XCM v1 (#2815)

* MultiAsset TWO

* Draft next MultiAsset API.

* XCM core builds

* XCM Executor builds

* XCM Builder builds

* API changes making their way throughout

* Some TODOs

* Further build fixes

* Basic compile builds

* First test fixed

* All executor tests fixed

* Typo

* Optimize subsume_assets and add test

* Optimize checked_sub

* XCM Builder first test fixed

* Fix builder tests

* Fix doc test

* fix some doc tests

* spelling

* named fields for AllOf

* Update xcm/src/v0/multiasset.rs

Co-authored-by: Alexander Popiak <alexander.popiak@parity.io>

* Update xcm/src/v0/multiasset.rs

Co-authored-by: Alexander Popiak <alexander.popiak@parity.io>

* Update xcm/src/v0/multiasset.rs

Co-authored-by: Alexander Popiak <alexander.popiak@parity.io>

* Update xcm/src/v0/multiasset.rs

Co-authored-by: Alexander Popiak <alexander.popiak@parity.io>

* Reformat

* Move to XCM version 1

* Spelling

* warnings

* Replace some more v0->v1s

* warnings

* format

* Add max_assets param

* building

* test fixes

* tests

* another test

* final test

* tests

* Rename Null -> Here

* Introduce

* More ergonomics

* More ergonomics

* test fix

* test fixes

* docs

* BuyExecution includes

* Fix XCM extrinsics

* fmt

* Make Vec<MultiAsset>/MultiAssets conversions safe

* More MultiAssets conversion safety

* spelling

* fix doc test

* Apply suggestions from code review

Co-authored-by: Amar Singh <asinghchrony@protonmail.com>

* Apply suggestions from code review

Co-authored-by: Amar Singh <asinghchrony@protonmail.com>

* fmt

* Add v0, remove VersionedMultiAsset

* Remove VersionedMultiLocation

* Update xcm/src/v1/order.rs

Co-authored-by: Amar Singh <asinghchrony@protonmail.com>

* Update xcm/src/v1/mod.rs

Co-authored-by: Amar Singh <asinghchrony@protonmail.com>

* XCM v0 backwards compatibility

* Full compatibility

* fmt

* Update xcm/pallet-xcm/src/lib.rs

* Update xcm/src/v0/order.rs

Co-authored-by: Shawn Tabrizi <shawntabrizi@gmail.com>

* Tweaks to versioning system

* Fixes

* fmt

* Update xcm/xcm-executor/src/assets.rs

Co-authored-by: Shawn Tabrizi <shawntabrizi@gmail.com>

* Update xcm/xcm-executor/src/assets.rs

Co-authored-by: Shawn Tabrizi <shawntabrizi@gmail.com>

* Grumbles

* Update xcm/src/v1/multiasset.rs

Co-authored-by: Shawn Tabrizi <shawntabrizi@gmail.com>

* fmt

* Update xcm/src/v1/multiasset.rs

Co-authored-by: Shawn Tabrizi <shawntabrizi@gmail.com>

* Update xcm/src/v1/multiasset.rs

Co-authored-by: Shawn Tabrizi <shawntabrizi@gmail.com>

* Fixes

* Formatting

Co-authored-by: Alexander Popiak <alexander.popiak@parity.io>
Co-authored-by: Amar Singh <asinghchrony@protonmail.com>
Co-authored-by: Shawn Tabrizi <shawntabrizi@gmail.com>

polkadot/xcm/xcm-executor/src/config.rs

@@ -22,7 +22,7 @@ use frame_support::{
 	dispatch::{Dispatchable, Parameter},
 	weights::{GetDispatchInfo, PostDispatchInfo},
 };
-use xcm::v0::SendXcm;
+use xcm::latest::SendXcm;
 
