Some vi key bindings will not work after running `lazygit`

[Cokile]

Fish Version:
fish, version 3.2.1

Operating System:
MacOS 10.15.7
Darwin MacBook-Pro.local 19.6.0 Darwin Kernel Version 19.6.0: Tue Jan 12 22:13:05 PST 2021; root:xnu-6153.141.16~1/RELEASE_X86_64 x86_64

Terminal:
iTerm2 build 3.4.4
xterm-256color

config.fish:

set fish_key_bindings fish_user_key_bindings

functions/fish_user_key_bindings.fish:

function fish_user_key_bindings
    fish_vi_key_bindings
    
    # map jk to Esc
    bind -M insert jk "if commandline -P; commandline -f cancel; else; set fish_bind_mode default; commandline -f backward-char force-repaint; end"
end

Steps to reproduce:

1. Install lazygit via Homebrew

$ brew install lazygit

2. Run lazygit

$ lazygit

3. Quit lazygit

Before running lazygit, all vi key bindings work as expected. But after running lazygit, some vi key bindings will not work:

1. cw, dw: just moving the cursor to the beginning of the next word, no characters will be deleted.
2. jk: just outputting the jk rather than switching to normal mode. But if press j only, nothing will appear, it seems fish is still waiting the subsequent input.

[zanchey]

After running lazygit in Terminal.app, even without vi bindings, fish is not behaving normally. Pressing right arrow works the first few times, then starts spitting [C (the tail end of the escape sequence) out to the terminal.

No differences in the stty -a output before or after.

[ridiculousfish]

This is curious. Some one is configuring fish as the receiving process for signals when some fd becomes readable (via O_ASYNC). This sends SIGIO on every select() on stdin, thus fish thinks it is constantly being interrupted, which breaks multi-character key bindings including cw and arrow keys.

No file descriptor in the fish process has O_ASYNC set, so maybe there is some funny behavior where lazygit sets it and then fish inherits the behavior? Not sure, it's strange.

[ridiculousfish]

@zanchey note I cherry-picked this into 3.2.2 as 797fbbb

[zanchey]

Many thanks!

[Cokile]

Thanks for the awesome work. BTW, I upgraded Lazygit to the latest release(v0.27), which replace termbox package with tcell, and the issue seems have gone.