Subject: [PATCH v5 5/9] pack-objects: perform name-hash traversal for unpacked objects

From: Taylor Blau <[email-masked]>
Date: Thu, 19 Jun 2025 19:30:20 -0400

With '--unpacked', pack-objects adds loose objects (which don't appear
in any of the excluded packs from '--stdin-packs') to the output pack
without considering them as reachability tips for the name-hash
traversal.

This was an oversight in the original implementation of '--stdin-packs',
since the code which enumerates and adds loose objects to the output
pack (`add_unreachable_loose_objects()`) did not have access to the
'rev_info' struct found in `read_packs_list_from_stdin()`.

Excluding unpacked objects from that traversal doesn't affect the
correctness of the resulting pack, but it does make it harder to
discover good deltas for loose objects.

Now that the 'rev_info' struct is declared outside of
`read_packs_list_from_stdin()`, we can pass it to
`add_objects_in_unpacked_packs()` and add any loose objects as tips to
the above-mentioned traversal, in theory producing slightly tighter
packs as a result.

Signed-off-by: Taylor Blau <[email-masked]>
---
 builtin/pack-objects.c | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index 4258ac1792..3437dbd7f1 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -3879,7 +3879,7 @@ static void read_packs_list_from_stdin(struct rev_info *revs)
 	string_list_clear(&exclude_packs, 0);
 }
 
-static void add_unreachable_loose_objects(void);
+static void add_unreachable_loose_objects(struct rev_info *revs);
 
 static void read_stdin_packs(int rev_list_unpacked)
 {
@@ -3906,7 +3906,7 @@ static void read_stdin_packs(int rev_list_unpacked)
 	ignore_packed_keep_in_core = 1;
 	read_packs_list_from_stdin(&revs);
 	if (rev_list_unpacked)
-		add_unreachable_loose_objects();
+		add_unreachable_loose_objects(&revs);
 
 	if (prepare_revision_walk(&revs))
 		die(_("revision walk setup failed"));
@@ -4025,7 +4025,7 @@ static void enumerate_cruft_objects(void)
 						_("Enumerating cruft objects"), 0);
 
 	add_objects_in_unpacked_packs();
-	add_unreachable_loose_objects();
+	add_unreachable_loose_objects(NULL);
 
 	stop_progress(&progress_state);
 }
@@ -4303,8 +4303,9 @@ static void add_objects_in_unpacked_packs(void)
 }
 
 static int add_loose_object(const struct object_id *oid, const char *path,
-			    void *data UNUSED)
+			    void *data)
 {
+	struct rev_info *revs = data;
 	enum object_type type = oid_object_info(the_repository, oid, NULL);
 
 	if (type < 0) {
@@ -4325,6 +4326,10 @@ static int add_loose_object(const struct object_id *oid, const char *path,
 	} else {
 		add_object_entry(oid, type, "", 0);
 	}
+
+	if (revs && type == OBJ_COMMIT)
+		add_pending_oid(revs, NULL, oid, 0);
+
 	return 0;
 }
 
@@ -4333,11 +4338,10 @@ static int add_loose_object(const struct object_id *oid, const char *path,
  * add_object_entry will weed out duplicates, so we just add every
  * loose object we find.
  */
-static void add_unreachable_loose_objects(void)
+static void add_unreachable_loose_objects(struct rev_info *revs)
 {
 	for_each_loose_file_in_objdir(repo_get_object_directory(the_repository),
-				      add_loose_object,
-				      NULL, NULL, NULL);
+				      add_loose_object, NULL, NULL, revs);
 }
 
 static int has_sha1_pack_kept_or_nonlocal(const struct object_id *oid)
@@ -4684,7 +4688,7 @@ static void get_object_list(struct rev_info *revs, int ac, const char **av)
 	if (keep_unreachable)
 		add_objects_in_unpacked_packs();
 	if (pack_loose_unreachable)
-		add_unreachable_loose_objects();
+		add_unreachable_loose_objects(NULL);
 	if (unpack_unreachable)
 		loosen_unused_packed_objects();
 
-- 
2.50.0.61.gf819b10624.dirty