Re: [PATCH v3 03/11] promisor-remote: implement promisor_remote_get_direct()

[Junio C Hamano <gitster@pobox.com>]

Christian Couder <christian.couder@gmail.com> writes:

> @@ -98,3 +99,19 @@ int has_promisor_remote(void)
>  {
>  	return !!promisor_remote_find(NULL);
>  }
> +
> +int promisor_remote_get_direct(const struct object_id *oids, int oid_nr)
> +{
> +	struct promisor_remote *o;
> +
> +	promisor_remote_init();
> +
> +	for (o = promisors; o; o = o->next) {
> +		if (fetch_objects(o->remote_name, oids, oid_nr) < 0)
> +			continue;
> +		return 0;

Suppose the caller asks to fetch 3 objects, A, B and C, from two
promisors.  The first promisor can give you A and B but cannot give
you C.  The second promisor only can give you C.

Does fetch_objects() return failure after attempting to fetch A, B
and C from the first promisor?  Then we go on to the second promisor
but do we ask all three?  That would mean the second promisor will
also fail because it cannot give you A and B, and then the whole
thing would fail.  It would be nicer if the mechanism would allow us
to fetch what is still missing from later promisor, perhaps.

As the original "fetch" protocol only allows you to fetch a pack
with everything you asked for in it, instead of feeding you a pack
with best effort, I think the answer to the above is "it is very
hard to improve over what we have here", but people may have
interesting ideas ;-)

> +	}
> +
> +	return -1;
> +}
> +

Adding trailing blank line at the end?

> diff --git a/promisor-remote.h b/promisor-remote.h
> index bfbf7c0f21..f9f5825417 100644
> --- a/promisor-remote.h
> +++ b/promisor-remote.h
> @@ -13,5 +13,6 @@ struct promisor_remote {
>  extern struct promisor_remote *promisor_remote_new(const char *remote_name);
>  extern struct promisor_remote *promisor_remote_find(const char *remote_name);
>  extern int has_promisor_remote(void);
> +extern int promisor_remote_get_direct(const struct object_id *oids, int oid_nr);
>  
>  #endif /* PROMISOR_REMOTE_H */