CLS command does not work in VSCode terminal

[mihailik]

Does this issue occur when all extensions are disabled?: Yes

• VS Code Version: 1.81.1 (user setup)
• OS Version: Windows_NT x64 10.0.19045

Steps to Reproduce:

1. open new terminal
2. type CLS, press Enter
3. terminal is cleared, all as expected
4. type dir, press Enter
5. repeat it 5-7 times until terminal is filled with text and a scrollbar appears
6. type CLS, press Enter
7. terminal content scrolled away out of view, but not cleared: you can scroll it back and the content is still there

I think it used to be worse, the CLS didn't clear terminal even at the start. Now it only fails when the existing content overflows.

Quite surprised this bug is missed like that.

If it is a bug in another component, like conpty or Windows itself -- please provide enough info to raise the issue to the corresponding team inside Microsoft. Every piece of code involved here is owned by the company, so leaving it open for so many years is frankly very silly.

[gjsjohnmurray]

I think #176709 and the Stack Overflow post it links to may be relevant to you.

[mihailik]

Wow that's one kind of attitude 🤣

[mihailik]

Of course microsoft/terminal#15065 is as much of a misdirection as xtermjs/xterm.js#1727

There is no need to ship a whole massive library and overhaul some OS subsystem to have a local workaround here.

There's a trivial ReadConsoleOutput Win32 API easy to re-sync. How it takes half-decade and dozens of bug reports brushed under the carpet?

[Tyriar]

@mihailik VS Code uses the new pseudoconsole APIs that emulate ptys on unix, not the old Windows console APIs (which ReadConsoleOutput is). It might be possible to sync with that but it would be a hack. It's even discouraged for a related reason in the docs you linked:

This API is not recommended and does not have a virtual terminal equivalent. This decision intentionally aligns the Windows platform with other operating systems where the individual client application is expected to remember its own drawn state for further manipulation. Applications remoting via cross-platform utilities and transports like SSH may not work as expected if using this API.

For microsoft/terminal#15065 I don't think we're tracking it in this repo but will be a priority for us as soon as it happens.

---

I think you are actually asking for is for the behavior change requested in xtermjs/xterm.js#1727 (which has been labeled with help wanted for 5 years and an easy solution was suggested 2 years ago).

When using new conpty (Windows 11 insider build 22621) here's what happens with cls in pwsh:

I don't have Windows 10.0.19045 available, could you record a gif to make sure we're on the same page?

[vscodenpa]

This issue has been closed automatically because it needs more information and has not had recent activity. See also our issue reporting guidelines.

Happy Coding!