Add possibility of executing or mocking additional inherents in xcm-emulator

cumulus/parachains/integration-tests/emulated/chains/parachains/assets/asset-hub-rococo/src/lib.rs

@@ -43,6 +43,7 @@ decl_test_parachains! {
 			ParachainInfo: asset_hub_rococo_runtime::ParachainInfo,
 			MessageOrigin: cumulus_primitives_core::AggregateMessageOrigin,
 			DigestProvider: (),
+			AdditionalInherentCode: (),
 		},
 		pallets = {
 			PolkadotXcm: asset_hub_rococo_runtime::PolkadotXcm,

cumulus/parachains/integration-tests/emulated/chains/parachains/assets/asset-hub-westend/src/lib.rs

@@ -43,6 +43,7 @@ decl_test_parachains! {
 			ParachainInfo: asset_hub_westend_runtime::ParachainInfo,
 			MessageOrigin: cumulus_primitives_core::AggregateMessageOrigin,
 			DigestProvider: (),
+			AdditionalInherentCode: (),
 		},
 		pallets = {
 			PolkadotXcm: asset_hub_westend_runtime::PolkadotXcm,

cumulus/xcm/xcm-emulator/src/lib.rs

@@ -142,6 +142,16 @@ where
 	}
 }
 
+// Implement optional inherent code to be executed
+// This will be executed after on-initialize and before on-finalize
+pub trait AdditionalInherentCode {
+	fn on_new_block() -> DispatchResult {
+		Ok(())
+	}
+}
+
+impl AdditionalInherentCode for () {}
+
 pub trait TestExt {
 	fn build_new_ext(storage: Storage) -> TestExternalities;
 	fn new_ext() -> TestExternalities;
@@ -269,6 +279,7 @@ pub trait Parachain: Chain {
 	type ParachainSystem;
 	type MessageProcessor: ProcessMessage + ServiceQueues;
 	type DigestProvider: Convert<BlockNumberFor<Self::Runtime>, Digest>;
+	type AdditionalInherentCode: AdditionalInherentCode;
 
 	fn init();
 
@@ -604,7 +615,8 @@ macro_rules! decl_test_parachains {
 					LocationToAccountId: $location_to_account:path,
 					ParachainInfo: $parachain_info:path,
 					MessageOrigin: $message_origin:path,
-					$( DigestProvider: $digest_provider:ty, )?
+					$( DigestProvider: $digest_provider:ty,)?
+					$( AdditionalInherentCode: $additional_inherent_code:ty,)?
 				},
 				pallets = {
 					$($pallet_name:ident: $pallet_path:path,)*
@@ -646,6 +658,7 @@ macro_rules! decl_test_parachains {
 				type ParachainInfo = $parachain_info;
 				type MessageProcessor = $crate::DefaultParaMessageProcessor<$name<N>, $message_origin>;
 				$crate::decl_test_parachains!(@inner_digest_provider $($digest_provider)?);
+				$crate::decl_test_parachains!(@inner_additional_inherent_code $($additional_inherent_code)?);
 
 				// We run an empty block during initialisation to open HRMP channels
 				// and have them ready for the next block
@@ -666,7 +679,7 @@ macro_rules! decl_test_parachains {
 
 				fn new_block() {
 					use $crate::{
-						Dispatchable, Chain, Convert, TestExt, Zero,
+						Dispatchable, Chain, Convert, TestExt, Zero, AdditionalInherentCode
 					};
 
 					let para_id = Self::para_id().into();
@@ -713,6 +726,9 @@ macro_rules! decl_test_parachains {
 						$crate::assert_ok!(
 							timestamp_set.dispatch(<Self as Chain>::RuntimeOrigin::none())
 						);
+						$crate::assert_ok!(
+							<Self as Parachain>::AdditionalInherentCode::on_new_block()
+						);
 					});
 				}
 
@@ -775,6 +791,8 @@ macro_rules! decl_test_parachains {
 	};
 	( @inner_digest_provider $digest_provider:ty ) => { type DigestProvider = $digest_provider; };
 	( @inner_digest_provider /* none */ ) => { type DigestProvider = (); };
+	( @inner_additional_inherent_code $additional_inherent_code:ty ) => { type AdditionalInherentCode = $additional_inherent_code; };
+	( @inner_additional_inherent_code /* none */ ) => { type AdditionalInherentCode = (); };
 }
 
 #[macro_export]

prdoc/pr_8809.prdoc

@@ -0,0 +1,12 @@
+title: Add possibility of executing or mocking additional inherents in xcm-emulator
+doc:
+- audience: Runtime Dev
+  description: |-
+    With the addition of https://github.com/paritytech/polkadot-sdk/pull/8083 there is no possibility right now of making the xcm-executor work with custom inherents. Custom inherents are usually driven by killing a storage item of the form `wasInherentSet` `on_initialize` and asserting that such inherent was set `on_finalize`. Before the xcm-emulator worked as these hooks were running just for the ParachainSystem pallet, but now, they run for all pallets.
+
+    My proposal is to add an item to the xcm-emulator parachain configuration of the form `AdditionalInherentCode`, which simply executes code that returns a `DispatchResult`. Whether users want to mock a storage item or run the inherent is up to them, this hook would allow them to do both.
+
+    This item is optional, meaning that if it is non-set then it would do nothing
+crates:
+- name: xcm-emulator
+  bump: major