pack-objects: enforce --depth limit in reused deltas

diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index 0fd52bd6b4b985b24d93ab7fb9887f57305b49fd..5c42a1d05e8dbc12e3f65bbf36657af1ff1a84eb 100644 (file)
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -1541,6 +1541,8 @@ static int pack_offset_sort(const void *_a, const void *_b)
  *   2. Updating our size/type to the non-delta representation. These were
  *      either not recorded initially (size) or overwritten with the delta type
  *      (type) when check_object() decided to reuse the delta.
+ *
+ *   3. Resetting our delta depth, as we are now a base object.
  */
 static void drop_reused_delta(struct object_entry *entry)
 {
@@ -1554,6 +1556,7 @@ static void drop_reused_delta(struct object_entry *entry)
                        p = &(*p)->delta_sibling;
        }
        entry->delta = NULL;
+       entry->depth = 0;
 
        oi.sizep = &entry->size;
        oi.typep = &entry->type;
@@ -1572,6 +1575,9 @@ static void drop_reused_delta(struct object_entry *entry)
  * Follow the chain of deltas from this entry onward, throwing away any links
  * that cause us to hit a cycle (as determined by the DFS state flags in
  * the entries).
+ *
+ * We also detect too-long reused chains that would violate our --depth
+ * limit.
  */
 static void break_delta_chains(struct object_entry *entry)
 {
@@ -1589,6 +1595,18 @@ static void break_delta_chains(struct object_entry *entry)
                 */
                entry->dfs_state = DFS_ACTIVE;
                break_delta_chains(entry->delta);
+
+               /*
+                * Once we've recursed, our base (if we still have one) knows
+                * its depth, so we can compute ours (and check it against
+                * the limit).
+                */
+               if (entry->delta) {
+                       entry->depth = entry->delta->depth + 1;
+                       if (entry->depth > depth)
+                               drop_reused_delta(entry);
+               }
+
                entry->dfs_state = DFS_DONE;
                break;