Only brings ErrorListPad to front in case of be loaded in Workbench

[netonjm]

Only brings ErrorListPad to front in case of be loaded in Workbench

Fixes #941969 - [FATAL] System.NullReferenceException exception in MonoDevelop.MacIntegration.MainToolbar.BuildResultsView.MouseDown()

[mrward]

Do we know why the ErrorPad is null here?

It reminds me of that other null reference exception where the ErrorPad is null when this should not be possible since it is part of MonoDevelop.Ide.

[Therzok]

Looking at WrapPad:
http://source.monodevelop.com/#MonoDevelop.Ide/MonoDevelop.Ide.Gui/Workbench.cs,28ef42ba3aee7408

It seems that the pad is removed from the list when destroyed.

GetPad<T> goes through Pads which is only constructed once. So it is possible for it to be null because someone destroyed the window (via the x button)

[Therzok]

I'm pretty sure we should be reconstructing the pad if not found.

[netonjm]

Yeah @Therzok, I think it depends on what behaviour we want in case of the user closes the panel (and it's destroyed).

In theory (please correct me if I'm wrong), this brings to the front the pad when build finishes the panel to show the build summary (errors/etc..) then here the question is do want always want to show it even though the user closes it?

For me makes sense as @Therzok says to force open since it is quite valuable information. thoughts @sevoku ?

I'm curious if being destroyed when opening it again will have the information of the finished build

[mrward]

In this case the user has clicked the error or warning icon in the status bar so we should always open the Errors window. If that means we need to re-create the Errors window then we should do that and then display it. Doing nothing would not be a good user experience.

There is a question of where this logic should go. I think the IdeApp.Workbench.GetPad should recreate the pad, if it needs to, since it knows about them instead of having the logic in several places.

[netonjm]

Makes completely sense @mrward @Therzok ! click the icon is an action entirely linked on this pad and it should recreate the panel absolutely! I was on a wrong premise.

And related to the IdeApp.Workbench.GetPad recreate, not completely sure if include it here, maybe I would include another method IdeApp.Workbench.GetOrCreatePad reusing the other logic

[netonjm]

I was investigating with @mrward , and we don't have any kind of dispose or remove the panel.
Hide panel don't destroy the object, it seems we only dispose panels on close the IDE. I added some additional logging in case of NRE to get more information related to that

[mrward]

Just wondering if we could capture some extra information here to help diagnose the problem. This change will prevent a fatal exception causing a crash and still reports the problem in telemetry 👍

[netonjm]

@monojenkins rebase