Fixes

pallets/xcm/src/lib.rs

@@ -67,13 +67,13 @@ pub mod pallet {
 	pub enum Event<T: Config> {
 		/// Downward message is invalid XCM.
 		/// \[ id \]
-		InvalidFormat([u8; 8]),
+		InvalidFormat([u8; 32]),
 		/// Downward message is unsupported version of XCM.
 		/// \[ id \]
-		UnsupportedVersion([u8; 8]),
+		UnsupportedVersion([u8; 32]),
 		/// Downward message executed with the given outcome.
 		/// \[ id, outcome \]
-		ExecutedDownward([u8; 8], Outcome),
+		ExecutedDownward([u8; 32], Outcome),
 	}
 
 	/// Origin for the parachains module.

primitives/utility/src/lib.rs

@@ -20,7 +20,7 @@
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use codec::Encode;
-use cumulus_primitives_core::UpwardMessageSender;
+use cumulus_primitives_core::{MessageSendError, UpwardMessageSender};
 use sp_std::marker::PhantomData;
 use xcm::{latest::prelude::*, WrapVersion};
 
@@ -33,22 +33,37 @@ use xcm::{latest::prelude::*, WrapVersion};
 /// for the `SendXcm` implementation.
 pub struct ParentAsUmp<T, W>(PhantomData<(T, W)>);
 impl<T: UpwardMessageSender, W: WrapVersion> SendXcm for ParentAsUmp<T, W> {
-	fn send_xcm(dest: impl Into<MultiLocation>, msg: Xcm<()>) -> SendResult {
-		let dest = dest.into();
+	type Ticket = Vec<u8>;
 
-		if dest.contains_parents_only(1) {
+	fn validate(
+		dest: &mut Option<MultiLocation>,
+		msg: &mut Option<Xcm<()>>,
+	) -> SendResult<Vec<u8>> {
+		let d = dest.take().ok_or(SendError::MissingArgument)?;
+		let xcm = msg.take().ok_or(SendError::MissingArgument)?;
+
+		if d.contains_parents_only(1) {
 			// An upward message for the relay chain.
 			let versioned_xcm =
-				W::wrap_version(&dest, msg).map_err(|()| SendError::DestinationUnsupported)?;
+				W::wrap_version(&d, msg).map_err(|()| SendError::DestinationUnsupported)?;
 			let data = versioned_xcm.encode();
-			let hash = data.using_encoded(sp_io::hashing::blake2_256);
 
-			T::send_upward_message(data).map_err(|e| SendError::Transport(e.into()))?;
-
-			Ok(hash)
+			Ok(data, MultiAssets::new())
 		} else {
+			*dest = Some(d.clone());
 			// Anything else is unhandled. This includes a message this is meant for us.
-			Err(SendError::CannotReachDestination(dest, msg))
+			Err(SendError::NotApplicable(d, xcm))
 		}
 	}
+
+	fn deliver(blob: Vec<u8>) -> Result<XcmHash, SendError> {
+		let hash = data.using_encoded(sp_io::hashing::blake2_256);
+
+		T::send_upward_message(data).map_err(|e| match e {
+			MessageSendError::TooBig => SendError::ExceedsMaxMessageSize,
+			e => SendError::Transport(e.into()),
+		})?;
+
+		Ok(hash)
+	}
 }