pretty: add merge and exclude options to %(describe)

Allow restricting the tags used by the placeholder %(describe) with the
options match and exclude.  E.g. the following command describes the
current commit using official version tags, without those for release
candidates:

   $ git log -1 --format='%(describe:match=v[0-9]*,exclude=*rc*)'

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

1 files changed, 16 insertions, 0 deletions

diff --git a/t/t4205-log-pretty-formats.sh b/t/t4205-log-pretty-formats.sh
index 5a44fa447d..7e36706212 100755
--- a/t/t4205-log-pretty-formats.sh
+++ b/t/t4205-log-pretty-formats.sh
@@ -972,4 +972,20 @@ test_expect_success '%(describe) vs git describe' '
 	test_must_be_empty err
 '
 
+test_expect_success '%(describe:match=...) vs git describe --match ...' '
+	test_when_finished "git tag -d tag-match" &&
+	git tag -a -m tagged tag-match&&
+	git describe --match "*-match" >expect &&
+	git log -1 --format="%(describe:match=*-match)" >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success '%(describe:exclude=...) vs git describe --exclude ...' '
+	test_when_finished "git tag -d tag-exclude" &&
+	git tag -a -m tagged tag-exclude &&
+	git describe --exclude "*-exclude" >expect &&
+	git log -1 --format="%(describe:exclude=*-exclude)" >actual &&
+	test_cmp expect actual
+'
+
 test_done