error:'
                     '\n'+tb)
 
         # Get the books themselves, but keep track of any that are less than the minimum.
@@ -398,11 +398,11 @@ class PALADIN(USBMS):
             import traceback
             tb = traceback.format_exc()
             raise DeviceError((('The Paladin database is corrupted. '
-                    ' Delete the file %s on your reader and then disconnect '
+                    f' Delete the file {dbpath} on your reader and then disconnect '
                     ' reconnect it. If you are using an SD card, you '
                     ' should delete the file on the card as well. Note that '
                     ' deleting this file will cause your reader to forget '
-                    ' any notes/highlights, etc.')%dbpath)+' Underlying error:'
+                    ' any notes/highlights, etc.'))+' Underlying error:'
                     '\n'+tb)
 
         db_collections = {}

src/calibre/devices/prs505/driver.py

@@ -170,7 +170,7 @@ class PRS505(USBMS):
     def filename_callback(self, fname, mi):
         if getattr(mi, 'application_id', None) is not None:
             base = fname.rpartition('.')[0]
-            suffix = '_%s'%mi.application_id
+            suffix = f'_{mi.application_id}'
             if not base.endswith(suffix):
                 fname = base + suffix + '.' + fname.rpartition('.')[-1]
         return fname
@@ -183,7 +183,7 @@ class PRS505(USBMS):
                 ('card_a', CACHE_XML, CACHE_EXT, 1),
                 ('card_b', CACHE_XML, CACHE_EXT, 2)
                 ]:
-            prefix = getattr(self, '_%s_prefix'%prefix)
+            prefix = getattr(self, f'_{prefix}_prefix')
             if prefix is not None and os.path.exists(prefix):
                 paths[source_id] = os.path.join(prefix, *(path.split('/')))
                 ext_paths[source_id] = os.path.join(prefix, *(ext_path.split('/')))
@@ -298,4 +298,4 @@ class PRS505(USBMS):
             cpath = os.path.join(thumbnail_dir, 'main_thumbnail.jpg')
             with open(cpath, 'wb') as f:
                 f.write(metadata.thumbnail[-1])
-            debug_print('Cover uploaded to: %r'%cpath)
+            debug_print(f'Cover uploaded to: {cpath!r}')

src/calibre/devices/prs505/sony_cache.py

@@ -103,8 +103,8 @@ class XMLCache:
         for source_id, path in paths.items():
             if source_id == 0:
                 if not os.path.exists(path):
-                    raise DeviceError(('The SONY XML cache %r does not exist. Try'
-                        ' disconnecting and reconnecting your reader.')%repr(path))
+                    raise DeviceError(f'The SONY XML cache {repr(path)!r} does not exist. Try'
+                        ' disconnecting and reconnecting your reader.')
                 with open(path, 'rb') as f:
                     raw = f.read()
             else:
@@ -117,8 +117,8 @@ class XMLCache:
                 xml_to_unicode(raw, strip_encoding_pats=True, assume_utf8=True, verbose=DEBUG)[0]
             )
             if self.roots[source_id] is None:
-                raise Exception(('The SONY database at %r is corrupted. Try '
-                        ' disconnecting and reconnecting your reader.')%path)
+                raise Exception(f'The SONY database at {path!r} is corrupted. Try '
+                        ' disconnecting and reconnecting your reader.')
 
         self.ext_paths, self.ext_roots = {}, {}
         for source_id, path in ext_paths.items():
@@ -265,7 +265,7 @@ class XMLCache:
         if title in self._playlist_to_playlist_id_map[bl_idx]:
             return self._playlist_to_playlist_id_map[bl_idx][title]
         debug_print('Creating playlist:', title)
-        ans = root.makeelement('{%s}playlist'%self.namespaces[bl_idx],
+        ans = root.makeelement(f'{{{self.namespaces[bl_idx]}}}playlist',
                 nsmap=root.nsmap, attrib={
                     'uuid' : uuid(),
                     'title': title,
@@ -303,11 +303,11 @@ class XMLCache:
                     if id_ in idmap:
                         item.set('id', idmap[id_])
                         if DEBUG:
-                            debug_print('Remapping id %s to %s'%(id_, idmap[id_]))
+                            debug_print(f'Remapping id {id_} to {idmap[id_]}')
 
         def ensure_media_xml_base_ids(root):
             for num, tag in enumerate(('library', 'watchSpecial')):
-                for x in root.xpath('//*[local-name()="%s"]'%tag):
+                for x in root.xpath(f'//*[local-name()="{tag}"]'):
                     x.set('id', str(num))
 
         def rebase_ids(root, base, sourceid, pl_sourceid):
@@ -538,7 +538,7 @@ class XMLCache:
             # add the ids that get_collections didn't know about.
             for id_ in ids + extra_ids:
                 item = playlist.makeelement(
-                        '{%s}item'%self.namespaces[bl_index],
+                        f'{{{self.namespaces[bl_index]}}}item',
                         nsmap=playlist.nsmap, attrib={'id':id_})
                 playlist.append(item)
 
@@ -569,14 +569,14 @@ class XMLCache:
         attrib = {
                 'page':'0', 'part':'0','pageOffset':'0','scale':'0',
                 'id':str(id_), 'sourceid':'1', 'path':lpath}
-        ans = root.makeelement('{%s}text'%namespace, attrib=attrib, nsmap=root.nsmap)
+        ans = root.makeelement(f'{{{namespace}}}text', attrib=attrib, nsmap=root.nsmap)
         root.append(ans)
         return ans
 
     def create_ext_text_record(self, root, bl_id, lpath, thumbnail):
         namespace = root.nsmap[None]
         attrib = {'path': lpath}
-        ans = root.makeelement('{%s}text'%namespace, attrib=attrib,
+        ans = root.makeelement(f'{{{namespace}}}text', attrib=attrib,
                 nsmap=root.nsmap)
         ans.tail = '\n'
         if len(root) > 0:
@@ -586,7 +586,7 @@ class XMLCache:
         root.append(ans)
         if thumbnail and thumbnail[-1]:
             ans.text = '\n' + '\t\t'
-            t = root.makeelement('{%s}thumbnail'%namespace,
+            t = root.makeelement(f'{{{namespace}}}thumbnail',
                 attrib={'width':str(thumbnail[0]), 'height':str(thumbnail[1])},
                 nsmap=root.nsmap)
             t.text = 'main_thumbnail.jpg'
@@ -757,7 +757,7 @@ class XMLCache:
         return m
 
     def book_by_lpath(self, lpath, root):
-        matches = root.xpath('//*[local-name()="text" and @path="%s"]'%lpath)
+        matches = root.xpath(f'//*[local-name()="text" and @path="{lpath}"]')
         if matches:
             return matches[0]
 
@@ -782,7 +782,7 @@ class XMLCache:
         for i in self.roots:
             for c in ('library', 'text', 'image', 'playlist', 'thumbnail',
                     'watchSpecial'):
-                matches = self.record_roots[i].xpath('//*[local-name()="%s"]'%c)
+                matches = self.record_roots[i].xpath(f'//*[local-name()="{c}"]')
                 if matches:
                     e = matches[0]
                     self.namespaces[i] = e.nsmap[e.prefix]

src/calibre/devices/prst1/driver.py

@@ -316,11 +316,11 @@ class PRST1(USBMS):
             import traceback
             tb = traceback.format_exc()
             raise DeviceError((('The SONY database is corrupted. '
-                    ' Delete the file %s on your reader and then disconnect '
+                    f' Delete the file {dbpath} on your reader and then disconnect '
                     ' reconnect it. If you are using an SD card, you '
                     ' should delete the file on the card as well. Note that '
                     ' deleting this file will cause your reader to forget '
-                    ' any notes/highlights, etc.')%dbpath)+' Underlying error:'
+                    ' any notes/highlights, etc.'))+' Underlying error:'
                     '\n'+tb)
 
     def get_lastrowid(self, cursor):
@@ -374,11 +374,11 @@ class PRST1(USBMS):
             import traceback
             tb = traceback.format_exc()
             raise DeviceError((('The SONY database is corrupted. '
-                    ' Delete the file %s on your reader and then disconnect '
+                    f' Delete the file {dbpath} on your reader and then disconnect '
                     ' reconnect it. If you are using an SD card, you '
                     ' should delete the file on the card as well. Note that '
                     ' deleting this file will cause your reader to forget '
-                    ' any notes/highlights, etc.')%dbpath)+' Underlying error:'
+                    ' any notes/highlights, etc.'))+' Underlying error:'
                     '\n'+tb)
 
