Problem

Since 037ea6e, Nvim occasionally exhibits some black "tearing"/flickering on startup.

It is difficult to capture so I recorded a slow motion video on my phone:

Before (no black tearing):

After (with black tearing):

Note that in both cases we can see the screen state being drawn incrementally, but in the latter video the background of the top half of the screen becomes black first. In real time this has a noticeable "flicker" effect.

Steps to reproduce

In my case this seems to be caused by the nvim__redraw call in the Tree-sitter highlighter, so the following is sufficient to reproduce the issue:

cat >test.vim <<EOF
colorscheme blue
au FileType c lua vim.treesitter.start()
EOF
nvim --clean -u test.vim src/nvim/main.c

Expected behavior

The background should not become black when redrawing.

Neovim version (nvim -v)

064f3e4

Vim (not Nvim) behaves the same?

No

Operating system/version

macOS

Terminal name/version

Ghostty

$TERM environment variable

xterm-ghostty

Installation

Source