Added fallback_max_weight to Transact for sending messages to V4 chai…

…ns (paritytech#6643)

Closes: paritytech#6585

Removing the `require_weight_at_most` parameter in V5 Transact had only
one problem. Converting a message from V5 to V4 to send to chains that
didn't upgrade yet. The conversion would not know what weight to give to
the Transact, since V4 and below require it.

To fix this, I added back the weight in the form of an `Option<Weight>`
called `fallback_max_weight`. This can be set to `None` if you don't
intend to deal with a chain that hasn't upgraded yet. If you set it to
`Some(_)`, the behaviour is the same. The plan is to totally remove this
in V6 since there will be a good conversion path from V6 to V5.

---------

Co-authored-by: GitHub Action <[email protected]>
Co-authored-by: Adrian Catangiu <[email protected]>

bridges/snowbridge/pallets/inbound-queue/src/test.rs

@@ -40,8 +40,8 @@ fn test_submit_happy_path() {
 				.into(),
 			nonce: 1,
 			message_id: [
-				11, 25, 133, 51, 23, 68, 111, 211, 132, 94, 254, 17, 194, 252, 198, 233, 10, 193,
-				156, 93, 72, 140, 65, 69, 79, 155, 154, 28, 141, 166, 171, 255,
+				97, 161, 116, 204, 182, 115, 192, 144, 130, 243, 240, 193, 122, 154, 108, 91, 247,
+				41, 226, 237, 202, 158, 238, 239, 210, 8, 147, 131, 84, 146, 171, 176,
 			],
 			fee_burned: 110000000000,
 		}

bridges/snowbridge/primitives/router/src/inbound/mod.rs

@@ -279,6 +279,7 @@ where
 			// Call create_asset on foreign assets pallet.
 			Transact {
 				origin_kind: OriginKind::Xcm,
+				fallback_max_weight: None,
 				call: (
 					create_call_index,
 					asset_id,

cumulus/parachains/integration-tests/emulated/common/src/xcm_helpers.rs

@@ -31,7 +31,7 @@ pub fn xcm_transact_paid_execution(
 	VersionedXcm::from(Xcm(vec![
 		WithdrawAsset(fees.clone().into()),
 		BuyExecution { fees, weight_limit },
-		Transact { origin_kind, call },
+		Transact { origin_kind, call, fallback_max_weight: None },
 		RefundSurplus,
 		DepositAsset {
 			assets: All.into(),
@@ -53,7 +53,7 @@ pub fn xcm_transact_unpaid_execution(
 
 	VersionedXcm::from(Xcm(vec![
 		UnpaidExecution { weight_limit, check_origin },
-		Transact { origin_kind, call },
+		Transact { origin_kind, call, fallback_max_weight: None },
 	]))
 }
 

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

@@ -43,7 +43,7 @@ fn transfer_and_transact_in_same_xcm(
 
 	// xcm to be executed at dest
 	let xcm_on_dest = Xcm(vec![
-		Transact { origin_kind: OriginKind::Xcm, call },
+		Transact { origin_kind: OriginKind::Xcm, call, fallback_max_weight: None },
 		ExpectTransactStatus(MaybeErrorCode::Success),
 		// since this is the last hop, we don't need to further use any assets previously
 		// reserved for fees (there are no further hops to cover transport fees for); we

cumulus/parachains/integration-tests/emulated/tests/bridges/bridge-hub-rococo/src/tests/snowbridge.rs

@@ -84,7 +84,11 @@ fn create_agent() {
 	let remote_xcm = VersionedXcm::from(Xcm(vec![
 		UnpaidExecution { weight_limit: Unlimited, check_origin: None },
 		DescendOrigin(Parachain(origin_para).into()),
-		Transact { origin_kind: OriginKind::Xcm, call: create_agent_call.encode().into() },
+		Transact {
+			origin_kind: OriginKind::Xcm,
+			call: create_agent_call.encode().into(),
+			fallback_max_weight: None,
+		},
 	]));
 
 	// Rococo Global Consensus
@@ -138,7 +142,11 @@ fn create_channel() {
 	let create_agent_xcm = VersionedXcm::from(Xcm(vec![
 		UnpaidExecution { weight_limit: Unlimited, check_origin: None },
 		DescendOrigin(Parachain(origin_para).into()),
-		Transact { origin_kind: OriginKind::Xcm, call: create_agent_call.encode().into() },
+		Transact {
+			origin_kind: OriginKind::Xcm,
+			call: create_agent_call.encode().into(),
+			fallback_max_weight: None,
+		},
 	]));
 
 	let create_channel_call =
@@ -147,7 +155,11 @@ fn create_channel() {
 	let create_channel_xcm = VersionedXcm::from(Xcm(vec![
 		UnpaidExecution { weight_limit: Unlimited, check_origin: None },
 		DescendOrigin(Parachain(origin_para).into()),
-		Transact { origin_kind: OriginKind::Xcm, call: create_channel_call.encode().into() },
+		Transact {
+			origin_kind: OriginKind::Xcm,
+			call: create_channel_call.encode().into(),
+			fallback_max_weight: None,
+		},
 	]));
 