         # Get the books themselves, but keep track of any that are less than the minimum.
@@ -546,11 +546,11 @@ class PRST1(USBMS):
             import traceback
             tb = traceback.format_exc()
             raise DeviceError((('The SONY database is corrupted. '
-                    ' Delete the file %s on your reader and then disconnect '
+                    f' Delete the file {dbpath} on your reader and then disconnect '
                     ' reconnect it. If you are using an SD card, you '
                     ' should delete the file on the card as well. Note that '
                     ' deleting this file will cause your reader to forget '
-                    ' any notes/highlights, etc.')%dbpath)+' Underlying error:'
+                    ' any notes/highlights, etc.'))+' Underlying error:'
                     '\n'+tb)
 
         db_collections = {}

src/calibre/devices/scanner.py

@@ -45,11 +45,9 @@ class USBDevice(_USBDevice):
         return self
 
     def __repr__(self):
-        return ('USBDevice(busnum=%s, devnum=%s, '
-                'vendor_id=0x%04x, product_id=0x%04x, bcd=0x%04x, '
-                'manufacturer=%s, product=%s, serial=%s)')%(
-                self.busnum, self.devnum, self.vendor_id, self.product_id,
-                self.bcd, self.manufacturer, self.product, self.serial)
+        return (f'USBDevice(busnum={self.busnum}, devnum={self.devnum}, '
+                f'vendor_id=0x{self.vendor_id:04x}, product_id=0x{self.product_id:04x}, bcd=0x{self.bcd:04x}, '
+                f'manufacturer={self.manufacturer}, product={self.product}, serial={self.serial})')
 
     __str__ = __repr__
     __unicode__ = __repr__

src/calibre/devices/smart_device_app/driver.py

@@ -402,8 +402,7 @@ class SMART_DEVICE_APP(DeviceConfig, DevicePlugin):
                 return
             total_elapsed = time.time() - self.debug_start_time
             elapsed = time.time() - self.debug_time
-            print('SMART_DEV (%7.2f:%7.3f) %s'%(total_elapsed, elapsed,
-                                                   inspect.stack()[1][3]), end='')
+            print(f'SMART_DEV ({total_elapsed:7.2f}:{elapsed:7.3f}) {inspect.stack()[1][3]}', end='')
             for a in args:
                 try:
                     if isinstance(a, dict):
@@ -712,7 +711,7 @@ class SMART_DEVICE_APP(DeviceConfig, DevicePlugin):
                           wait_for_response=self.can_send_ok_to_sendbook)
         if self.can_send_ok_to_sendbook:
             if opcode == 'ERROR':
-                raise UserFeedback(msg='Sending book %s to device failed' % lpath,
+                raise UserFeedback(msg=f'Sending book {lpath} to device failed',
                                    details=result.get('message', ''),
                                    level=UserFeedback.ERROR)
                 return
@@ -1493,7 +1492,7 @@ class SMART_DEVICE_APP(DeviceConfig, DevicePlugin):
             book = SDBook(self.PREFIX, lpath, other=mdata)
             length, lpath = self._put_file(infile, lpath, book, i, len(files))
             if length < 0:
-                raise ControlError(desc='Sending book %s to device failed' % lpath)
+                raise ControlError(desc=f'Sending book {lpath} to device failed')
             paths.append((lpath, length))
             # No need to deal with covers. The client will get the thumbnails
             # in the mi structure

src/calibre/devices/usbms/device.py

@@ -256,7 +256,7 @@ class Device(DeviceConfig, DevicePlugin):
             if dl in dlmap['readonly_drives']:
                 filtered.add(dl)
                 if debug:
-                    prints('Ignoring the drive %s as it is readonly' % dl)
+                    prints(f'Ignoring the drive {dl} as it is readonly')
             elif self.windows_filter_pnp_id(pnp_id):
                 filtered.add(dl)
                 if debug:
@@ -264,7 +264,7 @@ class Device(DeviceConfig, DevicePlugin):
             elif not drive_is_ok(dl, debug=debug):
                 filtered.add(dl)
                 if debug:
-                    prints('Ignoring the drive %s because failed to get free space for it' % dl)
+                    prints(f'Ignoring the drive {dl} because failed to get free space for it')
         dlmap['drive_letters'] = [dl for dl in dlmap['drive_letters'] if dl not in filtered]
 
         if not dlmap['drive_letters']:

src/calibre/devices/usbms/deviceconfig.py

@@ -57,7 +57,7 @@ class DeviceConfig:
     @classmethod
     def _config(cls):
         name = cls._config_base_name()
-        c = Config('device_drivers_%s' % name, _('settings for device drivers'))
+        c = Config(f'device_drivers_{name}', _('settings for device drivers'))
         c.add_opt('format_map', default=cls.FORMATS,
                 help=_('Ordered list of formats the device will accept'))
         c.add_opt('use_subdirs', default=cls.SUPPORTS_SUB_DIRS_DEFAULT,

src/calibre/devices/usbms/driver.py

@@ -47,7 +47,7 @@ def safe_walk(top, topdown=True, onerror=None, followlinks=False, maxdepth=128):
             try:
                 name = name.decode(filesystem_encoding)
             except UnicodeDecodeError:
-                debug_print('Skipping undecodeable file: %r' % name)
+                debug_print(f'Skipping undecodeable file: {name!r}')
                 continue
         if isdir(join(top, name)):
             dirs.append(name)

src/calibre/devices/utils.py

@@ -60,7 +60,7 @@ def build_template_regexp(template):
         template = template.rpartition('/')[2]
         return re.compile(re.sub(r'{([^}]*)}', f, template) + r'([_\d]*$)')
     except:
-        prints('Failed to parse template: %r'%template)
+        prints(f'Failed to parse template: {template!r}')
         template = '{title} - {authors}'
         return re.compile(re.sub(r'{([^}]*)}', f, template) + r'([_\d]*$)')
 

src/calibre/devices/winusb.py

@@ -69,8 +69,8 @@ class GUID(Structure):
             self.data1,
             self.data2,
             self.data3,
-            ''.join(['%02x' % d for d in self.data4[:2]]),
-            ''.join(['%02x' % d for d in self.data4[2:]]),
+            ''.join([f'{d:02x}' for d in self.data4[:2]]),
+            ''.join([f'{d:02x}' for d in self.data4[2:]]),
         )
 
 
@@ -394,7 +394,7 @@ def cwrap(name, restype, *argtypes, **kw):
     lib = cfgmgr if name.startswith('CM') else setupapi
     func = prototype((name, kw.pop('lib', lib)))
     if kw:
-        raise TypeError('Unknown keyword arguments: %r' % kw)
+        raise TypeError(f'Unknown keyword arguments: {kw!r}')
     if errcheck is not None:
         func.errcheck = errcheck
     return func
@@ -414,7 +414,7 @@ def bool_err_check(result, func, args):
 
 def config_err_check(result, func, args):
     if result != CR_CODES['CR_SUCCESS']:
-        raise WinError(result, 'The cfgmgr32 function failed with err: %s' % CR_CODE_NAMES.get(result, result))
+        raise WinError(result, f'The cfgmgr32 function failed with err: {CR_CODE_NAMES.get(result, result)}')
     return args
 
 
@@ -575,7 +575,7 @@ def get_device_id(devinst, buf=None):
             buf = create_unicode_buffer(devid_size.value)
             continue
         if ret != CR_CODES['CR_SUCCESS']:
-            raise WinError(ret, 'The cfgmgr32 function failed with err: %s' % CR_CODE_NAMES.get(ret, ret))
+            raise WinError(ret, f'The cfgmgr32 function failed with err: {CR_CODE_NAMES.get(ret, ret)}')
         break
     return wstring_at(buf), buf
 
@@ -610,7 +610,7 @@ def convert_registry_data(raw, size, dtype):
         if size == 0:
             return 0
         return cast(raw, POINTER(QWORD)).contents.value
-    raise ValueError('Unsupported data type: %r' % dtype)
+    raise ValueError(f'Unsupported data type: {dtype!r}')
 
 
 def get_device_registry_property(dev_list, p_devinfo, property_type=SPDRP_HARDWAREID, buf=None):
@@ -712,9 +712,8 @@ class USBDevice(_USBDevice):
         def r(x):
             if x is None:
                 return 'None'
-            return '0x%x' % x
-        return 'USBDevice(vendor_id={} product_id={} bcd={} devid={} devinst={})'.format(
-            r(self.vendor_id), r(self.product_id), r(self.bcd), self.devid, self.devinst)
+            return f'0x{x:x}'
+        return f'USBDevice(vendor_id={r(self.vendor_id)} product_id={r(self.product_id)} bcd={r(self.bcd)} devid={self.devid} devinst={self.devinst})'
 
 
 def parse_hex(x):
@@ -976,7 +975,7 @@ def get_device_string(hub_handle, device_port, index, buf=None, lang=0x409):
     data = cast(buf, PUSB_DESCRIPTOR_REQUEST).contents.Data
     sz, dtype = data.bLength, data.bType
     if dtype != 0x03:
-        raise OSError(errno.EINVAL, 'Invalid datatype for string descriptor: 0x%x' % dtype)
+        raise OSError(errno.EINVAL, f'Invalid datatype for string descriptor: 0x{dtype:x}')
     return buf, wstring_at(addressof(data.String), sz // 2).rstrip('\0')
 
