Optional ERC20-XCM gas limit override and tests

pallets/erc20-xcm-bridge/src/lib.rs

@@ -42,7 +42,8 @@ pub mod pallet {
 	use sp_core::{H160, H256, U256};
 	use sp_std::vec::Vec;
 	use xcm::latest::{
-		Error as XcmError, MultiAsset, MultiLocation, Result as XcmResult, XcmContext,
+		AssetId, Error as XcmError, Junction, MultiAsset, MultiLocation, Result as XcmResult,
+		XcmContext,
 	};
 	use xcm_executor::traits::{Convert, Error as MatchError, MatchesFungibles};
 	use xcm_executor::Assets;
@@ -65,14 +66,33 @@ pub mod pallet {
 		pub fn is_erc20_asset(asset: &MultiAsset) -> bool {
 			Erc20Matcher::<T::Erc20MultilocationPrefix>::is_erc20_asset(asset)
 		}
-		pub fn weight_of_erc20_transfer() -> Weight {
-			T::GasWeightMapping::gas_to_weight(T::Erc20TransferGasLimit::get(), true)
+		pub fn gas_limit_of_erc20_transfer(asset_id: &AssetId) -> u64 {
+			if let AssetId::Concrete(multilocation) = asset_id {
+				if let Some(Junction::GeneralKey {
+					length: _,
+					ref data,
+				}) = multilocation.interior().into_iter().next_back()
+				{
+					if let Ok(content) = core::str::from_utf8(&data[0..10]) {
+						if content == "gas_limit:" {
+							let mut bytes: [u8; 8] = Default::default();
+							bytes.copy_from_slice(&data[10..18]);
+							return u64::from_le_bytes(bytes);
+						}
+					}
+				}
+			};
+			T::Erc20TransferGasLimit::get()
+		}
+		pub fn weight_of_erc20_transfer(asset_id: &AssetId) -> Weight {
+			T::GasWeightMapping::gas_to_weight(Self::gas_limit_of_erc20_transfer(asset_id), true)
 		}
 		fn erc20_transfer(
 			erc20_contract_address: H160,
 			from: H160,
 			to: H160,
 			amount: U256,
+			gas_limit: u64,
 		) -> Result<(), Erc20TransferError> {
 			let mut input = Vec::with_capacity(ERC20_TRANSFER_CALL_DATA_SIZE);
 			// ERC20.transfer method hash
@@ -82,15 +102,14 @@ pub mod pallet {
 			// append amount to be transferred
 			input.extend_from_slice(H256::from_uint(&amount).as_bytes());
 
-			let weight_limit =
-				T::GasWeightMapping::gas_to_weight(T::Erc20TransferGasLimit::get(), true);
+			let weight_limit: Weight = T::GasWeightMapping::gas_to_weight(gas_limit, true);
 
 			let exec_info = T::EvmRunner::call(
 				from,
 				erc20_contract_address,
 				input,
 				U256::default(),
-				T::Erc20TransferGasLimit::get(),
+				gas_limit,
 				None,
 				None,
 				None,
@@ -140,6 +159,8 @@ pub mod pallet {
 			let beneficiary = T::AccountIdConverter::convert_ref(who)
 				.map_err(|()| MatchError::AccountIdConversionFailed)?;
 
+			let gas_limit = Self::gas_limit_of_erc20_transfer(&what.id);
+
 			// Get the global context to recover accounts origins.
 			XcmHoldingErc20sOrigins::with(|erc20s_origins| {
 				match erc20s_origins.drain(contract_address, amount) {
@@ -149,7 +170,13 @@ pub mod pallet {
 						tokens_to_transfer
 							.into_iter()
 							.try_for_each(|(from, subamount)| {
-								Self::erc20_transfer(contract_address, from, beneficiary, subamount)
+								Self::erc20_transfer(
+									contract_address,
+									from,
+									beneficiary,
+									subamount,
+									gas_limit,
+								)
 							})
 					})
 					.map_err(Into::into),
@@ -182,10 +209,12 @@ pub mod pallet {
 			let to = T::AccountIdConverter::convert_ref(to)
 				.map_err(|()| MatchError::AccountIdConversionFailed)?;
 
+			let gas_limit = Self::gas_limit_of_erc20_transfer(&asset.id);
+
 			// We perform the evm transfers in a storage transaction to ensure that if it fail
 			// any contract storage changes are rolled back.
 			frame_support::storage::with_storage_layer(|| {
-				Self::erc20_transfer(contract_address, from, to, amount)
+				Self::erc20_transfer(contract_address, from, to, amount, gas_limit)
 			})?;
 
