Terminal crashes when navigating in empty palette

[Don-Vito]

Environment

Windows Terminal version (if applicable): both 1.4 and 1.5

Steps to reproduce

1. Open command palette
2. Type filter that is not matched by any command
3. Press "UP"
4. Enjoy postmortem debugger

The reason is double bug here

void CommandPalette::SelectNextItem(const bool moveDown)
    {
        const auto selected = _filteredActionsView().SelectedIndex();
        const int numItems = ::base::saturated_cast<int>(_filteredActionsView().Items().Size());
       
        const auto newIndex = ((numItems + selected + (moveDown ? 1 : -1)) % numItems);
        _filteredActionsView().SelectedIndex(newIndex);
        _filteredActionsView().ScrollIntoView(_filteredActionsView().SelectedItem());
    }

We both do the math when numItems=0, and when we go up starting from selected=-1.

I have a fix here: #8420.
But I will probably extract it to a separate PR.

[zadjii-msft]

G U H

Yep that's an easily repro-able crash alright, thanks for hoping on the fix so quick

[ghost]

🎉This issue was addressed in #8422, which has now been successfully released as Windows Terminal Preview v1.6.10272.0.:tada:

Handy links:

• Release Notes
• Store Download