XCM v2: Scripting, Query responses, Exception handling and Error reporting (#3629)

* Intoduce XCM v2 Also some minor fix for v0/v1 * Minor version cleanup * Minor version cleanup * Introduce SendError for XcmSend trait to avoid cycles with having Outcome in Xcm * comment * Corrent type * Docs * Fix build * Fixes * Introduce the basic impl * Docs * Add function * Basic implementation * Weighed responses and on_report * Make XCM more script-like * Remove BuyExecution::orders * Fixes * Fixes * Fixes * Formatting * Initial draft and make pallet-xcm build * fix XCM tests * Formatting * Fixes * Formatting * spelling * Fixes * Fixes * spelling * tests for translation * extra fields to XCM pallet * Formatting * Fixes * spelling * first integration test * Another integration test * Formatting * fix tests * all tests * Fixes * Fixes * Formatting * Fixes * Fixes * Formatting * Bump * Remove unneeded structuring * add instruction * Fixes * spelling * Fixes * Fixes * Formatting * Fixes * Fixes * Formatting * Introduce and use VersionedResponse * Introduce versioning to dispatchables' params * Fixes * Formatting * Rest of merge * more work * Formatting * Basic logic * Fixes * Fixes * Add test * Fixes * Formatting * Fixes * Fixes * Fixes * Nits * Simplify * Spelling * Formatting * Return weight of unexecuted instructions in case of error as surplus * Formatting * Fixes * Test for instruction count limiting * Formatting * Docs
2026-05-31 01:41:03 +00:00 · 2021-08-26 12:41:16 +02:00
parent 4193f05fa3
commit 8b80b283d4
37 changed files with 3070 additions and 966 deletions
@@ -19,10 +19,10 @@
 use frame_support::{ensure, traits::Contains, weights::Weight};
 use polkadot_parachain::primitives::IsSystem;
 use sp_std::{marker::PhantomData, result::Result};
-use xcm::latest::{Junction, Junctions, MultiLocation, Order, Xcm};
+use xcm::latest::{Instruction::*, Junction, Junctions, MultiLocation, WeightLimit::*, Xcm};
 use xcm_executor::traits::{OnResponse, ShouldExecute};

-/// Execution barrier that just takes `shallow_weight` from `weight_credit`.
+/// Execution barrier that just takes `max_weight` from `weight_credit`.
 ///
 /// Useful to allow XCM execution by local chain users via extrinsics.
 /// E.g. `pallet_xcm::reserve_asset_transfer` to transfer a reserve asset
@@ -30,42 +30,53 @@ use xcm_executor::traits::{OnResponse, ShouldExecute};
 pub struct TakeWeightCredit;
 impl ShouldExecute for TakeWeightCredit {
 	fn should_execute<Call>(
-		_origin: &MultiLocation,
+		_origin: &Option<MultiLocation>,
 		_top_level: bool,
-		_message: &Xcm<Call>,
-		shallow_weight: Weight,
+		_message: &mut Xcm<Call>,
+		max_weight: Weight,
 		weight_credit: &mut Weight,
 	) -> Result<(), ()> {
-		*weight_credit = weight_credit.checked_sub(shallow_weight).ok_or(())?;
+		*weight_credit = weight_credit.checked_sub(max_weight).ok_or(())?;
 		Ok(())
 	}
 }

