Add more high level exception handling

The async void responsible for refreshing the inspection results now has a to level exception handler swallowing all exceptions. This is necessary since bubbling out of there will likely take down the host.

Moreover, we now log and swallow COM exceptions coming from the process of changing the status label of the refresh button. This means that COM registration issues for the command bar controls will no abort  the calling process. The only effect will be that the label does not change.

Author: MDoerner

Rubberduck.Core/UI/Command/MenuItems/CommandBars/RubberduckCommandBar.cs

@@ -2,6 +2,7 @@
 using System.Collections.Generic;
 using System.Globalization;
 using System.Linq;
+using System.Runtime.InteropServices;
 using Rubberduck.Resources;
 using Rubberduck.Parsing;
 using Rubberduck.Parsing.Symbols;
@@ -99,30 +100,49 @@ public void SetStatusLabelCaption(ParserState state, int? errorCount = null)
 
         private void SetStatusLabelCaption(string caption, int? errorCount = null)
         {
-            var reparseCommandButton = FindChildByTag(typeof(ReparseCommandMenuItem).FullName) as ReparseCommandMenuItem;
-            if (reparseCommandButton == null) { return; }
-
-            var showErrorsCommandButton = FindChildByTag(typeof(ShowParserErrorsCommandMenuItem).FullName) as ShowParserErrorsCommandMenuItem;
-            if (showErrorsCommandButton == null) { return; }
-
-            _uiDispatcher.Invoke(() =>
+            //This try-catch block guarantees that problems with the COM registration of the command bar classes
+            //only affect the status label text instead of aborting the status change or even crashing the host.
+            //See issue #5349 at https://github.com/rubberduck-vba/Rubberduck/issues/5349
+            try
             {
-                try
+                var reparseCommandButton =
+                    FindChildByTag(typeof(ReparseCommandMenuItem).FullName) as ReparseCommandMenuItem;
+                if (reparseCommandButton == null)
                 {
-                    reparseCommandButton.SetCaption(caption);
-                    reparseCommandButton.SetToolTip(string.Format(RubberduckUI.ReparseToolTipText, caption));
-                    if (errorCount.HasValue && errorCount.Value > 0)
-                    {
-                        showErrorsCommandButton.SetToolTip(
-                            string.Format(RubberduckUI.ParserErrorToolTipText, errorCount.Value));
-                    }
+                    return;
                 }
-                catch (Exception exception)
+
+                var showErrorsCommandButton =
+                    FindChildByTag(typeof(ShowParserErrorsCommandMenuItem).FullName) as ShowParserErrorsCommandMenuItem;
+                if (showErrorsCommandButton == null)
                 {
-                    Logger.Error(exception, "Exception thrown trying to set the status label caption on the UI thread.");
+                    return;
                 }
-            });
-            Localize();
+
+                _uiDispatcher.Invoke(() =>
+                {
+                    try
+                    {
+                        reparseCommandButton.SetCaption(caption);
+                        reparseCommandButton.SetToolTip(string.Format(RubberduckUI.ReparseToolTipText, caption));
+                        if (errorCount.HasValue && errorCount.Value > 0)
+                        {
+                            showErrorsCommandButton.SetToolTip(
+                                string.Format(RubberduckUI.ParserErrorToolTipText, errorCount.Value));
+                        }
+                    }
+                    catch (Exception exception)
+                    {
+                        Logger.Error(exception,
+                            "Exception thrown trying to set the status label caption on the UI thread.");
+                    }
+                });
+                Localize();
+            }
+            catch (COMException exception)
+            {
+                Logger.Error(exception, "COMException thrown trying to set the status label caption.");
+            }
         }
 
         private void SetContextSelectionCaption(string caption, int contextReferenceCount, string description)

Rubberduck.Core/UI/Inspections/InspectionResultsViewModel.cs

@@ -428,6 +428,20 @@ private void HandleStateChanged(object sender, ParserStateEventArgs e)
         }
 
         private async void RefreshInspections(CancellationToken token)
+        {
+            //We have to catch all exceptions here since this method is a fire-and-forget async action.
+            //Accordingly, any exception bubbling out of this method will likely take down the runtime and, thus, crash the host.
+            try
+            {
+                await RefreshInspections_Internal(token);
+            }
+            catch (Exception ex)
+            {
+                Logger.Error(ex,"Unhandled exception when refreshing inspection results.");
+            }
+        }
+
+        private async Task RefreshInspections_Internal(CancellationToken token)
         {
             var stopwatch = Stopwatch.StartNew();
             IsBusy = true;