 
@@ -996,7 +995,7 @@ def get_device_languages(hub_handle, device_port, buf=None):
     data = cast(buf, PUSB_DESCRIPTOR_REQUEST).contents.Data
     sz, dtype = data.bLength, data.bType
     if dtype != 0x03:
-        raise OSError(errno.EINVAL, 'Invalid datatype for string descriptor: 0x%x' % dtype)
+        raise OSError(errno.EINVAL, f'Invalid datatype for string descriptor: 0x{dtype:x}')
     data = cast(data.String, POINTER(USHORT*(sz//2)))
     return buf, list(filter(None, data.contents))
 

src/calibre/ebooks/__init__.py

@@ -245,7 +245,7 @@ def escape_xpath_attr(value):
                 if x:
                     q = "'" if '"' in x else '"'
                     ans.append(q + x + q)
-            return 'concat(%s)' % ', '.join(ans)
+            return 'concat({})'.format(', '.join(ans))
         else:
-            return "'%s'" % value
-    return '"%s"' % value
+            return f"'{value}'"
+    return f'"{value}"'

src/calibre/ebooks/chm/reader.py

@@ -55,7 +55,7 @@ class CHMReader(CHMFile):
                     t.write(open(input, 'rb').read())
                 input = t.name
         if not self.LoadCHM(input):
-            raise CHMError("Unable to open CHM file '%s'"%(input,))
+            raise CHMError(f"Unable to open CHM file '{input}'")
         self.log = log
         self.input_encoding = input_encoding
         self._sourcechm = input
@@ -188,7 +188,7 @@ class CHMReader(CHMFile):
             try:
                 data = self.GetFile(path)
             except:
-                self.log.exception('Failed to extract %s from CHM, ignoring'%path)
+                self.log.exception(f'Failed to extract {path} from CHM, ignoring')
                 continue
             if lpath.find(';') != -1:
                 # fix file names with ";<junk>" at the end, see _reformat()
@@ -203,7 +203,7 @@ class CHMReader(CHMFile):
                     pass
             except:
                 if iswindows and len(lpath) > 250:
-                    self.log.warn('%r filename too long, skipping'%path)
+                    self.log.warn(f'{path!r} filename too long, skipping')
                     continue
                 raise
 

src/calibre/ebooks/compression/tcr.py

@@ -119,7 +119,7 @@ def decompress(stream):
     txt = []
     stream.seek(0)
     if stream.read(9) != b'!!8-Bit!!':
-        raise ValueError('File %s contains an invalid TCR header.' % stream.name)
+        raise ValueError(f'File {stream.name} contains an invalid TCR header.')
 
     # Codes that the file contents are broken down into.
     entries = []

src/calibre/ebooks/conversion/cli.py

@@ -371,8 +371,7 @@ def read_sr_patterns(path, log=None):
             try:
                 re.compile(line)
             except:
-                msg = 'Invalid regular expression: %r from file: %r'%(
-                        line, path)
+                msg = f'Invalid regular expression: {line!r} from file: {path!r}'
                 if log is not None:
                     log.error(msg)
                     raise SystemExit(1)

src/calibre/ebooks/conversion/plugins/chm_input.py

@@ -23,7 +23,7 @@ class CHMInput(InputFormatPlugin):
         from calibre.ebooks.chm.reader import CHMReader
         log.debug('Opening CHM file')
         rdr = CHMReader(chm_path, log, input_encoding=self.opts.input_encoding)
-        log.debug('Extracting CHM to %s' % output_dir)
+        log.debug(f'Extracting CHM to {output_dir}')
         rdr.extract_content(output_dir, debug_dump=debug_dump)
         self._chm_reader = rdr
         return rdr.hhc_path
@@ -46,8 +46,8 @@ class CHMInput(InputFormatPlugin):
 
             # closing stream so CHM can be opened by external library
             stream.close()
-            log.debug('tdir=%s' % tdir)
-            log.debug('stream.name=%s' % stream.name)
+            log.debug(f'tdir={tdir}')
+            log.debug(f'stream.name={stream.name}')
             debug_dump = False
             odi = options.debug_pipeline
             if odi:

src/calibre/ebooks/conversion/plugins/comic_input.py

@@ -99,10 +99,9 @@ class ComicInput(InputFormatPlugin):
         comics = []
         with CurrentDir(tdir):
             if not os.path.exists('comics.txt'):
-                raise ValueError((
-                    '%s is not a valid comic collection'
+                raise ValueError(
+                    f'{stream.name} is not a valid comic collection'
                     ' no comics.txt was found in the file')
-                        %stream.name)
             with open('comics.txt', 'rb') as f:
                 raw = f.read()
             if raw.startswith(codecs.BOM_UTF16_BE):
@@ -125,7 +124,7 @@ class ComicInput(InputFormatPlugin):
                 if os.access(fname, os.R_OK):
                     comics.append([title, fname])
         if not comics:
-            raise ValueError('%s has no comics'%stream.name)
+            raise ValueError(f'{stream.name} has no comics')
         return comics
 
     def get_pages(self, comic, tdir2):
@@ -135,12 +134,11 @@ class ComicInput(InputFormatPlugin):
                 verbose=self.opts.verbose)
         thumbnail = None
         if not new_pages:
-            raise ValueError('Could not find any pages in the comic: %s'
-                    %comic)
+            raise ValueError(f'Could not find any pages in the comic: {comic}')
         if self.opts.no_process:
             n2 = []
             for i, page in enumerate(new_pages):
-                n2.append(os.path.join(tdir2, '{} - {}' .format(i, os.path.basename(page))))
+                n2.append(os.path.join(tdir2, f'{i} - {os.path.basename(page)}'))
                 shutil.copyfile(page, n2[-1])
             new_pages = n2
         else:
@@ -152,8 +150,7 @@ class ComicInput(InputFormatPlugin):
                 for f in failures:
                     self.log.warning('\t', f)
             if not new_pages:
-                raise ValueError('Could not find any valid pages in comic: %s'
-                        % comic)
+                raise ValueError(f'Could not find any valid pages in comic: {comic}')
             thumbnail = os.path.join(tdir2,
                     'thumbnail.'+self.opts.output_format.lower())
             if not os.access(thumbnail, os.R_OK):
@@ -193,7 +190,7 @@ class ComicInput(InputFormatPlugin):
                 comics.append((title, pages, wrappers))
 
         if not comics:
-            raise ValueError('No comic pages found in %s'%stream.name)
+            raise ValueError(f'No comic pages found in {stream.name}')
 
         mi  = MetaInformation(os.path.basename(stream.name).rpartition('.')[0],
             [_('Unknown')])
@@ -299,8 +296,8 @@ class ComicInput(InputFormatPlugin):
 
         pages = '\n'.join(page(i, src) for i, src in enumerate(pages))
         base = os.path.dirname(pages[0])
-        wrapper = '''
-        <html xmlns="{}">
+        wrapper = f'''
+        <html xmlns="{XHTML_NS}">
             <head>
                 <meta charset="utf-8"/>
                 <style type="text/css">
@@ -317,10 +314,10 @@ class ComicInput(InputFormatPlugin):
                 </style>
             </head>
             <body>
-            {}
+            {pages}
             </body>
         </html>
-        '''.format(XHTML_NS, pages)
+        '''
         path = os.path.join(base, cdir, 'wrapper.xhtml')
         with open(path, 'wb') as f:
             f.write(wrapper.encode('utf-8'))

src/calibre/ebooks/conversion/plugins/epub_input.py

@@ -281,7 +281,7 @@ class EPUBInput(InputFormatPlugin):
         path = getattr(stream, 'name', 'stream')
 
         if opf is None:
-            raise ValueError('%s is not a valid EPUB file (could not find opf)'%path)
+            raise ValueError(f'{path} is not a valid EPUB file (could not find opf)')
 
         opf = os.path.relpath(opf, os.getcwd())
         parts = os.path.split(opf)
@@ -369,7 +369,7 @@ class EPUBInput(InputFormatPlugin):
         root = parse(raw, log=log)
         ncx = safe_xml_fromstring('<ncx xmlns="http://www.daisy.org/z3986/2005/ncx/" version="2005-1" xml:lang="eng"><navMap/></ncx>')
         navmap = ncx[0]
-        et = '{%s}type' % EPUB_NS
+        et = f'{{{EPUB_NS}}}type'
         bn = os.path.basename(nav_path)
 
         def add_from_li(li, parent):

src/calibre/ebooks/conversion/plugins/epub_output.py

@@ -335,7 +335,7 @@ class EPUBOutput(OutputFormatPlugin):
 
         key = re.sub(r'[^a-fA-F0-9]', '', uuid)
         if len(key) < 16:
-            raise ValueError('UUID identifier %r is invalid'%uuid)
+            raise ValueError(f'UUID identifier {uuid!r} is invalid')
         key = bytearray(from_hex_bytes((key + key)[:32]))
         paths = []
         with CurrentDir(tdir):
@@ -362,10 +362,10 @@ class EPUBOutput(OutputFormatPlugin):
                 <enc:EncryptedData>
                     <enc:EncryptionMethod Algorithm="http://ns.adobe.com/pdf/enc#RC"/>
                     <enc:CipherData>
-                    <enc:CipherReference URI="%s"/>
+                    <enc:CipherReference URI="{}"/>
                     </enc:CipherData>
                 </enc:EncryptedData>
-                '''%(uri.replace('"', '\\"')))
+                '''.format(uri.replace('"', '\\"')))
             if fonts:
                 ans = '''<encryption
                     xmlns="urn:oasis:names:tc:opendocument:xmlns:container"
@@ -409,7 +409,7 @@ class EPUBOutput(OutputFormatPlugin):
                 frag = urlunquote(frag)
                 if frag and frag_pat.match(frag) is None:
                     self.log.warn(
-                            'Removing fragment identifier %r from TOC as Adobe Digital Editions cannot handle it'%frag)
+                            f'Removing fragment identifier {frag!r} from TOC as Adobe Digital Editions cannot handle it')
                     node.href = base
 
         for x in self.oeb.spine:
@@ -540,7 +540,7 @@ class EPUBOutput(OutputFormatPlugin):
         from calibre.ebooks.oeb.polish.toc import item_at_top
 
         def frag_is_at_top(root, frag):
-            elem = XPath('//*[@id="%s" or @name="%s"]'%(frag, frag))(root)
+            elem = XPath(f'//*[@id="{frag}" or @name="{frag}"]')(root)
             if elem:
                 elem = elem[0]
             else:

src/calibre/ebooks/conversion/plugins/fb2_input.py

@@ -77,7 +77,7 @@ class FB2Input(InputFormatPlugin):
             parser = css_parser.CSSParser(fetcher=None,
                     log=logging.getLogger('calibre.css'))
 