-/// Allows execution from `origin` if it is contained in `T` (i.e. `T::Contains(origin)`) taking payments into
-/// account.
+/// Allows execution from `origin` if it is contained in `T` (i.e. `T::Contains(origin)`) taking
+/// payments into account.
 ///
-/// Only allows for `TeleportAsset`, `WithdrawAsset` and `ReserveAssetDeposit` XCMs because they are the only ones
-/// that place assets in the Holding Register to pay for execution.
+/// Only allows for `TeleportAsset`, `WithdrawAsset` and `ReserveAssetDeposit` XCMs because they are
+/// the only ones that place assets in the Holding Register to pay for execution.
 pub struct AllowTopLevelPaidExecutionFrom<T>(PhantomData<T>);
 impl<T: Contains<MultiLocation>> ShouldExecute for AllowTopLevelPaidExecutionFrom<T> {
 	fn should_execute<Call>(
-		origin: &MultiLocation,
+		origin: &Option<MultiLocation>,
 		top_level: bool,
-		message: &Xcm<Call>,
-		shallow_weight: Weight,
+		message: &mut Xcm<Call>,
+		max_weight: Weight,
 		_weight_credit: &mut Weight,
 	) -> Result<(), ()> {
+		let origin = origin.as_ref().ok_or(())?;
 		ensure!(T::contains(origin), ());
 		ensure!(top_level, ());
-		match message {
-			Xcm::ReceiveTeleportedAsset { effects, .. } |
-			Xcm::WithdrawAsset { effects, .. } |
-			Xcm::ReserveAssetDeposited { effects, .. }
-				if matches!(
-					effects.first(),
-					Some(Order::BuyExecution { debt, ..}) if *debt >= shallow_weight
-				) =>
-				Ok(()),
+		let mut iter = message.0.iter_mut();
+		let i = iter.next().ok_or(())?;
+		match i {
+			ReceiveTeleportedAsset(..) | WithdrawAsset(..) | ReserveAssetDeposited(..) => (),
+			_ => return Err(()),
+		}
+		let mut i = iter.next().ok_or(())?;
+		while let ClearOrigin = i {
+			i = iter.next().ok_or(())?;
+		}
+		match i {
+			BuyExecution { weight_limit: Limited(ref mut weight), .. } if *weight >= max_weight => {
+				*weight = max_weight;
+				Ok(())
+			},
+			BuyExecution { ref mut weight_limit, .. } if weight_limit == &Unlimited => {
+				*weight_limit = Limited(max_weight);
+				Ok(())
+			},
 			_ => Err(()),
 		}
 	}
@@ -76,12 +87,13 @@ impl<T: Contains<MultiLocation>> ShouldExecute for AllowTopLevelPaidExecutionFro
 pub struct AllowUnpaidExecutionFrom<T>(PhantomData<T>);
 impl<T: Contains<MultiLocation>> ShouldExecute for AllowUnpaidExecutionFrom<T> {
 	fn should_execute<Call>(
-		origin: &MultiLocation,
+		origin: &Option<MultiLocation>,
 		_top_level: bool,
-		_message: &Xcm<Call>,
-		_shallow_weight: Weight,
+		_message: &mut Xcm<Call>,
+		_max_weight: Weight,
 		_weight_credit: &mut Weight,
 	) -> Result<(), ()> {
+		let origin = origin.as_ref().ok_or(())?;
 		ensure!(T::contains(origin), ());
 		Ok(())
 	}
@@ -103,14 +115,15 @@ impl<ParaId: IsSystem + From<u32>> Contains<MultiLocation> for IsChildSystemPara
 pub struct AllowKnownQueryResponses<ResponseHandler>(PhantomData<ResponseHandler>);
 impl<ResponseHandler: OnResponse> ShouldExecute for AllowKnownQueryResponses<ResponseHandler> {
 	fn should_execute<Call>(
-		origin: &MultiLocation,
+		origin: &Option<MultiLocation>,
 		_top_level: bool,
-		message: &Xcm<Call>,
-		_shallow_weight: Weight,
+		message: &mut Xcm<Call>,
+		_max_weight: Weight,
 		_weight_credit: &mut Weight,
 	) -> Result<(), ()> {
-		match message {
-			Xcm::QueryResponse { query_id, .. }
+		let origin = origin.as_ref().ok_or(())?;
+		match message.0.first() {
+			Some(QueryResponse { query_id, .. })
 				if ResponseHandler::expecting_response(origin, *query_id) =>
 				Ok(()),
 			_ => Err(()),