Subject: Re: [RFC PATCH resend] builtin/repack: Honor --keep-pack and .keep when repacking promisor objects

From: Junio C Hamano <[email-masked]>
Date: Thu, 30 Jan 2025 14:32:34 -0800

Tomáš Trnka <[email-masked]> writes:

> git-repack currently does not pass --keep-pack or --honor-pack-keep to
> the git-pack-objects handling promisor packs. This means that settings
> like gc.bigPackThreshold are completely ignored for promisor packs.
>
> The simple fix is to just copy the keep-pack logic into
> repack_promisor_objects(), although this could possibly be improved by
> making prepare_pack_objects() handle it instead.
>
> Signed-off-by: Tomáš Trnka <[email-masked]>
> ---

I don't have a strong opinion about the technical aspects of this
patch to be a reviewer.  I have no idea how you decided whom to Cc:,
but I recall these two threads that worked in the same "interaction
between repack and promisor objects" area (I am not saying and I do
not think they addressed the same problem as you are):

 * https://lore.kernel.org/git/[email-masked]/
 * https://lore.kernel.org/git/[email-masked]/

so asking review from the authors of these topics would be more
relevant than sending it to me (I did that already, and that is why
the remainder of the original patch is not culled from this
response---after the next line, there is nothing I wrote but the
original patch left for others' convenience).

Thanks.

>
> RFC: This probably needs a test, but where and how should it be
> implemented? Perhaps in t7700-repack.sh, copying one of the tests using
> prepare_for_keep_packs and just touching .promisor files? Or instead in
> t/t0410-partial-clone.sh using a copy/variant of one of the basic 
> repack tests there?
>
>  builtin/repack.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/builtin/repack.c b/builtin/repack.c
> index d6bb37e84a..fe62fe03eb 100644
> --- a/builtin/repack.c
> +++ b/builtin/repack.c
> @@ -388,15 +388,23 @@ static int has_pack_ext(const struct generated_pack_data *data,
>  }
>  
>  static void repack_promisor_objects(const struct pack_objects_args *args,
> -				    struct string_list *names)
> +				    struct string_list *names,
> +				    struct string_list *keep_pack_list)
>  {
>  	struct child_process cmd = CHILD_PROCESS_INIT;
>  	FILE *out;
>  	struct strbuf line = STRBUF_INIT;
> +	int i;
>  
>  	prepare_pack_objects(&cmd, args, packtmp);
>  	cmd.in = -1;
>  
> +	if (!pack_kept_objects)
> +		strvec_push(&cmd.args, "--honor-pack-keep");
> +	for (i = 0; i < keep_pack_list->nr; i++)
> +		strvec_pushf(&cmd.args, "--keep-pack=%s",
> +			     keep_pack_list->items[i].string);
> +
>  	/*
>  	 * NEEDSWORK: Giving pack-objects only the OIDs without any ordering
>  	 * hints may result in suboptimal deltas in the resulting pack. See if
> @@ -1350,7 +1358,7 @@ int cmd_repack(int argc,
>  		strvec_push(&cmd.args, "--delta-islands");
>  
>  	if (pack_everything & ALL_INTO_ONE) {
> -		repack_promisor_objects(&po_args, &names);
> +		repack_promisor_objects(&po_args, &names, &keep_pack_list);
>  
>  		if (has_existing_non_kept_packs(&existing) &&
>  		    delete_redundant &&
>
> base-commit: 92999a42db1c5f43f330e4f2bca4026b5b81576f