From: Aaron Plattner <aplattner@nvidia•com>
To: <git@vger•kernel.org>
Cc: Aaron Plattner <aplattner@nvidia•com>, Jeff King <peff@peff•net>
Subject: [PATCH v3 1/2] object: apply skip_hash and discard_tree optimizations to unknown blobs too
Date: Mon, 8 Dec 2025 17:48:56 -0800 [thread overview]
Message-ID: <20251209014900.402637-2-aplattner@nvidia.com> (raw)
In-Reply-To: <20251209014900.402637-1-aplattner@nvidia.com>
parse_object_with_flags() has an optimization to skip parsing blobs if
PARSE_OBJECT_SKIP_HASH_CHECK is set and the object hasn't been seen
before or might be a blob but hasn't been parsed yet. The latter can
happen, for example, if add_tree_entries() walks a path that references
a blob object that hasn't been seen before: lookup_blob() marks the
referenced oid as being a blob, but does not provide any additional
information about it until it is parsed.
It's possible for an object to be created without even a type, such as
when prepare_revision_walk() uses mark_uninteresting() to mark all
promisor objects as uninteresting. These objects have obj->parsed ==
false and obj->type == OBJ_NONE.
The skip_hash optimization does not consider this kind of object, so
parse_object_with_flags() proceeds to fully parse the object to
determine its type.
Improve the optimization by applying it to OBJ_NONE objects as well as
OBJ_BLOB ones. Apply a similar fix for trees.
Fixes: 8db2dad7a045 ("parse_object(): check on-disk type of suspected blob")
Signed-off-by: Aaron Plattner <aplattner@nvidia•com>
---
object.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/object.c b/object.c
index b08fc7a163..4669b8d65e 100644
--- a/object.c
+++ b/object.c
@@ -328,7 +328,7 @@ struct object *parse_object_with_flags(struct repository *r,
return &commit->object;
}
- if ((!obj || obj->type == OBJ_BLOB) &&
+ if ((!obj || obj->type == OBJ_NONE || obj->type == OBJ_BLOB) &&
odb_read_object_info(r->objects, oid, NULL) == OBJ_BLOB) {
if (!skip_hash && stream_object_signature(r, repl) < 0) {
error(_("hash mismatch %s"), oid_to_hex(oid));
@@ -344,7 +344,7 @@ struct object *parse_object_with_flags(struct repository *r,
* have the on-disk object with the correct type.
*/
if (skip_hash && discard_tree &&
- (!obj || obj->type == OBJ_TREE) &&
+ (!obj || obj->type == OBJ_NONE || obj->type == OBJ_TREE) &&
odb_read_object_info(r->objects, oid, NULL) == OBJ_TREE) {
return &lookup_tree(r, oid)->object;
}
--
2.52.0
next prev parent reply other threads:[~2025-12-09 1:49 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-09 1:48 [PATCH v3 0/2] improve --exclude-promisor-objects performance Aaron Plattner
2025-12-09 1:48 ` Aaron Plattner [this message]
2025-12-09 1:48 ` [PATCH v3 2/2] packfile: skip hash checks in add_promisor_object() Aaron Plattner
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