add null check before updateresultmanifest

Author: taooceros

Flow.Launcher.Core/Plugin/PluginManager.cs

@@ -183,6 +183,8 @@ public static async Task<List<Result>> QueryForPlugin(PluginPair pair, Query que
                         throw new ArgumentOutOfRangeException();
                 }
                 token.ThrowIfCancellationRequested();
+                if (results == null)
+                    return results;
                 UpdatePluginMetadata(results, metadata, query);
 
                 metadata.QueryCount += 1;

Flow.Launcher/ViewModel/MainViewModel.cs

@@ -363,7 +363,7 @@ private void QueryContextMenu()
                             }
 
                             if (!match.IsSearchPrecisionScoreMet()) return false;
-                            
+
                             r.Score = match.Score;
                             return true;
 
@@ -512,7 +512,7 @@ async Task QueryTask(PluginPair plugin)
                         await Task.Yield();
 
                         var results = await PluginManager.QueryForPlugin(plugin, query, currentCancellationToken);
-                        if (!currentCancellationToken.IsCancellationRequested)
+                        if (!currentCancellationToken.IsCancellationRequested && results != null)
                             _resultsUpdateQueue.Post(new ResultsForUpdate(results, plugin.Metadata, query,
                                 currentCancellationToken));
                     }