1 files changed, 30 insertions, 1 deletions

diff --git a/builtin/index-pack.c b/builtin/index-pack.c
index 347a92c2f1..f811d1112a 100644
--- a/builtin/index-pack.c
+++ b/builtin/index-pack.c
@@ -817,6 +817,35 @@ static void record_outgoing_link(const struct object_id *oid)
 	oidset_insert(&outgoing_links, oid);
 }
 
+static void maybe_record_name_entry(const struct name_entry *entry)
+{
+	/*
+	 * Checking only trees here results in a significantly faster packfile
+	 * indexing, but the drawback is that if the packfile to be indexed
+	 * references a local blob only directly (that is, never through a
+	 * local tree), that local blob is in danger of being garbage
+	 * collected. Such a situation may arise if we push local commits,
+	 * including one with a change to a blob in the root tree, and then the
+	 * server incorporates them into its main branch through a "rebase" or
+	 * "squash" merge strategy, and then we fetch the new main branch from
+	 * the server.
+	 *
+	 * This situation has not been observed yet - we have only noticed
+	 * missing commits, not missing trees or blobs. (In fact, if it were
+	 * believed that only missing commits are problematic, one could argue
+	 * that we should also exclude trees during the outgoing link check;
+	 * but it is safer to include them.)
+	 *
+	 * Due to the rarity of the situation (it has not been observed to
+	 * happen in real life), and because the "penalty" in such a situation
+	 * is merely to refetch the missing blob when it's needed (and this
+	 * happens only once - when refetched, the blob goes into a promisor
+	 * pack, so it won't be GC-ed, the tradeoff seems worth it.
+	*/
+	if (S_ISDIR(entry->mode))
+		record_outgoing_link(&entry->oid);
+}
+
 static void do_record_outgoing_links(struct object *obj)
 {
 	if (obj->type == OBJ_TREE) {
@@ -831,7 +860,7 @@ static void do_record_outgoing_links(struct object *obj)
 			 */
 			return;
 		while (tree_entry_gently(&desc, &entry))
-			record_outgoing_link(&entry.oid);
+			maybe_record_name_entry(&entry);
 	} else if (obj->type == OBJ_COMMIT) {
 		struct commit *commit = (struct commit *) obj;
 		struct commit_list *parents = commit->parents;