promisor-remote: check advertised name or URL

A previous commit introduced a "promisor.acceptFromServer" configuration
variable with only "None" or "All" as valid values.

Let's introduce "KnownName" and "KnownUrl" as valid values for this
configuration option to give more choice to a client about which
promisor remotes it might accept among those that the server advertised.

In case of "KnownName", the client will accept promisor remotes which
are already configured on the client and have the same name as those
advertised by the client.

In case of "KnownUrl", the client will accept promisor remotes which
have both the same name and the same URL configured on the client as the
name and URL advertised by the server.

Signed-off-by: Christian Couder <[email protected]>

Documentation/config/promisor.txt

@@ -11,6 +11,11 @@ promisor.advertise::
 promisor.acceptFromServer::
 	If set to "all", a client will accept all the promisor remotes
 	a server might advertise using the "promisor-remote"
-	capability, see linkgit:gitprotocol-v2[5]. Default is "none",
-	which means no promisor remote advertised by a server will be
-	accepted.
+	capability, see linkgit:gitprotocol-v2[5]. If set to
+	"knownName" the client will accept promisor remotes which are
+	already configured on the client and have the same name as
+	those advertised by the client. If set to "knownUrl", the
+	client will accept promisor remotes which have both the same
+	name and the same URL configured on the client as the name and
+	URL advertised by the server. Default is "none", which means
+	no promisor remote advertised by a server will be accepted.

promisor-remote.c

@@ -362,19 +362,54 @@ void promisor_remote_info(struct repository *repo, struct strbuf *buf)
 	strvec_clear(&urls);
 }
 
+/*
+ * Find first index of 'vec' where there is 'val'. 'val' is compared
+ * case insensively to the strings in 'vec'. If not found 'vec->nr' is
+ * returned.
+ */
+static size_t strvec_find_index(struct strvec *vec, const char *val)
+{
+	for (size_t i = 0; i < vec->nr; i++)
+		if (!strcasecmp(vec->v[i], val))
+			return i;
+	return vec->nr;
+}
+
 enum accept_promisor {
 	ACCEPT_NONE = 0,
+	ACCEPT_KNOWN_URL,
+	ACCEPT_KNOWN_NAME,
 	ACCEPT_ALL
 };
 
 static int should_accept_remote(enum accept_promisor accept,
-				const char *remote_name UNUSED,
-				const char *remote_url UNUSED)
+				const char *remote_name, const char *remote_url,
+				struct strvec *names, struct strvec *urls)
 {
+	size_t i;
+
 	if (accept == ACCEPT_ALL)
 		return 1;
 
-	BUG("Unhandled 'enum accept_promisor' value '%d'", accept);
+	i = strvec_find_index(names, remote_name);
+
+	if (i >= names->nr)
+		/* We don't know about that remote */
+		return 0;
+
+	if (accept == ACCEPT_KNOWN_NAME)
+		return 1;
+
+	if (accept != ACCEPT_KNOWN_URL)
+		BUG("Unhandled 'enum accept_promisor' value '%d'", accept);
+
+	if (!strcasecmp(urls->v[i], remote_url))
+		return 1;
+
+	warning(_("known remote named '%s' but with url '%s' instead of '%s'"),
+		remote_name, urls->v[i], remote_url);
+
+	return 0;
 }
 
 static void filter_promisor_remote(struct repository *repo,
@@ -384,10 +419,16 @@ static void filter_promisor_remote(struct repository *repo,
 	struct strbuf **remotes;
 	char *accept_str;
 	enum accept_promisor accept = ACCEPT_NONE;
+	struct strvec names = STRVEC_INIT;
+	struct strvec urls = STRVEC_INIT;
 
 	if (!git_config_get_string("promisor.acceptfromserver", &accept_str)) {
 		if (!accept_str || !*accept_str || !strcasecmp("None", accept_str))
 			accept = ACCEPT_NONE;
+		else if (!strcasecmp("KnownUrl", accept_str))
+			accept = ACCEPT_KNOWN_URL;
+		else if (!strcasecmp("KnownName", accept_str))
+			accept = ACCEPT_KNOWN_NAME;
 		else if (!strcasecmp("All", accept_str))
 			accept = ACCEPT_ALL;
 		else
@@ -398,6 +439,9 @@ static void filter_promisor_remote(struct repository *repo,
 	if (accept == ACCEPT_NONE)
 		return;
 
