Fix error on clicking previous button for the first time (#573)

* merge master (#1)

* Translated using Weblate (Silesian)

Currently translated at 100.0% (321 of 321 strings)

Translation: Music/Music
Translate-URL: https://l10n.elementary.io/projects/music/music/szl/

* Translated using Weblate (Silesian)

Currently translated at 2.2% (1 of 45 strings)

Translation: Music/Music (Extra)
Translate-URL: https://l10n.elementary.io/projects/music/extra/szl/

* Specify ver 10.17.0 for node_js (#572)

* Enable playback buttons on startup if media is available (#571)

* Enable playback buttons on startup if media is available

* Fix error on play_media at startup

Co-authored-by: Jeremy Wootten <[email protected]>

Co-authored-by: gkkulik <[email protected]>
Co-authored-by: Jeremy Wootten <[email protected]>

* Fix error on clicking previous button for the first time

Co-authored-by: gkkulik <[email protected]>
Co-authored-by: Jeremy Wootten <[email protected]>

Author: 3 people

src/PlaybackManager.vala

@@ -433,6 +433,10 @@ public class Music.PlaybackManager : Object {
         } else {
             _playing_queued_song = false;
 
+            if (_current.is_empty) {
+                queue_media (library.get_medias ());
+            }
+
             if (current_media == null) {
                 _current_index = _current.size - 1;
                 rv = _current.get (_current_index);
@@ -461,8 +465,6 @@ public class Music.PlaybackManager : Object {
 
                 rv = _current.get (_current_index);
             } else {
-                queue_media (library.get_medias ());
-
                 _current_index = _current.size - 1;
                 rv = _current.get (_current_index);
             }