 	// Rococo Global Consensus

cumulus/parachains/integration-tests/emulated/tests/bridges/bridge-hub-westend/src/tests/transact.rs

@@ -49,7 +49,7 @@ fn transfer_and_transact_in_same_xcm(
 
 	// xcm to be executed at dest
 	let xcm_on_dest = Xcm(vec![
-		Transact { origin_kind: OriginKind::Xcm, call },
+		Transact { origin_kind: OriginKind::Xcm, call, fallback_max_weight: None },
 		ExpectTransactStatus(MaybeErrorCode::Success),
 		// since this is the last hop, we don't need to further use any assets previously
 		// reserved for fees (there are no further hops to cover transport fees for); we

cumulus/parachains/integration-tests/emulated/tests/collectives/collectives-westend/src/tests/fellowship.rs

@@ -41,6 +41,7 @@ fn fellows_whitelist_call() {
 					)
 					.encode()
 					.into(),
+					fallback_max_weight: None
 				}
 			]))),
 		});

cumulus/parachains/integration-tests/emulated/tests/people/people-westend/src/tests/governance.rs

@@ -48,7 +48,11 @@ fn relay_commands_add_registrar() {
 			dest: bx!(VersionedLocation::from(Location::new(0, [Parachain(1004)]))),
 			message: bx!(VersionedXcm::from(Xcm(vec![
 				UnpaidExecution { weight_limit: Unlimited, check_origin: None },
-				Transact { origin_kind, call: add_registrar_call.encode().into() }
+				Transact {
+					origin_kind,
+					call: add_registrar_call.encode().into(),
+					fallback_max_weight: None
+				}
 			]))),
 		});
 
@@ -107,7 +111,11 @@ fn relay_commands_add_registrar_wrong_origin() {
 				dest: bx!(VersionedLocation::from(Location::new(0, [Parachain(1004)]))),
 				message: bx!(VersionedXcm::from(Xcm(vec![
 					UnpaidExecution { weight_limit: Unlimited, check_origin: None },
-					Transact { origin_kind, call: add_registrar_call.encode().into() }
+					Transact {
+						origin_kind,
+						call: add_registrar_call.encode().into(),
+						fallback_max_weight: None
+					}
 				]))),
 			});
 
@@ -194,7 +202,11 @@ fn relay_commands_kill_identity() {
 			dest: bx!(VersionedLocation::from(Location::new(0, [Parachain(1004)]))),
 			message: bx!(VersionedXcm::from(Xcm(vec![
 				UnpaidExecution { weight_limit: Unlimited, check_origin: None },
-				Transact { origin_kind, call: kill_identity_call.encode().into() }
+				Transact {
+					origin_kind,
+					call: kill_identity_call.encode().into(),
+					fallback_max_weight: None
+				}
 			]))),
 		});
 
@@ -252,7 +264,11 @@ fn relay_commands_kill_identity_wrong_origin() {
 				dest: bx!(VersionedLocation::from(Location::new(0, [Parachain(1004)]))),
 				message: bx!(VersionedXcm::from(Xcm(vec![
 					UnpaidExecution { weight_limit: Unlimited, check_origin: None },
-					Transact { origin_kind, call: kill_identity_call.encode().into() }
+					Transact {
+						origin_kind,
+						call: kill_identity_call.encode().into(),
+						fallback_max_weight: None
+					}
 				]))),
 			});
 
@@ -298,7 +314,11 @@ fn relay_commands_add_remove_username_authority() {
 			dest: bx!(VersionedLocation::from(Location::new(0, [Parachain(1004)]))),
 			message: bx!(VersionedXcm::from(Xcm(vec![
 				UnpaidExecution { weight_limit: Unlimited, check_origin: None },
-				Transact { origin_kind, call: add_username_authority.encode().into() }
+				Transact {
+					origin_kind,
+					call: add_username_authority.encode().into(),
+					fallback_max_weight: None
+				}
 			]))),
 		});
 
@@ -383,7 +403,11 @@ fn relay_commands_add_remove_username_authority() {
 			dest: bx!(VersionedLocation::from(Location::new(0, [Parachain(1004)]))),
 			message: bx!(VersionedXcm::from(Xcm(vec![
 				UnpaidExecution { weight_limit: Unlimited, check_origin: None },
-				Transact { origin_kind, call: remove_username_authority.encode().into() }
+				Transact {
+					origin_kind,
+					call: remove_username_authority.encode().into(),
+					fallback_max_weight: None
+				}
 			]))),
 		});
 