 			Ok(asset.clone().into())

pallets/moonbeam-xcm-benchmarks/src/weights/moonbeam_xcm_benchmarks_fungible.rs

@@ -32,21 +32,22 @@ pub struct WeightInfo<T>(PhantomData<T>);
 impl<T: frame_system::Config + pallet_erc20_xcm_bridge::Config> WeightInfo<T> {
 	pub(crate) fn withdraw_asset(asset: &MultiAsset) -> Weight {
 		if pallet_erc20_xcm_bridge::Pallet::<T>::is_erc20_asset(asset) {
-			pallet_erc20_xcm_bridge::Pallet::<T>::weight_of_erc20_transfer()
+			pallet_erc20_xcm_bridge::Pallet::<T>::weight_of_erc20_transfer(&asset.id)
+
 		} else {
 			Weight::from_parts(200_000_000 as u64, ASSET_BURN_MAX_PROOF_SIZE)
 		}
 	}
 	pub(crate) fn transfer_asset(asset: &MultiAsset) -> Weight {
 		if pallet_erc20_xcm_bridge::Pallet::<T>::is_erc20_asset(asset) {
-			pallet_erc20_xcm_bridge::Pallet::<T>::weight_of_erc20_transfer()
+			pallet_erc20_xcm_bridge::Pallet::<T>::weight_of_erc20_transfer(&asset.id)
 		} else {
 			Weight::from_parts(200_000_000 as u64, ASSET_TRANSFER_MAX_PROOF_SIZE)
 		}
 	}
 	pub(crate) fn transfer_reserve_asset(asset: &MultiAsset) -> Weight {
 		if pallet_erc20_xcm_bridge::Pallet::<T>::is_erc20_asset(asset) {
-			pallet_erc20_xcm_bridge::Pallet::<T>::weight_of_erc20_transfer()
+			pallet_erc20_xcm_bridge::Pallet::<T>::weight_of_erc20_transfer(&asset.id)
 		} else {
 			Weight::from_parts(200_000_000 as u64, ASSET_TRANSFER_MAX_PROOF_SIZE)
 		}

test/suites/dev/test-xcm-v3/test-xcm-erc20-excess-gas.ts

@@ -10,6 +10,7 @@ import {
   sovereignAccountOfSibling,
 } from "../../../helpers/xcm.js";
 import { parseEther } from "ethers";
+import { stringToU8a } from "@polkadot/util";
 
 export const ERC20_TOTAL_SUPPLY = 1_000_000_000n;
 
@@ -178,95 +179,101 @@ describeSuite({
       },
     });
 
-    // UNCOMMENT when https://github.com/moonbeam-foundation/moonbeam/pull/2422 is merged
-
-    // it({
-    //   id: "T03",
-    //   title: "Incoming ERC20 transfer should succeed if setting a custom gas limit",
-    //   test: async function () {
-    //     const amountTransferred = 1_000_000n;
-    //     const paraSovereign = sovereignAccountOfSibling(context, paraId);
+    it({
+      id: "T03",
+      title: "Incoming ERC20 transfer should succeed if setting a custom gas limit",
+      test: async function () {
+        const amountTransferred = 1_000_000n;
+        const paraSovereign = sovereignAccountOfSibling(context, paraId);
 
-    //     // Deploy contract
-    //     const { contractAddress, status } = await context.deployContract!("ERC20ExcessGas", {
-    //       args: ["ERC20", "20S", paraSovereign, ERC20_TOTAL_SUPPLY],
-    //     });
-    //     expect(status).eq("success");
+        // Deploy contract
+        const { contractAddress, status } = await context.deployContract!("ERC20ExcessGas", {
+          args: ["ERC20", "20S", paraSovereign, ERC20_TOTAL_SUPPLY],
+        });
+        expect(status).eq("success");
 
-    //     // Get pallet indices
-    //     const metadata = await polkadotJs.rpc.state.getMetadata();
-    //     const balancesPalletIndex = metadata.asLatest.pallets
-    //       .find(({ name }) => name.toString() == "Balances")!
-    //       .index.toNumber();
-    //     const erc20XcmPalletIndex = metadata.asLatest.pallets
-    //       .find(({ name }) => name.toString() == "Erc20XcmBridge")!
-    //       .index.toNumber();
+        // Get pallet indices
+        const metadata = await polkadotJs.rpc.state.getMetadata();
+        const balancesPalletIndex = metadata.asLatest.pallets
+          .find(({ name }) => name.toString() == "Balances")!
+          .index.toNumber();
+        const erc20XcmPalletIndex = metadata.asLatest.pallets
+          .find(({ name }) => name.toString() == "Erc20XcmBridge")!
+          .index.toNumber();
 
