Add support for transfer_assets_using_type_and_then extrinsic in pallet-xcm precompile (#54)

* start adding transfer_assets_using_type_and_then to pallet-xcm precompile

* add function variant for address type

* use WeightLimit::Unlimited in all selectors

* add remaining functions and overall refactor

* remove unnecessary selectors and add a couple tests

* add more tests

* pr suggestions

* add documentation for solidity selectors

* fmt

* fix test

* fix rust tests compilation

* add clarification for SCALE encoding in custom xcm

Author: Agusrodri

pallets/emergency-para-xcm/src/mock.rs

@@ -19,6 +19,7 @@ use crate as pallet_emergency_para_xcm;
 use cumulus_pallet_parachain_system::ParachainSetCode;
 use cumulus_primitives_core::{
 	relay_chain::BlockNumber as RelayBlockNumber, AggregateMessageOrigin, ParaId,
+	XcmpMessageHandler,
 };
 use frame_support::parameter_types;
 use frame_support::traits::ConstU32;

precompiles/pallet-xcm/Cargo.toml

@@ -16,10 +16,12 @@ xcm-primitives = { workspace = true }
 # Substrate
 frame-support = { workspace = true }
 frame-system = { workspace = true }
+scale-info = { workspace = true }
 sp-core = { workspace = true }
 sp-runtime = { workspace = true }
 sp-std = { workspace = true }
 sp-weights = { workspace = true }
+parity-scale-codec = { workspace = true, features = [ "derive" ] }
 
 # Frontier
 evm = { workspace = true, features = [ "with-codec" ] }
@@ -28,6 +30,7 @@ pallet-evm = { workspace = true, features = [ "forbid-evm-reentrancy" ] }
 
 # Polkadot
 xcm = { workspace = true }
+xcm-executor = { workspace = true }
 pallet-xcm = { workspace = true }
 
 # Cumulus
@@ -61,7 +64,9 @@ std = [
 	"frame-system/std",
 	"pallet-evm/std",
     "pallet-xcm/std",
+	"parity-scale-codec/std",
 	"precompile-utils/std",
+	"scale-info/std",
 	"sp-core/std",
 	"sp-std/std",
 	"xcm/std",

precompiles/pallet-xcm/XcmInterface.sol

@@ -29,68 +29,139 @@ interface XCM {
         uint256 amount;
     }
 
+    // The values start at `0` and are represented as `uint8`
+    enum TransferType {
+        Teleport,
+        LocalReserve,
+        DestinationReserve
+    }
+
     /// @dev Function to send assets via XCM using transfer_assets() pallet-xcm extrinsic.
-    /// @custom:selector 59df8416
+    /// @custom:selector 9ea8ada7
     /// @param dest The destination chain.
     /// @param beneficiary The actual account that will receive the tokens on dest.
-    /// @param assets The combination (array) of assets to send.
+    /// @param assets The combination (array) of assets to send in Location format.
     /// @param feeAssetItem The index of the asset that will be used to pay for fees.
-    /// @param weight The weight to be used for the whole XCM operation.
-    /// (uint64::MAX in refTime means Unlimited weight) 
     function transferAssetsLocation(
         Location memory dest,
         Location memory beneficiary,
         AssetLocationInfo[] memory assets,
-        uint32 feeAssetItem,
-        Weight memory weight
+        uint32 feeAssetItem
     ) external;
 
     /// @dev Function to send assets via XCM to a 20 byte-like parachain 
     /// using transfer_assets() pallet-xcm extrinsic.
-    /// @custom:selector b489262e
+    /// @custom:selector a0aeb5fe
     /// @param paraId The para-id of the destination chain.
     /// @param beneficiary The actual account that will receive the tokens on paraId destination.
-    /// @param assets The combination (array) of assets to send.
+    /// @param assets The combination (array) of assets to send in Address format.
     /// @param feeAssetItem The index of the asset that will be used to pay for fees.
-    /// @param weight The weight to be used for the whole XCM operation.
-    /// (uint64::MAX in refTime means Unlimited weight)
     function transferAssetsToPara20(
         uint32 paraId,
         address beneficiary,
         AssetAddressInfo[] memory assets,
-        uint32 feeAssetItem,
-        Weight memory weight
+        uint32 feeAssetItem
     ) external;
 
     /// @dev Function to send assets via XCM to a 32 byte-like parachain 
     /// using transfer_assets() pallet-xcm extrinsic.
-    /// @custom:selector 4461e6f5
+    /// @custom:selector f23032c3
     /// @param paraId The para-id of the destination chain.
     /// @param beneficiary The actual account that will receive the tokens on paraId destination.
-    /// @param assets The combination (array) of assets to send.
+    /// @param assets The combination (array) of assets to send in Address format.
     /// @param feeAssetItem The index of the asset that will be used to pay for fees.
-    /// @param weight The weight to be used for the whole XCM operation.
-    /// (uint64::MAX in refTime means Unlimited weight)
     function transferAssetsToPara32(
         uint32 paraId,
         bytes32 beneficiary,
         AssetAddressInfo[] memory assets,
-        uint32 feeAssetItem,
-        Weight memory weight
+        uint32 feeAssetItem
     ) external;
 
