pretty format %(trailers): add a "keyonly"

Add support for a "keyonly". This allows for easier parsing out of the
key and value. Before if you didn't want to make assumptions about how
the key was formatted. You'd need to parse it out as e.g.:

    --pretty=format:'%H%x00%(trailers:separator=%x00%x00)' \
                       '%x00%(trailers:separator=%x00%x00,valueonly)'

And then proceed to deduce keys by looking at those two and
subtracting the value plus the hardcoded ": " separator from the
non-valueonly %(trailers) line. Now it's possible to simply do:

    --pretty=format:'%H%x00%(trailers:separator=%x00%x00,keyonly)' \
                    '%x00%(trailers:separator=%x00%x00,valueonly)'

Which at least reduces it to a state machine where you get N keys and
correlate them with N values. Even better would be to have a way to
change the ": " delimiter to something easily machine-readable (a key
might contain ": " too). A follow-up change will add support for that.

I don't really have a use-case for just "keyonly" myself. I suppose it
would be useful in some cases as "key=*" matches case-insensitively,
so a plain "keyonly" will give you the variants of the keys you
matched. I'm mainly adding it to fix the inconsistency with
"valueonly".

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 30 insertions, 1 deletions

diff --git a/t/t4205-log-pretty-formats.sh b/t/t4205-log-pretty-formats.sh
index cb09a13..4c9f6eb 100755
--- a/t/t4205-log-pretty-formats.sh
+++ b/t/t4205-log-pretty-formats.sh
@@ -715,6 +715,22 @@ test_expect_success '%(trailers:key) without value is error' '
 	test_cmp expect actual
 '
 
+test_expect_success '%(trailers:keyonly) shows only keys' '
+	git log --no-walk --pretty="format:%(trailers:keyonly)" >actual &&
+	test_write_lines \
+		"Signed-off-by" \
+		"Acked-by" \
+		"[ v2 updated patch description ]" \
+		"Signed-off-by" >expect &&
+	test_cmp expect actual
+'
+
+test_expect_success '%(trailers:key=foo,keyonly) shows only key' '
+	git log --no-walk --pretty="format:%(trailers:key=Acked-by,keyonly)" >actual &&
+	echo "Acked-by" >expect &&
+	test_cmp expect actual
+'
+
 test_expect_success '%(trailers:key=foo,valueonly) shows only value' '
 	git log --no-walk --pretty="format:%(trailers:key=Acked-by,valueonly)" >actual &&
 	echo "A U Thor <author@example.com>" >expect &&
@@ -732,6 +748,12 @@ test_expect_success '%(trailers:valueonly) shows only values' '
 	test_cmp expect actual
 '
 
+test_expect_success '%(trailers:key=foo,keyonly,valueonly) shows nothing' '
+	git log --no-walk --pretty="format:%(trailers:key=Acked-by,keyonly,valueonly)" >actual &&
+	echo >expect &&
+	test_cmp expect actual
+'
+
 test_expect_success 'pretty format %(trailers:separator) changes separator' '
 	git log --no-walk --pretty=format:"X%(trailers:separator=%x00)X" >actual &&
 	(
@@ -754,7 +776,7 @@ test_expect_success 'pretty format %(trailers:separator=X,unfold) changes separa
 	test_cmp expect actual
 '
 
-test_expect_success 'pretty format %(trailers) combining separator/key/valueonly' '
+test_expect_success 'pretty format %(trailers) combining separator/key/keyonly/valueonly' '
 	git commit --allow-empty -F - <<-\EOF &&
 	Important fix
 
@@ -781,6 +803,13 @@ test_expect_success 'pretty format %(trailers) combining separator/key/valueonly
 		"Does not close any tickets" \
 		"Another fix #567, #890" \
 		"Important fix #1234" >expect &&
+	test_cmp expect actual &&
+
+	git log --pretty="%s% (trailers:separator=%x2c%x20,key=Closes,keyonly)" HEAD~3.. >actual &&
+	test_write_lines \
+		"Does not close any tickets" \
+		"Another fix Closes, Closes" \
+		"Important fix Closes" >expect &&
 	test_cmp expect actual
 '