Delete notes when deleting a custom column

Also change the data dir name

src/calibre/db/backend.py

@@ -680,11 +680,11 @@ class DB:
 
     def initialize_custom_columns(self):  # {{{
         self.custom_columns_deleted = False
+        self.deleted_fields = []
         with self.conn:
             # Delete previously marked custom columns
-            for record in self.conn.get(
+            for (num, label) in self.conn.get(
-                    'SELECT id FROM custom_columns WHERE mark_for_delete=1'):
+                    'SELECT id,label FROM custom_columns WHERE mark_for_delete=1'):
-                num = record[0]
                 table, lt = self.custom_table_names(num)
                 self.execute('''\
                         DROP INDEX   IF EXISTS {table}_idx;
@@ -703,6 +703,7 @@ class DB:
                         '''.format(table=table, lt=lt)
                 )
                 self.prefs.set('update_all_last_mod_dates_on_start', True)
+                self.deleted_fields.append('#'+label)
             self.execute('DELETE FROM custom_columns WHERE mark_for_delete=1')
 
         # Load metadata for custom columns

src/calibre/db/constants.py

@@ -8,7 +8,7 @@ COVER_FILE_NAME = 'cover.jpg'
 METADATA_FILE_NAME = 'metadata.opf'
 DEFAULT_TRASH_EXPIRY_TIME_SECONDS = 14 * 86400
 TRASH_DIR_NAME =  '.caltrash'
-NOTES_DIR_NAME = '.notes'
+NOTES_DIR_NAME = '.calnotes'
 DATA_DIR_NAME = 'data'
 DATA_FILE_PATTERN = f'{DATA_DIR_NAME}/**/*'
 BOOK_ID_PATH_TEMPLATE = ' ({})'

src/calibre/db/notes/connect.py

@@ -87,6 +87,22 @@ class Notes:
             )
         SchemaUpgrade(conn, '\n'.join(triggers))
         conn.notes_dbpath = dbpath
+        for cat in backend.deleted_fields:
+            self.delete_field(conn, cat)
+
+    def delete_field(self, conn, field_name):
+        note_ids = conn.get('SELECT id from notes_db.notes WHERE colname=?', (field_name,))
+        if note_ids:
+            conn.execute(
+                'DELETE FROM notes_db.notes_resources_link WHERE note IN (SELECT id FROM notes_db.notes WHERE colname=?)', (field_name,)
+            )
+            conn.execute('DELETE FROM notes_db.notes WHERE colname=?', (field_name,))
+            self.remove_unreferenced_resources(conn)
+
+    def remove_unreferenced_resources(self, conn):
+        for (rhash,) in conn.get('SELECT hash FROM notes_db.resources WHERE id NOT IN (SELECT resource FROM notes_db.notes_resources_link)'):
+            remove_with_retry(self.path_for_resource(conn, rhash))
+        conn.execute('DELETE FROM notes_db.resources WHERE id NOT IN (SELECT resource FROM notes_db.notes_resources_link)')
 
     def path_for_resource(self, conn, resource_hash_or_resource_id: Union[str,int]) -> str:
         if isinstance(resource_hash_or_resource_id, str):
@@ -162,7 +178,7 @@ class Notes:
             if x.startswith('res-'):
                 rname = x.split('-', 1)[1]
                 with open(os.path.join(srcdir, x), 'rb') as rsrc:
-                    resources.add(self.add_resource(conn, rsrc, rname))
+                    resources.add(self.add_resource(conn, rsrc, rname, update_name=False))
         note_id = self.set_note(conn, field_name, item_id, item_value, marked_up_text, resources, searchable_text)
         if note_id > -1:
             remove_with_retry(srcdir, is_dir=True)
@@ -242,7 +258,7 @@ class Notes:
             for path in items[:extra]:
                 remove_with_retry(path, is_dir=True)
 
-    def add_resource(self, conn, path_or_stream_or_data, name):
+    def add_resource(self, conn, path_or_stream_or_data, name, update_name=True):
         if isinstance(path_or_stream_or_data, bytes):
             data = path_or_stream_or_data
         elif isinstance(path_or_stream_or_data, str):
@@ -271,7 +287,7 @@ class Notes:
         base_name, ext = os.path.splitext(name)
         c = 0
         for (resource_id, existing_name) in conn.execute('SELECT id,name FROM notes_db.resources WHERE hash=?', (resource_hash,)):
-            if existing_name != name:
+            if existing_name != name and update_name:
                 while True:
                     try:
                         conn.execute('UPDATE notes_db.resources SET name=? WHERE id=?', (name, resource_id))

src/calibre/db/tests/notes.py

@@ -87,6 +87,19 @@ def test_cache_api(self: 'NotesTest'):
     self.ae(cache.get_notes_resource(h1)['data'], b'resource1')
     self.ae(cache.get_notes_resource(h2)['data'], b'resource2')
     self.assertFalse(os.listdir(notes.retired_dir))
+    # test delete custom column with notes
+    tags = cache.field_for('#tags', 1)
+    tag_id = cache.get_item_id('#tags', tags[0])
+    h1 = cache.add_notes_resource(b'resource1t', 'r1.jpg')
+    h2 = cache.add_notes_resource(b'resource2t', 'r1.jpg')
+    cache.set_notes_for('#tags', tag_id, doc, resource_ids=(h1, h2))
+    self.ae(cache.notes_for('#tags', tag_id), doc)
+    cache.delete_custom_column('tags')
+    cache.close()
+    cache = self.init_cache(cache.backend.library_path)
+    self.ae(cache.notes_for('#tags', tag_id), '')
+    self.assertIsNone(cache.get_notes_resource(h1))
+    self.assertIsNone(cache.get_notes_resource(h2))
 
 
 def test_fts(self: 'NotesTest'):