Deploy versioned git_transport structure

src/remote.c

@@ -1024,10 +1024,25 @@ void git_remote_set_cred_acquire_cb(
 	remote->cred_acquire_cb = cred_acquire_cb;
 }
 
+static bool transport_has_valid_version(const git_transport *transport)
+{
+	if (!transport)
+		return true;
+
+	if (transport->version > 0 && transport->version <= GIT_TRANSPORT_VERSION)
+		return true;
+
+	giterr_set(GITERR_INVALID, "Invalid version %d on git_transport", transport->version);
+	return false;
+}
+
 int git_remote_set_transport(git_remote *remote, git_transport *transport)
 {
 	assert(remote && transport);
 
+	if (!transport_has_valid_version(transport))
+		return -1;
+
 	if (remote->transport) {
 		giterr_set(GITERR_NET, "A transport is already bound to this remote");
 		return -1;

src/transports/local.c

@@ -403,11 +403,10 @@ int git_transport_local(git_transport **out, git_remote *owner, void *param)
 
 	GIT_UNUSED(param);
 
-	t = git__malloc(sizeof(transport_local));
+	t = git__calloc(1, sizeof(transport_local));
 	GITERR_CHECK_ALLOC(t);
 
-	memset(t, 0x0, sizeof(transport_local));
-		
+	t->parent.version = GIT_TRANSPORT_VERSION;
 	t->parent.connect = local_connect;
 	t->parent.negotiate_fetch = local_negotiate_fetch;
 	t->parent.download_pack = local_download_pack;

src/transports/smart.c

@@ -303,6 +303,7 @@ int git_transport_smart(git_transport **out, git_remote *owner, void *param)
 	t = git__calloc(sizeof(transport_smart), 1);
 	GITERR_CHECK_ALLOC(t);
 
+	t->parent.version = GIT_TRANSPORT_VERSION;
 	t->parent.set_callbacks = git_smart__set_callbacks;
 	t->parent.connect = git_smart__connect;
 	t->parent.close = git_smart__close;

tests-clar/network/remotes.c

@@ -279,3 +279,23 @@ void test_network_remotes__cannot_load_with_an_empty_url(void)
 	cl_git_fail(git_remote_load(&remote, _repo, "empty-remote-url"));
 	cl_assert(giterr_last()->klass == GITERR_INVALID);
 }
+
+void test_network_remotes__check_structure_version(void)
+{
+	git_transport transport = GIT_TRANSPORT_INIT;
+	const git_error *err;
+
+	git_remote_free(_remote);
+	cl_git_pass(git_remote_new(&_remote, _repo, NULL, "test-protocol://localhost", NULL));
+
+	transport.version = 0;
+	cl_git_fail(git_remote_set_transport(_remote, &transport));
+	err = giterr_last();
+	cl_assert_equal_i(GITERR_INVALID, err->klass);
+
+	giterr_clear();
+	transport.version = 1024;
+	cl_git_fail(git_remote_set_transport(_remote, &transport));
+	err = giterr_last();
+	cl_assert_equal_i(GITERR_INVALID, err->klass);
+}