Slow formatting in neovim

[zoeesilcock]

Formatting is very slow when called via zig#fmt#Format() and when using zig_fmt_autosave on neovim. In all of my testing I have found that running zig fmt ****.zig directly in the terminal is instant, so my suspicion is that the shell is too slow at pushing large amounts of data through stdout.

I tested with a file that has 2297 lines and got the following results (two different machines, so they aren't comparable to each other):

• Windows (PowerShell): 31 seconds
• Mac: 13 seconds

I really want to use format-on-save, but it really doesn't take long to hit a line count that leads to a pause on every save which is very distracting.

The workaround I am using now is to disable format-on-save and bind a key to run the shell command and reload the file manually: <cmd>!zig fmt %<CR><cmd>:e<CR><cmd>LspRestart<CR>. But it would be more convenient if I could just leave zig_fmt_autosave enabled. It's also problematic for new users as it isn't obvious that neovim includes this plugin and that it has format-on-save enabled by default and could give the impression that zig or zig fmt is slow.

Versions:

PS > nvim -v       
NVIM v0.10.2
Build type: Release
LuaJIT 2.1.1713484068
Run "nvim -V1 -v" for more info
PS > zig version
0.13.0