log: let --invert-grep only invert --grep

The option --invert-grep is documented to filter out commits whose
messages match the --grep filters.  However, it also affects the
header matches (--author, --committer), which is not intended.

Move the handling of that option to grep.c, as only the code there can
distinguish between matches in the header from those in the message
body.  If --invert-grep is given then enable extended expressions (not
the regex type, we just need git grep's --not to work), negate the body
patterns and check if any of them match by piggy-backing on the
collect_hits mechanism of grep_source_1().

Collecting the matches in struct grep_opt is a bit iffy, but with
"last_shown" we have a precedent for writing state information to that
struct.

Reported-by: Dotan Cohen <dotancohen@gmail.com>
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

grep.c

@@ -699,6 +699,14 @@ static struct grep_expr *compile_pattern_expr(struct grep_pat **list)
 	return compile_pattern_or(list);
 }
 
+static struct grep_expr *grep_not_expr(struct grep_expr *expr)
+{
+	struct grep_expr *z = xcalloc(1, sizeof(*z));
+	z->node = GREP_NODE_NOT;
+	z->u.unary = expr;
+	return z;
+}
+
 static struct grep_expr *grep_true_expr(void)
 {
 	struct grep_expr *z = xcalloc(1, sizeof(*z));
@@ -797,7 +805,7 @@ void compile_grep_patterns(struct grep_opt *opt)
 		}
 	}
 
-	if (opt->all_match || header_expr)
+	if (opt->all_match || opt->no_body_match || header_expr)
 		opt->extended = 1;
 	else if (!opt->extended)
 		return;
@@ -808,6 +816,9 @@ void compile_grep_patterns(struct grep_opt *opt)
 	if (p)
 		die("incomplete pattern expression: %s", p->pattern);
 
+	if (opt->no_body_match && opt->pattern_expression)
+		opt->pattern_expression = grep_not_expr(opt->pattern_expression);
+
 	if (!header_expr)
 		return;
 
@@ -1057,6 +1068,8 @@ static int match_expr_eval(struct grep_opt *opt, struct grep_expr *x,
 			if (h && (*col < 0 || tmp.rm_so < *col))
 				*col = tmp.rm_so;
 		}
+		if (x->u.atom->token == GREP_PATTERN_BODY)
+			opt->body_hit |= h;
 		break;
 	case GREP_NODE_NOT:
 		/*
@@ -1825,16 +1838,19 @@ int grep_source(struct grep_opt *opt, struct grep_source *gs)
 	 * we do not have to do the two-pass grep when we do not check
 	 * buffer-wide "all-match".
 	 */
-	if (!opt->all_match)
+	if (!opt->all_match && !opt->no_body_match)
 		return grep_source_1(opt, gs, 0);
 
 	/* Otherwise the toplevel "or" terms hit a bit differently.
 	 * We first clear hit markers from them.
 	 */
 	clr_hit_marker(opt->pattern_expression);
+	opt->body_hit = 0;
 	grep_source_1(opt, gs, 1);
 
-	if (!chk_hit_marker(opt->pattern_expression))
+	if (opt->all_match && !chk_hit_marker(opt->pattern_expression))
+		return 0;
+	if (opt->no_body_match && opt->body_hit)
 		return 0;
 
 	return grep_source_1(opt, gs, 0);

grep.h

@@ -148,6 +148,8 @@ struct grep_opt {
 	int word_regexp;
 	int fixed;
 	int all_match;
+	int no_body_match;
+	int body_hit;
 #define GREP_BINARY_DEFAULT	0
 #define GREP_BINARY_NOMATCH	1
 #define GREP_BINARY_TEXT	2

revision.c

@@ -2493,7 +2493,7 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
 	} else if (!strcmp(arg, "--all-match")) {
 		revs->grep_filter.all_match = 1;
 	} else if (!strcmp(arg, "--invert-grep")) {
-		revs->invert_grep = 1;
+		revs->grep_filter.no_body_match = 1;
 	} else if ((argcount = parse_long_opt("encoding", argv, &optarg))) {
 		if (strcmp(optarg, "none"))
 			git_log_output_encoding = xstrdup(optarg);
@@ -3778,7 +3778,7 @@ static int commit_match(struct commit *commit, struct rev_info *opt)
 				     (char *)message, strlen(message));
 	strbuf_release(&buf);
 	unuse_commit_buffer(commit, message);
-	return opt->invert_grep ? !retval : retval;
+	return retval;
 }
 
 static inline int want_ancestry(const struct rev_info *revs)

revision.h

@@ -246,8 +246,6 @@ 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

@@ -2010,4 +2010,23 @@ test_expect_success 'log --end-of-options' '
        test_cmp expect actual
 '
 
+test_expect_success 'set up commits with different authors' '
+	git checkout --orphan authors &&
+	test_commit --author "Jim <jim@example.com>" jim_1 &&
+	test_commit --author "Val <val@example.com>" val_1 &&
+	test_commit --author "Val <val@example.com>" val_2 &&
+	test_commit --author "Jim <jim@example.com>" jim_2 &&
+	test_commit --author "Val <val@example.com>" val_3 &&
+	test_commit --author "Jim <jim@example.com>" jim_3
+'
+
+test_expect_success 'log --invert-grep --grep --author' '
+	cat >expect <<-\EOF &&
+	val_3
+	val_1
+	EOF
+	git log --format=%s --author=Val --grep 2 --invert-grep >actual &&
+	test_cmp expect actual
+'
+
 test_done