Fix RepoObjectsTree (left panel) remaining blank when ReloadAsync is …

[amaiorano]

…cancelled (e.g. by spamming refresh)

Problem is that if during ReloadAsync, a System.OperationCanceledException is thrown due to cancellation, we cannot use token anymore in the finally block to switch to main thread. Doing so causes another exception to be thrown, and we never end up executing the code below, which includes "treeMain.EndUpdate()" required to restore rendering of the tree view.

Fixes #5778

[amaiorano]

This is to fix #5778. I think this is the right fix - not to use 'token' after CancellationException is thrown.

[codecov]

Codecov Report

Merging #5779 into master will decrease coverage by <.01%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master    #5779      +/-   ##
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- Coverage   36.95%   36.94%   -0.01%     
==========================================
  Files         619      619              
  Lines       47403    47404       +1     
  Branches     6320     6321       +1     
==========================================
- Hits        17519    17515       -4     
- Misses      29106    29108       +2     
- Partials      778      781       +3

[amaiorano]

Amended the commit with your suggeston @RussKie

[jbialobr]

The token protection has to only be excluded for EndUpdate the rest has to remain unchanged.

        public async Task ReloadAsync()
        {
            var currentBranch = Module.GetSelectedBranch();
            await this.SwitchToMainThreadAsync();

            var token = CancelBackgroundTasks();
            Enabled = false;

            try
            {
                treeMain.BeginUpdate();
                var tasks = _rootNodes.Select(r => r.ReloadAsync(token)).ToArray();
                await Task.WhenAll(tasks).ConfigureAwait(false);
            }
            finally
            {
                await this.SwitchToMainThreadAsync();
                if (!token.IsCancellationRequested)
                {
                    Enabled = true;
                    var selectedNode = treeMain.AllNodes().FirstOrDefault(n =>
                        _rootNodes.Any(rn => $"{rn.TreeViewNode.FullPath}{treeMain.PathSeparator}{currentBranch}" == n.FullPath));
                    if (selectedNode != null)
                    {
                        _rootNodes.ForEach(t => t.IgnoreSelectionChangedEvent = true);
                        treeMain.SelectedNode = selectedNode;
                        _rootNodes.ForEach(t => t.IgnoreSelectionChangedEvent = false);
                        treeMain.SelectedNode.EnsureVisible();
                    }
                }

                treeMain.EndUpdate();
            }
        }

[amaiorano]

Yes, that makes sense @jbialobr. At first I wondered if we should include Enabled = true next to treeMain.EndUpdate, but I suppose it's fine since cancelling means another update is in flight. So during the time between cancelling and the next update, we'll see the tree's contents disabled. I'll upload an amendment with this version.

Edit: @jbialobr the code I will upload is slightly different from yours - I think you had an older version of this function that you modified? Anyway, you'll see the diff.

[RussKie]

Thank you all