format-patch: teach --cover-from-description option

Before, when format-patch generated a cover letter, only the body would
be populated with a branch's description while the subject would be
populated with placeholder text. However, users may want to have the
subject of their cover letter automatically populated in the same way.

Teach format-patch to accept the `--cover-from-description` option and
corresponding `format.coverFromDescription` config, allowing users to
populate different parts of the cover letter (including the subject
now).

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

1 files changed, 172 insertions, 0 deletions

diff --git a/t/t4014-format-patch.sh b/t/t4014-format-patch.sh
index 72b09896cf..88db01308a 100755
--- a/t/t4014-format-patch.sh
+++ b/t/t4014-format-patch.sh
@@ -1517,6 +1517,178 @@ test_expect_success 'format patch ignores color.ui' '
 	test_cmp expect actual
 '
 
+test_expect_success 'cover letter with invalid --cover-from-description and config' '
+	test_config branch.rebuild-1.description "config subject
+
+body" &&
+	test_must_fail git format-patch --cover-letter --cover-from-description garbage master &&
+	test_config format.coverFromDescription garbage &&
+	test_must_fail git format-patch --cover-letter master
+'
+
+test_expect_success 'cover letter with format.coverFromDescription = default' '
+	test_config branch.rebuild-1.description "config subject
+
+body" &&
+	test_config format.coverFromDescription default &&
+	git checkout rebuild-1 &&
+	git format-patch --stdout --cover-letter master >actual &&
+	grep "^Subject: \[PATCH 0/2\] \*\*\* SUBJECT HERE \*\*\*$" actual &&
+	! grep "^\*\*\* BLURB HERE \*\*\*$" actual &&
+	grep "^config subject$" actual &&
+	grep "^body$" actual
+'
+
+test_expect_success 'cover letter with --cover-from-description default' '
+	test_config branch.rebuild-1.description "config subject
+
+body" &&
+	git checkout rebuild-1 &&
+	git format-patch --stdout --cover-letter --cover-from-description default master >actual &&
+	grep "^Subject: \[PATCH 0/2\] \*\*\* SUBJECT HERE \*\*\*$" actual &&
+	! grep "^\*\*\* BLURB HERE \*\*\*$" actual &&
+	grep "^config subject$" actual &&
+	grep "^body$" actual
+'
+
+test_expect_success 'cover letter with format.coverFromDescription = none' '
+	test_config branch.rebuild-1.description "config subject
+
+body" &&
+	test_config format.coverFromDescription none &&
+	git checkout rebuild-1 &&
+	git format-patch --stdout --cover-letter master >actual &&
+	grep "^Subject: \[PATCH 0/2\] \*\*\* SUBJECT HERE \*\*\*$" actual &&
+	grep "^\*\*\* BLURB HERE \*\*\*$" actual &&
+	! grep "^config subject$" actual &&
+	! grep "^body$" actual
+'
+
+test_expect_success 'cover letter with --cover-from-description none' '
+	test_config branch.rebuild-1.description "config subject
+
+body" &&
+	git checkout rebuild-1 &&
+	git format-patch --stdout --cover-letter --cover-from-description none master >actual &&
+	grep "^Subject: \[PATCH 0/2\] \*\*\* SUBJECT HERE \*\*\*$" actual &&
+	grep "^\*\*\* BLURB HERE \*\*\*$" actual &&
+	! grep "^config subject$" actual &&
+	! grep "^body$" actual
+'
+
+test_expect_success 'cover letter with format.coverFromDescription = message' '
+	test_config branch.rebuild-1.description "config subject
+
+body" &&
+	test_config format.coverFromDescription message &&
+	git checkout rebuild-1 &&
+	git format-patch --stdout --cover-letter master >actual &&
+	grep "^Subject: \[PATCH 0/2\] \*\*\* SUBJECT HERE \*\*\*$" actual &&
+	! grep "^\*\*\* BLURB HERE \*\*\*$" actual &&
+	grep "^config subject$" actual &&
+	grep "^body$" actual
+'
+
+test_expect_success 'cover letter with --cover-from-description message' '
+	test_config branch.rebuild-1.description "config subject
+
+body" &&
+	git checkout rebuild-1 &&
+	git format-patch --stdout --cover-letter --cover-from-description message master >actual &&
+	grep "^Subject: \[PATCH 0/2\] \*\*\* SUBJECT HERE \*\*\*$" actual &&
