Re: Itches with the current rev spec

[Michael J Gruber <git@drmicha.warpmail.net>]

Matthieu Moy venit, vidit, dixit 25.04.2013 10:22:
> Ramkumar Ramachandra <artagnon@gmail.com> writes:
> 
>> Hi,
>>
>> So, I have three serious itches that would be nice to address:
>>
>> 1. git reset --hard HEAD~1/ git show HEAD~1 is a very common idiom
>> that's unnecessarily cumbersome to type out.  We can make the <rev>
>> part of <rev>~<n> optional without being ambiguous: you might argue
>> that ~<n> normally refers to a /home/<n>, but who uses numbers in
>> place of usernames?  Even if they do, how can that path possibly be
>> inside our repository?
> 
> It's a bit more complex than that: the ~<username> is expanded by the
> shell, before Git has any opportunity to guess anything.
> 
> ~1 would be unusable for zsh users and tcsh users at least by default:
> 
> zsh% echo ~1
> zsh: not enough directory stack entries.
> 
> tcsh% echo ~1
> Unknown user: 1.
> 
> (An obvious workaround is to shell-quote it, but as the goal is to have
> something easy to type, \~1 or '~1' do not give so much benefit over
> HEAD~1)
> 
> That said, it seems to work fine for bash (even if the number is a PID,
> it's not expanded), so it may be a good idea to add it as a shortcut,
> with a warning in the doc about shell expansion.

I've been using a patch for that for ages without problems; it had been
rejected because of the reasons above, plus:

Note that even in bash ~1 has a different meaning when your directory
stack is non-empty. It's just that I don't use that feature, and bash
leaves '~1' as is when there is no stack (you haven't used pushd),
whereas zsh errors out.

So, I do understand that some consider this semi-broken, even though
it's not. But we avoid clashes with shell expansion in most cases for
most shells.

As for rebase, I still have to look up what "git rebase A B" means. This
would be much clearer with a range notation. I seem to recall I even
suggested it, but that might have been in a parallel universe.

Michael