built-in commenting does not use whitespaces depending on 'commentstring' about neovim

[clason]

If there are no spaces in the 'commentstring', there will be no spaces in the comment.

This is intentional. Feel free to contact the filetype plugin maintainers to change this in Vim.

[clason]

When considered from the user's perspective.

That is not the only relevant perspective, though, and this was chosen as a deliberate compromise.

I understand that the filetype plugin is managed by another people and there is nothing you can do about it.

But you (who clearly care about this) can: contact the maintainer and ask them to add spaces. If they do, the changes will end up here and make you happy.

[BoltsJ]

FWIW, the built in Vim comment plugin puts in the spaces, so nvim's behavior here differs from upstream Vim.

[umlx5h]

Okay, I'll use another plugin since it doesn't seem to solve the problem.
I just don't think it is appropriate as the default behavior.

[clason]

It is exactly because it's default behavior that this is appropriate. It's supposed to be a minimal implementation leveraging existing builtin functionality, not being a VS Code kitchen sink. And, yes, using a more full-featured plugin because you need the additional functionality is perfectly fine (and also intended use).

[umlx5h]

It is exactly because it's default behavior that this is appropriate.

it may be appropriate in terms of implementation, but it is not appropriate when looking at just the function of commenting. When considered from the user's perspective.

VSCode is just an example of this. If you know an editor that does not use spaces, please let me know.

I understand that the filetype plugin is managed by another people and there is nothing you can do about it.

[mkalinski]

In case someone finds this having the same issue: if you want to have spaces in commentstring for every filetype without having to contact maintainers for every odd ftplugin, it can be done quite easily with an autocommand:

vim.api.nvim_create_autocmd('FileType', {
    group = vim.api.nvim_create_augroup('commentstring_fix', {}),
    callback = function(ctx)
        local cms_value = vim.api.nvim_get_option_value(
            'commentstring',
            {buf = ctx.buf}
        )

        -- Note that this is the literal '%s'.
        -- All other '%s' in this function are patterns.
        local s_start, s_end = string.find(cms_value, '%s', 1, true)

        if s_start == nil then
            return
        end

        local s_before = s_start - 1
        local s_after = s_end + 1
        local s_prepend = ''
        local s_append = ''

        if s_start > 1
            and string.find(
                string.sub(cms_value, s_before, s_before),
                '%s'
            ) == nil
        then
            s_prepend = ' '
        end

        if s_end < #cms_value
            and string.find(
                string.sub(cms_value, s_after, s_after),
                '%s'
            ) == nil
        then
            s_append = ' '
        end

        if s_prepend ~= '' or s_append ~= '' then
            vim.api.nvim_set_option_value(
                'commentstring',
                table.concat{
                    string.sub(cms_value, 1, s_before),
                    s_prepend,
                    '%s',
                    s_append,
                    string.sub(cms_value, s_after)
                },
                {buf = ctx.buf}
            )
        end
    end
})