Fix moving libraries via calibre leaving behind a copy of the metadata_db_prefs_backup.json file in the original library folder

src/calibre/db/backend.py

@@ -1669,7 +1669,7 @@ class DB(object):
     def move_library_to(self, all_paths, newloc, progress=lambda x: x):
         if not os.path.exists(newloc):
             os.makedirs(newloc)
-        old_dirs = set()
+        old_dirs, old_files = set(), set()
         items, path_map = self.get_top_level_move_items(all_paths)
         for x in items:
             src = os.path.join(self.library_path, x)
@@ -1683,13 +1683,14 @@ class DB(object):
                 if os.path.exists(dest):
                     os.remove(dest)
                 shutil.copyfile(src, dest)
+                old_files.add(src)
             x = path_map[x]
             if not isinstance(x, unicode):
                 x = x.decode(filesystem_encoding, 'replace')
             progress(x)
 
         dbpath = os.path.join(newloc, os.path.basename(self.dbpath))
-        opath = self.dbpath
+        opath, odir = self.dbpath, self.library_path
         self.conn.close()
         self.library_path, self.dbpath = newloc, dbpath
         if self._conn is not None:
@@ -1703,7 +1704,16 @@ class DB(object):
         for loc in old_dirs:
             try:
                 shutil.rmtree(loc)
-            except:
+            except EnvironmentError:
+                pass
+        for loc in old_files:
+            try:
+                os.remove(loc)
+            except EnvironmentError:
+                pass
+        try:
+            os.rmdir(odir)
+        except EnvironmentError:
             pass
 
     def restore_book(self, book_id, path, formats):

src/calibre/db/tests/filesystem.py

@@ -108,6 +108,7 @@ class FilesystemTest(BaseTest):
         all_ids = cache.all_book_ids()
         fmt1 = cache.format(1, 'FMT1')
         cov = cache.cover(1)
+        odir = cache.backend.library_path
         with TemporaryDirectory('moved_lib') as tdir:
             cache.move_library_to(tdir)
             self.assertIn('moved_lib', cache.backend.library_path)
@@ -117,6 +118,8 @@ class FilesystemTest(BaseTest):
             cache.reload_from_db()
             self.assertEqual(all_ids, cache.all_book_ids())
             cache.backend.close()
+            self.assertFalse(os.path.exists(odir))
+            os.mkdir(odir)  # needed otherwise tearDown() fails
 
     def test_long_filenames(self):
         ' Test long file names '