Re: [PATCH v3 7/8] fetch-pack: put shallow info in output parameter

[Jonathan Tan <jonathantanmy@google.com>]

>  static void update_shallow(struct fetch_pack_args *args,
> -			   struct ref **sought, int nr_sought,
> +			   struct ref *refs,

update_shallow() now takes in a linked list of refs instead of an array.
I see that the translation of this function is straightforward -
occasionally, we need to iterate through the linked list and count up
from 0 at the same time, but that is not a problem.

>  			   struct shallow_info *si)
>  {
>  	struct oid_array ref = OID_ARRAY_INIT;
>  	int *status;
> -	int i;
> +	int i = 0;

Remove the " = 0" - I've verified that it does not need to be there, and
it might inhibit useful "unintialized variable" warnings if others were
to change the code later.

Optional: I would also remove this declaration and declare "int i;" in
each of the blocks that need it.

>  static int fetch_refs_via_pack(struct transport *transport,
> -			       int nr_heads, struct ref **to_fetch)
> +			       int nr_heads, struct ref **to_fetch,
> +			       struct ref **fetched_refs)
>  {
>  	int ret = 0;
>  	struct git_transport_data *data = transport->data;
> @@ -354,8 +356,12 @@ static int fetch_refs_via_pack(struct transport *transport,
>  	if (report_unmatched_refs(to_fetch, nr_heads))
>  		ret = -1;
>  
> +	if (fetched_refs)
> +		*fetched_refs = refs;
> +	else
> +		free_refs(refs);
> +
>  	free_refs(refs_tmp);
> -	free_refs(refs);
>  	free(dest);
>  	return ret;
>  }

Instead of just freeing the linked list, we return it if requested by
the client. This makes sense.

> -int transport_fetch_refs(struct transport *transport, struct ref *refs)
> +int transport_fetch_refs(struct transport *transport, struct ref *refs,
> +			 struct ref **fetched_refs)
>  {
>  	int rc;
>  	int nr_heads = 0, nr_alloc = 0, nr_refs = 0;
>  	struct ref **heads = NULL;
> +	struct ref *nop_head = NULL, **nop_tail = &nop_head;
>  	struct ref *rm;
>  
>  	for (rm = refs; rm; rm = rm->next) {
>  		nr_refs++;
>  		if (rm->peer_ref &&
>  		    !is_null_oid(&rm->old_oid) &&
> -		    !oidcmp(&rm->peer_ref->old_oid, &rm->old_oid))
> +		    !oidcmp(&rm->peer_ref->old_oid, &rm->old_oid)) {
> +			/*
> +			 * These need to be reported as fetched, but we don't
> +			 * actually need to fetch them.
> +			 */
> +			if (fetched_refs) {
> +				struct ref *nop_ref = copy_ref(rm);
> +				*nop_tail = nop_ref;
> +				nop_tail = &nop_ref->next;
> +			}
>  			continue;
> +		}
>  		ALLOC_GROW(heads, nr_heads + 1, nr_alloc);
>  		heads[nr_heads++] = rm;
>  	}
> @@ -1245,7 +1263,11 @@ int transport_fetch_refs(struct transport *transport, struct ref *refs)
>  			heads[nr_heads++] = rm;
>  	}
>  
> -	rc = transport->vtable->fetch(transport, nr_heads, heads);
> +	rc = transport->vtable->fetch(transport, nr_heads, heads, fetched_refs);
> +	if (fetched_refs && nop_head) {
> +		*nop_tail = *fetched_refs;
> +		*fetched_refs = nop_head;
> +	}
>  
>  	free(heads);
>  	return rc;

And sometimes, even if we are merely simulating the fetching of refs, we
still need to report those refs in fetched_refs. This is correct.

I also see that t5703 now passes.

Besides enabling the writing of subsequent patches, I see that this also
makes the API clearer in that the input refs to transport_fetch_refs()
are not overloaded to output shallow information. Other than the " = 0"
change above, this patch looks good to me.