Neovim version (nvim -v)

v0.7.0-dev+1002-g59fa5f4ec

Vim (not Nvim) behaves the same?

no, 8.2.4293

Operating system/version

macOS 12.1

Terminal name/version

iTerm2, 3.4.12

$TERM environment variable

tmux-256color

Installation

brew install nvim -s --HEAD

How to reproduce the issue

Hard to reproduce, first open nvim in such a way that it does not occupy the entire terminal screen. In my case it happens with a combination of tmux+tmux-resurrect at times. Then find the PID of the tty and nvim running in it, I use htop. Finally send SIGWINCH to both tty and nvim. In my case it just messes up the nvim buffer, things look haywire.

Expected behavior

Neovim should not open erratically such that it does not occupy the full size of tty it is opened in. Moreover, if it has opened like this, it should honor SIGWINCH and resize itself.

Actual behavior

Neovim does not open to fully occupy the size of tty it is opened in. If it does open like this, it does not honor a SIGWINCH sent from another tty command line.