Subject: Re: [PATCH 2/3] path-walk: fix setup of pending objects

From: Junio C Hamano <[email-masked]>
Date: Wed, 20 Aug 2025 12:02:59 -0700

"Derrick Stolee via GitGitGadget" <[email-masked]> writes:

> The core problem here is that the "maybe_interesting" member of 'struct
> type_and_oid_list' is not initialized to '1'. This member was added in
> 6333e7ae0b (path-walk: mark trees and blobs as UNINTERESTING,
> 2024-12-20) in a way to help when creating packfiles for a small commit
> range using the sparse path algorithm (enabled by pack.useSparse=true).

OK, in other words, the bug is fairly contained within the path-walk
traversal.  We treat things as reachable not just from ref tips and
reflogs (where path-walk code can use the tree object to compute on
what pathname each blob comes from) and the main index array (that
has paths, even though it needs separate way to compute than those
for trees), but also from places like REUC and TREE extensions that
make associations between pathnames and objects.  Are they also OK?

> To help avoid this from happening in the future, a follow-up change will
> make initializing lists use a shared method instead of allowing for an
> update to this initialization process to miss some existing copies.

Great.  Future-proofing is 100 times better than just a bugfix.

>
> Signed-off-by: Derrick Stolee <[email-masked]>
> ---
>  path-walk.c       | 2 ++
>  t/t7700-repack.sh | 2 +-
>  2 files changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/path-walk.c b/path-walk.c
> index 2d4ddbadd50f..1215ed398f4f 100644
> --- a/path-walk.c
> +++ b/path-walk.c
> @@ -385,6 +385,7 @@ static int setup_pending_objects(struct path_walk_info *info,
>  					list->type = OBJ_TREE;
>  					strmap_put(&ctx->paths_to_lists, path, list);
>  				}
> +				list->maybe_interesting = 1;
>  				oid_array_append(&list->oids, &obj->oid);
>  				free(path);
>  			} else {
> @@ -404,6 +405,7 @@ static int setup_pending_objects(struct path_walk_info *info,
>  					list->type = OBJ_BLOB;
>  					strmap_put(&ctx->paths_to_lists, path, list);
>  				}
> +				list->maybe_interesting = 1;
>  				oid_array_append(&list->oids, &obj->oid);
>  			} else {
>  				/* assume a root tree, such as a lightweight tag. */
> diff --git a/t/t7700-repack.sh b/t/t7700-repack.sh
> index 1998d9bf291c..030e9e5b2dc7 100755
> --- a/t/t7700-repack.sh
> +++ b/t/t7700-repack.sh
> @@ -838,7 +838,7 @@ test_expect_success '-n overrides repack.updateServerInfo=true' '
>  	test_server_info_missing
>  '
>  
> -test_expect_failure 'pending objects are repacked appropriately' '
> +test_expect_success 'pending objects are repacked appropriately' '
>  	git init pending &&
>  
>  	(