Ensure xcm versions over bridge (on sending chains) (#2481)

## Summary

This pull request proposes a solution for improved control of the
versioned XCM flow over the bridge (across different consensus chains)
and resolves the situation where the sending chain/consensus has already
migrated to a higher XCM version than the receiving chain/consensus.

## Problem/Motivation

The current flow over the bridge involves a transfer from AssetHubRococo
(AHR) to BridgeHubRococo (BHR) to BridgeHubWestend (BHW) and finally to
AssetHubWestend (AHW), beginning with a reserve-backed transfer on AHR.

In this process:
1. AHR sends XCM `ExportMessage` through `XcmpQueue`, incorporating XCM
version checks using the `WrapVersion` feature, influenced by
`pallet_xcm::SupportedVersion` (managed by
`pallet_xcm::force_xcm_version` or version discovery).

2. BHR handles the `ExportMessage` instruction, utilizing the latest XCM
version. The `HaulBlobExporter` converts the inner XCM to
[`VersionedXcm::from`](https://github.com/paritytech/polkadot-sdk/blob/63ac2471aa0210f0ac9903bdd7d8f9351f9a635f/polkadot/xcm/xcm-builder/src/universal_exports.rs#L465-L467),
also using the latest XCM version.

However, challenges arise:
- Incompatibility when BHW uses a different version than BHR. For
instance, if BHR migrates to **XCMv4** while BHW remains on **XCMv3**,
BHR's `VersionedXcm::from` uses `VersionedXcm::V4` variant, causing
encoding issues for BHW.
  ```
	/// Just a simulation of possible error, which could happen on BHW
	/// (this code is based on actual master without XCMv4)
	let encoded = hex_literal::hex!("0400");
	println!("{:?}", VersionedXcm::<()>::decode(&mut &encoded[..]));

Err(Error { cause: None, desc: "Could not decode `VersionedXcm`, variant
doesn't exist" })
  ``` 
- Similar compatibility issues exist between AHR and AHW.

## Solution

This pull request introduces the following solutions:

1. **New trait `CheckVersion`** - added to the `xcm` module and exposing
`pallet_xcm::SupportedVersion`. This enhancement allows checking the
actual XCM version for desired destinations outside of the `pallet_xcm`
module.

2. **Version Check in `HaulBlobExporter`** uses `CheckVersion` to check
known/configured destination versions, ensuring compatibility. For
example, in the scenario mentioned, BHR can store the version `3` for
BHW. If BHR is on XCMv4, it will attempt to downgrade the message to
version `3` instead of using the latest version `4`.

3. **Version Check in `pallet-xcm-bridge-hub-router`** - this check
ensures compatibility with the real destination's XCM version,
preventing the unnecessary sending of messages to the local bridge hub
if versions are incompatible.

These additions aim to improve the control and compatibility of XCM
flows over the bridge and addressing issues related to version
mismatches.

## Possible alternative solution

_(More investigation is needed, and at the very least, it should extend
to XCMv4/5. If this proves to be a viable option, I can open an RFC for
XCM.)._

Add the `XcmVersion` attribute to the `ExportMessage` so that the
sending chain can determine, based on what is stored in
`pallet_xcm::SupportedVersion`, the version the destination is using.
This way, we may not need to handle the version in `HaulBlobExporter`.

```
ExportMessage {
	network: NetworkId,
	destination: InteriorMultiLocation,
	xcm: Xcm<()>
	destination_xcm_version: Version, // <- new attritbute
},
```

```
pub trait ExportXcm {
        fn validate(
		network: NetworkId,
		channel: u32,
		universal_source: &mut Option<InteriorMultiLocation>,
		destination: &mut Option<InteriorMultiLocation>,
		message: &mut Option<Xcm<()>>,
                destination_xcm_version: Version, , // <- new attritbute
	) -> SendResult<Self::Ticket>;
```

## Future Directions

This PR does not fix version discovery over bridge, further
investigation will be conducted here:
https://github.com/paritytech/polkadot-sdk/issues/2417.

## TODO

- [x] `pallet_xcm` mock for tests uses hard-coded XCM version `2` -
change to 3 or lastest?
- [x] fix `pallet-xcm-bridge-hub-router`
- [x] fix HaulBlobExporter with version determination
[here](https://github.com/paritytech/polkadot-sdk/blob/2183669d05f9b510f979a0cc3c7847707bacba2e/polkadot/xcm/xcm-builder/src/universal_exports.rs#L465)
- [x] add unit-tests to the runtimes
- [x] run benchmarks for `ExportMessage`
- [x] extend local run scripts about `force_xcm_version(dest, version)`
- [ ] when merged, prepare governance calls for Rococo/Westend
- [ ] add PRDoc

