Re: [PATCH v2] help: colorize man pages

From: Junio C Hamano <gitster@pobox.com>
Date: May 18, 2021, 14:50 UTC
Message-ID: <xmqqa6os2j05.fsf@gitster.g>
In-Reply-To: <20210518132056.2003135-1-felipe.contreras@gmail.com>

Felipe Contreras <felipe.contreras@gmail.com> writes:

Show 5 quoted lines

> +color.man::
> +	When set to `always`, always colorize the man pages. When `false`
> +	(or `never`), never.  When set to `true` or `auto`, use color only
> +	when the output is written to the terminal. If unset, then the
> +	value of `color.ui` is used (`auto` by default).

Makes sense and is more in line with the rest of the system to have subcommand specific color.* variable.

There are two things that make me wonder in the above description, though.

Show 20 quoted lines

> +static void colorize_man(void)
> +{
> +	if (!want_color(man_color) || !pager_use_color)
> +		return;
> +
> +	/* Disable groff colors */
> +	setenv("GROFF_NO_SGR", "1", 0);
> +
> +	/* Bold */
> +	setenv("LESS_TERMCAP_md", GIT_COLOR_BOLD_RED, 0);
> +	setenv("LESS_TERMCAP_me", GIT_COLOR_RESET, 0);
> +
> +	/* Underline */
> +	setenv("LESS_TERMCAP_us", GIT_COLOR_BLUE GIT_COLOR_UNDERLINE, 0);
> +	setenv("LESS_TERMCAP_ue", GIT_COLOR_RESET, 0);
> +
> +	/* Standout */
> +	setenv("LESS_TERMCAP_so", GIT_COLOR_MAGENTA GIT_COLOR_REVERSE, 0);
> +	setenv("LESS_TERMCAP_se", GIT_COLOR_RESET, 0);
> +}

This seems very specific to use of "less" and hopefully does not do anything (bad) when a different pager is used by "man".

 - Would it help readers to somehow tell that color.man does not
   apply at all to those whose "man" does not "less" in the
   documentation?

 - What does it mean to set this variable to "always"?  For commands
   that we control how the various pieces of output are colored (or
   not), e.g.

   $ git -c color.ui=always log -1 -p >git-log-output.txt

   it is obvious what "always" means, but given the implementation
   that tweaks how "less" should behave, a similar command (below)
   would not colorize its output like the "git log" example above
   does, would it?

   $ git -c color.man=always help -m git >git-help-text.txt

I am just wondering if we are better off not to mention "always" in the documentation patch above. It seems more like that the configuration variable is to answer this question and nothing else:

    when 'git help' shows manual pages and internally uses 'less' as
    its pager, do we tell it to colorize the output?

for which sensible answers are 'true' or 'false'. For that matter, it is not clear what "auto" ought to mean, either.

Thanks.