Re: [PATCH v3 2/8] upload-pack: implement ref-in-want

[Jonathan Tan <jonathantanmy@google.com>]

> +    wanted-refs section
> +	* This section is only included if the client has requested a
> +	  ref using a 'want-ref' line and if a packfile section is also
> +	  included in the response.
> +
> +	* Always begins with the section header "wanted-refs"

Add a period at the end to be consistent with the others.

> +	* The server will send a ref listing ("<oid> <refname>") for
> +	  each reference requested using 'want-ref' lines.
> +
> +	* The server MUST NOT send any refs which were not requested
> +	  using 'want-ref' lines.

We might want tag following refs to be included here in the future, but
at that time, I think we can amend this to say that if include-tag-ref
is sent by the user, the server may send additional refs, otherwise the
server must not do so. So this is fine.

> +test_expect_success 'mix want and want-ref' '
> +	cat >expected_refs <<-EOF &&
> +	$(git rev-parse f) refs/heads/master
> +	EOF
> +	git rev-parse e f | sort >expected_commits &&
> +
> +	test-pkt-line pack >in <<-EOF &&
> +	command=fetch
> +	0001
> +	no-progress
> +	want-ref refs/heads/master
> +	want $(git rev-parse e)
> +	have $(git rev-parse a)
> +	done
> +	0000
> +	EOF
> +
> +	git serve --stateless-rpc >out <in &&
> +	check_output
> +'

Overall the tests look good, although I might be a bit biased since they
are based on what I wrote a while ago [1]. I was wondering about the
behavior when the client mixes "want" and "want-ref" (as will happen if
they fetch both a ref by name and an exact SHA-1), and this test indeed
shows the expected behavior.

[1] https://public-inbox.org/git/d0d42b3bb4cf755f122591e191354c53848f197d.1485381677.git.jonathantanmy@google.com/

> +test_expect_success 'want-ref with ref we already have commit for' '
> +	cat >expected_refs <<-EOF &&
> +	$(git rev-parse c) refs/heads/o/foo
> +	EOF
> +	>expected_commits &&
> +
> +	test-pkt-line pack >in <<-EOF &&
> +	command=fetch
> +	0001
> +	no-progress
> +	want-ref refs/heads/o/foo
> +	have $(git rev-parse c)
> +	done
> +	0000
> +	EOF
> +
> +	git serve --stateless-rpc >out <in &&
> +	check_output
> +'

Likewise for this test - the ref is still reported, but the packfile
does not contain the requested object.

>  struct upload_pack_data {
>  	struct object_array wants;
> +	struct string_list wanted_refs;

Document here that this is a map from ref names to owned struct
object_id instances.

> +static int parse_want_ref(const char *line, struct string_list *wanted_refs)
> +{
> +	const char *arg;
> +	if (skip_prefix(line, "want-ref ", &arg)) {
> +		struct object_id oid;
> +		struct string_list_item *item;
> +		struct object *o;
> +
> +		if (read_ref(arg, &oid))
> +			die("unknown ref %s", arg);
> +
> +		item = string_list_append(wanted_refs, arg);
> +		item->util = oiddup(&oid);
> +
> +		o = parse_object_or_die(&oid, arg);
> +		if (!(o->flags & WANTED)) {
> +			o->flags |= WANTED;
> +			add_object_array(o, NULL, &want_obj);
> +		}

Makes sense - besides adding it to wanted_refs, this adds the object to
want_obj, just like how the other code paths for "want" adds it.

> +static void send_wanted_ref_info(struct upload_pack_data *data)
> +{
> +	const struct string_list_item *item;
> +
> +	if (!data->wanted_refs.nr)
> +		return;
> +
> +	packet_write_fmt(1, "wanted-refs\n");
> +
> +	for_each_string_list_item(item, &data->wanted_refs) {
> +		packet_write_fmt(1, "%s %s\n",
> +				 oid_to_hex(item->util),
> +				 item->string);
> +	}
> +
> +	packet_delim(1);
> +}

The documentation states that the "wanted-refs" section is only sent if
there is at least one "want-ref" from the client, and each "want-ref"
causes one entry to be added to data->wanted_refs, so this is correct.

Thanks - besides adding the period in the documentation, this patch
looks good to me.