TabView attempts to set its width to an absurdly small number, excepts

[DHowett-MSFT]

Describe the bug

microsoft-ui-xaml/dev/TabView/TabView.cpp

Lines 314 to 326 in 6541430

	double widthTaken = 0.0;
	if (auto leftContentColumn = m_leftContentColumn.get())
	{
	widthTaken += leftContentColumn.ActualWidth();
	}
	if (auto addButtonColumn = m_addButtonColumn.get())
	{
	widthTaken += addButtonColumn.ActualWidth();
	}
	if (auto rightContentColumn = m_rightContentColumn.get())
	{
	widthTaken += rightContentColumn.ActualWidth();
	}

Stepping through these three conditionals during Windows Terminal startup (MUX package version 2.2.190702001-prerelease) shows that each column is "2147000000 pixels wide". When we attempt to derive an availableWidth from the width taken and set it, regardless of the TabWidthMode, we get an "invalid argument" HRESULT.

	Name	Value	Type
	availableWidth	-6442450453.0000000	double
	widthTaken	6442450944.0000000	double

Steps to reproduce the bug
This reproduces in a local dev build of Windows Terminal. I'm not sure how to reproduce it elsewhere.

Expected behavior
Doesn't crash.

Version Info

NuGet package version:
2.2.190702001-prerelease

Additional context
We're not inserting content into any of the TabView's left/add/right columns.

Xaml islands? We've got a window with xaml content in it, so I believe that it's already laid itself out correctly (ActualWidth is 491.00 on line 330 where availableWidth is calculated.)

[jevansaks]

Thanks, @DHowett-MSFT , can you share a branch/commitSha to check out for a build of terminal that repros this? That would help us debug locally.

I'm assigning to @teaP -- she'll be back on wednesday.

[DHowett-MSFT]

Sure: microsoft/terminal@cc45a50c, branch dev/duhowett/nuget_updates

Incidentally, would the change from is-a ListView to has-a ListView changing the return type of Items from IObservableVector to IVector warrant me filing another issue? Relevant here.

[jevansaks]

Incidentally, would the change from is-a ListView to has-a ListView changing the return type of Items from IObservableVector to IVector warrant me filing another issue? Relevant here.

Yes, if only so that we don't lose track of it. It should be straightforward to change it, I doubt it was intentional.

[DHowett-MSFT]

Done; #1021. Thanks!

[DHowett-MSFT]

I'm not seeing this any more.

[teaP]

A lot has changed since this bug was filed so if you're not seeing it anymore -- awesome. Let me know if it comes back!