conhost VK_F4 regression

[tamlin-mike]

Environment

Windows 10.0.18363.592 (bug also present in some earlier build(s))

Steps to reproduce

• cmd.exe
• C:\>aaa bbb ccc ddd
• Home, Ctrl-Right. Cursor should now be before the first 'b'.
• F4, Space. 'bbb' gets deleted.

Expected behavior

Visual cursor position remains (i.e. now just before ' ccc').

Actual behavior

1. Visual cursor position moves to EOL.
2. To make it worse, the insertion-point still is where the caret was, If you now type 'x' command line goes from 'aaa ccc ddd' to 'aaa x ccc ddd', while the cursor remains at EOL!

[zadjii-msft]

Yikes yep that's annoying. I bet that this regressed in one of our earlier COOKED_READ refactors, though it's hard to know when exactly.

[DHowett-MSFT]

Regressed in 19H1 (10.0.18362)

[DHowett-MSFT]

(Verified using CHOP)

[zadjii-msft]

note to self: still reproing in 10.0.22518.1000

[zadjii-msft]

Sharing notes because it's too close to 5pm:

Important to remember that the cmdline functions that open a popup do not get handled in CommandLine::ProcessCommandLine. It has to wait for more input, so it gets processed later. So somewhere inside of CopyFromCharPopup::Process is where I need to be doing the final call back to AdjustCursorPosition, not at the bottom of CommandLine::ProcessCommandLine

[lhecker]

FYI I'm currently working towards rewriting the command line implementation from scratch, because the original code was hard to maintain and the rewrite that brought this issue is even worse (and incorrect on top of it). Thanks for pinging this issue - now I know to remember to test it.
Contrary to what you said, you will be able to use it on Windows 10, even in conhost, and I'd be happy to show you how.

Also, while I understand your anger, don't write comments like that please.