 /// The trait to parameterize the `XcmExecutor`.
 pub trait Config {

polkadot/xcm/xcm-executor/src/lib.rs

@@ -22,8 +22,8 @@ use frame_support::{
 	weights::GetDispatchInfo,
 };
 use sp_std::{marker::PhantomData, prelude::*};
-use xcm::v0::{
-	Error as XcmError, ExecuteXcm, MultiAsset, MultiLocation, Order, Outcome, Response, SendXcm,
+use xcm::latest::{
+	Error as XcmError, ExecuteXcm, MultiAssets, MultiLocation, Order, Outcome, Response, SendXcm,
 	Xcm,
 };
 
@@ -34,7 +34,7 @@ use traits::{
 };
 
 mod assets;
-pub use assets::{AssetId, Assets};
+pub use assets::Assets;
 mod config;
 pub use config::Config;
 
@@ -94,10 +94,10 @@ impl<Config: config::Config> ExecuteXcm<Config::Call> for XcmExecutor<Config> {
 }
 
 impl<Config: config::Config> XcmExecutor<Config> {
-	fn reanchored(mut assets: Assets, dest: &MultiLocation) -> Vec<MultiAsset> {
+	fn reanchored(mut assets: Assets, dest: &MultiLocation) -> MultiAssets {
 		let inv_dest = Config::LocationInverter::invert_location(&dest);
 		assets.prepend_location(&inv_dest);
-		assets.into_assets_iter().collect::<Vec<_>>()
+		assets.into_assets_iter().collect::<Vec<_>>().into()
 	}
 
 	/// Execute the XCM and return the portion of weight of `shallow_weight + deep_weight` that `message` did not use.
@@ -144,17 +144,15 @@ impl<Config: config::Config> XcmExecutor<Config> {
 			(origin, Xcm::WithdrawAsset { assets, effects }) => {
 				// Take `assets` from the origin account (on-chain) and place in holding.
 				let mut holding = Assets::default();
-				for asset in assets {
-					ensure!(!asset.is_wildcard(), XcmError::Wildcard);
+				for asset in assets.inner() {
 					let withdrawn = Config::AssetTransactor::withdraw_asset(&asset, &origin)?;
-					holding.saturating_subsume_all(withdrawn);
+					holding.subsume_assets(withdrawn);
 				}
 				Some((holding, effects))
 			},
-			(origin, Xcm::ReserveAssetDeposit { assets, effects }) => {
+			(origin, Xcm::ReserveAssetDeposited { assets, effects }) => {
 				// check whether we trust origin to be our reserve location for this asset.
-				for asset in assets.iter() {
-					ensure!(!asset.is_wildcard(), XcmError::Wildcard);
+				for asset in assets.inner() {
 					// We only trust the origin to send us assets that they identify as their
 					// sovereign assets.
 					ensure!(
@@ -162,31 +160,28 @@ impl<Config: config::Config> XcmExecutor<Config> {
 						XcmError::UntrustedReserveLocation
 					);
 				}
-				Some((Assets::from(assets), effects))
+				Some((assets.into(), effects))
 			},
-			(origin, Xcm::TransferAsset { assets, dest }) => {
+			(origin, Xcm::TransferAsset { assets, beneficiary }) => {
 				// Take `assets` from the origin account (on-chain) and place into dest account.
-				for asset in assets {
-					ensure!(!asset.is_wildcard(), XcmError::Wildcard);
-					Config::AssetTransactor::teleport_asset(&asset, &origin, &dest)?;
+				for asset in assets.inner() {
+					Config::AssetTransactor::beam_asset(&asset, &origin, &beneficiary)?;
 				}
 				None
 			},
 			(origin, Xcm::TransferReserveAsset { mut assets, dest, effects }) => {
 				// Take `assets` from the origin account (on-chain) and place into dest account.
 				let inv_dest = Config::LocationInverter::invert_location(&dest);
-				for asset in assets.iter_mut() {
-					ensure!(!asset.is_wildcard(), XcmError::Wildcard);
-					Config::AssetTransactor::teleport_asset(&asset, &origin, &dest)?;
-					asset.reanchor(&inv_dest)?;
+				for asset in assets.inner() {
+					Config::AssetTransactor::beam_asset(asset, &origin, &dest)?;
 				}
-				Config::XcmSender::send_xcm(dest, Xcm::ReserveAssetDeposit { assets, effects })?;
+				assets.reanchor(&inv_dest)?;
+				Config::XcmSender::send_xcm(dest, Xcm::ReserveAssetDeposited { assets, effects })?;
 				None
 			},
-			(origin, Xcm::TeleportAsset { assets, effects }) => {
+			(origin, Xcm::ReceiveTeleportedAsset { assets, effects }) => {
 				// check whether we trust origin to teleport this asset to us via config trait.
-				for asset in assets.iter() {
-					ensure!(!asset.is_wildcard(), XcmError::Wildcard);
+				for asset in assets.inner() {
 					// We only trust the origin to send us assets that they identify as their
 					// sovereign assets.
 					ensure!(
@@ -198,7 +193,7 @@ impl<Config: config::Config> XcmExecutor<Config> {
 					// don't want to punish a possibly innocent chain/user).
 					Config::AssetTransactor::can_check_in(&origin, asset)?;
 				}
-				for asset in assets.iter() {
+				for asset in assets.inner() {
 					Config::AssetTransactor::check_in(&origin, asset);
 				}
 				Some((Assets::from(assets), effects))
@@ -252,41 +247,41 @@ impl<Config: config::Config> XcmExecutor<Config> {
 
