Shift+Enter always submits, breaking PSReadline features [Windows.Terminal]

[Jaykul]

• Your Windows build number: (Type ver at a Windows Command Prompt)

Microsoft Windows [Version 10.0.18362.86]

• What you're doing and what's happening: (Copy & paste specific commands and their output, or include screen shots)

Trying to add an empty line in a multi-line input by pressing Shift + Enter with PSReadline in PowerShell

• What's wrong / what should be happening instead:

Shift+Enter is treated as Enter, and it tries to run my incomplete command line

[zadjii-msft]

So I'm not sure this is fixable without a lot of work.

Because the Windows Terminal is using ConPTY as a backend, we can only send keypresses to the attached client app that are encodable by VT sequences. Unfortunately, there's no way to differentiate between Enter and Shift+Enter with just VT.

So, we need to add support for encoding entire INPUT_RECORDs as VT sequences. Then add support to conpty (in InputStatemachineEngine.*) for parsing such an input record. Then we need to enable the terminal to tell conpty that it should expect such a type of input sequences, and the terminal needs to be able to synthesize them.

It's something that's doable, but not without at least a weeks worth of work, not including testing.

[Jaykul]

Ouch. Didn't even think of that.

At least in PSReadLine it's settable, so I will just have to try to learn to use Ctrl+Enter instead
... that seems to send a linefeed instead of a carriage return, so it's detectable.

There's probably a bigger picture here about helping those of us who aren't used to VT learn which combinations just aren't going to work...

[pingzing]

This actually seems to be a bit of a broader problem--a lot of PSReadLine hotkeys that use Ctrl+ chords don't work either. Ctrl+Space and Ctrl+. come to mind as well.

EDIT: Interestingly, it seems similar to the issue experienced by xterm.js-based terminal emulators on Windows, as noted in the PSReadLine repo: PowerShell/PSReadLine#877 Ctrl+. is interpreted as Ctrl+@ in the Windows Terminal as well, for example. At a guess, because xterm.js on Windows uses WinPTY which does a pretty similar thing to ConPTY's VT processing?

[flxflx]

The issue seems to prevent the typing of certain characters on non-US keyboard layouts. For example, I cannot type backspace (alt-gr+?) on my German keyboard. This makes Terminal pretty much unusable for me.