@@ -443,7 +467,11 @@ fn relay_commands_add_remove_username_authority_wrong_origin() {
 				dest: bx!(VersionedLocation::from(Location::new(0, [Parachain(1004)]))),
 				message: bx!(VersionedXcm::from(Xcm(vec![
 					UnpaidExecution { weight_limit: Unlimited, check_origin: None },
-					Transact { origin_kind, call: add_username_authority.encode().into() }
+					Transact {
+						origin_kind,
+						call: add_username_authority.encode().into(),
+						fallback_max_weight: None
+					}
 				]))),
 			});
 
@@ -483,6 +511,7 @@ fn relay_commands_add_remove_username_authority_wrong_origin() {
 						Transact {
 							origin_kind: OriginKind::SovereignAccount,
 							call: remove_username_authority.encode().into(),
+							fallback_max_weight: None,
 						}
 					]))),
 				});

cumulus/parachains/pallets/ping/src/lib.rs

@@ -114,6 +114,7 @@ pub mod pallet {
 						})
 						.encode()
 						.into(),
+						fallback_max_weight: None,
 					}]),
 				) {
 					Ok((hash, cost)) => {
@@ -214,6 +215,7 @@ pub mod pallet {
 					})
 					.encode()
 					.into(),
+					fallback_max_weight: None,
 				}]),
 			) {
 				Ok((hash, cost)) =>

cumulus/parachains/runtimes/assets/asset-hub-rococo/src/weights/xcm/mod.rs

@@ -84,7 +84,11 @@ impl<Call> XcmWeightInfo<Call> for AssetHubRococoXcmWeight<Call> {
 	fn transfer_reserve_asset(assets: &Assets, _dest: &Location, _xcm: &Xcm<()>) -> Weight {
 		assets.weigh_assets(XcmFungibleWeight::<Runtime>::transfer_reserve_asset())
 	}
-	fn transact(_origin_type: &OriginKind, _call: &DoubleEncoded<Call>) -> Weight {
+	fn transact(
+		_origin_type: &OriginKind,
+		_fallback_max_weight: &Option<Weight>,
+		_call: &DoubleEncoded<Call>,
+	) -> Weight {
 		XcmGeneric::<Runtime>::transact()
 	}
 	fn hrmp_new_channel_open_request(

cumulus/parachains/runtimes/assets/asset-hub-westend/src/weights/xcm/mod.rs

@@ -83,7 +83,11 @@ impl<Call> XcmWeightInfo<Call> for AssetHubWestendXcmWeight<Call> {
 	fn transfer_reserve_asset(assets: &Assets, _dest: &Location, _xcm: &Xcm<()>) -> Weight {
 		assets.weigh_assets(XcmFungibleWeight::<Runtime>::transfer_reserve_asset())
 	}
-	fn transact(_origin_type: &OriginKind, _call: &DoubleEncoded<Call>) -> Weight {
+	fn transact(
+		_origin_type: &OriginKind,
+		_fallback_max_weight: &Option<Weight>,
+		_call: &DoubleEncoded<Call>,
+	) -> Weight {
 		XcmGeneric::<Runtime>::transact()
 	}
 	fn hrmp_new_channel_open_request(

cumulus/parachains/runtimes/assets/test-utils/src/test_cases.rs

@@ -1205,14 +1205,20 @@ pub fn create_and_manage_foreign_assets_for_local_consensus_parachain_assets_wor
 			let xcm = Xcm(vec![
 				WithdrawAsset(buy_execution_fee.clone().into()),
 				BuyExecution { fees: buy_execution_fee.clone(), weight_limit: Unlimited },
-				Transact { origin_kind: OriginKind::Xcm, call: foreign_asset_create.into() },
+				Transact {
+					origin_kind: OriginKind::Xcm,
+					call: foreign_asset_create.into(),
+					fallback_max_weight: None,
+				},
 				Transact {
 					origin_kind: OriginKind::SovereignAccount,
 					call: foreign_asset_set_metadata.into(),
+					fallback_max_weight: None,
 				},
 				Transact {
 					origin_kind: OriginKind::SovereignAccount,
 					call: foreign_asset_set_team.into(),
+					fallback_max_weight: None,
 				},
 				ExpectTransactStatus(MaybeErrorCode::Success),
 			]);
@@ -1318,7 +1324,11 @@ pub fn create_and_manage_foreign_assets_for_local_consensus_parachain_assets_wor
 			let xcm = Xcm(vec![
 				WithdrawAsset(buy_execution_fee.clone().into()),
 				BuyExecution { fees: buy_execution_fee.clone(), weight_limit: Unlimited },
-				Transact { origin_kind: OriginKind::Xcm, call: foreign_asset_create.into() },
+				Transact {
+					origin_kind: OriginKind::Xcm,
+					call: foreign_asset_create.into(),
+					fallback_max_weight: None,
+				},
 				ExpectTransactStatus(MaybeErrorCode::from(DispatchError::BadOrigin.encode())),
 			]);
 