-            XHTML_CSS_NAMESPACE = '@namespace "%s";\n' % XHTML_NS
+            XHTML_CSS_NAMESPACE = f'@namespace "{XHTML_NS}";\n'
             text = XHTML_CSS_NAMESPACE + css
             log.debug('Parsing stylesheet...')
             stylesheet = parser.parseString(text)
@@ -115,7 +115,7 @@ class FB2Input(InputFormatPlugin):
                 if not note.get('id', None):
                     note.set('id', 'cite%d' % c)
                     all_ids.add(note.get('id'))
-                a.set('href', '#%s' % note.get('id'))
+                a.set('href', '#{}'.format(note.get('id')))
         for x in result.xpath('//*[@link_note or @link_cite]'):
             x.attrib.pop('link_note', None)
             x.attrib.pop('link_cite', None)
@@ -148,7 +148,7 @@ class FB2Input(InputFormatPlugin):
             cpath = os.path.abspath('fb2_cover_calibre_mi.jpg')
         else:
             for img in doc.xpath('//f:coverpage/f:image', namespaces=NAMESPACES):
-                href = img.get('{%s}href'%XLINK_NS, img.get('href', None))
+                href = img.get(f'{{{XLINK_NS}}}href', img.get('href', None))
                 if href is not None:
                     if href.startswith('#'):
                         href = href[1:]
@@ -182,8 +182,7 @@ class FB2Input(InputFormatPlugin):
                 try:
                     data = base64_decode(raw)
                 except TypeError:
-                    self.log.exception('Binary data with id=%s is corrupted, ignoring'%(
-                        elem.get('id')))
+                    self.log.exception('Binary data with id={} is corrupted, ignoring'.format(elem.get('id')))
                 else:
                     with open(fname, 'wb') as f:
                         f.write(data)

src/calibre/ebooks/conversion/plugins/html_input.py

@@ -254,7 +254,7 @@ class HTMLInput(InputFormatPlugin):
             try:
                 link_ = link_.decode('utf-8', 'error')
             except:
-                self.log.warn('Failed to decode link %r. Ignoring'%link_)
+                self.log.warn(f'Failed to decode link {link_!r}. Ignoring')
                 return None, None
         if self.root_dir_for_absolute_links and link_.startswith('/'):
             link_ = link_.lstrip('/')
@@ -262,7 +262,7 @@ class HTMLInput(InputFormatPlugin):
         try:
             l = Link(link_, base if base else os.getcwd())
         except:
-            self.log.exception('Failed to process link: %r'%link_)
+            self.log.exception(f'Failed to process link: {link_!r}')
             return None, None
         if l.path is None:
             # Not a local resource
@@ -311,7 +311,7 @@ class HTMLInput(InputFormatPlugin):
             bhref = os.path.basename(link)
             id, href = self.oeb.manifest.generate(id='added', href=sanitize_file_name(bhref))
             if media_type == 'text/plain':
-                self.log.warn('Ignoring link to text file %r'%link_)
+                self.log.warn(f'Ignoring link to text file {link_!r}')
                 return None
             if media_type == self.BINARY_MIME:
                 # Check for the common case, images

src/calibre/ebooks/conversion/plugins/lit_input.py

@@ -47,7 +47,7 @@ class LITInput(InputFormatPlugin):
                     self.log('LIT file with all text in single <pre> tag detected')
                     html = separate_paragraphs_single_line(pre.text)
                     html = convert_basic(html).replace('<html>',
-                            '<html xmlns="%s">'%XHTML_NS)
+                            f'<html xmlns="{XHTML_NS}">')
                     html = xml_to_unicode(html, strip_encoding_pats=True,
                             resolve_entities=True)[0]
                     if opts.smarten_punctuation:

src/calibre/ebooks/conversion/plugins/lrf_input.py

@@ -39,19 +39,18 @@ class LRFInput(InputFormatPlugin):
         char_button_map = {}
         for x in doc.xpath('//CharButton[@refobj]'):
             ro = x.get('refobj')
-            jump_button = doc.xpath('//*[@objid="%s"]'%ro)
+            jump_button = doc.xpath(f'//*[@objid="{ro}"]')
             if jump_button:
                 jump_to = jump_button[0].xpath('descendant::JumpTo[@refpage and @refobj]')
                 if jump_to:
-                    char_button_map[ro] = '%s.xhtml#%s'%(jump_to[0].get('refpage'),
+                    char_button_map[ro] = '{}.xhtml#{}'.format(jump_to[0].get('refpage'),
                             jump_to[0].get('refobj'))
         plot_map = {}
         for x in doc.xpath('//Plot[@refobj]'):
             ro = x.get('refobj')
-            image = doc.xpath('//Image[@objid="%s" and @refstream]'%ro)
+            image = doc.xpath(f'//Image[@objid="{ro}" and @refstream]')
             if image:
-                imgstr = doc.xpath('//ImageStream[@objid="%s" and @file]'%
-                    image[0].get('refstream'))
+                imgstr = doc.xpath('//ImageStream[@objid="{}" and @file]'.format(image[0].get('refstream')))
                 if imgstr:
                     plot_map[ro] = imgstr[0].get('file')
 

src/calibre/ebooks/conversion/plugins/lrf_output.py

@@ -153,7 +153,7 @@ class LRFOutput(OutputFormatPlugin):
         ps['textheight']     = height
         book = Book(title=opts.title, author=opts.author,
                 bookid=uuid4().hex,
-                publisher='%s %s'%(__appname__, __version__),
+                publisher=f'{__appname__} {__version__}',
                 category=_('Comic'), pagestyledefault=ps,
                 booksetting=BookSetting(screenwidth=width, screenheight=height))
         for page in pages:

src/calibre/ebooks/conversion/plugins/mobi_input.py

@@ -37,7 +37,7 @@ class MOBIInput(InputFormatPlugin):
                 mr.extract_content('.', parse_cache)
 
         if mr.kf8_type is not None:
-            log('Found KF8 MOBI of type %r'%mr.kf8_type)
+            log(f'Found KF8 MOBI of type {mr.kf8_type!r}')
             if mr.kf8_type == 'joint':
                 self.mobi_is_joint = True
             from calibre.ebooks.mobi.reader.mobi8 import Mobi8Reader

src/calibre/ebooks/conversion/plugins/oeb_output.py

@@ -83,7 +83,7 @@ class OEBOutput(OutputFormatPlugin):
 
         def manifest_items_with_id(id_):
             return root.xpath('//*[local-name() = "manifest"]/*[local-name() = "item" '
-                ' and @id="%s"]'%id_)
+                f' and @id="{id_}"]')
 
         if len(cov) == 1:
             cov = cov[0]

src/calibre/ebooks/conversion/plugins/pdb_input.py

@@ -24,8 +24,7 @@ class PDBInput(InputFormatPlugin):
         Reader = get_reader(header.ident)
 
         if Reader is None:
-            raise PDBError('No reader available for format within container.\n Identity is %s. Book type is %s' %
-                           (header.ident, IDENTITY_TO_NAME.get(header.ident, _('Unknown'))))
+            raise PDBError('No reader available for format within container.\n Identity is {}. Book type is {}'.format(header.ident, IDENTITY_TO_NAME.get(header.ident, _('Unknown'))))
 
         log.debug(f'Detected ebook format as: {IDENTITY_TO_NAME[header.ident]} with identity: {header.ident}')
 

src/calibre/ebooks/conversion/plugins/pdb_output.py

@@ -44,7 +44,7 @@ class PDBOutput(OutputFormatPlugin):
         Writer = get_writer(opts.format)
 
         if Writer is None:
-            raise PDBError('No writer available for format %s.' % format)
+            raise PDBError(f'No writer available for format {format}.')
 
