Deferred syntax loading overrides other colorschemes

[gregorias]

The deferred colorscheme update in https://github.com/eddyekofo94/gruvbox-flat.nvim/blame/172269867994c0da7adcf02e89a068cda85eb805/lua/gruvbox/util.lua#L206 can cause gruvbox-flat to override other colorscheme if two ColorScheme events happen next to each other.

This is a real situation as I have a function that updates colorscheme based on a global variable:

local update = function()
    -- Based on my measurements on MacBook Air M2, this function takes 0.2 ms
    -- w/o colorscheme change, and 4ms when a colorscheme change happens.
    local f = io.open("/Users/grzesiek/.config/fish/BACKGROUND.variable", "r")
    if not f then
        return nil
    end
    local contents = f:read("*a")
    f:close()

    if vim.o.background == "light" and contents.find(contents, "dark") then
        vim.o.background = "dark"
        vim.cmd("colorscheme gruvbox-flat")
    elseif vim.o.background == "dark" and contents.find(contents, "light") then
        vim.o.background = "light"
        vim.cmd("colorscheme gruvbox-material")
    end
end

The background change followed by colorscheme generates two ColorScheme events.

Could we just delete the deferred update?