sequencer: release todo list on error paths

We're not releasing the `todo_list` in `sequencer_pick_revisions()` when
hitting an error path. Restructure the function to have a common exit
path such that we can easily clean up the list and thus plug this memory
leak.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

2 files changed, 48 insertions, 19 deletions

diff --git a/sequencer.c b/sequencer.c
index cade9b0ca8..ea559c31f1 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -5490,8 +5490,10 @@ int sequencer_pick_revisions(struct repository *r,
 	int i, res;
 
 	assert(opts->revs);
-	if (read_and_refresh_cache(r, opts))
-		return -1;
+	if (read_and_refresh_cache(r, opts)) {
+		res = -1;
+		goto out;
+	}
 
 	for (i = 0; i < opts->revs->pending.nr; i++) {
 		struct object_id oid;
@@ -5506,11 +5508,14 @@ int sequencer_pick_revisions(struct repository *r,
 				enum object_type type = oid_object_info(r,
 									&oid,
 									NULL);
-				return error(_("%s: can't cherry-pick a %s"),
-					name, type_name(type));
+				res = error(_("%s: can't cherry-pick a %s"),
+					    name, type_name(type));
+				goto out;
 			}
-		} else
-			return error(_("%s: bad revision"), name);
+		} else {
+			res = error(_("%s: bad revision"), name);
+			goto out;
+		}
 	}
 
 	/*
@@ -5525,14 +5530,23 @@ int sequencer_pick_revisions(struct repository *r,
 	    opts->revs->no_walk &&
 	    !opts->revs->cmdline.rev->flags) {
 		struct commit *cmit;
-		if (prepare_revision_walk(opts->revs))
-			return error(_("revision walk setup failed"));
+
+		if (prepare_revision_walk(opts->revs)) {
+			res = error(_("revision walk setup failed"));
+			goto out;
+		}
+
 		cmit = get_revision(opts->revs);
-		if (!cmit)
-			return error(_("empty commit set passed"));
+		if (!cmit) {
+			res = error(_("empty commit set passed"));
+			goto out;
+		}
+
 		if (get_revision(opts->revs))
 			BUG("unexpected extra commit from walk");
-		return single_pick(r, cmit, opts);
+
+		res = single_pick(r, cmit, opts);
+		goto out;
 	}
 
 	/*
@@ -5542,16 +5556,30 @@ int sequencer_pick_revisions(struct repository *r,
 	 */
 
 	if (walk_revs_populate_todo(&todo_list, opts) ||
-			create_seq_dir(r) < 0)
-		return -1;
-	if (repo_get_oid(r, "HEAD", &oid) && (opts->action == REPLAY_REVERT))
-		return error(_("can't revert as initial commit"));
-	if (save_head(oid_to_hex(&oid)))
-		return -1;
-	if (save_opts(opts))
-		return -1;
+			create_seq_dir(r) < 0) {
+		res = -1;
+		goto out;
+	}
+
+	if (repo_get_oid(r, "HEAD", &oid) && (opts->action == REPLAY_REVERT)) {
+		res = error(_("can't revert as initial commit"));
+		goto out;
+	}
+
+	if (save_head(oid_to_hex(&oid))) {
+		res = -1;
+		goto out;
+	}
+
+	if (save_opts(opts)) {
+		res = -1;
+		goto out;
+	}
+
 	update_abort_safety_file();
 	res = pick_commits(r, &todo_list, opts);
+
+out:
 	todo_list_release(&todo_list);
 	return res;
 }
diff --git a/t/t3510-cherry-pick-sequence.sh b/t/t3510-cherry-pick-sequence.sh
index 7eb52b12ed..93c725bac3 100755
--- a/t/t3510-cherry-pick-sequence.sh
+++ b/t/t3510-cherry-pick-sequence.sh
@@ -12,6 +12,7 @@ test_description='Test cherry-pick continuation features
 
 '
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 # Repeat first match 10 times