         setattr(opts, 'max_line_length', 0)
         setattr(opts, 'force_max_line_length', False)

src/calibre/ebooks/conversion/plugins/pml_input.py

@@ -47,7 +47,7 @@ class PMLInput(InputFormatPlugin):
         self.log.debug('Converting PML to HTML...')
         hizer = PML_HTMLizer()
         html = hizer.parse_pml(pml_stream.read().decode(ienc), html_path)
-        html = '<html><head><title></title></head><body>%s</body></html>'%html
+        html = f'<html><head><title></title></head><body>{html}</body></html>'
         html_stream.write(html.encode('utf-8', 'replace'))
 
         if pclose:
@@ -106,7 +106,7 @@ class PMLInput(InputFormatPlugin):
                     html_path = os.path.join(os.getcwd(), html_name)
 
                     pages.append(html_name)
-                    log.debug('Processing PML item %s...' % pml)
+                    log.debug(f'Processing PML item {pml}...')
                     ttoc = self.process_pml(pml, html_path)
                     toc += ttoc
                 images = self.get_images(stream, tdir, True)

src/calibre/ebooks/conversion/plugins/recipe_input.py

@@ -111,8 +111,7 @@ class RecipeInput(InputFormatPlugin):
                     self.recipe_source = raw
                     if recipe.requires_version > numeric_version:
                         log.warn(
-                        'Downloaded recipe needs calibre version at least: %s' %
-                        ('.'.join(recipe.requires_version)))
+                        'Downloaded recipe needs calibre version at least: {}'.format('.'.join(recipe.requires_version)))
                         builtin = True
                 except:
                     log.exception('Failed to compile downloaded recipe. Falling '
@@ -130,8 +129,7 @@ class RecipeInput(InputFormatPlugin):
                     log('Using downloaded builtin recipe')
 
             if recipe is None:
-                raise ValueError('%r is not a valid recipe file or builtin recipe' %
-                        recipe_or_file)
+                raise ValueError(f'{recipe_or_file!r} is not a valid recipe file or builtin recipe')
 
             disabled = getattr(recipe, 'recipe_disabled', None)
             if disabled is not None:

src/calibre/ebooks/conversion/plugins/rtf_input.py

@@ -164,7 +164,7 @@ class RTFInput(InputFormatPlugin):
         try:
             return self.rasterize_wmf(name)
         except Exception:
-            self.log.exception('Failed to convert WMF image %r'%name)
+            self.log.exception(f'Failed to convert WMF image {name!r}')
         return self.replace_wmf(name)
 
     def replace_wmf(self, name):
@@ -217,7 +217,7 @@ class RTFInput(InputFormatPlugin):
         css += '\n' +'\n'.join(color_classes)
 
         for cls, val in iteritems(border_styles):
-            css += '\n\n.%s {\n%s\n}'%(cls, val)
+            css += f'\n\n.{cls} {{\n{val}\n}}'
 
         with open('styles.css', 'ab') as f:
             f.write(css.encode('utf-8'))
@@ -229,16 +229,16 @@ class RTFInput(InputFormatPlugin):
             style = ['border-style: hidden', 'border-width: 1px',
                     'border-color: black']
             for x in ('bottom', 'top', 'left', 'right'):
-                bs = elem.get('border-cell-%s-style'%x, None)
+                bs = elem.get(f'border-cell-{x}-style', None)
                 if bs:
                     cbs = border_style_map.get(bs, 'solid')
-                    style.append('border-%s-style: %s'%(x, cbs))
-                bw = elem.get('border-cell-%s-line-width'%x, None)
+                    style.append(f'border-{x}-style: {cbs}')
+                bw = elem.get(f'border-cell-{x}-line-width', None)
                 if bw:
-                    style.append('border-%s-width: %spt'%(x, bw))
-                bc = elem.get('border-cell-%s-color'%x, None)
+                    style.append(f'border-{x}-width: {bw}pt')
+                bc = elem.get(f'border-cell-{x}-color', None)
                 if bc:
-                    style.append('border-%s-color: %s'%(x, bc))
+                    style.append(f'border-{x}-color: {bc}')
             style = ';\n'.join(style)
             if style not in border_styles:
                 border_styles.append(style)

src/calibre/ebooks/conversion/plugins/snb_input.py

@@ -98,9 +98,9 @@ class SNBInput(InputFormatPlugin):
                     lines = []
                     for line in snbc.find('.//body'):
                         if line.tag == 'text':
-                            lines.append('<p>%s</p>' % html_encode(line.text))
+                            lines.append(f'<p>{html_encode(line.text)}</p>')
                         elif line.tag == 'img':
-                            lines.append('<p><img src="%s" /></p>' % html_encode(line.text))
+                            lines.append(f'<p><img src="{html_encode(line.text)}" /></p>')
                     with open(os.path.join(tdir, fname), 'wb') as f:
                         f.write((HTML_TEMPLATE % (chapterName, '\n'.join(lines))).encode('utf-8', 'replace'))
                     oeb.toc.add(ch.text, fname)

src/calibre/ebooks/conversion/plugins/snb_output.py

@@ -141,7 +141,7 @@ class SNBOutput(OutputFormatPlugin):
                 if tocitem.href.find('#') != -1:
                     item = tocitem.href.split('#')
                     if len(item) != 2:
-                        log.error('Error in TOC item: %s' % tocitem)
+                        log.error(f'Error in TOC item: {tocitem}')
                     else:
                         if item[0] in outputFiles:
                             outputFiles[item[0]].append((item[1], tocitem.title))
@@ -176,16 +176,16 @@ class SNBOutput(OutputFormatPlugin):
                 from calibre.ebooks.oeb.base import OEB_DOCS, OEB_IMAGES
                 if m.hrefs[item.href].media_type in OEB_DOCS:
                     if item.href not in outputFiles:
-                        log.debug('File %s is unused in TOC. Continue in last chapter' % item.href)
+                        log.debug(f'File {item.href} is unused in TOC. Continue in last chapter')
                         mergeLast = True
                     else:
                         if oldTree is not None and mergeLast:
-                            log.debug('Output the modified chapter again: %s' % lastName)
+                            log.debug(f'Output the modified chapter again: {lastName}')
                             with open(os.path.join(snbcDir, lastName), 'wb') as f:
                                 f.write(etree.tostring(oldTree, pretty_print=True, encoding='utf-8'))
                             mergeLast = False
 
-                    log.debug('Converting %s to snbc...' % item.href)
+                    log.debug(f'Converting {item.href} to snbc...')
                     snbwriter = SNBMLizer(log)
                     snbcTrees = None
                     if not mergeLast:
@@ -199,11 +199,11 @@ class SNBOutput(OutputFormatPlugin):
                             with open(os.path.join(snbcDir, lastName), 'wb') as f:
                                 f.write(etree.tostring(oldTree, pretty_print=True, encoding='utf-8'))
                     else:
-                        log.debug('Merge %s with last TOC item...' % item.href)
+                        log.debug(f'Merge {item.href} with last TOC item...')
                         snbwriter.merge_content(oldTree, oeb_book, item, [('', _('Start'))], opts)
 
             # Output the last one if needed
-            log.debug('Output the last modified chapter again: %s' % lastName)
+            log.debug(f'Output the last modified chapter again: {lastName}')
             if oldTree is not None and mergeLast:
                 with open(os.path.join(snbcDir, lastName), 'wb') as f:
                     f.write(etree.tostring(oldTree, pretty_print=True, encoding='utf-8'))
@@ -211,7 +211,7 @@ class SNBOutput(OutputFormatPlugin):
 
             for item in m:
                 if m.hrefs[item.href].media_type in OEB_IMAGES:
-                    log.debug('Converting image: %s ...' % item.href)
+                    log.debug(f'Converting image: {item.href} ...')
                     content = m.hrefs[item.href].data
                     # Convert & Resize image
                     self.HandleImage(content, os.path.join(snbiDir, ProcessFileName(item.href)))

src/calibre/ebooks/conversion/plugins/txt_input.py

@@ -198,13 +198,13 @@ class TXTInput(InputFormatPlugin):
             if file_ext in {'md', 'textile', 'markdown'}:
                 options.formatting_type = {'md': 'markdown'}.get(file_ext, file_ext)
                 log.info('File extension indicates particular formatting. '
-                        'Forcing formatting type to: %s'%options.formatting_type)
+                        f'Forcing formatting type to: {options.formatting_type}')
                 options.paragraph_type = 'off'
 
         # Get the encoding of the document.
         if options.input_encoding:
             ienc = options.input_encoding
-            log.debug('Using user specified input encoding of %s' % ienc)
+            log.debug(f'Using user specified input encoding of {ienc}')
         else:
             det_encoding = detect(txt[:4096])
             det_encoding, confidence = det_encoding['encoding'], det_encoding['confidence']
@@ -218,7 +218,7 @@ class TXTInput(InputFormatPlugin):
             log.debug(f'Detected input encoding as {ienc} with a confidence of {confidence * 100}%')
         if not ienc:
             ienc = 'utf-8'
-            log.debug('No input encoding specified and could not auto detect using %s' % ienc)
+            log.debug(f'No input encoding specified and could not auto detect using {ienc}')
         # Remove BOM from start of txt as its presence can confuse markdown
         import codecs
         for bom in (codecs.BOM_UTF16_LE, codecs.BOM_UTF16_BE, codecs.BOM_UTF8, codecs.BOM_UTF32_LE, codecs.BOM_UTF32_BE):
@@ -240,12 +240,12 @@ class TXTInput(InputFormatPlugin):
                 log.debug('Could not reliably determine paragraph type using block')
                 options.paragraph_type = 'block'
             else:
-                log.debug('Auto detected paragraph type as %s' % options.paragraph_type)
+                log.debug(f'Auto detected paragraph type as {options.paragraph_type}')
 
