@matheusbsbs / matheus-bagliano / commits / 65904b8b2b

promisor-remote: skip move_to_tail when no-op

Previously, when promisor_remote_move_to_tail() is called for a promisor_remote which is currently the final element in promisors, a cycle is created in the promisors linked list. This cycle leads to a double free later on in promisor_remote_clear() when the final element of the promisors list is removed: promisors is set to promisors->next (a no-op, as promisors->next == promisors); the previous value of promisors is free()'d; then the new value of promisors (which is equal to the previous value of promisors) is also free()'d. This double-free error was unrecoverable for the user without removing the filter or re-cloning the repo and hoping to miss this edge case. Now, when promisor_remote_move_to_tail() would be a no-op, just do a no-op. In cases of promisor_remote_move_to_tail() where r is not already at the tail of the list, it works as before. Helped-by: Jeff King <peff@peff.net> Signed-off-by: Emily Shaffer <emilyshaffer@google.com> Acked-by: Christian Couder <christian.couder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Emily Shaffer committed Sep 30, 2019 at 15:03 UTC 65904b8b2b27c71a96d8a9c37c19bcc8f2d1380c

2 files changed +16

promisor-remote.c

@@ -89,6 +89,9 @@ static struct promisor_remote *promisor_remote_lookup(const char *remote_name,

89 static void promisor_remote_move_to_tail(struct promisor_remote *r,

90 struct promisor_remote *previous)

91 {

92 + if (r->next == NULL)

93 + return;

94 +

95 if (previous)

96 previous->next = r->next;

97 else

t/t0410-partial-clone.sh

+13

@@ -429,6 +429,19 @@ test_expect_success 'rev-list dies for missing objects on cmd line' '

429 done

430 '

431

432 +test_expect_success 'single promisor remote can be re-initialized gracefully' '

433 + # ensure one promisor is in the promisors list

434 + rm -rf repo &&

435 + test_create_repo repo &&

436 + test_create_repo other &&

437 + git -C repo remote add foo "file://$(pwd)/other" &&

438 + git -C repo config remote.foo.promisor true &&

439 + git -C repo config extensions.partialclone foo &&

440 +

441 + # reinitialize the promisors list

442 + git -C repo fetch --filter=blob:none foo

443 +'

444 +

445 test_expect_success 'gc repacks promisor objects separately from non-promisor objects' '

446 rm -rf repo &&

447 test_create_repo repo &&