Rendering complex status on 'update-status' causing wezterm to feel slow and appear choppy

[dylan-hoefsloot]

What Operating System(s) are you seeing this problem on?

macOS

Which Wayland compositor or X11 Window manager(s) are you using?

No response

WezTerm version

20240811-112922-0ac1e948

Did you try the latest nightly build to see if the issue is better (or worse!) than your current version?

Yes, and I updated the version box above to show the version of the nightly that I tried

Describe the bug

When rendering a complex status bar using wezterm.on('update-status' ... input lag becomes noticeable and navigating lines looks choppy.

Commenting out this section of my config resolves the issue.

At first I thought the status bar must be taking too long to render and hence causing the slowness, however changing the status update interval to a number even as high as 10 seconds didn't change things at all config.status_update_interval = 10000

This then led me to check if status_update_interval was working as I expected. I am not sure how it is supposed to work, however changing it didn't seem to effect how long re-renders took when information changed.

My guess is that this update must be running synchronously, otherwise I would think this wouldn't be a problem.

To Reproduce

Use io.popen to run system commands in the update_status function which seems to take long enough to cause input time to suffer

Configuration

function execute(command)
  local handle = io.popen(command)
  local result = handle:read("*a"):gsub('\n', '') -- Remove newline
  handle:close()
  return result
end

function git_branch(file_path)
  return execute("git -C " .. file_path .. " branch --show-current 2>/dev/null")
end

function git_root(file_path)
  return execute("git -C " .. file_path .. " --no-optional-locks rev-parse --show-toplevel 2>/dev/null")
end

function right_status(window, pane)
  local cwd_uri = pane:get_current_working_dir()
  if cwd_uri then
    local branch = git_branch(cwd_uri.file_path)
    local root = git_root(cwd_uri.file_path)
  end
end

wezterm.on('update-status', function(window, pane)
  right_status(window, pane)
end)

Expected Behavior

Either expected this to not degrade performance or be able to specify longer status_update_interval that remedies the performance issue

Logs

Debug Overlay
wezterm version: 20240811-112922-0ac1e948 aarch64-apple-darwin
Window Environment: macOS 14.5 (23F79)
Lua Version: Lua 5.4
WebGPU: name=Apple M1 Pro, device_type=IntegratedGpu, backend=Metal, vendor=0, device=0

Anything else?

Running hyperfine to check the performance of the two git commands (although this is outside of lua and wezterm) shows they take about 3-5ms each.

This might be greater with the overhead of running them from lua, just thought it was worth mentioning