pack-objects: avoid reading uninitalized data

In the main loop of find_deltas, we do: struct object_entry *entry = *list++; ... if (!*list_size) ... break Because we look at and increment *list _before_ the check of list_size, in the very last iteration of the loop we will look at uninitialized data, and increment the pointer beyond one past the end of the allocated space. Since we don't actually do anything with the data until after the check, this is not a problem in practice. But since it technically violates the C standard, and because it provokes a spurious valgrind warning, let's just move the initialization of entry to a safe place. This fixes valgrind errors in t5300, t5301, t5302, t303, and t9400. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Jeff King committed Oct 23, 2008 at 04:31 UTC 421b488a58fea89ceb55d5b358738e9251d44f5e

1 file changed +2 -1

builtin-pack-objects.c

+2 -1

@@ -1377,7 +1377,7 @@ static void find_deltas(struct object_entry **list, unsigned *list_size,

1377 memset(array, 0, array_size);

1378

1379 for (;;) {

1380 - struct object_entry *entry = *list++;

1380 + struct object_entry *entry;

1381 struct unpacked *n = array + idx;

1382 int j, max_depth, best_base = -1;

1383

@@ -1386,6 +1386,7 @@ static void find_deltas(struct object_entry **list, unsigned *list_size,

1386 progress_unlock();

1387 break;

1388 }

1389 + entry = *list++;

1390 (*list_size)--;

1391 if (!entry->preferred_base) {

1392 (*processed)++;