Terminal text does not reflow if it's not visible when resizing the window

[akbyrd]

Type: Bug

When resizing the integrated terminal only the text that is visible reflows. Scrolling up to previous output will still be wrapped at the old line length. This makes it harder to scroll back and read through long output.

I think this can also truncate text at the end of lines, causing it to disappear entirely sometimes. But I haven't found a solid repro yet.

Here's my terminal after running a command with long output.

And here is my terminal after maximizing the window

VS Code version: Code 1.74.3 (97dec17, 2023-01-09T16:59:02.252Z)
OS version: Windows_NT x64 10.0.19043
Modes:
Sandboxed: No

System Info

Item	Value
CPUs	AMD Ryzen Threadripper PRO 3945WX 12-Cores (24 x 3993)
GPU Status	2d_canvas: enabled canvas_oop_rasterization: disabled_off direct_rendering_display_compositor: disabled_off_ok gpu_compositing: enabled multiple_raster_threads: enabled_on opengl: enabled_on rasterization: enabled raw_draw: disabled_off_ok skia_renderer: enabled_on video_decode: enabled video_encode: enabled vulkan: disabled_off webgl: enabled webgl2: enabled webgpu: disabled_off
Load (avg)	undefined
Memory (System)	31.86GB (17.51GB free)
Process Argv
Screen Reader	no
VM	0%

Extensions: none

[meganrogge]

/duplicate #134448

[akbyrd]

The linked issue appears to be very different. It is not related to text reflow. This issue is not duplicate of that one.

[meganrogge]

Yep you're correct, separate issue. I cannot reproduce on Windows and it looks like xterm.js does reflow the whole buffer despite at one time considering an approach where only the viewport would be impacted xtermjs/xterm.js#4232. Do you have terminal.integrated.windowsEnableContpy enabled? If so, this is likely a conpty issue

[Tyriar]

This is tracked in xtermjs/xterm.js#4231

/duplicate

[akbyrd]

I just repro'd with the Insiders, no extensions and no user settings. I tested with terminal.integrated.windowsEnableConpty both enabled and disabled and it occurred with each. I tried maximizing and fullscreening - occurred with each.

I can test on other machines, though I'm moderately sure this happens on every PC I use.

I also managed to track down the issue with the buffer being corrupted and text being truncated.

• Snap window to left side of screen
• Produce some log spam in the console
• Toggle fullscreen - on
• Toggle fullscreen - off
• Toggle fullscreen - on
• Notice buffer is corrupted

It doesn't seem to be related to the size of the terminal panel when it's not maximized (inside vscode itself, not the entire application window)

This is the script I'm using to test:

$line = "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat."

for (($i = 0); $i -lt 32; $i++)
{
    echo ($line + " " + $i)
}

VS Code version: Code - Insiders 1.75.0-insider (270c3b1, 2023-01-25T05:23:17.608Z)
OS version: Windows_NT x64 10.0.19043
Modes:
Sandboxed: Yes

System Info

Item	Value
CPUs	AMD Ryzen Threadripper PRO 3945WX 12-Cores (24 x 3993)
GPU Status	2d_canvas: enabled canvas_oop_rasterization: disabled_off direct_rendering_display_compositor: disabled_off_ok gpu_compositing: enabled multiple_raster_threads: enabled_on opengl: enabled_on rasterization: enabled raw_draw: disabled_off_ok skia_renderer: enabled_on video_decode: enabled video_encode: enabled vulkan: disabled_off webgl: enabled webgl2: enabled webgpu: disabled_off
Load (avg)	undefined
Memory (System)	31.86GB (16.13GB free)
Process Argv	--crash-reporter-id 8269a231-0af4-431f-8bf1-913cb9006f50
Screen Reader	no
VM	0%

Extensions: none

A/B Experiments

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[akbyrd]

Should the buffer corruption be a separate issue? That's a lot more severe than text reflowing.

[Tyriar]

I believe they're both the same problem. In addition to this, conpty (Windows terminal pty emulation layer) re-draws the viewport at the bottom of the terminal and it can sometimes act up. This is out of our control unfortunately.

[akbyrd]

That's unfortunate. It makes the integrated terminal unreliable enough that I can't really trust it with anything non-trivial. I've always kept a separate terminal open and I guess I'll need to continue to do so.

For example, my current use case is merging changelists in perforce. I have a bunch of them to do in sequence so I start a merge, go edit some text while I wait for it to complete, then fullscreen the window and look through the output to make sure everything behaved.

I simply can't do that in the integrated terminal both because the text is a jumbled mess using half the available screen and because the output gets corrupted to the point I can't understand it or know that I haven't missed something important because it was truncated.