`ListView` prediction breaks `RevertLine()`

[ltrzesniewski]

Prerequisites

• Write a descriptive title.
• Make sure you are able to repro it on the latest released version
• Search the existing issues, especially the pinned issues.

Exception report

N/A

Screenshot

Environment data

PS Version: 7.5.4
PS HostName: ConsoleHost (Windows Terminal)
PSReadLine Version: 2.4.5
PSReadLine EditMode: Windows
OS: 10.0.26100.7306 (WinBuild.160101.0800)
BufferWidth: 361
BufferHeight: 96

Steps to reproduce

In a pwsh -NoProfile session, run the following:

Set-PSReadLineKeyHandler -Chord "Ctrl+r" -ScriptBlock {
    [Microsoft.PowerShell.PSConsoleReadLine]::RevertLine()
    [Microsoft.PowerShell.PSConsoleReadLine]::Insert("Inserted Text")
}

Set-PSReadLineOption -PredictionViewStyle ListView

Then, type foo (without pressing the enter key) and press Ctrl+R.

Expected behavior

Pressing Ctrl+R should replace foo by Inserted Text in the prompt.

Actual behavior

Pressing Ctrl+R adds Inserted Text to the existing foo: the end result is fooInserted Text in the prompt.

[daxian-dbw]

This is because RevertLine behaves differently when list view is active. When list view is active, RevertLine reverts back to the original user input, even if a different list item gets selected by UpArrow/DownArrow.

Maybe RevertLine should continue erase the whole line when no item is selected in the list view (meaning the user didn't select anything in the list, so no need to revert to the original user input.)

To work around it for now, your key handler needs to have 2 RevertLine calls in it.

[ltrzesniewski]

Thanks for the explanation!

This is because RevertLine behaves differently when list view is active.

Well, that's exactly the problem described here. This was surprising to me. 😅

The method's documentation is:

Reverts all of the input to the current input.

I didn't realize this was related to the list view. From its behavior, I thought this was an equivalent of a Clear() method, which doesn't exist. I guess I should have been more careful given the documentation I didn't understand.

In any case, I suppose this method requires a more precise documentation.

[ltrzesniewski]

Maybe RevertLine should either be a no-op, or just remove the prediction in InlineView mode?

That would better match its description and behavior in ListView mode, but it would be a breaking change.