Setting foreground to "NONE" on component is ignored

[miversen33]

To start, here is a screenshot showing the issue

This is accomplished with the following cokeline configuration

vim.api.nvim_set_hl(0, 'BufferLineFill', { fg = 'NONE', bg = 'NONE' })
require("cokeline").setup({
    fill_hl = "BufferLineFill",
    default_hl = {
        fg = "NONE",
        bg = "NONE"
    },
    components = {
        {
            text = function(buffer)
                return
                buffer.is_focused and ""
                or " "
            end,
            fg = "NONE",
            bg = "NONE"
        },
        {
            text = function(buffer) return buffer.filename .. ' ' end,
            style = function(buffer)
                if buffer.is_hovered and not buffer.is_focused then
                    return 'underline'
                end
            end
        },
    }
})

I would expect this to set the Foreground of the first component to NONE as that is what I am actively telling it to do. However it is being overriden by something.

Below is a repo lua config that can be used to recreate this issue

-- Minimal configuration
-- mini.lua
-- Use with the --clean -u flags. EG nvim --clean -u mini.lua
-- This config will create a temp directory and will blow away that temp directory
-- everytime this configuration is loaded. Great for simulating a new installation
-- of a plugin

-- Setting some basic vim options
-- Some junk because I am sick of formatting tables in print
local _print = _G.print
local clean_string = function(...)
    local args = { n = select("#", ...), ... }
    local formatted_args = {}
    for i=1, args.n do
        local item = select(i, ...)
        if not item then item = 'nil' end
        local t_type = type(item)
        if t_type == 'table' or t_type == 'function' or t_type == 'userdata' then
            item = vim.inspect(item)
        end
        table.insert(formatted_args, item)
    end
    return table.concat(formatted_args, ' ')
end
_G.print = function(...)
    _print(clean_string(...))
end

vim.opt.mouse = 'a'
vim.opt.termguicolors = true
-- If you want to play around with this, you can set the do_clean
-- variable to false. This will allow changes made to
-- underlying plugins to persist between sessions, while
-- still keeping everything in its own directory so
-- as to not affect your existing neovim installation.
--
-- Setting this to true will result in a fresh clone of
-- all modules
local do_clean = true

local sep = vim.loop.os_uname().sysname:lower():match('windows') and '\\' or '/' -- \ for windows, mac and linux both use \

local mod_path = string.format("%s%sclean-test%s", vim.fn.stdpath('cache'), sep, sep)
if vim.loop.fs_stat(mod_path) and do_clean then
    print("Found previous clean test setup. Cleaning it out")
    -- Clearing out the mods directory and recreating it so 
    -- you have a fresh run everytime
    vim.fn.delete(mod_path, 'rf')
end

vim.fn.mkdir(mod_path, 'p')

local modules = {
    {'nvim-lua/plenary.nvim'},
    {'nvim-tree/nvim-web-devicons'},
    {'willothy/nvim-cokeline', mod = "cokeline"},
}

for _, module in ipairs(modules) do
    local repo = module[1]
    local branch = module.branch
    local module_name = repo:match('/(.*)')
    local module_path = string.format('%s%s%s', mod_path, sep, module_name)
    if not vim.loop.fs_stat(module_name) then
        -- The module doesn't exist, download it
        local cmd = {
            'git',
            'clone'
        }
        if branch then
            table.insert(cmd, '--branch')
            table.insert(cmd, branch)
        end
        table.insert(cmd, string.format('https://github.com/%s', repo))
        table.insert(cmd, module_path)
        vim.fn.system(cmd)
        local message = string.format("Downloaded %s", module_name)
        if branch then
            message = string.format("%s on branch %s", message, branch)
        end
        print(message)
    end
    vim.opt.runtimepath:append(module_path)
end

print("Finished installing plugins. Beginning Setup of plugins")

for _, module in ipairs(modules) do
    if module.mod then
        print(string.format("Loading %s", module.mod))
        local success, err = pcall(require, module.mod)
        if not success then
            print(string.format("Failed to load module %s", module.mod))
            error(err)
        end
    end
end

-- --> Do you module setups below this line <-- --
vim.api.nvim_set_hl(0, 'BufferLineFill', { fg = 'NONE', bg = 'NONE' })
require('cokeline').setup({
    fill_hl = "BufferLineFill",
    default_hl = {
        fg = "NONE",
        bg = "NONE"
    },
    components = {
        {
            text = function(buffer)
                return
                buffer.is_focused and ""
                or " "
            end,
            fg = "NONE",
            bg = "NONE"
        },
        {
            text = function(buffer) return buffer.filename .. ' ' end,
            style = function(buffer)
                if buffer.is_hovered and not buffer.is_focused then
                    return 'underline'
                end
            end
        },
    }
})
-- --> Do your module setups above this line <-- --

print("Completed minimal setup!")

I took a quick peek at the source, but nothing is standing out as overriding the foreground so I don't really know what is happening here.

This functionality is a bit important when you start messing with some of the weirder nerdfonts (such as nf-pl-left_hard_divider) as you have to set the Foreground to the color you want the "background" to be, and the Background to the color you want the foreground to be

[willothy]

Thanks for reporting! I'm currently reworking highlights to use nvim_[get/set]_hl (#150) - I'll make sure this isn't still an issue in that patch.

[willothy]

Hmm... this actually may not be a cokeline issue. I need to look into it more, but even setting fg to "NONE" directly before every call to set_hl has the same result.

[miversen33]

What is really interesting is fg=NONE works just fine on components that aren't active. I don't know if that helps at all. Below is a screenshot of my current cokeline configuration showing this

[willothy]

That is good to know! I'll keep looking into it today.

[willothy]

Quite stumped by this at the moment, but I'll keep trying. Until then, you can use the highlight option to set a highlight group entirely for a component, I'm able to get foreground transparency with that. You might have to create a few highlight groups, but that's the only workaround I've found atm. This is a weird one haha

[willothy]

Idea: why not conditionally use 🭨 when you need no background there instead? As far as I can tell, you can't set fg to none in the tabline in Vim at all.

[miversen33]

Psh, you think I would look at literally any other characters in the powerline fonts? 😂

I will give that a shot and see if it works. It makes sense that is should I think.

[willothy]

Yeah, not sure why setting fg isn't possible but I can't get it to work at all. May be a terminal emulator thing? I'm on Wezterm. I haven't tried other terminals but if they don't work either, it may be worth submitting an issue upstream to Neovim.

And I'm not sure how I thought I got it working before, pretty sure I was just confused because I can't replicate what I described.

[miversen33]

Sorry I hadn't gotten back to you on this. The icon provided isn't in the fonts I have setup for my terminal (I am using wezterm as well). I can see transparent foregrounds just kinda being a pain in the ass to support within neovim itself so it is very possible that this is something that just can't be done (in which case I will need to either accept my current solution of a color that you generally don't see, or fix my font setup to provide a unicode character that will work in my setup).

This may just be a limitation of neovim, you are right. I don't know that I care enough to open up anything upstream on Neovim for this (mainly because I don't want to go through the effort of trying to recreate the issue in a minimal configuration when I don't fully understand where in the highlight process the issue exists in the first place).

Probably worth closing this out unless you want to dig deeper into it lol

[willothy]

Fair, no worries! I use FiraMono so maybe it's nerdfont-specific, though I had thought that Wezterm shipped with nerdfonts by default. Understandable, this is a pretty weird issue, definitely tough to create a plugin-less minimal config.

I'll close this for now, I think I've dug enough into it to conclude that it's just not possible unfortunately, but if I find anything else out I'll reopen this and update.

Hope you find a solution that works!