"Terminal: Clear" not working as desired

[vivekmalhotra]

Steps to Reproduce:

1. Run a python file using command palette >Python: Run file in terminal window
2. Terminal shows the output. Now, clear the terminal using command palette >Terminal: Clear
3. Terminal gets clear now. Run the file again in the terminal >Python: Run file in terminal window
4. Here is where issue shows up - the terminal still shows all the previous outputs from before the last clear command. IMO, desired should be that terminal should not show any previously cleared outputs.
5. Attached below is a gif of the screen reproducing & visualizing this issue

Does this issue occur when all extensions are disabled?:
Yes, the issue reoccurs. (Note: All except the "Python" extension were disabled. Python extension is needed to run the python file in terminal.

I had also posted in Super User forum thinking this was some issue with my system. And then I tried it on a clean build of VS code and it got repeated. Hence, I decided to post it as a bug.

Link to Super User forum question

VS Code version: Code - Insiders 1.36.0-insider (c089daa, 2019-06-07T05:19:15.188Z)
OS version: Windows_NT x64 10.0.18362

System Info

Item	Value
CPUs	Intel(R) Core(TM) i7-8700K CPU @ 3.70GHz (12 x 3696)
GPU Status	2d_canvas: enabled flash_3d: enabled flash_stage3d: enabled flash_stage3d_baseline: enabled gpu_compositing: enabled multiple_raster_threads: enabled_on native_gpu_memory_buffers: disabled_software oop_rasterization: disabled_off protected_video_decode: enabled rasterization: enabled skia_deferred_display_list: disabled_off skia_renderer: disabled_off surface_synchronization: enabled_on video_decode: enabled viz_display_compositor: disabled_off webgl: enabled webgl2: enabled
Load (avg)	undefined
Memory (System)	15.68GB (7.71GB free)
Process Argv
Screen Reader	no
VM	0%

Extensions (1)

Extension	Author (truncated)	Version
python	ms-	2019.5.18875

[vscodebot]

(Experimental duplicate detection)
Thanks for submitting this issue. Please also check if it is already covered by an existing one, like:

• 'Run Python File in Terminal'not working (#74917)

[Tyriar]

@vivekmalhotra this is happening because Terminal: Clear tells the frontend (the thing rendering everything) to clear, but the way that the conpty backend works is it will sometimes reprint what it thinks should be visible. Since it doesn't know about our clear it reprints the unwanted output, this doesn't happen on a regular linux/mac backend that conpty is trying to emulate.

@zadjii-msft is there anything that can be done here to tell conpty to not reprint the screen? I suspect python.exe does not enter alt mode so I'm not sure why a reprint is necessary.

[zadjii-msft]

Hmm. That might not be a scenario that works for us right now. We might need to add an extra input sequence/signal to tell conpty to clear the buffer.

I am a little curious why the whole buffer got repainted, that does seem like a bug. However, since conpty does think that all that text is still there (because its buffer wasn't cleared, only the frontend buffer was), it might get more confused by not repainting the entire thing.

[Tyriar]

@zadjii-msft might be better to fix the bug if there is one, rather than add an explicit manually clear the buffer sequence that only works on conpty.

[vscodebot]

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!

[vivekmalhotra]

@zadjii-msft @Tyriar
I can confirm that the issue is still prevalent in the latest insiders build.
Unsure on how to re-open this issue?

[zadjii-msft]

This is a bug that's external to VsCode. It'll be fixed by work on the ConPTY API that'll be tracked by microsoft/terminal#1193.

[vivekmalhotra]

This is a bug that's external to VsCode. It'll be fixed by work on the ConPTY API that'll be tracked by microsoft/terminal#1193.

Thanks for the reply, Mike

[Tyriar]

@vivekmalhotra the bot closed it because of the needs more info label, reopened.

[ghost]

Terminal clear

I run npm in terminal，then end it with "Ctrl + C" , useing code clear and get result as left（I have click enter several times）,useing "ctrl + shift + p" and "terminal clear" get result as right，it clear all and terminal crashed.

terminal will back to line 1 and enterable but not clear character。

用了clear命令后，terminal返回第一行并且可编辑，但是并没有清理界面字符，使用 控制中心的Terminal clear 指令后可以清理，但是terminal崩溃了

[solacens]

So who should be fixing the issue now? VS Code here or Windows Terminal? 😢

Any workaround at the moment? This issue is quite annoying.

[ghost]

No debounce，Push 1s Enter，it still effective，more than 1s

[zadjii-msft]

@solacens

It'll be fixed by work on the ConPTY API that'll be tracked by microsoft/terminal#1193.

[solacens]

@zadjii-msft Thanks for the information. I will keep track on the related issue.

[Tyriar]

@GearTheWorld the milestone of the issue which is the month in which the work is done. It'll get released in early July.

[vivekmalhotra]

@GearTheWorld the milestone of the issue which is the month in which the work is done. It'll get released in early July.

Great to hear this is now fixed - thanks @Tyriar! Coincidentally, the issue got fixed on June 9th, exactly 4 years after it was first created. Time flies... 😊

[rzhao271]

I still see a lot of whitespace in the terminal:

[heartacker]

same here

[Tyriar]

@zadjii-msft is this behaving as expected? Does calling into the conpty clear API not reset its internal buffer cursor position to 0,0?

[Svish]

VS Code, on Windows, with regular cmd terminal, when i run clear, it does scroll the buffer so my cursor is at position 0,0, but that's not what clear is supposed to do. It's supposed to clear the terminal, i.e. empty the buffer completely so that I'm at a fresh start.

I use it frequently in the command-line when dealing with commands that spit out a lot of text or errors. Sometimes it's difficult to see where the output from one command ends and the next begins, and in those cases it's super handy to just run clear and empty the buffer completely, so that the only output on the screen will be from the command I'm about to run.

This doesn't work at all in VS Code currently. Running clear simply scrolls the buffer up a bit, so it looks empty, but when I run my next command outputting a bunch of text, and then try to scroll up to find the beginning, I eventually get to old output, making it a lot harder. Only workaround is to exit the terminal and open a new one, which is a hassle and should be uneccessary.

clear should clear.

[Tyriar]

@Svish this is talking about the Terminal: Clear VS Code command, not the clear shell command. This is what you're talking about xtermjs/xterm.js#1727

[Pieras2]

I see many comments but for me it started to work weeks ago. I use gitbash in vac and "clear" works now as a charm

[VLFrosttide]

Still having an issue of the terminal clearing, then it skiping lines when I start writing , same as this guy here
#109012
Clearing it with the workbench.action.terminal.clear.

[tungrix]

Ctrl + K seems work for me instead of typing clear in terminal.

[Tyriar]

Closing this as it was fixed on our end with #184734, you may not get the fix until a future Windows update unfortunately

[mehedihasanziku]

Closing this as it was fixed on our end with #184734, you may not get the fix until a future Windows update unfortunately

@Tyriar This answer doesn't help us, anyway to force update? which package from windows need to be updated?
node-pty we need update our node package? Please refer us window update link

Update: I think this way it's working

https://github.com/microsoft/terminal/releases - Update Terminal to latest, prefer to use only Latest not Pre-release

Assets > .msixbundle format and install that, that's it.

It didn't work in first attempt of vscode restart, but after reset this setting both here, probably did the work, maybe it will work after pc restart also.

[Tyriar]

This answer doesn't help us, anyway to force update? which package from windows need to be updated?
node-pty we need update our node package?

@mehedihasanziku I'm not sure the version exactly but it's not a package you can install independently but Windows itself, you might be able to find the version by following links to the microsoft/terminal repo.