cumulus/parachains/runtimes/bridge-hubs/bridge-hub-rococo/src/weights/xcm/mod.rs

@@ -84,7 +84,11 @@ impl<Call> XcmWeightInfo<Call> for BridgeHubRococoXcmWeight<Call> {
 	fn transfer_reserve_asset(assets: &Assets, _dest: &Location, _xcm: &Xcm<()>) -> Weight {
 		assets.weigh_assets(XcmFungibleWeight::<Runtime>::transfer_reserve_asset())
 	}
-	fn transact(_origin_type: &OriginKind, _call: &DoubleEncoded<Call>) -> Weight {
+	fn transact(
+		_origin_type: &OriginKind,
+		_fallback_max_weight: &Option<Weight>,
+		_call: &DoubleEncoded<Call>,
+	) -> Weight {
 		XcmGeneric::<Runtime>::transact()
 	}
 	fn hrmp_new_channel_open_request(

cumulus/parachains/runtimes/bridge-hubs/bridge-hub-westend/src/weights/xcm/mod.rs

@@ -85,7 +85,11 @@ impl<Call> XcmWeightInfo<Call> for BridgeHubWestendXcmWeight<Call> {
 	fn transfer_reserve_asset(assets: &Assets, _dest: &Location, _xcm: &Xcm<()>) -> Weight {
 		assets.weigh_assets(XcmFungibleWeight::<Runtime>::transfer_reserve_asset())
 	}
-	fn transact(_origin_type: &OriginKind, _call: &DoubleEncoded<Call>) -> Weight {
+	fn transact(
+		_origin_type: &OriginKind,
+		_fallback_max_weight: &Option<Weight>,
+		_call: &DoubleEncoded<Call>,
+	) -> Weight {
 		XcmGeneric::<Runtime>::transact()
 	}
 	fn hrmp_new_channel_open_request(

cumulus/parachains/runtimes/coretime/coretime-rococo/src/coretime.rs

@@ -135,6 +135,7 @@ impl CoretimeInterface for CoretimeAllocator {
 			Instruction::Transact {
 				origin_kind: OriginKind::Native,
 				call: request_core_count_call.encode().into(),
+				fallback_max_weight: Some(Weight::from_parts(1_000_000_000, 200_000)),
 			},
 		]);
 
@@ -164,6 +165,7 @@ impl CoretimeInterface for CoretimeAllocator {
 			Instruction::Transact {
 				origin_kind: OriginKind::Native,
 				call: request_revenue_info_at_call.encode().into(),
+				fallback_max_weight: Some(Weight::from_parts(1_000_000_000, 200_000)),
 			},
 		]);
 
@@ -192,6 +194,7 @@ impl CoretimeInterface for CoretimeAllocator {
 			Instruction::Transact {
 				origin_kind: OriginKind::Native,
 				call: credit_account_call.encode().into(),
+				fallback_max_weight: Some(Weight::from_parts(1_000_000_000, 200_000)),
 			},
 		]);
 
@@ -256,6 +259,7 @@ impl CoretimeInterface for CoretimeAllocator {
 			Instruction::Transact {
 				origin_kind: OriginKind::Native,
 				call: assign_core_call.encode().into(),
+				fallback_max_weight: Some(Weight::from_parts(1_000_000_000, 200_000)),
 			},
 		]);
 

cumulus/parachains/runtimes/coretime/coretime-rococo/src/weights/xcm/mod.rs

@@ -84,7 +84,11 @@ impl<Call> XcmWeightInfo<Call> for CoretimeRococoXcmWeight<Call> {
 	fn transfer_reserve_asset(assets: &Assets, _dest: &Location, _xcm: &Xcm<()>) -> Weight {
 		assets.weigh_assets(XcmFungibleWeight::<Runtime>::transfer_reserve_asset())
 	}
-	fn transact(_origin_type: &OriginKind, _call: &DoubleEncoded<Call>) -> Weight {
+	fn transact(
+		_origin_type: &OriginKind,
+		_fallback_max_weight: &Option<Weight>,
+		_call: &DoubleEncoded<Call>,
+	) -> Weight {
 		XcmGeneric::<Runtime>::transact()
 	}
 	fn hrmp_new_channel_open_request(