[PATCH] sequencer: assign only free()able strings to gpg_sign

[Johannes Schindelin <johannes.schindelin@gmx.de>]

The gpg_sign member of the replay_opts structure is of type `char *`,
meaning that the sequencer deems the string to which gpg_sign points to
be under its custody, i.e. it needs to be free()d by the sequencer.

Therefore, let's only assign malloc()ed buffers to it.

Reported-by: Kaartic Sivaraam <kaartic.sivaraam@gmail.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---

	Phillip, if you want to squash these changes into your patches,
	I'd totally fine with that.

Based-On: pw/sequencer-in-process-commit at https://github.com/dscho/git
Fetch-Base-Via: git fetch https://github.com/dscho/git pw/sequencer-in-process-commit
Published-As: https://github.com/dscho/git/releases/tag/sequencer-owns-gpg-sign-v1
Fetch-It-Via: git fetch https://github.com/dscho/git sequencer-owns-gpg-sign-v1
 sequencer.c                   |  2 +-
 t/t3404-rebase-interactive.sh | 10 ++++++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/sequencer.c b/sequencer.c
index 7051b20b762..1b2599668f5 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -160,7 +160,7 @@ static int git_sequencer_config(const char *k, const char *v, void *cb)
 	}
 
 	if (!strcmp(k, "commit.gpgsign")) {
-		opts->gpg_sign = git_config_bool(k, v) ? "" : NULL;
+		opts->gpg_sign = git_config_bool(k, v) ? xstrdup("") : NULL;
 		return 0;
 	}
 
diff --git a/t/t3404-rebase-interactive.sh b/t/t3404-rebase-interactive.sh
index 9ed0a244e6c..040ef1a4dbc 100755
--- a/t/t3404-rebase-interactive.sh
+++ b/t/t3404-rebase-interactive.sh
@@ -1318,6 +1318,16 @@ test_expect_success 'editor saves as CR/LF' '
 
 SQ="'"
 test_expect_success 'rebase -i --gpg-sign=<key-id>' '
+	test_when_finished "test_might_fail git rebase --abort" &&
+	set_fake_editor &&
+	FAKE_LINES="edit 1" git rebase -i --gpg-sign="\"S I Gner\"" HEAD^ \
+		>out 2>err &&
+	test_i18ngrep "$SQ-S\"S I Gner\"$SQ" err
+'
+
+test_expect_success 'rebase -i --gpg-sign=<key-id> overrides commit.gpgSign' '
+	test_when_finished "test_might_fail git rebase --abort" &&
+	test_config commit.gpgsign true &&
 	set_fake_editor &&
 	FAKE_LINES="edit 1" git rebase -i --gpg-sign="\"S I Gner\"" HEAD^ \
 		>out 2>err &&

base-commit: 28d6daed4f119940ace31e523b3b272d3d153d04
-- 
2.15.1.windows.2