[gnome-music/wip/mschraal/artistsview-empty-selection-crash] artistsview: Fix crash on empty selection

[Marinus Schraal <mschraal src gnome org>]

commit 404211c8f8e2e4dfde08573c0d38da143c4b8c63
Author: Marinus Schraal <mschraal gnome org>
Date:   Wed Feb 2 11:38:35 2022 +0100

    artistsview: Fix crash on empty selection
    
    Check if there is anything to select first.
    
    Fixes: #492

 gnomemusic/views/artistsview.py | 6 ++++++
 1 file changed, 6 insertions(+)
---
diff --git a/gnomemusic/views/artistsview.py b/gnomemusic/views/artistsview.py
index f3e1d0640..a132241d2 100644
--- a/gnomemusic/views/artistsview.py
+++ b/gnomemusic/views/artistsview.py
@@ -215,11 +215,17 @@ class ArtistsView(Gtk.Paned):
             self._selected_artist = None
 
     def select_all(self):
+        if self._model.get_n_items() == 0:
+            return
+
         artist_albums = self._artist_view.get_visible_child().get_child()
         for row in artist_albums:
             row.get_child().select_all()
 
     def deselect_all(self):
+        if self._model.get_n_items() == 0:
+            return
+
         artist_albums = self._artist_view.get_visible_child().get_child()
         for row in artist_albums:
             row.get_child().deselect_all()