Part of: https://github.com/paritytech/parity-bridges-common/issues/2719

---------

Co-authored-by: command-bot <>

polkadot/xcm/xcm-builder/src/universal_exports.rs

@@ -422,11 +422,25 @@ impl<
 	}
 }
 
-pub struct HaulBlobExporter<Bridge, BridgedNetwork, Price>(
-	PhantomData<(Bridge, BridgedNetwork, Price)>,
+pub struct HaulBlobExporter<Bridge, BridgedNetwork, DestinationVersion, Price>(
+	PhantomData<(Bridge, BridgedNetwork, DestinationVersion, Price)>,
 );
-impl<Bridge: HaulBlob, BridgedNetwork: Get<NetworkId>, Price: Get<MultiAssets>> ExportXcm
-	for HaulBlobExporter<Bridge, BridgedNetwork, Price>
+/// `ExportXcm` implementation for `HaulBlobExporter`.
+///
+/// # Type Parameters
+///
+/// ```text
+/// - Bridge: Implements `HaulBlob`.
+/// - BridgedNetwork: The relative location of the bridged consensus system with the expected `GlobalConsensus` junction.
+/// - DestinationVersion: Implements `GetVersion` for retrieving XCM version for the destination.
+/// - Price: potential fees for exporting.
+/// ```
+impl<
+		Bridge: HaulBlob,
+		BridgedNetwork: Get<MultiLocation>,
+		DestinationVersion: GetVersion,
+		Price: Get<MultiAssets>,
+	> ExportXcm for HaulBlobExporter<Bridge, BridgedNetwork, DestinationVersion, Price>
 {
 	type Ticket = (Vec<u8>, XcmHash);
 
@@ -437,17 +451,35 @@ impl<Bridge: HaulBlob, BridgedNetwork: Get<NetworkId>, Price: Get<MultiAssets>>
 		destination: &mut Option<InteriorMultiLocation>,
 		message: &mut Option<Xcm<()>>,
 	) -> Result<((Vec<u8>, XcmHash), MultiAssets), SendError> {
-		let bridged_network = BridgedNetwork::get();
+		let (bridged_network, bridged_network_location_parents) = {
+			let MultiLocation { parents, interior: mut junctions } = BridgedNetwork::get();
+			match junctions.take_first() {
+				Some(GlobalConsensus(network)) => (network, parents),
+				_ => return Err(SendError::NotApplicable),
+			}
+		};
 		ensure!(&network == &bridged_network, SendError::NotApplicable);
 		// We don't/can't use the `channel` for this adapter.
 		let dest = destination.take().ok_or(SendError::MissingArgument)?;
-		let universal_dest = match dest.pushed_front_with(GlobalConsensus(bridged_network)) {
-			Ok(d) => d.into(),
-			Err((dest, _)) => {
-				*destination = Some(dest);
-				return Err(SendError::NotApplicable)
-			},
-		};
+
+		// Let's resolve the known/supported XCM version for the destination because we don't know
+		// if it supports the same/latest version.
+		let (universal_dest, version) =
+			match dest.pushed_front_with(GlobalConsensus(bridged_network)) {
+				Ok(d) => {
+					let version = DestinationVersion::get_version_for(&MultiLocation::from(
+						AncestorThen(bridged_network_location_parents, d),
+					))
+					.ok_or(SendError::DestinationUnsupported)?;
+					(d, version)
+				},
+				Err((dest, _)) => {
+					*destination = Some(dest);
+					return Err(SendError::NotApplicable)
+				},
+			};
+
+		// Let's adjust XCM with `UniversalOrigin`, `DescendOrigin` and`SetTopic`.
 		let (local_net, local_sub) = universal_source
 			.take()
 			.ok_or(SendError::MissingArgument)?
@@ -462,7 +494,17 @@ impl<Bridge: HaulBlob, BridgedNetwork: Get<NetworkId>, Price: Get<MultiAssets>>
 		if local_sub != Here {
 			message.0.insert(1, DescendOrigin(local_sub));
 		}
-		let message = VersionedXcm::from(message);
+
+		// We cannot use the latest `Versioned` because we don't know if the target chain already
+		// supports the same version. Therefore, we better control the destination version with best
+		// efforts.
+		let message = VersionedXcm::from(message)
+			.into_version(version)
+			.map_err(|()| SendError::DestinationUnsupported)?;
+		let universal_dest = VersionedInteriorMultiLocation::from(universal_dest)
+			.into_version(version)
+			.map_err(|()| SendError::DestinationUnsupported)?;
+
 		let id = maybe_id.unwrap_or_else(|| message.using_encoded(sp_io::hashing::blake2_256));
 		let blob = BridgeMessage { universal_dest, message }.encode();
 		Ok(((blob, id), Price::get()))