Navidrome: pin music-folder selection by id, not name (survives renames)

Follow-up hardening to #789. The selection was keyed purely by folder name,
so renaming a music folder in Navidrome silently reverted the scan to all
libraries. Now persist the folder id (stable across renames) as the primary
key alongside the name (kept for display + back-compat), and restore by id
first with a name fallback. Self-heals on reconnect: pre-id installs and
drifted/renamed names get the id + fresh name written back, so the settings
dropdown keeps highlighting the right folder.

Tests: restore-by-id-after-rename (+ name heal), name-fallback self-heals id,
no-drift writes nothing.

core/navidrome_client.py

@@ -224,7 +224,10 @@ class NavidromeClient(MediaServerClient):
                     logger.info(f"Set music folder to: {folder_name} (ID: {self.music_folder_id})")
                     from database.music_database import MusicDatabase
                     db = MusicDatabase()
+                    # Persist the id (stable across renames) as the primary key,
+                    # keep the name for display + back-compat fallback.
                     db.set_preference('navidrome_music_folder', folder_name)
+                    db.set_preference('navidrome_music_folder_id', folder['key'])
                     return True
             # If folder_name is empty, clear the selection
             if not folder_name:
@@ -233,6 +236,7 @@ class NavidromeClient(MediaServerClient):
                 from database.music_database import MusicDatabase
                 db = MusicDatabase()
                 db.set_preference('navidrome_music_folder', '')
+                db.set_preference('navidrome_music_folder_id', '')
                 logger.info("Cleared music folder selection — will use all libraries")
                 return True
             logger.warning(f"Music folder '{folder_name}' not found")
@@ -284,18 +288,35 @@ class NavidromeClient(MediaServerClient):
                 try:
                     from database.music_database import MusicDatabase
                     db = MusicDatabase()
+                    saved_id = db.get_preference('navidrome_music_folder_id')
                     saved_folder = db.get_preference('navidrome_music_folder')
-                    if saved_folder:
+                    if saved_id or saved_folder:
                         # Use the non-reentrant fetch: we're still inside
                         # ensure_connection() here (_is_connecting=True), so the
                         # public get_music_folders() would re-enter the guard and
                         # return [], silently dropping the saved selection.
                         folders = self._fetch_music_folders()
-                        for folder in folders:
+                        # Match by id first (stable across renames in Navidrome);
-                            if folder['title'] == saved_folder:
+                        # fall back to name for installs saved before the id was
-                                self.music_folder_id = folder['key']
+                        # persisted.
-                                logger.info(f"Restored music folder preference: {saved_folder} (ID: {self.music_folder_id})")
+                        matched = None
-                                break
+                        if saved_id:
+                            matched = next((f for f in folders if f['key'] == str(saved_id)), None)
+                        if matched is None and saved_folder:
+                            matched = next((f for f in folders if f['title'] == saved_folder), None)
+                        if matched is not None:
+                            self.music_folder_id = matched['key']
+                            logger.info(f"Restored music folder preference: {matched['title']} (ID: {self.music_folder_id})")
+                            # Self-heal drifted prefs: a pre-id install (no saved
+                            # id) or a folder renamed in Navidrome (stale name).
+                            # id stays the durable key; name is kept fresh so the
+                            # settings dropdown highlights the right option.
+                            if str(saved_id or '') != matched['key'] or (saved_folder or '') != matched['title']:
+                                try:
+                                    db.set_preference('navidrome_music_folder_id', matched['key'])
+                                    db.set_preference('navidrome_music_folder', matched['title'])
+                                except Exception as heal_err:
+                                    logger.debug(f"Could not self-heal music folder prefs: {heal_err}")
                 except Exception as e:
                     logger.warning(f"Could not restore music folder preference: {e}")
             else:

tests/media_server/test_navidrome_pinning.py

@@ -97,33 +97,62 @@ def test_fetch_music_folders_parses_without_ensure_connection(nav_client):
     ]
 
