Scrolling using vim-smoothie lags when lualine.nvim is enabled

[bool3max]

• nvim --version:

NVIM v0.5.0-dev+972-g84faeb07d
Build type: RelWithDebInfo
LuaJIT 2.0.5

• latest versions of both plugins
• terminal: kitty 0.19.3 (also occurs in xterm)

Scrolling using vim-smoothie while lualine.nvim is enabled produces lag, especially towards the end of the scrolling motion. This does not occur while using vim-airline (though lualine.nvim is the first statusline plugin I've ever used, but I had to test with another one).

[bool3max]

It is less noticeable (though still apparent) using the default scroll speed (let g:smoothie_update_interval=10), but when using let g:smoothie_update_interval=5, a slower scroll speed, it becomes immediately apparent. The last few lines to-be-scrolled take a second to go by.

[hoob3rt]

This does not happen on my system unless I set g:smoothie_update_interval=1, even on xterm.
Keep in my that vim-smoothie is really cpu heavy as shown below

But no lag happens when lualine.nvim is not installed so this is definitely an issue, I will try to resolve this asap.

[bool3max]

Yeah the less delay between updates the more lag there is, without lualine I can get a very smooth motion with it set to 5, with it not so much. I love the plugin, hope you get it resolved!

[hoob3rt]

can you try setting up lualine this way?

require('lualine').sections = {
  lualine_a = { 'mode' },
  -- lualine_b = { 'branch' },
  lualine_c = { 'filename' },
  lualine_x = { 'encoding', 'fileformat', 'filetype' },
  lualine_y = { 'progress' },
  lualine_z = { 'location'  },
}

I think the branch function might be a problem

[bool3max]

Using that I get this:

[hoob3rt]

try this way

    local lualine = require('lualine')
    lualine.sections = {
      lualine_a = { 'mode' },
      -- lualine_b = { 'branch' },
      lualine_c = { 'filename' },
      lualine_x = { 'encoding', 'fileformat', 'filetype' },
      lualine_y = { 'progress' },
      lualine_z = { 'location'  },
    }
    lualine.status()

[bool3max]

Yeah that works, it doesn't lag anymore!

[hoob3rt]

Great! Thanks for pointing that out. I know why this is happening but I have a more universal fix in mind than just fixing the branch function.

Some functions like branch, fileformat should probably only run once per file, not on every update like this is happenig like now.
I will try to resolve this next friday. You can keep using lualine without the branch functionality for now or try creating a pr.

[eric-hansen]

I'm not super familiar with the Lua API but why not make the calls async with vim.loop instead?

[hoob3rt]

I'm not super familiar with the Lua API but why not make the calls async with vim.loop instead?

Yes function like branch have to be made async as well. Thanks for pointing vim.loop out, it looks like it could be an easy to implement solution.

[hoob3rt]

could you confirm if f62c0d4 solves this issue?

[bool3max]

yeah, seems to be fixed, nice.