Re: [PATCH] git: show alias info only with lone -h

>
> I have a few (unsent) patches I've been working on that touch the help
> mechanism, so I have some thoughts below.
>
> On Sat, Jul 26, 2025 at 4:13 AM Jeff King <peff@peff.net> wrote:
> >
> > On Fri, Jul 25, 2025 at 04:52:40PM -0700, Junio C Hamano wrote:
> >
> > > When it redirects to our commands, it is less risky as we aim to
> > > make all our commands honor a single "-h" via t0450.
> > >
> > >    $ git -c alias.c=checkout c -h
> > >    'c' is aliased to 'checkout'
> > >    usage: git checkout [<options>] <branch>
> > >       or: git checkout [<options>] [<branch>] -- <file>...
> > >
> > >        -b <branch>           create and checkout a new branch
> > >        -B <branch>           create/reset and checkout a branch
> > >    ...
> > >        --pathspec-from-file <file>
> > >                              read pathspec from file
> > >        --pathspec-file-nul   with --pathspec-from-file, pathspec elements are separated with NUL character
> > >
> > > But then, it may not be such a good idea to pay attention to "do we
> > > have extra '-h'?" when alias expands to our commands, e.g.
> >
> > Another interesting case: even for our own commands, the alias itself
> > may add extra arguments, which confuses things further. So:
> >
> >   $ git -c alias.gi='grep --cached' gi -h
> >   'gi' is aliased to 'grep --cached'
> >   fatal: no pattern given
> >
> > runs git-grep, but even though the user said only "-h" the alias added
> > another option which prevents the help-mode from activating.
> >
> > In this case it is not too harmful, but you can come up with
> > pathological cases where it actually runs a real command:
> >
> >   git -c alias.grep-for-foo='grep -e foo' grep-for-foo -h
> >
> > which runs a real grep.
> >
> > I guess one way to deal with it would be if the user runs "foo -h", and
> > alias.foo is "bar --other arguments", then we run just "bar -h",
> > dropping the extra arguments provided by the alias.
>
> This is intriguing: it would mean that an alias is not purely a
> textual replacement? That's true for ! aliases today, but other than
> shelling out it's pretty close.