         # Detect formatting
         if options.formatting_type == 'auto':
             options.formatting_type = detect_formatting_type(txt)
-            log.debug('Auto detected formatting as %s' % options.formatting_type)
+            log.debug(f'Auto detected formatting as {options.formatting_type}')
 
         if options.formatting_type == 'heuristic':
             setattr(options, 'enable_heuristics', True)

src/calibre/ebooks/conversion/plumber.py

@@ -945,7 +945,7 @@ OptionRecommendation(name='search_replace',
 
         from calibre import browser
         from calibre.ptempfile import PersistentTemporaryFile
-        self.log('Downloading cover from %r'%url)
+        self.log(f'Downloading cover from {url!r}')
         br = browser()
         raw = br.open_novisit(url).read()
         buf = io.BytesIO(raw)
@@ -999,7 +999,7 @@ OptionRecommendation(name='search_replace',
                     setattr(self.opts, attr, x)
                     return
             self.log.warn(
-                'Profile (%s) %r is no longer available, using default'%(which, sval))
+                f'Profile ({which}) {sval!r} is no longer available, using default')
             for x in profiles():
                 if x.short_name == 'default':
                     setattr(self.opts, attr, x)
@@ -1017,7 +1017,7 @@ OptionRecommendation(name='search_replace',
             self.log('Conversion options changed from defaults:')
             for rec in self.changed_options:
                 if rec.option.name not in ('username', 'password'):
-                    self.log(' ', '%s:' % rec.option.name, repr(rec.recommended_value))
+                    self.log(' ', f'{rec.option.name}:', repr(rec.recommended_value))
         if self.opts.verbose > 1:
             self.log.debug('Resolved conversion options')
             try:
@@ -1204,7 +1204,7 @@ OptionRecommendation(name='search_replace',
             try:
                 fkey = list(map(float, fkey.split(',')))
             except Exception:
-                self.log.error('Invalid font size key: %r ignoring'%fkey)
+                self.log.error(f'Invalid font size key: {fkey!r} ignoring')
                 fkey = self.opts.dest.fkey
 
         from calibre.ebooks.oeb.transforms.jacket import Jacket
@@ -1298,7 +1298,7 @@ OptionRecommendation(name='search_replace',
             self.dump_oeb(self.oeb, out_dir)
             self.log('Processed HTML written to:', out_dir)
 
-        self.log.info('Creating %s...'%self.output_plugin.name)
+        self.log.info(f'Creating {self.output_plugin.name}...')
         our = CompositeProgressReporter(0.67, 1., self.ui_reporter)
         self.output_plugin.report_progress = our
         our(0., _('Running %s plugin')%self.output_plugin.name)

src/calibre/ebooks/conversion/preprocess.py

@@ -41,7 +41,7 @@ _ligpat = re.compile('|'.join(LIGATURES))
 def sanitize_head(match):
     x = match.group(1).strip()
     x = _span_pat.sub('', x)
-    return '<head>\n%s\n</head>' % x
+    return f'<head>\n{x}\n</head>'
 
 
 def chap_head(match):
@@ -200,12 +200,12 @@ class Dehyphenator:
             "((ed)?ly|'?e?s||a?(t|s)?ion(s|al(ly)?)?|ings?|er|(i)?ous|"
             "(i|a)ty|(it)?ies|ive|gence|istic(ally)?|(e|a)nce|m?ents?|ism|ated|"
             "(e|u)ct(ed)?|ed|(i|ed)?ness|(e|a)ncy|ble|ier|al|ex|ian)$")
-        self.suffixes = re.compile(r'^%s' % self.suffix_string, re.IGNORECASE)
-        self.removesuffixes = re.compile(r'%s' % self.suffix_string, re.IGNORECASE)
+        self.suffixes = re.compile(rf'^{self.suffix_string}', re.IGNORECASE)
+        self.removesuffixes = re.compile(rf'{self.suffix_string}', re.IGNORECASE)
         # remove prefixes if the prefix was not already the point of hyphenation
         self.prefix_string = '^(dis|re|un|in|ex)'
-        self.prefixes = re.compile(r'%s$' % self.prefix_string, re.IGNORECASE)
-        self.removeprefix = re.compile(r'%s' % self.prefix_string, re.IGNORECASE)
+        self.prefixes = re.compile(rf'{self.prefix_string}$', re.IGNORECASE)
+        self.removeprefix = re.compile(rf'{self.prefix_string}', re.IGNORECASE)
 
     def dehyphenate(self, match):
         firsthalf = match.group('firstpart')
@@ -295,10 +295,10 @@ class CSSPreProcessor:
     # Remove some of the broken CSS Microsoft products
     # create
     MS_PAT     = re.compile(r'''
-        (?P<start>^|;|\{)\s*    # The end of the previous rule or block start
-        (%s).+?                 # The invalid selectors
-        (?P<end>$|;|\})         # The end of the declaration
-        '''%'mso-|panose-|text-underline|tab-interval',
+        (?P<start>^|;|\{{)\s*    # The end of the previous rule or block start
+        ({}).+?                 # The invalid selectors
+        (?P<end>$|;|\}})         # The end of the declaration
+        '''.format('mso-|panose-|text-underline|tab-interval'),
         re.MULTILINE|re.IGNORECASE|re.VERBOSE)
 
     def ms_sub(self, match):
@@ -433,13 +433,13 @@ def book_designer_rules():
         lambda match : '<span style="page-break-after:always"> </span>'),
         # Create header tags
         (re.compile(r'<h2[^><]*?id=BookTitle[^><]*?(align=)*(?(1)(\w+))*[^><]*?>[^><]*?</h2>', re.IGNORECASE),
-        lambda match : '<h1 id="BookTitle" align="%s">%s</h1>'%(match.group(2) if match.group(2) else 'center', match.group(3))),
+        lambda match : '<h1 id="BookTitle" align="{}">{}</h1>'.format(match.group(2) if match.group(2) else 'center', match.group(3))),
         (re.compile(r'<h2[^><]*?id=BookAuthor[^><]*?(align=)*(?(1)(\w+))*[^><]*?>[^><]*?</h2>', re.IGNORECASE),
-        lambda match : '<h2 id="BookAuthor" align="%s">%s</h2>'%(match.group(2) if match.group(2) else 'center', match.group(3))),
+        lambda match : '<h2 id="BookAuthor" align="{}">{}</h2>'.format(match.group(2) if match.group(2) else 'center', match.group(3))),
         (re.compile(r'<span[^><]*?id=title[^><]*?>(.*?)</span>', re.IGNORECASE|re.DOTALL),
-        lambda match : '<h2 class="title">%s</h2>'%(match.group(1),)),
+        lambda match : f'<h2 class="title">{match.group(1)}</h2>'),
         (re.compile(r'<span[^><]*?id=subtitle[^><]*?>(.*?)</span>', re.IGNORECASE|re.DOTALL),
-        lambda match : '<h3 class="subtitle">%s</h3>'%(match.group(1),)),
+        lambda match : f'<h3 class="subtitle">{match.group(1)}</h3>'),
     ]
     return ans
 
@@ -494,8 +494,7 @@ class HTMLPreProcessor:
                 rules.insert(0, (search_re, replace_txt))
                 user_sr_rules[(search_re, replace_txt)] = search_pattern
             except Exception as e:
-                self.log.error('Failed to parse %r regexp because %s' %
-                        (search, as_unicode(e)))
+                self.log.error(f'Failed to parse {search!r} regexp because {as_unicode(e)}')
 
         # search / replace using the sr?_search / sr?_replace options
         for i in range(1, 4):
@@ -572,9 +571,8 @@ class HTMLPreProcessor:
             except Exception as e:
                 if rule in user_sr_rules:
                     self.log.error(
-                        'User supplied search & replace rule: %s -> %s '
-                        'failed with error: %s, ignoring.'%(
-                            user_sr_rules[rule], rule[1], e))
+                        f'User supplied search & replace rule: {user_sr_rules[rule]} -> {rule[1]} '
+                        f'failed with error: {e}, ignoring.')
                 else:
                     raise
 