+	! grep "^\*\*\* BLURB HERE \*\*\*$" actual &&
+	grep "^config subject$" actual &&
+	grep "^body$" actual
+'
+
+test_expect_success 'cover letter with format.coverFromDescription = subject' '
+	test_config branch.rebuild-1.description "config subject
+
+body" &&
+	test_config format.coverFromDescription subject &&
+	git checkout rebuild-1 &&
+	git format-patch --stdout --cover-letter master >actual &&
+	grep "^Subject: \[PATCH 0/2\] config subject$" actual &&
+	! grep "^\*\*\* BLURB HERE \*\*\*$" actual &&
+	! grep "^config subject$" actual &&
+	grep "^body$" actual
+'
+
+test_expect_success 'cover letter with --cover-from-description subject' '
+	test_config branch.rebuild-1.description "config subject
+
+body" &&
+	git checkout rebuild-1 &&
+	git format-patch --stdout --cover-letter --cover-from-description subject master >actual &&
+	grep "^Subject: \[PATCH 0/2\] config subject$" actual &&
+	! grep "^\*\*\* BLURB HERE \*\*\*$" actual &&
+	! grep "^config subject$" actual &&
+	grep "^body$" actual
+'
+
+test_expect_success 'cover letter with format.coverFromDescription = auto (short subject line)' '
+	test_config branch.rebuild-1.description "config subject
+
+body" &&
+	test_config format.coverFromDescription auto &&
+	git checkout rebuild-1 &&
+	git format-patch --stdout --cover-letter master >actual &&
+	grep "^Subject: \[PATCH 0/2\] config subject$" actual &&
+	! grep "^\*\*\* BLURB HERE \*\*\*$" actual &&
+	! grep "^config subject$" actual &&
+	grep "^body$" actual
+'
+
+test_expect_success 'cover letter with --cover-from-description auto (short subject line)' '
+	test_config branch.rebuild-1.description "config subject
+
+body" &&
+	git checkout rebuild-1 &&
+	git format-patch --stdout --cover-letter --cover-from-description auto master >actual &&
+	grep "^Subject: \[PATCH 0/2\] config subject$" actual &&
+	! grep "^\*\*\* BLURB HERE \*\*\*$" actual &&
+	! grep "^config subject$" actual &&
+	grep "^body$" actual
+'
+
+test_expect_success 'cover letter with format.coverFromDescription = auto (long subject line)' '
+	test_config branch.rebuild-1.description "this is a really long first line and it is over 100 characters long which is the threshold for long subjects
+
+body" &&
+	test_config format.coverFromDescription auto &&
+	git checkout rebuild-1 &&
+	git format-patch --stdout --cover-letter master >actual &&
+	grep "^Subject: \[PATCH 0/2\] \*\*\* SUBJECT HERE \*\*\*$" actual &&
+	! grep "^\*\*\* BLURB HERE \*\*\*$" actual &&
+	grep "^this is a really long first line and it is over 100 characters long which is the threshold for long subjects$" actual &&
+	grep "^body$" actual
+'
+
+test_expect_success 'cover letter with --cover-from-description auto (long subject line)' '
+	test_config branch.rebuild-1.description "this is a really long first line and it is over 100 characters long which is the threshold for long subjects
+
+body" &&
+	git checkout rebuild-1 &&
+	git format-patch --stdout --cover-letter --cover-from-description auto master >actual &&
+	grep "^Subject: \[PATCH 0/2\] \*\*\* SUBJECT HERE \*\*\*$" actual &&
+	! grep "^\*\*\* BLURB HERE \*\*\*$" actual &&
+	grep "^this is a really long first line and it is over 100 characters long which is the threshold for long subjects$" actual &&
+	grep "^body$" actual
+'
+
+test_expect_success 'cover letter with command-line --cover-from-description overrides config' '
+	test_config branch.rebuild-1.description "config subject
+
+body" &&
+	test_config format.coverFromDescription none &&
+	git checkout rebuild-1 &&
+	git format-patch --stdout --cover-letter --cover-from-description subject master >actual &&
+	grep "^Subject: \[PATCH 0/2\] config subject$" actual &&
+	! grep "^\*\*\* BLURB HERE \*\*\*$" actual &&
+	! grep "^config subject$" actual &&
+	grep "^body$" actual
+'
+
 test_expect_success 'cover letter using branch description (1)' '
 	git checkout rebuild-1 &&
 	test_config branch.rebuild-1.description hello &&