-    //     // Send some native tokens to the sovereign account of paraId (to pay fees)
-    //     await polkadotJs.tx.balances.transfer(paraSovereign, parseEther("1")).signAndSend(alith);
-    //     await context.createBlock();
+        // Send some native tokens to the sovereign account of paraId (to pay fees)
+        await polkadotJs.tx.balances.transfer(paraSovereign, parseEther("1")).signAndSend(alith);
+        await context.createBlock();
 
-    //     // Create the incoming xcm message
-    //     const config: XcmFragmentConfig = {
-    //       assets: [
-    //         {
-    //           multilocation: {
-    //             parents: 0,
-    //             interior: {
-    //               X1: { PalletInstance: Number(balancesPalletIndex) },
-    //             },
-    //           },
-    //           fungible: 100_000_000_000_000_000n,
-    //         },
-    //         {
-    //           multilocation: {
-    //             parents: 0,
-    //             interior: {
-    //               X3: [
-    //                 {
-    //                   PalletInstance: erc20XcmPalletIndex,
-    //                 },
-    //                 {
-    //                   AccountKey20: {
-    //                     network: "Any",
-    //                     key: contractAddress,
-    //                   },
-    //                 },
-    //                 {
-    //                   GeneralIndex: 300_000n,
-    //                 },
-    //               ],
-    //             },
-    //           },
-    //           fungible: amountTransferred,
-    //         },
-    //       ],
-    //       beneficiary: CHARLETH_ADDRESS,
-    //     };
+        // Create the incoming xcm message
+        const config: XcmFragmentConfig = {
+          assets: [
+            {
+              multilocation: {
+                parents: 0,
+                interior: {
+                  X1: { PalletInstance: Number(balancesPalletIndex) },
+                },
+              },
+              fungible: 100_000_000_000_000_000n,
+            },
+            {
+              multilocation: {
+                parents: 0,
+                interior: {
+                  X3: [
+                    {
+                      PalletInstance: erc20XcmPalletIndex,
+                    },
+                    {
+                      AccountKey20: {
+                        network: null,
+                        key: contractAddress,
+                      },
+                    },
+                    // Override default gas limit with optional GeneralKey.
+                    // b'gas_limit:' + 300000(little endian) + zeros padding
+                    {
+                      GeneralKey: {
+                        data: [
+                          103, 97, 115, 95, 108, 105, 109, 105, 116, 58, 224, 147, 4, 0, 0, 0, 0, 0,
+                          0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+                        ],
+                        length: 32,
+                      },
+                    },
+                  ],
+                },
+              },
+              fungible: amountTransferred,
+            },
+          ],
+          beneficiary: CHARLETH_ADDRESS,
+        };
 
-    //     const xcmMessage = new XcmFragment(config)
-    //       .withdraw_asset()
-    //       .clear_origin()
-    //       .buy_execution()
-    //       .deposit_asset_v3(2n)
-    //       .as_v3();
+        const xcmMessage = new XcmFragment(config)
+          .withdraw_asset()
+          .clear_origin()
+          .buy_execution()
+          .deposit_asset_v3(2n)
+          .as_v3();
 
-    //     // Mock the reception of the xcm message
-    //     await injectHrmpMessageAndSeal(context, paraId, {
-    //       type: "XcmVersionedXcm",
-    //       payload: xcmMessage,
-    //     });
+        // Mock the reception of the xcm message
+        await injectHrmpMessageAndSeal(context, paraId, {
+          type: "XcmVersionedXcm",
+          payload: xcmMessage,
+        });
 
-    //     // Charleth should have received the tokens
-    //     expect(
-    //       await context.readContract!({
-    //         contractName: "ERC20ExcessGas",
-    //         contractAddress: contractAddress as `0x${string}`,
-    //         functionName: "balanceOf",
-    //         args: [CHARLETH_ADDRESS],
-    //       })
-    //     ).equals(amountTransferred);
-    //   },
-    // });
+        // Charleth should have received the tokens
+        expect(
+          await context.readContract!({
+            contractName: "ERC20ExcessGas",
+            contractAddress: contractAddress as `0x${string}`,
+            functionName: "balanceOf",
+            args: [CHARLETH_ADDRESS],
+          })
+        ).equals(amountTransferred);
+      },
+    });
   },
 });