Subject: Re: [PATCH/RFC] git-grep: correct exit code with --quiet and -L

From: Junio C Hamano <[email-masked]>
Date: Tue, 15 Aug 2017 14:33:01 -0700

Anthony Sottile <[email-masked]> writes:

> The handling of `status_only` no longer interferes with the handling of
> `unmatch_name_only`.  `--quiet` no longer affects the exit code when using
> `-L`/`--files-without-match`.

I agree with the above statement of yours that --quiet should not
affect what the exit status is.

But I am not sure what the exit code from these commands _should_
be:

    $ git grep -L qfwfq \*.h    ;# no file matches
    $ git grep -L \# \*.h       ;# some but not all files match
    $ git grep -L . \*.h        ;# all files match

with or without --quiet.  I seem to get 0, 0, 1, which I am not sure
is correct.  I do recall writing "git grep" _without_ thinking what
the exit code should be when we added --files-without-match, so the
exit status the current code gives out may be just a random garbage.

Asking GNU grep (because --files-without-match is not a POSIX thing):

    $ grep -L qfwfq *.h          ;# no file matches
    $ grep -L \# *.h             ;# some but not all files match
    $ grep -L . *.h              ;# all files match

I seem to get 1, 0, 0.  So the exit status should reflect if there
was _any_ hit from any file that were inspected.

> @@ -1755,7 +1755,7 @@ static int grep_source_1(struct grep_opt *opt, struct grep_source *gs, int colle
>  		}
>  		if (hit) {
>  			count++;
> -			if (opt->status_only)
> +			if (!opt->unmatch_name_only && opt->status_only)
>  				return 1;
>  			if (opt->name_only) {
>  				show_name(opt, gs->name);

Does the change in this hunk have any effect?

Just before this hunk there is this code:

		/* "grep -v -e foo -e bla" should list lines
		 * that do not have either, so inversion should
		 * be done outside.
		 */
		if (opt->invert)
			hit = !hit;
		if (opt->unmatch_name_only) {
			if (hit)
				return 0;
			goto next_line;

If (opt->unmatch_name_only && hit) then the function would have
already returned and the control wouldn't have reached here.

Which would mean that when the control reaches the line this hunk
touches, either one of these must be false, and because we are
inside "if (hit)", opt->unmatch_name_only must be false.

> @@ -1820,13 +1820,14 @@ static int grep_source_1(struct grep_opt *opt, struct grep_source *gs, int colle
>  	if (collect_hits)
>  		return 0;
>  
> -	if (opt->status_only)
> -		return 0;
>  	if (opt->unmatch_name_only) {
>  		/* We did not see any hit, so we want to show this */
> -		show_name(opt, gs->name);
> +		if (!opt->status_only)
> +			show_name(opt, gs->name);
>  		return 1;
>  	}
> +	if (opt->status_only)
> +		return 0;

This hunk makes sense to me (provided if the semantics we want out
of --files-without-match is sensible, which is dubious), even though
I would have limited the change to just a single line, i.e.

	if (opt->status_only)
-		return 0;
+		return opt->unmatch_name_only;
	if (opt->unmatch_name_only) {
		/* We did not see any hit, ... */

But I suspect we want to fix the exit code not to be affected by
the "--files-without-match" option in the first place, so all the
code changes we see in this patch might be moot X-<.