Using Highlight Groups rather than load_colors

[mehalter]

I have a quick question. I'm sure I must be doing something wrong... I am currently using load_colors to set up colors for Heirline and for a simple example, I am getting the fg and bg of the StatusLine and setting that as the hl variable manually with something like this:

bg = utils.get_highlight("StatusLine").bg,
fg = utils.get_highlight("StatusLine").fg,

And then setting them as the topmost level hl with hl = { fg = "fg", bg = "bg" }. This works great but I am trying to move this to using the highlight group notation with strings, but when I do hl = "StatusLine" I am getting different results. I have verified that the StatusLine highlight group I have in my theme only sets fg and bg and doesn't set anything like reverse = true or anything, but this is what I'm getting:

With hl = { fg = "fg", bg = "bg" }:

With hl = "StatusLine":

It seems to me like for some reason when I use the hlgroup notation the colors get reversed as well as bolded. I did some testing and this is what I get when I do hl = { fg = "fg", bg = "bg", reverse = true }:

hl = { fg = "fg", bg = "bg", reverse = true, bold = true }:

Is there any reason for this to be happening or something I might be doing incorrectly?

[mehalter]

Hm as I opened this I am starting to think this is a problem with my surround function for some reason. I am investigating this currently

[mehalter]

I guess I'm still confused why changing a global highlight group from a manual definition to the hlgroup string definition would change behavior if they should be resolving to the same set of highlights. So maybe this is something else and not my own fault 🤔

[mehalter]

I think this has to do with the colors not updating when you reload the colorscheme. For example, if I do this:

hl = utils.get_highlight("StatusLine")

I get the same results as hl = "StatusLine"

but if I do

hl = function() return utils.get_highlight("StatusLine") end

it works as expected.

[rebelot]

When you use hl = "HlName" heirline calls utils.get_highlight at evaluation to be able to merge the highlight with the parent, so it will always pick up hl defined in the current theme.

When you use hl = utils.get_highlight("HlName") you are "hard coding" the returned values in the component definition, which are only valid for the current theme.

As you found out, wrapping it into a function allows re-evaluation of 'get_highlight` and updates correctly on colorscheme changes (as long as the hlgroup exists in the new theme).

The best way to ensure consistency on colorscheme changes is to never use the result of utils.get_highlight directly, instead, wrap it into a function, use hlgroups names directly, or use color name aliases defined in setup_colors with the instruction in the cookbook #theming.

Is there anything you think I could do?

[mehalter]

Hm, I guess I'm wondering why it doesn't seem to work correctly when I use the hlgroup name directly. Do you have any idea why that would be?

[mehalter]

The simplest example that illustrates this is

require("heirline").setup({ hl = "StatusLine", provider = "Hello, World!" })

[mehalter]

This results in:

where if I specify the fg/bg directly or with the function calling get_highlight I get this:

require("heirline").setup({ hl = function() return utils.get_highlight("StatusLine") end, provider = "Hello, World!" })

[rebelot]

require("heirline").setup({ hl = "StatusLine", provider = "Hello, World!" })

gives me the expected result, unless I load heirline config before the intended colorscheme.

this is what I get with nvim --clean --cmd 'hi StatusLine'

The strange thing is that, for some reason, bold and reverse get stuck within the component highlight logic... I will investigate