 
+def _fake_request(endpoint, params=None):
+    if endpoint == 'ping':
+        return {'status': 'ok', 'version': '1.16.1'}
+    if endpoint == 'getMusicFolders':
+        return {'musicFolders': {'musicFolder': [
+            {'id': 1, 'name': 'Music'},
+            {'id': 2, 'name': 'Audiobooks'},
+        ]}}
+    return None
+
+
+def _prefs(values):
+    """A MusicDatabase mock whose get_preference reads from `values`."""
+    db = MagicMock()
+    db.get_preference.side_effect = lambda key, *a, **k: values.get(key)
+    return db
+
+
+def _connect_with(nav_client, fake_db):
+    with patch('core.navidrome_client.config_manager.get_navidrome_config',
+               return_value={'base_url': 'http://nav', 'username': 'u', 'password': 'p'}), \
+         patch('database.music_database.MusicDatabase', return_value=fake_db), \
+         patch.object(nav_client, '_make_request', side_effect=_fake_request):
+        assert nav_client.ensure_connection() is True
+
+
 def test_setup_client_restores_saved_music_folder(nav_client):
     """Regression for #789: a saved music-folder selection must survive
     _setup_client. The restore runs while still inside ensure_connection()
     (_is_connecting=True); the old code called the public get_music_folders(),
     which re-entered the guard, got [], and left music_folder_id=None — so
     every scan imported all libraries regardless of the user's selection."""
-    def fake_request(endpoint, params=None):
+    fake_db = _prefs({'navidrome_music_folder_id': '2', 'navidrome_music_folder': 'Audiobooks'})
-        if endpoint == 'ping':
+    _connect_with(nav_client, fake_db)
-            return {'status': 'ok', 'version': '1.16.1'}
-        if endpoint == 'getMusicFolders':
-            return {'musicFolders': {'musicFolder': [
-                {'id': 1, 'name': 'Music'},
-                {'id': 2, 'name': 'Audiobooks'},
-            ]}}
-        return None
-
-    fake_db = MagicMock()
-    fake_db.get_preference.return_value = 'Audiobooks'
-
-    with patch('core.navidrome_client.config_manager.get_navidrome_config',
-               return_value={'base_url': 'http://nav', 'username': 'u', 'password': 'p'}), \
-         patch('database.music_database.MusicDatabase', return_value=fake_db), \
-         patch.object(nav_client, '_make_request', side_effect=fake_request):
-        assert nav_client.ensure_connection() is True
-
-    # Selection ('Audiobooks') was restored to its folder id, not left None.
     assert nav_client.music_folder_id == '2'
+    # Nothing drifted → no self-heal writes.
+    fake_db.set_preference.assert_not_called()
+
+
+def test_setup_client_restores_by_id_after_folder_rename(nav_client):
+    """Hardening: the id is the primary key, so a folder renamed in Navidrome
+    (stored name no longer matches its title) still resolves by id — and the
+    stale name is healed so the settings dropdown stays correct."""
+    fake_db = _prefs({'navidrome_music_folder_id': '2', 'navidrome_music_folder': 'Old Stale Name'})
+    _connect_with(nav_client, fake_db)
+    assert nav_client.music_folder_id == '2'
+    fake_db.set_preference.assert_any_call('navidrome_music_folder', 'Audiobooks')
+
+
+def test_setup_client_name_fallback_self_heals_id(nav_client):
+    """Back-compat: installs saved before the id was persisted match by name,
+    and the id is written back so a later rename can't break the match."""
+    fake_db = _prefs({'navidrome_music_folder_id': None, 'navidrome_music_folder': 'Audiobooks'})
+    _connect_with(nav_client, fake_db)
+    assert nav_client.music_folder_id == '2'
+    fake_db.set_preference.assert_any_call('navidrome_music_folder_id', '2')
 
 
 def test_navidrome_album_exposes_cover_art_url(nav_client):