@@ -595,10 +593,10 @@ class HTMLPreProcessor:
         # Handle broken XHTML w/ SVG (ugh)
         if 'svg:' in html and SVG_NS not in html:
             html = html.replace(
-                '<html', '<html xmlns:svg="%s"' % SVG_NS, 1)
+                '<html', f'<html xmlns:svg="{SVG_NS}"', 1)
         if 'xlink:' in html and XLINK_NS not in html:
             html = html.replace(
-                '<html', '<html xmlns:xlink="%s"' % XLINK_NS, 1)
+                '<html', f'<html xmlns:xlink="{XLINK_NS}"', 1)
 
         html = XMLDECL_RE.sub('', html)
 

src/calibre/ebooks/conversion/utils.py

@@ -174,7 +174,7 @@ class HeuristicProcessor:
         ]
 
         for word in ITALICIZE_WORDS:
-            html = re.sub(r'(?<=\s|>)' + re.escape(word) + r'(?=\s|<)', '<i>%s</i>' % word, html)
+            html = re.sub(r'(?<=\s|>)' + re.escape(word) + r'(?=\s|<)', f'<i>{word}</i>', html)
 
         search_text = re.sub(r'(?s)<head[^>]*>.*?</head>', '', html)
         search_text = re.sub(r'<[^>]*>', '', search_text)
@@ -183,7 +183,7 @@ class HeuristicProcessor:
                 ital_string = str(match.group('words'))
                 # self.log.debug("italicising "+str(match.group(0))+"    with <i>"+ital_string+"</i>")
                 try:
-                    html = re.sub(re.escape(str(match.group(0))), '<i>%s</i>' % ital_string, html)
+                    html = re.sub(re.escape(str(match.group(0))), f'<i>{ital_string}</i>', html)
                 except OverflowError:
                     # match.group(0) was too large to be compiled into a regex
                     continue
@@ -305,7 +305,7 @@ class HeuristicProcessor:
 
                 chapter_marker = arg_ignorecase+init_lookahead+full_chapter_line+blank_lines+lp_n_lookahead_open+n_lookahead+lp_n_lookahead_close+ \
                     lp_opt_title_open+title_line_open+title_header_open+lp_title+title_header_close+title_line_close+lp_opt_title_close
-                chapdetect = re.compile(r'%s' % chapter_marker)
+                chapdetect = re.compile(rf'{chapter_marker}')
 
                 if analyze:
                     hits = len(chapdetect.findall(html))
@@ -383,9 +383,9 @@ class HeuristicProcessor:
             em_en_unwrap_regex = em_en_lookahead+line_ending+blanklines+line_opening
             shy_unwrap_regex = soft_hyphen+line_ending+blanklines+line_opening
 
-        unwrap = re.compile('%s' % unwrap_regex, re.UNICODE)
-        em_en_unwrap = re.compile('%s' % em_en_unwrap_regex, re.UNICODE)
-        shy_unwrap = re.compile('%s' % shy_unwrap_regex, re.UNICODE)
+        unwrap = re.compile(f'{unwrap_regex}', re.UNICODE)
+        em_en_unwrap = re.compile(f'{em_en_unwrap_regex}', re.UNICODE)
+        shy_unwrap = re.compile(f'{shy_unwrap_regex}', re.UNICODE)
 
         if format == 'txt':
             content = unwrap.sub(' ', content)
@@ -449,7 +449,7 @@ class HeuristicProcessor:
         for i in range(2):
             html = re.sub(r'\s*<span[^>]*>\s*(<span[^>]*>\s*</span>){0,2}\s*</span>\s*', ' ', html)
             html = re.sub(
-                r'\s*{open}\s*({open}\s*{close}\s*){{0,2}}\s*{close}'.format(open=open_fmt_pat, close=close_fmt_pat), ' ', html)
+                rf'\s*{open_fmt_pat}\s*({open_fmt_pat}\s*{close_fmt_pat}\s*){{0,2}}\s*{close_fmt_pat}', ' ', html)
         # delete surrounding divs from empty paragraphs
         html = re.sub(r'<div[^>]*>\s*<p[^>]*>\s*</p>\s*</div>', '<p> </p>', html)
         # Empty heading tags
@@ -560,7 +560,7 @@ class HeuristicProcessor:
         line_two = '(?P<line_two>'+re.sub(r'(ou|in|cha)', 'linetwo_', self.line_open)+ \
                      r'\s*(?P<line_two_content>.*?)'+re.sub(r'(ou|in|cha)', 'linetwo_', self.line_close)+')'
         div_break_candidate_pattern = line+r'\s*<div[^>]*>\s*</div>\s*'+line_two
-        div_break_candidate = re.compile(r'%s' % div_break_candidate_pattern, re.IGNORECASE|re.UNICODE)
+        div_break_candidate = re.compile(rf'{div_break_candidate_pattern}', re.IGNORECASE|re.UNICODE)
 
         def convert_div_softbreaks(match):
             init_is_paragraph = self.check_paragraph(match.group('init_content'))
@@ -583,7 +583,7 @@ class HeuristicProcessor:
     def detect_scene_breaks(self, html):
         scene_break_regex = self.line_open+'(?!('+self.common_in_text_beginnings+'|.*?'+self.common_in_text_endings+ \
                                              r'<))(?P<break>((?P<break_char>((?!\s)\W))\s*(?P=break_char)?){1,10})\s*'+self.line_close
-        scene_breaks = re.compile(r'%s' % scene_break_regex, re.IGNORECASE|re.UNICODE)
+        scene_breaks = re.compile(rf'{scene_break_regex}', re.IGNORECASE|re.UNICODE)
         html = scene_breaks.sub(self.scene_break_open+r'\g<break></p>', html)
         return html
 

src/calibre/ebooks/covers.py

@@ -762,7 +762,7 @@ def test(scale=0.25):
     for r, color in enumerate(sorted(default_color_themes)):
         for c, style in enumerate(sorted(all_styles())):
             mi.series_index = c + 1
-            mi.title = 'An algorithmic cover [%s]' % color
+            mi.title = f'An algorithmic cover [{color}]'
             prefs = override_prefs(cprefs, override_color_theme=color, override_style=style)
             scale_cover(prefs, scale)
             img = generate_cover(mi, prefs=prefs, as_qimage=True)

src/calibre/ebooks/djvu/djvubzzdec.py

@@ -85,7 +85,7 @@ class BZZDecoderError(Exception):
         self.msg = msg
 
     def __str__(self):
-        return 'BZZDecoderError: %s' % (self.msg)
+        return f'BZZDecoderError: {self.msg}'
 
 
 # This table has been designed for the ZPCoder

src/calibre/ebooks/docx/block_styles.py

@@ -39,7 +39,7 @@ inherit = Inherit()
 
 
 def binary_property(parent, name, XPath, get):
-    vals = XPath('./w:%s' % name)(parent)
+    vals = XPath(f'./w:{name}')(parent)
     if not vals:
         return inherit
     val = get(vals[0], 'w:val', 'on')
@@ -108,7 +108,7 @@ border_edges = ('left', 'top', 'right', 'bottom', 'between')
 
 def read_single_border(parent, edge, XPath, get):
     color = style = width = padding = None
-    for elem in XPath('./w:%s' % edge)(parent):
+    for elem in XPath(f'./w:{edge}')(parent):
         c = get(elem, 'w:color')
         if c is not None:
             color = simple_color(c)
@@ -145,20 +145,20 @@ def read_border(parent, dest, XPath, get, border_edges=border_edges, name='pBdr'
 
 
 def border_to_css(edge, style, css):
-    bs = getattr(style, 'border_%s_style' % edge)
-    bc = getattr(style, 'border_%s_color' % edge)
-    bw = getattr(style, 'border_%s_width' % edge)
+    bs = getattr(style, f'border_{edge}_style')
+    bc = getattr(style, f'border_{edge}_color')
+    bw = getattr(style, f'border_{edge}_width')
     if isinstance(bw, numbers.Number):
         # WebKit needs at least 1pt to render borders and 3pt to render double borders
         bw = max(bw, (3 if bs == 'double' else 1))
     if bs is not inherit and bs is not None:
-        css['border-%s-style' % edge] = bs
+        css[f'border-{edge}-style'] = bs
     if bc is not inherit and bc is not None:
-        css['border-%s-color' % edge] = bc
+        css[f'border-{edge}-color'] = bc
     if bw is not inherit and bw is not None:
         if isinstance(bw, numbers.Number):
-            bw = '%.3gpt' % bw
-        css['border-%s-width' % edge] = bw
+            bw = f'{bw:.3g}pt'
+        css[f'border-{edge}-width'] = bw
 
 
 def read_indent(parent, dest, XPath, get):
@@ -305,12 +305,12 @@ class Frame:
         else:
             if self.h_rule != 'auto':
                 t = 'min-height' if self.h_rule == 'atLeast' else 'height'
-                ans[t] = '%.3gpt' % self.h
+                ans[t] = f'{self.h:.3g}pt'
             if self.w is not None:
-                ans['width'] = '%.3gpt' % self.w
-            ans['padding-top'] = ans['padding-bottom'] = '%.3gpt' % self.v_space
+                ans['width'] = f'{self.w:.3g}pt'
+            ans['padding-top'] = ans['padding-bottom'] = f'{self.v_space:.3g}pt'
             if self.wrap not in {None, 'none'}:
-                ans['padding-left'] = ans['padding-right'] = '%.3gpt' % self.h_space
+                ans['padding-left'] = ans['padding-right'] = f'{self.h_space:.3g}pt'
                 if self.x_align is None:
                     fl = 'left' if self.x/page.width < 0.5 else 'right'
                 else:
@@ -412,12 +412,12 @@ class ParagraphStyle:
                 c['page-break-after'] = 'avoid'
             for edge in ('left', 'top', 'right', 'bottom'):
                 border_to_css(edge, self, c)
-                val = getattr(self, 'padding_%s' % edge)
+                val = getattr(self, f'padding_{edge}')
                 if val is not inherit:
-                    c['padding-%s' % edge] = '%.3gpt' % val
-                val = getattr(self, 'margin_%s' % edge)
+                    c[f'padding-{edge}'] = f'{val:.3g}pt'
+                val = getattr(self, f'margin_{edge}')
                 if val is not inherit:
-                    c['margin-%s' % edge] = val
+                    c[f'margin-{edge}'] = val
 
