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

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

SZEDER Gábor <szeder.dev@gmail.com> writes:

> I think we should check whether the '--no-index' option is present on
> the command line, and simply not call __git_complete_index_file() if
> it is, to let Bash list all paths; i.e. each of those calls should be
> protected by an additional 'if test -z "$(__git_find_on_cmdline
> "--no-index")' condition, perhaps.


Ah, I did not think of the "we made 'git diff' work without Git"
mode at all.

But I would avoid scanning the command line for '--no-index' for two
reasons:

 (1) "git diff -S --no-index maint master" would not give you the
     '--no-index' mode.

 (2) When run outside the working tree of a repository, you do not
     have to say '--no-index'.

These make detecting the "'git diff' but not Git" mode tedious and
error-prone.

I have not tried this, but if we arranged the code to fall back
further to Bash-native "paths in $PWD" after the completion code in
the posted patch found nothing, would it be sufficient?

When trying to complete an untracked file in the working tree of a
repository, if the file shares the same prefix with a tracked file,
you cannot complete the untracked file without a prefix long enough
to disambiguate it from the tracked one.  Such a prefix may not even
exist (e.g., 'foo' is tracked and 'foo~' is untracked; when you type
"git diff --no-index foo<TAB>", you get 'foo' but not 'foo~', so you
end up typing 'foo~' in full).  In that sense, it is a regression,
but supporting Git usage is the primary mission of 'git diff', so
the trade-off may not be so bad.

Thoughts?