Terminal unexpected display

[nonprenom]

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

• VS Code Version: 1.85.2
• OS Version: windows 10

Steps to Reproduce:

1. give focus to a running terminal tab :

• anti aliasing looks activated
• there are spaces between the characters
  2 The terminal is running correctly
  3 to fix it, I can
• close and reopen the terminal
• change some settings of the terminal (curson blink on/off for example)

Now that i'm thinking about, maybe it's because I previously connect to my PC from remote RDP ?

Version: 1.85.2
Commit: 8b37750
Date: 2024-01-18T06:40:10.514Z
Electron: 25.9.7
ElectronBuildId: 26354273
Chromium: 114.0.5735.289
Node.js: 18.15.0
V8: 11.4.183.29-electron.0
OS: Windows_NT x64 10.0.19045

[VSCodeTriageBot]

Thanks for creating this issue! It looks like you may be using an old version of VS Code, the latest stable release is 1.86.0. Please try upgrading to the latest version and checking whether this issue remains.

Happy Coding!

[meganrogge]

I cannot reproduce. Can you in insiders?

[mmastrac]

I see the same thing on Mac. It happens after VSCode has been running for a while. The only real setting I've tweaked is that I've set my scrollback to 25000.

Below is a screenshot of a newly opened terminal next to the old one, which will work fine for some time. Eventually they all become like this and I need to restart them.

Confirmed that toggling the cursor blink setting resets these terminals to a working state.

Version: 1.86.0
Commit: 05047486b6df5eb8d44b2ecd70ea3bdf775fd937
Date: 2024-01-31T10:29:11.933Z (1 wk ago)
Electron: 27.2.3
ElectronBuildId: 26495564
Chromium: 118.0.5993.159
Node.js: 18.17.1
V8: 11.8.172.18-electron.0
OS: Darwin arm64 22.6.0

[mmastrac]

Here's some debugging info, hopefully it helps.

I dumped the styles from the div that holds the terminal window: https://gist.github.com/mmastrac/faa9001068b56a3f05787100e15b94f8

<div class="terminal-widget-container"></div>

And from the xterm-rows div, styles https://gist.github.com/mmastrac/457fd04902bc62120f2c25f676446ea6:

<div class="xterm-rows" aria-hidden="true" style="line-height: normal; letter-spacing: 7.22222px;"><div style="width: 325px; height: 14px; line-height: 14px; overflow: hidden;"><span>Enumerating objects: 17, done.</span></div><div style="width: 325px; height: 14px; line-height: 14px; overflow: hidden;"><span>Counting objects: 100% (17/17), done.</span></div><div style="width: 325px; height: 14px; line-height: 14px; overflow: hidden;"><span>Delta compression using up to 12 threads</span></div><div style="width: 325px; height: 14px; line-height: 14px; overflow: hidden;"><span>Compressing objects: 100% (9/9), done.</span></div><div style="width: 325px; height: 14px; line-height: 14px; overflow: hidden;"><span>Writing objects: 100% (9/9), 705 bytes | 705.</span></div><div style="width: 325px; height: 14px; line-height: 14px; overflow: hidden;"><span>00 KiB/s, done.</span></div><div style="width: 325px; height: 14px; line-height: 14px; overflow: hidden;"><span>Total 9 (delta 8), reused 0 (delta 0), pack-r</span></div><div style="width: 325px; height: 14px; line-height: 14px; overflow: hidden;"><span>eused 0</span></div><div style="width: 325px; height: 14px; line-height: 14px; overflow: hidden;"><span>remote: Resolving deltas: 100% (8/8), complet</span></div><div style="width: 325px; height: 14px; line-height: 14px; overflow: hidden;"><span>ed with 8 local objects.</span></div><div style="width: 325px; height: 14px; line-height: 14px; overflow: hidden;"><span>To https://github.com/mmastrac/deno.git</span></div><div style="width: 325px; height: 14px; line-height: 14px; overflow: hidden;"><span>   d0c83ce1c..5228d029e  deno_core_bump -&gt; de</span></div><div style="width: 325px; height: 14px; line-height: 14px; overflow: hidden;"><span>no_core_bump</span></div><div style="width: 325px; height: 14px; line-height: 14px; overflow: hidden;"><span class="xterm-fg-2">✔</span><span> </span><span class="xterm-fg-3">~/Documents/github/deno/deno</span><span> [</span><span style="color:#c353c3;">deno_core_bum</span></div><div style="width: 325px; height: 14px; line-height: 14px; overflow: hidden;"><span style="color:#c353c3;">p</span><span>|</span><span class="xterm-bold xterm-fg-12">⚑ 22</span><span>] </span></div><div style="width: 325px; height: 14px; line-height: 14px; overflow: hidden;"><span class="xterm-fg-7">1</span><span class="xterm-fg-7">6:06</span><span> $ </span><span class="xterm-cursor xterm-cursor-outline"> </span></div></div>

