Merge branch 'cj/log-invert-grep'

"git log --invert-grep --grep=WIP" will show only commits that do
not have the string "WIP" in their messages.

* cj/log-invert-grep:
  log: teach --invert-grep option

Documentation/rev-list-options.txt

@@ -66,6 +66,10 @@ if it is part of the log message.
 	Limit the commits output to ones that match all given `--grep`,
 	instead of ones that match at least one.
 
+--invert-grep::
+	Limit the commits output to ones with log message that do not
+	match the pattern specified with `--grep=<pattern>`.
+
 -i::
 --regexp-ignore-case::
 	Match the regular expression limiting patterns without regard to letter

contrib/completion/git-completion.bash

@@ -1425,7 +1425,7 @@ __git_log_gitk_options="
 # Options that go well for log and shortlog (not gitk)
 __git_log_shortlog_options="
 	--author= --committer= --grep=
-	--all-match
+	--all-match --invert-grep
 "
 
 __git_log_pretty_formats="oneline short medium full fuller email raw format:"

revision.c

@@ -2017,6 +2017,8 @@ 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);
@@ -2915,7 +2917,7 @@ 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)

revision.h

@@ -169,6 +169,8 @@ struct rev_info {
 
 	/* Filter by commit log message */
 	struct grep_opt	grep_filter;
+	/* Negate the match of grep_filter */
+	int invert_grep;
 
 	/* Display history graph */
 	struct git_graph *graph;

t/t4202-log.sh

@@ -212,6 +212,21 @@ test_expect_success 'log --grep' '
 	test_cmp expect actual
 '
 
+cat > expect << EOF
+second
+initial
+EOF
+test_expect_success 'log --invert-grep --grep' '
+	git log --pretty="tformat:%s" --invert-grep --grep=th --grep=Sec >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'log --invert-grep --grep -i' '
+	echo initial >expect &&
+	git log --pretty="tformat:%s" --invert-grep -i --grep=th --grep=Sec >actual &&
+	test_cmp expect actual
+'
+
 test_expect_success 'log --grep option parsing' '
 	echo second >expect &&
 	git log -1 --pretty="tformat:%s" --grep sec >actual &&