Re: [PATCH] completion: complete tracked paths for 'git diff'

[Junio C Hamano <gitster@pobox.com>]

Junio C Hamano <gitster@pobox.com> writes:

> When completing arguments for 'git diff', _git_diff() delegates to
> __git_complete_revlist_file(), which only completes revision
> references.  This is good [*], as mixing both revs and paths in a
> single list to have the user pick is simply too confusing.
>
> If no reference matches, or if '--' is given, however, _git_diff()
> leaves COMPREPLY empty. Bash then falls back to default filename
> completion in $PWD. This fails when 'git -C <path>' is used because
> $PWD is not the target repository.
>
> Update _git_diff() to use __git_complete_index_file() when '--' is
> present, or when revision reference completion yields no matching
> candidates, so that tracked paths are offered as candidates.

This changes behavior even in the case where '-C <there>' is not
used.  The new behavior omits untracked paths from suggestions,
which is clearly better behavior.

I'll add the above paragraph to the proposed log message when I
queue this on 'seen'.