revision.c: make --no-notes reset --notes list

With most command line options, later instances of an option
override earlier ones. With cumulative options like
"--notes", however, there is no way to say "forget the
--notes I gave you before".

Let's have --no-notes trigger this forgetting, so that:

  git log --notes=foo --no-notes --notes=bar

will show only the "bar" notes.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

revision.c

@@ -1389,6 +1389,12 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
 	} else if (!strcmp(arg, "--no-notes")) {
 		revs->show_notes = 0;
 		revs->show_notes_given = 1;
+		revs->notes_opt.use_default_notes = -1;
+		/* we have been strdup'ing ourselves, so trick
+		 * string_list into free()ing strings */
+		revs->notes_opt.extra_notes_refs.strdup_strings = 1;
+		string_list_clear(&revs->notes_opt.extra_notes_refs, 0);
+		revs->notes_opt.extra_notes_refs.strdup_strings = 0;
 	} else if (!strcmp(arg, "--standard-notes")) {
 		revs->show_notes_given = 1;
 		revs->notes_opt.use_default_notes = 1;

t/t3301-notes.sh

@@ -269,6 +269,22 @@ test_expect_success 'git log --notes --notes=X shows both' '
 	grep alternate output
 '
 
+test_expect_success 'git log --no-notes resets default state' '
+	git log -1 --notes --notes=alternate \
+		--no-notes --notes=alternate \
+		>output &&
+	! grep xyzzy output &&
+	grep alternate output
+'
+
+test_expect_success 'git log --no-notes resets ref list' '
+	git log -1 --notes --notes=alternate \
+		--no-notes --notes \
+		>output &&
+	grep xyzzy output &&
+	! grep alternate output
+'
+
 test_expect_success 'create -m notes (setup)' '
 	: > a5 &&
 	git add a5 &&