Vim status line leaked into scrollback

[dragonJACson]

Status line leaked into scrollback buffer

Issue description

The vim status line ("-- INSERT --") incorrectly appears within the terminal scrollback buffer instead of staying fixed at the bottom of the terminal window. (The line starts with 21888)

Environment

Issue reproducible on both environments, Ghostty itself runs on macOS 15.2

• Remote: Debian 10 with Vim (VIM - Vi IMproved 8.1 (2018 May 18, compiled Sep 27 2023 19:47:00)
• Local: macOS 15.2 with Vim (VIM - Vi IMproved 9.1 (2024 Jan 02, compiled Nov 9 2024 23:15:55)
• Vim configuration: Default settings, no customization
• Terminfo: xterm-256color
• Steps to reproduce
  • seq 1 100000 > numbers.txt
  • vim numbers.txt
  • Enter insert mode and keep scrolling
• Ghostty version:

ghostty --version
Ghostty 1.0.2-main+a2445359

Version
  - version: 1.0.2-main+a2445359
  - channel: tip
Build Config
  - Zig version: 0.13.0
  - build mode : builtin.OptimizeMode.ReleaseFast
  - app runtime: apprt.Runtime.none
  - font engine: font.main.Backend.coretext
  - renderer   : renderer.Metal
  - libxev     : main.Backend.kqueue

• Ghostty config:

font-family = Sarasa Term Slab SC
font-size = 16
theme = OneHalfDark

window-save-state = always
scrollback-limit = 10000000

Asciinema recording:
demo2.cast.zip

[dragonJACson]

Record.2025-01-09.12.49.36.mp4

For a clearer demonstration of the issue, you can view the screen recording where the status line leaking occurs at timestamp 00:26.

[dragonJACson]

Update to today's 9073 build, I could still reproduce this issue
New findings:

1. When I resize the window, the affected line becomes normal (reproduce at 00:34, resize window at 00:53)
2. When I scroll until the affected line moves out of view, then scrolling back, the line becomes normal (reproduce at 01:32, fix at 1:46)

Recording.at.2025-01-11.11.48.04.mp4

[dragonJACson]

Can someone reproduce this issue? Or just I have some wrong configuration? :(
I try to use Terminal Inspector to debug this, but it seems that the inspector do think there is something in the cell, but after resizing the terminal, the cell became empty (starting from 00:12 in the video)

Recording.at.2025-01-13.09.19.26.mp4

And I try to look at control sequence, find nothing strange (00:20)

Recording.at.2025-01-13.09.24.34.mp4

[00-kat]

I was able to reproduce this on Linux with Ghostty 1.1.0-r39.g4eb5885-1-arch and Vim 9.1.1065.

(I'm not in insert mode so -- INSERT -- isn't present, but note the line numbers and percentage on the middle of the right-hand-side of my screen.)

[00-kat]

Additional notes:

• Seems to happen every 300-350 lines.
• :set virtualedit=all then move your cursor to that position and select the text, then deselect it and observe that it no longer exists.

Not sure if this is a Vim issue or a Ghostty issue though.

[mitchellh]

Thanks for the asciinema, reproduced easily, #7066. Apologies for the delay.