     /// @dev Function to send assets via XCM to the relay chain 
     /// using transfer_assets() pallet-xcm extrinsic.
-    /// @custom:selector d7c89659
+    /// @custom:selector 6521cc2c
     /// @param beneficiary The actual account that will receive the tokens on the relay chain.
-    /// @param assets The combination (array) of assets to send.
+    /// @param assets The combination (array) of assets to send in Address format.
     /// @param feeAssetItem The index of the asset that will be used to pay for fees.
-    /// @param weight The weight to be used for the whole XCM operation.
-    /// (uint64::MAX in refTime means Unlimited weight)
     function transferAssetsToRelay(
         bytes32 beneficiary,
         AssetAddressInfo[] memory assets,
-        uint32 feeAssetItem,
-        Weight memory weight
+        uint32 feeAssetItem
+    ) external;
+
+    /// @dev Function to send assets through transfer_assets_using_type_and_then() pallet-xcm
+    /// extrinsic.
+    /// Important: in this selector RemoteReserve type (for either assets or fees) is not allowed.
+    /// If users want to send assets and fees (in Location format) with a remote reserve, 
+    /// they must use the selector fc19376c.
+    /// @custom:selector 8425d893
+    /// @param dest The destination chain.
+    /// @param assets The combination (array) of assets to send in Location format.
+    /// @param assetsTransferType The TransferType corresponding to assets being sent.
+    /// @param remoteFeesIdIndex The index of the asset (inside assets array) to use as fees.
+    /// @param feesTransferType The TransferType corresponding to the asset used as fees.
+    /// @param customXcmOnDest The XCM message to execute on destination chain (SCALE encoded).
+    function transferAssetsUsingTypeAndThenLocation(
+        Location memory dest,
+        AssetLocationInfo[] memory assets,
+        TransferType assetsTransferType,
+        uint8 remoteFeesIdIndex,
+        TransferType feesTransferType,
+        bytes memory customXcmOnDest
+    ) external;
+
+    /// @dev Function to send assets through transfer_assets_using_type_and_then() pallet-xcm
+    /// extrinsic.
+    /// @custom:selector fc19376c
+    /// @param dest The destination chain.
+    /// @param assets The combination (array) of assets to send in Location format.
+    /// @param remoteFeesIdIndex The index of the asset (inside assets array) to use as fees.
+    /// @param customXcmOnDest The XCM message to execute on destination chain (SCALE encoded).
+    /// @param remoteReserve The remote reserve corresponding for assets and fees. They MUST
+    /// share the same reserve.
+    function transferAssetsUsingTypeAndThenLocation(
+        Location memory dest,
+        AssetLocationInfo[] memory assets,
+        uint8 remoteFeesIdIndex,
+        bytes memory customXcmOnDest,
+        Location memory remoteReserve
+    ) external;
+
+    /// @dev Function to send assets through transfer_assets_using_type_and_then() pallet-xcm
+    /// extrinsic.
+    /// Important: in this selector RemoteReserve type (for either assets or fees) is not allowed.
+    /// If users want to send assets and fees (in Address format) with a remote reserve, 
+    /// they must use the selector aaecfc62.
+    /// @custom:selector 998093ee
+    /// @param dest The destination chain.
+    /// @param assets The combination (array) of assets to send in Address format.
+    /// @param assetsTransferType The TransferType corresponding to assets being sent.
+    /// @param remoteFeesIdIndex The index of the asset (inside assets array) to use as fees.
+    /// @param feesTransferType The TransferType corresponding to the asset used as fees.
+    /// @param customXcmOnDest The XCM message to execute on destination chain (SCALE encoded).
+    function transferAssetsUsingTypeAndThenAddress(
+        Location memory dest,
+        AssetAddressInfo[] memory assets,
+        TransferType assetsTransferType,
+        uint8 remoteFeesIdIndex,
+        TransferType feesTransferType,
+        bytes memory customXcmOnDest
+    ) external;
+
+    /// @dev Function to send assets through transfer_assets_using_type_and_then() pallet-xcm
+    /// extrinsic.
+    /// @custom:selector aaecfc62
+    /// @param dest The destination chain.
+    /// @param assets The combination (array) of assets to send in Address format.
+    /// @param remoteFeesIdIndex The index of the asset (inside assets array) to use as fees.
+    /// @param customXcmOnDest The XCM message to execute on destination chain (SCALE encoded).
+    /// @param remoteReserve The remote reserve corresponding for assets and fees. They MUST
+    /// share the same reserve.
+    function transferAssetsUsingTypeAndThenAddress(
+        Location memory dest,
+        AssetAddressInfo[] memory assets,
+        uint8 remoteFeesIdIndex,
+        bytes memory customXcmOnDest,
+        Location memory remoteReserve
     ) external;
 }