             if self.line_height not in {inherit, '1'}:
                 c['line-height'] = self.line_height
@@ -426,7 +426,7 @@ class ParagraphStyle:
                 val = getattr(self, x)
                 if val is not inherit:
                     if x == 'font_size':
-                        val = '%.3gpt' % val
+                        val = f'{val:.3g}pt'
                     c[x.replace('_', '-')] = val
             ta = self.text_align
             if ta is not inherit:
@@ -465,11 +465,11 @@ class ParagraphStyle:
 
     def apply_between_border(self):
         for prop in ('width', 'color', 'style'):
-            setattr(self, 'border_bottom_%s' % prop, getattr(self, 'border_between_%s' % prop))
+            setattr(self, f'border_bottom_{prop}', getattr(self, f'border_between_{prop}'))
 
     def has_visible_border(self):
         for edge in border_edges[:-1]:
-            bw, bs = getattr(self, 'border_%s_width' % edge), getattr(self, 'border_%s_style' % edge)
+            bw, bs = getattr(self, f'border_{edge}_width'), getattr(self, f'border_{edge}_style')
             if bw is not inherit and bw and bs is not inherit and bs != 'none':
                 return True
         return False

src/calibre/ebooks/docx/char_styles.py

@@ -149,7 +149,7 @@ def read_font(parent, dest, XPath, get):
     for col in XPath('./w:rFonts')(parent):
         val = get(col, 'w:asciiTheme')
         if val:
-            val = '|%s|' % val
+            val = f'|{val}|'
         else:
             val = get(col, 'w:ascii')
         if val:
@@ -168,7 +168,7 @@ def read_font_cs(parent, dest, XPath, get):
     for col in XPath('./w:rFonts')(parent):
         val = get(col, 'w:csTheme')
         if val:
-            val = '|%s|' % val
+            val = f'|{val}|'
         else:
             val = get(col, 'w:cs')
         if val:
@@ -248,9 +248,9 @@ class RunStyle:
         for x in ('color', 'style', 'width'):
             val = getattr(self, 'border_'+x)
             if x == 'width' and val is not inherit:
-                val = '%.3gpt' % val
+                val = f'{val:.3g}pt'
             if val is not inherit:
-                ans['border-%s' % x] = val
+                ans[f'border-{x}'] = val
 
     def clear_border_css(self):
         for x in ('color', 'style', 'width'):
@@ -282,7 +282,7 @@ class RunStyle:
 
             self.get_border_css(c)
             if self.padding is not inherit:
-                c['padding'] = '%.3gpt' % self.padding
+                c['padding'] = f'{self.padding:.3g}pt'
 
             for x in ('color', 'background_color'):
                 val = getattr(self, x)
@@ -292,10 +292,10 @@ class RunStyle:
             for x in ('letter_spacing', 'font_size'):
                 val = getattr(self, x)
                 if val is not inherit:
-                    c[x.replace('_', '-')] = '%.3gpt' % val
+                    c[x.replace('_', '-')] = f'{val:.3g}pt'
 
             if self.position is not inherit:
-                c['vertical-align'] = '%.3gpt' % self.position
+                c['vertical-align'] = f'{self.position:.3g}pt'
 
             if self.highlight is not inherit and self.highlight != 'transparent':
                 c['background-color'] = self.highlight

src/calibre/ebooks/docx/cleanup.py

@@ -127,7 +127,7 @@ def cleanup_markup(log, root, styles, dest_dir, detect_cover, XPath, uuid):
                 span[-1].tail = '\xa0'
 
     # Move <hr>s outside paragraphs, if possible.
-    pancestor = XPath('|'.join('ancestor::%s[1]' % x for x in ('p', 'h1', 'h2', 'h3', 'h4', 'h5', 'h6')))
+    pancestor = XPath('|'.join(f'ancestor::{x}[1]' for x in ('p', 'h1', 'h2', 'h3', 'h4', 'h5', 'h6')))
     for hr in root.xpath('//span/hr'):
         p = pancestor(hr)
         if p:
@@ -156,7 +156,7 @@ def cleanup_markup(log, root, styles, dest_dir, detect_cover, XPath, uuid):
     # Process dir attributes
     class_map = dict(itervalues(styles.classes))
     parents = ('p', 'div') + tuple('h%d' % i for i in range(1, 7))
-    for parent in root.xpath('//*[(%s)]' % ' or '.join('name()="%s"' % t for t in parents)):
+    for parent in root.xpath('//*[({})]'.format(' or '.join(f'name()="{t}"' for t in parents))):
         # Ensure that children of rtl parents that are not rtl have an
         # explicit dir set. Also, remove dir from children if it is the same as
         # that of the parent.
@@ -172,7 +172,7 @@ def cleanup_markup(log, root, styles, dest_dir, detect_cover, XPath, uuid):
 
     # Remove unnecessary span tags that are the only child of a parent block
     # element
-    for parent in root.xpath('//*[(%s) and count(span)=1]' % ' or '.join('name()="%s"' % t for t in parents)):
+    for parent in root.xpath('//*[({}) and count(span)=1]'.format(' or '.join(f'name()="{t}"' for t in parents))):
         if len(parent) == 1 and not parent.text and not parent[0].tail and not parent[0].get('id', None):
             # We have a block whose contents are entirely enclosed in a <span>
             span = parent[0]

src/calibre/ebooks/docx/container.py

@@ -137,7 +137,7 @@ class DOCX:
         try:
             raw = self.read('[Content_Types].xml')
         except KeyError:
-            raise InvalidDOCX('The file %s docx file has no [Content_Types].xml' % self.name)
+            raise InvalidDOCX(f'The file {self.name} docx file has no [Content_Types].xml')
         root = fromstring(raw)
         self.content_types = {}
         self.default_content_types = {}
@@ -159,7 +159,7 @@ class DOCX:
         try:
             raw = self.read('_rels/.rels')
         except KeyError:
-            raise InvalidDOCX('The file %s docx file has no _rels/.rels' % self.name)
+            raise InvalidDOCX(f'The file {self.name} docx file has no _rels/.rels')
         root = fromstring(raw)
         self.relationships = {}
         self.relationships_rmap = {}
@@ -177,7 +177,7 @@ class DOCX:
         if name is None:
             names = tuple(n for n in self.names if n == 'document.xml' or n.endswith('/document.xml'))
             if not names:
-                raise InvalidDOCX('The file %s docx file has no main document' % self.name)
+                raise InvalidDOCX(f'The file {self.name} docx file has no main document')
             name = names[0]
         return name
 

src/calibre/ebooks/docx/fields.py

@@ -145,11 +145,11 @@ class Fields:
         field_types = ('hyperlink', 'xe', 'index', 'ref', 'noteref')
         parsers = {x.upper():getattr(self, 'parse_'+x) for x in field_types}
         parsers.update({x:getattr(self, 'parse_'+x) for x in field_types})
-        field_parsers = {f.upper():globals()['parse_%s' % f] for f in field_types}
-        field_parsers.update({f:globals()['parse_%s' % f] for f in field_types})
+        field_parsers = {f.upper():globals()[f'parse_{f}'] for f in field_types}
+        field_parsers.update({f:globals()[f'parse_{f}'] for f in field_types})
 
         for f in field_types:
-            setattr(self, '%s_fields' % f, [])
+            setattr(self, f'{f}_fields', [])
         unknown_fields = {'TOC', 'toc', 'PAGEREF', 'pageref'}  # The TOC and PAGEREF fields are handled separately
 
         for field in self.fields:
@@ -159,7 +159,7 @@ class Fields:
                 if func is not None:
                     func(field, field_parsers[field.name], log)
                 elif field.name not in unknown_fields:
-                    log.warn('Encountered unknown field: %s, ignoring it.' % field.name)
+                    log.warn(f'Encountered unknown field: {field.name}, ignoring it.')
                     unknown_fields.add(field.name)
 
     def get_runs(self, field):

src/calibre/ebooks/docx/fonts.py

@@ -64,7 +64,7 @@ class Family:
 
         self.embedded = {}
         for x in ('Regular', 'Bold', 'Italic', 'BoldItalic'):
-            for y in XPath('./w:embed%s[@r:id]' % x)(elem):
+            for y in XPath(f'./w:embed{x}[@r:id]')(elem):
                 rid = get(y, 'r:id')
                 key = get(y, 'w:fontKey')
                 subsetted = get(y, 'w:subsetted') in {'1', 'true', 'on'}
@@ -166,14 +166,14 @@ class Fonts:
                     os.mkdir(dest_dir)
                 fname = self.write(name, dest_dir, docx, variant)
                 if fname is not None:
-                    d = {'font-family':'"%s"' % name.replace('"', ''), 'src': 'url("fonts/%s")' % fname}
+                    d = {'font-family':'"{}"'.format(name.replace('"', '')), 'src': f'url("fonts/{fname}")'}
                     if 'Bold' in variant:
                         d['font-weight'] = 'bold'
                     if 'Italic' in variant:
                         d['font-style'] = 'italic'
                     d = [f'{k}: {v}' for k, v in iteritems(d)]
                     d = ';\n\t'.join(d)
-                    defs.append('@font-face {\n\t%s\n}\n' % d)
+                    defs.append(f'@font-face {{\n\t{d}\n}}\n')
         return '\n'.join(defs)
 
     def write(self, name, dest_dir, docx, variant):