log: teach --invert-grep option

"git log --grep=<string>" shows only commits with messages that
match the given string, but sometimes it is useful to be able to
show only commits that do *not* have certain messages (e.g. "show
me ones that are not FIXUP commits").

Originally, we had the invert-grep flag in grep_opt, but because
"git grep --invert-grep" does not make sense except in conjunction
with "--files-with-matches", which is already covered by
"--files-without-matches", it was moved it to revisions structure.
To have the flag there expresses the function to the feature better.

When the newly inserted two tests run, the history would have commits
with messages "initial", "second", "third", "fourth", "fifth", "sixth"
and "Second", committed in this order.  The commits that does not match
either "th" or "Sec" is "second" and "initial". For the case insensitive
case only "initial" matches.

Signed-off-by: Christoph Junghans <ottxor@gentoo.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/revision.c b/revision.c
index 615535c..84b33a3 100644
--- a/revision.c
+++ b/revision.c
@@ -1952,6 +1952,8 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
 		grep_set_pattern_type_option(GREP_PATTERN_TYPE_PCRE, &revs->grep_filter);
 	} else if (!strcmp(arg, "--all-match")) {
 		revs->grep_filter.all_match = 1;
+	} else if (!strcmp(arg, "--invert-grep")) {
+		revs->invert_grep = 1;
 	} else if ((argcount = parse_long_opt("encoding", argv, &optarg))) {
 		if (strcmp(optarg, "none"))
 			git_log_output_encoding = xstrdup(optarg);
@@ -2848,7 +2850,7 @@ static int commit_match(struct commit *commit, struct rev_info *opt)
 				     (char *)message, strlen(message));
 	strbuf_release(&buf);
 	unuse_commit_buffer(commit, message);
-	return retval;
+	return opt->invert_grep ? !retval : retval;
 }
 
 static inline int want_ancestry(const struct rev_info *revs)