[mmastrac]

The problem appears to be this style. If I toggle the letter-spacing style rule, the terminal appears to be fixed:

I'm not sure why, but only the terminals that are in an accessible mode (why are some of them switching to be accessible?) seem to be broken.

[nonprenom]

@meganrogge
Can it be connected to a previous remote desktop connection to the PC running vscode ?
When connecting and disconnecting, the resolution change and, maybe, the terminal is not refresh correctly ?
@mmastrac Are you using such a remote desktop connection on your mac when it happend ?

[mmastrac]

@nonprenom I'm not using any sort of remote desktop. It just appears that a terminal "rots" after being in the background long enough (maybe the laptop going to sleep?).

[adamhamlin]

Have had same issue for weeks

[meganrogge]

What do you mean by terminals in accessible mode?

[nonprenom]

Hi So it happend to me often without RDP before or switching reslution - what can I save or check to help here ?

[mmastrac]

What do you mean by terminals in accessible mode?

It appears the affected terminal is switching from a canvas/GPU renderer to an HTML renderer. There are a few accessibility messages scattered around the terminals that switch when browsing the DOM.

I am not sure how any of the terminal rendering code works, so that's just a guess that it's accessibility.

[Vectorrent]

I've been seeing this issue randomly for the better part of a year:

Not sure what causes it. It seems to occur with long-running terminal sessions, after some time has passed. In my case, they are training runs for machine learning.

I'm using Code-OSS on Arch Linux with x11.

This seems to happen more frequently when my system "freezes", for whatever reason. While doing ML, my system will often hang, as weights are written to disk, or big pages are swapped between memory/disk. During this time, my entire system becomes unresponsive, as those tasks take priority. It is EXTREMELY COMMON for this issue to occur just after that happens. Though it will only affect 1 or 2 terminals, typically; not all of them.

There's also an uncommon version of this bug, where the extra spaces are not distributed uniformly, as you see here. Instead, there might be 1 or 2 extra "columns" of spaces splitting the terminal, in random positions. But otherwise, the rest of the text looks fine - except for a few columns of whitespace.

[Tyriar]

The problem appears to be this style. If I toggle the letter-spacing style rule, the terminal appears to be fixed:

I'm not sure why, but only the terminals that are in an accessible mode (why are some of them switching to be accessible?) seem to be broken.

This is new info for me, I was not aware of letter-spacing to looks like this. Perhaps something is going wrong here:

https://github.com/Tyriar/xterm.js/blob/8e015ebf872001352c8f382364f6d58048b7800b/src/browser/renderer/dom/DomRenderer.ts#L267-L272

[mmastrac]

@Tyriar Let me know if you'd like me to set a breakpoint somewhere and monitor a running instance. For now I'll try to set a breakpoint on that line and see if I can get you the cached W width.

[Tyriar]

Reproduced just now:

1. 3 terminals showing
2. switch from gpu accel on to off
3. kill 2 terminals, the last one had the spaced wrong

Selection is showing wrong:

Width cache:

High letter spacing:

[Tyriar]

The letter spacing is determined by this line:

https://github.com/xtermjs/xterm.js/blob/8e015ebf872001352c8f382364f6d58048b7800b/src/browser/renderer/dom/DomRendererRowFactory.ts#L149-L150

The width cache gives 0:

[Tyriar]

Width cache _flat:

[Tyriar]

xtermjs/xterm.js#4973 should fix it

[mmastrac]

Thank you, @Tyriar. Appreciate the investigation and fix.