Fixed a couple issues with per-server caching

sublime/app.py

@@ -561,7 +561,7 @@ class SublimeMusicApp(Gtk.Application):
         self.loading_state = False
 
         # Update the window according to the new server configuration.
-        self.update_window(force=True)
+        self.update_window()
 
     def on_stack_change(self, stack, child):
         self.state.current_tab = stack.get_visible_child_name()

sublime/cache_manager.py

@@ -86,6 +86,8 @@ class CacheManager(metaclass=Singleton):
 
     @staticmethod
     def calculate_server_hash(server: ServerConfiguration):
+        if server is None:
+            return None
         server_info = (server.name + server.server_address + server.username)
         return hashlib.md5(server_info.encode('utf-8')).hexdigest()[:8]
 
@@ -145,9 +147,8 @@ class CacheManager(metaclass=Singleton):
         def load_cache_info(self):
             cache_meta_file = self.calculate_abs_path('.cache_meta')
 
-            if not cache_meta_file.exists():
-                return
-
+            meta_json = {}
+            if cache_meta_file.exists():
                 with open(cache_meta_file, 'r') as f:
                     try:
                         meta_json = json.load(f)

sublime/ui/albums.py

@@ -291,6 +291,7 @@ class AlbumsGrid(Gtk.Overlay):
     parameters_changed = False
     current_min_size_request = 30
     overshoot_update_in_progress = False
+    server_hash = None
 
     def update_params(
             self,
@@ -383,6 +384,11 @@ class AlbumsGrid(Gtk.Overlay):
             force: bool = False,
             selected_id: str = None,
     ):
+        new_hash = CacheManager.calculate_server_hash(state.config.server)
+        if self.server_hash != new_hash:
+            self.parameters_changed = True
+        self.server_hash = new_hash
+
         self.update_grid(force=force, selected_id=selected_id)
 
         # Update the detail panel.

sublime/ui/artists.py

@@ -251,7 +251,20 @@ class ArtistDetailPanel(Gtk.Box):
     def update(self, state: ApplicationState):
         if state.selected_artist_id is None:
             self.artist_action_buttons.hide()
+            self.artist_id = None
+            self.artist_indicator.set_text('')
+            self.artist_name.set_markup('')
+            self.artist_stats.set_markup('')
+
+            self.artist_bio.set_markup('')
+            self.similar_artists_box.hide()
+
+            self.artist_artwork.set_from_file(None)
+
+            self.albums = []
+            self.albums_list.update(None)
         else:
+            self.artist_action_buttons.show()
             self.update_artist_view(state.selected_artist_id, state=state)
 
     # TODO need to handle when this is force updated. Need to delete a bunch of
@@ -402,6 +415,9 @@ class AlbumsListWithSongs(Gtk.Overlay):
         for c in self.box.get_children():
             self.box.remove(c)
 
+        if artist is None:
+            return
+
         for album in artist.get('album', artist.get('child', [])):
             album_with_songs = AlbumWithSongs(album, show_artist_name=False)
             album_with_songs.connect(