+	if (accept != ACCEPT_ALL)
+		promisor_info_vecs(repo, &names, &urls);
+
 	/* Parse remote info received */
 
 	remotes = strbuf_split_str(info, ';', 0);
@@ -423,14 +467,16 @@ static void filter_promisor_remote(struct repository *repo,
 
 		decoded_url = url_decode(remote_url);
 
-		if (should_accept_remote(accept, remote_name, decoded_url))
+		if (should_accept_remote(accept, remote_name, decoded_url, &names, &urls))
 			strvec_push(accepted, remote_name);
 
 		strbuf_list_free(elems);
 		free(decoded_url);
 	}
 
 	free(accept_str);
+	strvec_clear(&names);
+	strvec_clear(&urls);
 	strbuf_list_free(remotes);
 }
 

t/t5710-promisor-remote-capability.sh

@@ -117,6 +117,74 @@ test_expect_success "fetch with promisor.acceptfromserver set to 'None'" '
 		--no-local --filter="blob:limit=5k" server client &&
 	test_when_finished "rm -rf client" &&
 
+	# Check that the largest object is not missing on the server
+	check_missing_objects server 0 "" &&
+
+	# Reinitialize server so that the largest object is missing again
+	initialize_server
+'
+
+test_expect_success "fetch with promisor.acceptfromserver set to 'KnownName'" '
+	git -C server config promisor.advertise true &&
+
+	# Clone from server to create a client
+	GIT_NO_LAZY_FETCH=0 git clone -c remote.server2.promisor=true \
+		-c remote.server2.fetch="+refs/heads/*:refs/remotes/server2/*" \
+		-c remote.server2.url="file://$(pwd)/server2" \
+		-c promisor.acceptfromserver=KnownName \
+		--no-local --filter="blob:limit=5k" server client &&
+	test_when_finished "rm -rf client" &&
+
+	# Check that the largest object is still missing on the server
+	check_missing_objects server 1 "$oid"
+'
+
+test_expect_success "fetch with 'KnownName' and different remote names" '
+	git -C server config promisor.advertise true &&
+
+	# Clone from server to create a client
+	GIT_NO_LAZY_FETCH=0 git clone -c remote.serverTwo.promisor=true \
+		-c remote.serverTwo.fetch="+refs/heads/*:refs/remotes/server2/*" \
+		-c remote.serverTwo.url="file://$(pwd)/server2" \
+		-c promisor.acceptfromserver=KnownName \
+		--no-local --filter="blob:limit=5k" server client &&
+	test_when_finished "rm -rf client" &&
+
+	# Check that the largest object is not missing on the server
+	check_missing_objects server 0 "" &&
+
+	# Reinitialize server so that the largest object is missing again
+	initialize_server
+'
+
+test_expect_success "fetch with promisor.acceptfromserver set to 'KnownUrl'" '
+	git -C server config promisor.advertise true &&
+
+	# Clone from server to create a client
+	GIT_NO_LAZY_FETCH=0 git clone -c remote.server2.promisor=true \
+		-c remote.server2.fetch="+refs/heads/*:refs/remotes/server2/*" \
+		-c remote.server2.url="file://$(pwd)/server2" \
+		-c promisor.acceptfromserver=KnownUrl \
+		--no-local --filter="blob:limit=5k" server client &&
+	test_when_finished "rm -rf client" &&
+
+	# Check that the largest object is still missing on the server
+	check_missing_objects server 1 "$oid"
+'
+
+test_expect_success "fetch with 'KnownUrl' and different remote urls" '
+	ln -s server2 serverTwo &&
+
+	git -C server config promisor.advertise true &&
+
+	# Clone from server to create a client
+	GIT_NO_LAZY_FETCH=0 git clone -c remote.server2.promisor=true \
+		-c remote.server2.fetch="+refs/heads/*:refs/remotes/server2/*" \
+		-c remote.server2.url="file://$(pwd)/serverTwo" \
+		-c promisor.acceptfromserver=KnownUrl \
+		--no-local --filter="blob:limit=5k" server client &&
+	test_when_finished "rm -rf client" &&
+
 	# Check that the largest object is not missing on the server
 	check_missing_objects server 0 ""
 '