On Sat, Jul 26, 2025 at 8:28 PM Junio C Hamano [off-list ref] wrote:

"D. Ben Knoble" [off-list ref] writes:

quoted

When asking for short help on a previous command, the user may use their
shell history to recall a command like

    git rebase new-base

Then inserting "-h" after "rebase" doesn't yield the help; make it so.

I doubt this is a good idea for at least two reasons.

As I said in the cover letter, I think this is the most controversial
and can be dropped. However…

 * As "git help cli" says, we should be discouraging, not
   encouraging peope to say "git rebase new-base -h".

…that's not what I'm encouraging here. Instead, it's more like below:

 * "git rebase -h new-base" that shows help is probably a bug (think
   what should happen with s/rebase/grep/) in the first place.

And at least according to my tests, "git grep -h new-base" still greps
rather than shows help. Compare
- "git grep -h squash" (greps squash)
- "git rebase -h @{u}" (shows help)

If anything, we probably should fix the "-h" codepath to

 - react and do the short-help only when "-h" is the only command
   line option; with argument, it should probably barf, saying "-h
   does not take an argument".

I think we have the first half already ("argc == 2" in the preimage).
I'm not interested in writing the second half right now, personally,
if we end up dropping this patch, so someone else could take that up.

 - if "-h" resulted in reported an alias, it should stop there.
   E.g. "git -c alias.x=ls-files x -h" would currently invoke "git
   ls-files -h" after reporting that 'x' is aliased to 'ls-files'.
   If the alias is to one of our commands, it is not too risky, but
   otherwise we should not assume it is safe to append "-h" to the
   underlying command and run it.  Imagine

   $ git -c alias.x='!echo rm -rf .' x -h

   and worse yet, if your alias did not have "echo" in it ;-)???

The only end-user expectation we can safely assume is when they
say,

   $ git frotz -h

is that they would get a help on 'frotz' without doing any harm.
If frotz is an alias to some external command, for which we have no
idea what it would do when we run it with "-h" appended to the
command line, the user would be in a lot of pain if the aliased
operation is destructive.

I think this is being discussed on another series, and I'll leave it there :)