merge(3p/git): Merge git subtree at v2.29.2 r/1890

This also bumps the stable nixpkgs to 20.09 as of 2020-11-21, because
there is some breakage in the git build related to the netrc
credentials helper which someone has taken care of in nixpkgs.

The stable channel is not used for anything other than git, so this
should be fine.

Change-Id: I3575a19dab09e1e9556cf8231d717de9890484fb

1 files changed, 17 insertions, 10 deletions

diff --git a/third_party/git/pack-objects.h b/third_party/git/pack-objects.h
index 857d43850b..9d88e3e518 100644
--- a/third_party/git/pack-objects.h
+++ b/third_party/git/pack-objects.h
@@ -183,12 +183,10 @@ static inline void packing_data_unlock(struct packing_data *pdata)
 }
 
 struct object_entry *packlist_alloc(struct packing_data *pdata,
-				    const unsigned char *sha1,
-				    uint32_t index_pos);
+				    const struct object_id *oid);
 
 struct object_entry *packlist_find(struct packing_data *pdata,
-				   const struct object_id *oid,
-				   uint32_t *index_pos);
+				   const struct object_id *oid);
 
 static inline uint32_t pack_name_hash(const char *name)
 {
@@ -253,12 +251,21 @@ static inline void oe_set_in_pack(struct packing_data *pack,
 				  struct object_entry *e,
 				  struct packed_git *p)
 {
-	if (!p->index)
+	if (pack->in_pack_by_idx) {
+		if (p->index) {
+			e->in_pack_idx = p->index;
+			return;
+		}
+		/*
+		 * We're accessing packs by index, but this pack doesn't have
+		 * an index (e.g., because it was added since we created the
+		 * in_pack_by_idx array). Bail to oe_map_new_pack(), which
+		 * will convert us to using the full in_pack array, and then
+		 * fall through to our in_pack handling.
+		 */
 		oe_map_new_pack(pack);
-	if (pack->in_pack_by_idx)
-		e->in_pack_idx = p->index;
-	else
-		pack->in_pack[e - pack->objects] = p;
+	}
+	pack->in_pack[e - pack->objects] = p;
 }
 
 static inline struct object_entry *oe_delta(
@@ -285,7 +292,7 @@ static inline void oe_set_delta(struct packing_data *pack,
 
 void oe_set_delta_ext(struct packing_data *pack,
 		      struct object_entry *e,
-		      const unsigned char *sha1);
+		      const struct object_id *oid);
 
 static inline struct object_entry *oe_delta_child(
 		const struct packing_data *pack,