[PATCH 07/10] builtin/rebase.c: fix "options.onto_name" leak

["Ævar Arnfjörð Bjarmason" <avarab@gmail.com>]

In [1] we started saving away the earlier xstrdup()'d
"options.onto_name" assignment to free() it, but when [2] added this
"keep_base" branch it didn't free() the already assigned
"squash_onto_name" before re-assigning to "options.onto_name". Let's
do that, and fix the memory leak.

1. 9dba809a69a (builtin rebase: support --root, 2018-09-04)
2. 414d924beb4 (rebase: teach rebase --keep-base, 2019-08-27)

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
 builtin/rebase.c                 | 3 ++-
 t/t3416-rebase-onto-threedots.sh | 1 +
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/builtin/rebase.c b/builtin/rebase.c
index 91bf55be6e6..f7fd20d71c0 100644
--- a/builtin/rebase.c
+++ b/builtin/rebase.c
@@ -1658,7 +1658,8 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 		strbuf_addstr(&buf, options.upstream_name);
 		strbuf_addstr(&buf, "...");
 		strbuf_addstr(&buf, branch_name);
-		options.onto_name = xstrdup(buf.buf);
+		free(squash_onto_name);
+		options.onto_name = squash_onto_name = xstrdup(buf.buf);
 	} else if (!options.onto_name)
 		options.onto_name = options.upstream_name;
 	if (strstr(options.onto_name, "...")) {
diff --git a/t/t3416-rebase-onto-threedots.sh b/t/t3416-rebase-onto-threedots.sh
index ea501f2b42b..f8c4ed78c9e 100755
--- a/t/t3416-rebase-onto-threedots.sh
+++ b/t/t3416-rebase-onto-threedots.sh
@@ -5,6 +5,7 @@ test_description='git rebase --onto A...B'
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 . "$TEST_DIRECTORY/lib-rebase.sh"
 
-- 
2.39.0.1153.g589e4efe9dc