Repository navigation
bug: prompt flickering on input sync issue #1302
Description
nushell/nushell@684b4df introduced input flickering in nushell for the platforms/terminals/multiplexers I tested below:
| OS | Term | multiplexer | flicker |
|---|---|---|---|
| Windows | Windows Terminal | n/a | no |
| Windows | Windows Terminal | zellij | yes |
| Windows | Alacritty | n/a | yes |
| Windows | Noctty | n/a | no |
| Windows | Noctty | zellij | yes |
| Windows | Alacritty | n/a | yes |
| macOS | Alacritty | n/a | no |
| macOS | Alacritty | tmux | yes |
| macOS | Ghostty | n/a | no |
| macOS | Ghostty | tmux | yes |
$ git bisect good
684b4dff76d6eca70e8e3d0de3c1f4bcc219755c is the first bad commit
commit 684b4dff76d6eca70e8e3d0de3c1f4bcc219755c
Author: Martin Kronberger <kronberger@proton.me>
Date: Sun Oct 18 19:31:23 2026 +0200
chore: bump reedline to 39db5e3 (#19290)
## Description
Bumps reedline to `39db5e3`, six PRs past `d704744`:
...Describe the problem you are observing.
Steps to reproduce
nu --no-config-file with the appropriate os/term/mux triple above should produce prompt/input flickering issues when typing rapidly
Screenshots/Screencaptures
Alacritty on macOS:
Activity
mkatychev commentedon Nov 10, 2026
My initial suspicion out of the 5 commits in nushell/nushell@684b4df is #1254
EDIT: reverting 1254 fixes the issue: mkatychev#1
kronberger-droid commentedon Nov 10, 2026
Well I will not just revert it. But good that you found the change which introduced it and tested it in different terminals. That's a great help, will look into it soon.
mkatychev commentedon Nov 11, 2026
wouldn't dream of it, just wanted to confirm that I could isolate the commit
kronberger-droid commentedon Nov 11, 2026
@mkatychev
Can you check out #1304 and test the baseline plus both commits and report back. I would like to make this fix as minimal as possible and this would help me a lot, since I neither have windows or mac to test this on.
mkatychev commentedon Nov 11, 2026
@kronberger-droid I tested #1304 and unfortunately the issue persists in macOS/(Alacritty|Ghostty)/tmux at the same frequency
fix(painter): hide the cursor inside the synchronized frame
fix(painter): stop bracketing repaints in synchronized updates
kronberger-droid commentedon Nov 11, 2026
@mkatychev
Did you check it on all commits? I also rebased it onto main. So now the last checkout should essentially be your bisection.
mkatychev commentedon Nov 11, 2026
@kronberger-droid I did the testing and can report that 14be1e0 and 8db160c do flicker and 1fa34e1 does not! I suspect moving
self.stdout.queue(SetAttribute(Attribute::Reset))?;outside oflet painteddid the trick!fix(painter): stop bracketing repaints in synchronized updates
kronberger-droid commentedon Nov 11, 2026
@mkatychev
Can you check out the latest version of the PR? It should now be the minimal change to fix it.
mkatychev commentedon Nov 11, 2026
1f4c41d has the issue fixed!
kronberger-droid commentedon Nov 11, 2026
@mkatychev Thanks for testing!
mkatychev commentedon Nov 11, 2026
@kronberger-droid Actually I was able to produce the flicker effect again but it took quite a bit of effort 😆, I think there's still a desync issue it is just far less pronounced
flicker_2.mp4