format-patch: use --notes behavior for format.notes

When we had multiple `format.notes` config values where we had `<ref1>`,
`false`, `<ref2>` (in that order), then we would print out the notes for
both `<ref1>` and `<ref2>`. This doesn't make sense, however, since we
parse the config in a top-down manner and a `false` should be able to
override previous configurations, just like how `--no-notes` will
override previous `--notes`.

Duplicate the logic that handles the `--[no-]notes[=]` option to
`format.notes` for consistency. As a result, when parsing the config
from top to bottom, `format.notes = true` will behave like `--notes`,
`format.notes = <ref>` will behave like `--notes=<ref>` and
`format.notes = false` will behave like `--no-notes`.

This change isn't strictly backwards compatible but since it is an edge
case where a sane user would not mix notes refs with `false` and this
feature is relatively new (released only in v2.23.0), this change should
be harmless.

Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/log.c

@@ -867,19 +867,8 @@ static int git_format_config(const char *var, const char *value, void *cb)
 		return 0;
 	}
 	if (!strcmp(var, "format.notes")) {
-		struct strbuf buf = STRBUF_INIT;
 		int b = git_parse_maybe_bool(value);
-		if (!b)
-			return 0;
-		rev->show_notes = 1;
-		if (b < 0) {
-			strbuf_addstr(&buf, value);
-			expand_notes_ref(&buf);
-			string_list_append(&rev->notes_opt.extra_notes_refs,
-					strbuf_detach(&buf, NULL));
-		} else {
-			rev->notes_opt.use_default_notes = 1;
-		}
+		rev->show_notes = set_display_notes(&rev->notes_opt, b, b < 0 ? value : NULL);
 		return 0;
 	}
 

t/t4014-format-patch.sh

@@ -808,6 +808,38 @@ test_expect_success 'format-patch with multiple notes refs' '
 	! grep "this is note 2" out
 '
 
+test_expect_success 'format-patch with multiple notes refs in config' '
+	test_when_finished "test_unconfig format.notes" &&
+
+	git notes --ref note1 add -m "this is note 1" HEAD &&
+	test_when_finished git notes --ref note1 remove HEAD &&
+	git notes --ref note2 add -m "this is note 2" HEAD &&
+	test_when_finished git notes --ref note2 remove HEAD &&
+
+	git config format.notes note1 &&
+	git format-patch -1 --stdout >out &&
+	grep "this is note 1" out &&
+	! grep "this is note 2" out &&
+	git config format.notes note2 &&
+	git format-patch -1 --stdout >out &&
+	! grep "this is note 1" out &&
+	grep "this is note 2" out &&
+	git config --add format.notes note1 &&
+	git format-patch -1 --stdout >out &&
+	grep "this is note 1" out &&
+	grep "this is note 2" out &&
+
+	git config --replace-all format.notes note1 &&
+	git config --add format.notes false &&
+	git format-patch -1 --stdout >out &&
+	! grep "this is note 1" out &&
+	! grep "this is note 2" out &&
+	git config --add format.notes note2 &&
+	git format-patch -1 --stdout >out &&
+	! grep "this is note 1" out &&
+	grep "this is note 2" out
+'
+
 echo "fatal: --name-only does not make sense" > expect.name-only
 echo "fatal: --name-status does not make sense" > expect.name-status
 echo "fatal: --check does not make sense" > expect.check