Re: [PATCH] diff-lib.c: Fix diff-files --diff-filter --quiet exit code

Jakob Pfender [off-list ref] writes:

Given the following status:

	$ git status -s
	 M bar
	UU foo

There is an unexpected difference in the return code of git diff-files
when used with --quiet as opposed to --exit-code:

	$ git diff-files --diff-filter=U --quiet
	$ echo $?
	0

	$ git diff-files --diff-filter=U --exit-code
	<usual output, lots of 0's and U<TAB>foo>
	$ echo $?
	1

Notice the different return codes. Now, according to the documentation,
--quiet implies --return-code. However, the return code of the former is
clearly not correct if --return-code was supposed to be on.

This patch removes a useless bit of code that caused the return codes to
differ.

How did you determine it is "useless bit"?

The code notices that the caller, by specifying --quiet, does not want any
details of the changes and instead wants to know if there is a change or
not.  And it breaks out of the loop because it already found what it
wanted to know, namely, there is a change.

When you have a post-process filter (like -w or -S), the path we found to
be different here may be uninteresting and there may be no output (hence
we should exit with status 0).  So it is true that the optimization you
are removing needs to be disabled in _some_ situations, and the current
code doesn't, and it needs fixing.

But is it a justifiable fix to disable the optimization for even the
normal cases?