[REGR #3956] Terminal incorrectly splits part of escape sequence

[Sidneys1]

Environment

Windows build number: 10.0.19041.0
Windows Terminal version (if applicable): Dev build @ 4882917
    Fix flipped sense in TerminalDispatch::CursorPosition (#4113)

Any other software?

PowerShell: 7.0.0-rc.1 and PowerShell 6.1.3
oh-my-posh: 2.0.342

Steps to reproduce

# Start powershell

# Install posh-git from the gallery
Install-Module posh-git -Scope CurrentUser

# Install oh-my-posh from the gallery, enter Y or A at the prompt
Install-Module oh-my-posh -Scope CurrentUser

# Load the oh-my-posh module
Import-Module oh-my-posh

# Set the theme to Paradox
Set-Theme Paradox

Expected behavior

Prompt is printed cleanly (as seen in the store release v0.7.3451.0):

Actual behavior

Right-most character of prompt is cut off (see timestamp) and part of an escape sequence has bled back to the beginning of the line (see "97ms"):

The existing prompt corrects itself after resizing the window, but subsequent prompts repeat the behavior:

This happens at any buffer size

Related Issues

Possibly related to #4037 (seems to be splitting an escape sequence) and/or #635 (although the "snap back" behavior is not exhibited)?

[DHowett-MSFT]

So, this regressed between 0.7 and 0.8? That's not great. Neither 4037 nor 635 should have changed behavior since 0.7. This may have been related to #4005.

[DHowett-MSFT]

If you set your startup project to Host.EXE (this is just traditional conhost), does the issue still reproduce?

[Sidneys1]

I'll have to check in the morning. I have another computer with a build only a few commits older that I don't remember behaving like this, so I'll take a look at that too. I'll also run some `git bisect` experiments and see if I can identify the problem commit.

[Sidneys1]

If you set your startup project to Host.EXE (this is just traditional conhost), does the issue still reproduce?

It does not appear to, even when changing the font to match (Cascadia Code PL):

[Sidneys1]

Additionally, an older build (e294e66) on a different computer does not exhibit the same behavior. There was a different font being used, but copying the font to the computer with the problem and using it did not fix the problem...

I'm running git bisect now to see where things go wrong :)

[Sidneys1]

Bisect confirmed the faulty commit is #3956 :( Lots of changes to sift through...

Edit: and it looks like the source branch is deleted, so I can't bisect the individual commits there :(

[zadjii-msft]

@Sidneys1 by any chance, does #4125 fix this for you?

git fetch origin pull/4125/head:pull/4125 && git checkout pull/4125

should check out the PR

[Sidneys1]

@Sidneys1 by any chance, does #4125 fix this for you?

...yes.... and also no. It fixes the original issue, and introduces a lot more:

Looks like a lot of characters are being duplicated when typing, and clear put the prompt at the bottom of the visible buffer instead of the top...

[Sidneys1]

As you can see though the duplication is only visual, the commands run as typed.

[zadjii-msft]

Woah that's maybe not so good 😅 @miniksa for visibility

[miniksa]

Hnnn ok.

[miniksa]

My biggest problem right now is now I have to go learn how the hell to install oh-my-posh. The repro steps leave something to be desired...

[DHowett-MSFT]

Hey now- we got a bisect out of it, which is a heck of a lot more useful than most bug reports. Don't be too hard on them! 😄

[miniksa]

Yeah, true. Sorry, Sidneys1. I'm still just salty about how much of a pain in the ass StateMachine::ProcessString is turning out to be.

[miniksa]

Bisect confirmed the faulty commit is #3956 :( Lots of changes to sift through...

Edit: and it looks like the source branch is deleted, so I can't bisect the individual commits there :(

I restored dev/miniksa/gardening3 in the mean time. I'm chasing down what I think is the problem though.

[Sidneys1]

My biggest problem right now is now I have to go learn how the hell to install oh-my-posh. The repro steps leave something to be desired...

All, good :) Your best bet is:

# Start powershell
Install-Module oh-my-posh -Scope CurrentUser
# Enter Y or A at the prompt
Import-Module oh-my-posh
Set-Theme Paradox

[miniksa]

Thanks. However, I just launched straight up Powershell in my 4116 branch and it's totally toasted so I'm going to guess it's related.

[Sidneys1]

Updated the ticket itself with better reproduction steps.

Eventually if I have time I'll isolate the exact sequence that triggers the bug so you can reproduce without oh-my-posh.

[miniksa]

I hope to figure it out today. Stay tuned.

[miniksa]

master merged into 4116 seems to resolve both visible behaviors:

1. the messed up right edge
2. the reprinting of the text over and over.

I'm going to guess #4107 whose fix was committed yesterday was also contributing here.

[miniksa]

@Sidneys1, everything seems fine now that I merged master into dev/miniksa/4116. So I think I might resolve this as a duplicate to 4116/4125.

[Sidneys1]

Confirmed that dev/miniska/4116 @ 1ff0037 fixes both problems for me.

[miniksa]

Excellent, thanks. Sorry about that.

[miniksa]

/dup #4116

[ghost]

Hi! We've identified this issue as a duplicate of another one that already exists on this Issue Tracker. This specific instance is being closed in favor of tracking the concern over on the referenced thread. Thanks for your report!