Re: [PATCH] help: allow redirecting to help for aliased command

From: Taylor Blau <me@ttaylorr.com>
Date: Sep 26, 2018, 18:12 UTC
Message-ID: <20180926181251.GB63889@syl>
In-Reply-To: <xmqqzhw4mgq3.fsf@gitster-ct.c.googlers.com>

On Wed, Sep 26, 2018 at 08:16:36AM -0700, Junio C Hamano wrote:

Show 30 quoted lines

> Rasmus Villemoes <rv@rasmusvillemoes.dk> writes:
>
> > I often use 'git <cmd> --help' as a quick way to get the documentation
> > for a command. However, I've also trained my muscle memory to use my
> > aliases (cp=cherry-pick, co=checkout etc.), which means that I often end
> > up doing
> >
> >   git cp --help
> >
> > to which git correctly informs me that cp is an alias for
> > cherry-pick. However, I already knew that, and what I really wanted was
> > the man page for the cherry-pick command.
> >
> > This introduces a help.followAlias config option that transparently
> > redirects to (the first word of) the alias text (provided of course it
> > is not a shell command), similar to the option for autocorrect of
> > misspelled commands.
>
> While I do agree with you that it would sometimes be very handy if
> "git cp --help" behaved identically to "git cherry-pick --help" just
> like "git cp -h" behaves identically to "git cherry-pick -h" when
> you have "[alias] cp = cherry-pick", I do not think help.followAlias
> configuration is a good idea.  I may know, perhaps because I use it
> all the time, by heart that "cp" is aliased to "cherry-pick" and
> want "git cp --help" to directly give me the manpage, but I may not
> remember if "co" was commit or checkout and want to be concisely
> told that it is aliased to checkout without seeing the full manpage.
> Which means you'd want some way to command line override anyway, and
> having to say "git -c help.followAlias=false cp --help" is not a
> great solution.

I think I responded partially to this hunk in another thread, but I think I can add some additional information here where it is more relevant.

One approach to take when digesting this is that 'git co --help' shows you the manual page for 'git-checkout(1)' (or whatever you have it aliased to), so that answers the question for the caller who has a terminal open.

In the case where you are scripting (and want to know what 'git co' means for programmatic usage), I think that there are two options. One, which you note above, is the 'git -c help.followAlias=false ...' approach, which I don't think is so bad for callers, given the tradeoff.

Another way to go is 'git config alias.co', which should provide the same answer. I think that either would be fine.

Perhaps we could assume that 'help.followAlias' is false when it is unset, _and_ isatty(2) says that we aren't a TTY. Otherwise, since I feel that this is a good feature that should be the new default, we can assume it's set to true.

Thanks, Taylor