commit-tree: do not pay attention to commit.gpgsign

ba3c69a9 (commit: teach --gpg-sign option, 2011-10-05) introduced a
"signed commit" by teaching the --[no]-gpg-sign option and the
commit.gpgsign configuration variable to various commands that
create commits.

Teaching these to "git commit" and "git merge", both of which are
end-user facing Porcelain commands, was perfectly fine.  Allowing
the plumbing "git commit-tree" to suddenly change the behaviour to
surprise the scripts by paying attention to commit.gpgsign was not.

Among the in-tree scripts, filter-branch, quiltimport, rebase and
stash are the commands that run "commit-tree".  If any of these
wants to allow users to always sign every single commit, they should
offer their own configuration (e.g. "filterBranch.gpgsign") with an
option to disable signing (e.g. "git filter-branch --no-gpgsign").

Ignoring commit.gpgsign option _obviously_ breaks the backward
compatibility, but it is easy to follow the standard pattern in
scripts to honor whatever configuration variable they choose to
follow.  E.g.

	case $(git config --bool commit.gpgsign) in
	true) sign=-S ;;
	*) sign= ;;
	esac &&
	git commit-tree $sign ...whatever other args...

Do so to make sure that "git rebase" keeps paying attention to the
configuration variable, which unfortunately is a documented mistake.

Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 10 insertions, 3 deletions

diff --git a/t/t7510-signed-commit.sh b/t/t7510-signed-commit.sh
index 13331e533b..7b365ee115 100755
--- a/t/t7510-signed-commit.sh
+++ b/t/t7510-signed-commit.sh
@@ -45,12 +45,18 @@ test_expect_success GPG 'create signed commits' '
 	git tag seventh-signed &&
 
 	echo 8 >file && test_tick && git commit -a -m eighth -SB7227189 &&
-	git tag eighth-signed-alt
+	git tag eighth-signed-alt &&
+
+	# commit.gpgsign is still on but this must not be signed
+	git tag ninth-unsigned $(echo 9 | git commit-tree HEAD^{tree}) &&
+	# explicit -S of course must sign.
+	git tag tenth-signed $(echo 9 | git commit-tree -S HEAD^{tree})
 '
 
 test_expect_success GPG 'verify and show signatures' '
 	(
-		for commit in initial second merge fourth-signed fifth-signed sixth-signed seventh-signed
+		for commit in initial second merge fourth-signed \
+			fifth-signed sixth-signed seventh-signed tenth-signed
 		do
 			git verify-commit $commit &&
 			git show --pretty=short --show-signature $commit >actual &&
@@ -60,7 +66,8 @@ test_expect_success GPG 'verify and show signatures' '
 		done
 	) &&
 	(
-		for commit in merge^2 fourth-unsigned sixth-unsigned seventh-unsigned
+		for commit in merge^2 fourth-unsigned sixth-unsigned \
+			seventh-unsigned ninth-unsigned
 		do
 			test_must_fail git verify-commit $commit &&
 			git show --pretty=short --show-signature $commit >actual &&