Transactional processing for XCM (paritytech#1222)

Moved from: paritytech/polkadot#6951

closes paritytech#490

- [x] update cumulus

--- 
This PR introduces transactional processing of certain xcm instructions.
For the list of instructions checkout
paritytech#490. The transactional
processing is implemented as an xcm-executor config item. The two
implementations in this PR are `FrameTransactionalProcessor` and `()`.
The `()` implementation does no transactional processing. Each
implementation of the `ProcessTransaction` trait has an
`IS_TRANSACTIONAL` const that tells the XCVM if transactional processing
is actually implemented. If Transactional processing is implemented,
changes to touched registers should also be rolled back to prevent
inconsistencies.


Note for reviewers:
Check out the following safety assumption:
https://github.com/paritytech/polkadot-sdk/pull/1222/files#diff-4effad7d8c1c9de19fd27e18661cbf2128c8718f3b2420a27d2f816e0749ea53R30

---------

Co-authored-by: Keith Yeung <kungfukeith11@gmail.com>
Co-authored-by: Francisco Aguirre <franciscoaguirreperez@gmail.com>
Co-authored-by: command-bot <>

substrate/frame/contracts/mock-network/src/parachain.rs

@@ -41,9 +41,10 @@ use xcm::latest::prelude::*;
 use xcm_builder::CurrencyAdapter as XcmCurrencyAdapter;
 use xcm_builder::{
 	AccountId32Aliases, AllowExplicitUnpaidExecutionFrom, AllowTopLevelPaidExecutionFrom,
-	ConvertedConcreteId, EnsureXcmOrigin, FixedRateOfFungible, FixedWeightBounds, FungiblesAdapter,
-	IsConcrete, NativeAsset, NoChecking, ParentAsSuperuser, ParentIsPreset,
-	SignedAccountId32AsNative, SignedToAccountId32, SovereignSignedViaLocation, WithComputedOrigin,
+	ConvertedConcreteId, EnsureXcmOrigin, FixedRateOfFungible, FixedWeightBounds,
+	FrameTransactionalProcessor, FungiblesAdapter, IsConcrete, NativeAsset, NoChecking,
+	ParentAsSuperuser, ParentIsPreset, SignedAccountId32AsNative, SignedToAccountId32,
+	SovereignSignedViaLocation, WithComputedOrigin,
 };
 use xcm_executor::{traits::JustTry, Config, XcmExecutor};
 
@@ -284,6 +285,7 @@ impl Config for XcmConfig {
 	type CallDispatcher = RuntimeCall;
 	type SafeCallFilter = Everything;
 	type Aliasers = Nothing;
+	type TransactionalProcessor = FrameTransactionalProcessor;
 }
 
 impl mock_msg_queue::Config for Runtime {

substrate/frame/contracts/mock-network/src/relay_chain.rs

@@ -35,8 +35,8 @@ use xcm_builder::{
 	AccountId32Aliases, AllowExplicitUnpaidExecutionFrom, AllowSubscriptionsFrom,
 	AllowTopLevelPaidExecutionFrom, ChildParachainAsNative, ChildParachainConvertsVia,
 	ChildSystemParachainAsSuperuser, DescribeAllTerminal, DescribeFamily, FixedRateOfFungible,
-	FixedWeightBounds, HashedDescription, IsConcrete, SignedAccountId32AsNative,
-	SignedToAccountId32, SovereignSignedViaLocation, WithComputedOrigin,
+	FixedWeightBounds, FrameTransactionalProcessor, HashedDescription, IsConcrete,
+	SignedAccountId32AsNative, SignedToAccountId32, SovereignSignedViaLocation, WithComputedOrigin,
 };
 use xcm_executor::{Config, XcmExecutor};
 
@@ -185,6 +185,7 @@ impl Config for XcmConfig {
 	type CallDispatcher = RuntimeCall;
 	type SafeCallFilter = Everything;
 	type Aliasers = Nothing;
+	type TransactionalProcessor = FrameTransactionalProcessor;
 }
 
 pub type LocalOriginToLocation = SignedToAccountId32<RuntimeOrigin, AccountId, RelayNetwork>;