Re: git diff --quiet exits with 1 on clean tree with CRLF conversions

[Mike Crowe <mac@mcrowe.com>]

On Friday 17 February 2017 at 14:05:17 -0800, Junio C Hamano wrote:
> Mike Crowe <mac@mcrowe.com> writes:
> 
> > If "git diff --quiet" finds it necessary to compare actual file contents,
> > and a file requires CRLF conversion, then it incorrectly exits with an exit
> > code of 1 even if there have been no changes.
> >
> > The patch below adds a test file that shows the problem.
> 
> If "git diff" does not show any output and "git diff --exit-code" or
> "git diff --quiet" says there are differences, then it is a bug.
> 
> I would however have expected that any culprit would involve a code
> that says "under QUICK option, we do not have to bother doing
> this".  The part you quoted:
> 
> > 	if (!DIFF_FILE_VALID(p->one) || /* (1) */
> > 	    !DIFF_FILE_VALID(p->two) ||
> > 	    (p->one->oid_valid && p->two->oid_valid) ||
> > 	    (p->one->mode != p->two->mode) ||
> > 	    diff_populate_filespec(p->one, CHECK_SIZE_ONLY) ||
> > 	    diff_populate_filespec(p->two, CHECK_SIZE_ONLY) ||
> > 	    (p->one->size != p->two->size) ||
> > 	    !diff_filespec_is_identical(p->one, p->two)) /* (2) */
> > 		p->skip_stat_unmatch_result = 1;
> 
> is used by "git diff" with and without "--quiet", afacr, so I
> suspect that the bug lies somewhere else.

I can't say that I really understand the code fully, but it appears that
the first pass generates a queue of files that contain differences. The
result of the quiet diff comes from the size of that queue,
diff_queued_diff.nr, being non-zero in diffcore_std. I'm assuming that the
result of the noisy diff comes from actually comparing the files.

But, I've only spent a short while looking so I may have got the wrong end
of the stick.

Thanks.

Mike.