 		if let Some((mut holding, effects)) = maybe_holding_effects {
 			for effect in effects.into_iter() {
-				total_surplus += Self::execute_effects(&origin, &mut holding, effect, trader)?;
+				total_surplus += Self::execute_orders(&origin, &mut holding, effect, trader)?;
 			}
 		}
 
 		Ok(total_surplus)
 	}
 
-	fn execute_effects(
+	fn execute_orders(
 		origin: &MultiLocation,
 		holding: &mut Assets,
-		effect: Order<Config::Call>,
+		order: Order<Config::Call>,
 		trader: &mut Config::Trader,
 	) -> Result<Weight, XcmError> {
 		log::trace!(
-			target: "xcm::execute_effects",
+			target: "xcm::execute_orders",
 			"origin: {:?}, holding: {:?}, effect: {:?}",
 			origin,
 			holding,
-			effect,
+			order,
 		);
 		let mut total_surplus = 0;
-		match effect {
-			Order::DepositAsset { assets, dest } => {
-				let deposited = holding.saturating_take(assets);
+		match order {
+			Order::DepositAsset { assets, max_assets, beneficiary } => {
+				let deposited = holding.limited_saturating_take(assets, max_assets as usize);
 				for asset in deposited.into_assets_iter() {
-					Config::AssetTransactor::deposit_asset(&asset, &dest)?;
+					Config::AssetTransactor::deposit_asset(&asset, &beneficiary)?;
 				}
 			},
-			Order::DepositReserveAsset { assets, dest, effects } => {
-				let deposited = holding.saturating_take(assets);
+			Order::DepositReserveAsset { assets, max_assets, dest, effects } => {
+				let deposited = holding.limited_saturating_take(assets, max_assets as usize);
 				for asset in deposited.assets_iter() {
 					Config::AssetTransactor::deposit_asset(&asset, &dest)?;
 				}
 				let assets = Self::reanchored(deposited, &dest);
-				Config::XcmSender::send_xcm(dest, Xcm::ReserveAssetDeposit { assets, effects })?;
+				Config::XcmSender::send_xcm(dest, Xcm::ReserveAssetDeposited { assets, effects })?;
 			},
 			Order::InitiateReserveWithdraw { assets, reserve, effects } => {
 				let assets = Self::reanchored(holding.saturating_take(assets), &reserve);
@@ -299,29 +294,37 @@ impl<Config: config::Config> XcmExecutor<Config> {
 					Config::AssetTransactor::check_out(&origin, &asset);
 				}
 				let assets = Self::reanchored(assets, &dest);
-				Config::XcmSender::send_xcm(dest, Xcm::TeleportAsset { assets, effects })?;
+				Config::XcmSender::send_xcm(dest, Xcm::ReceiveTeleportedAsset { assets, effects })?;
 			},
 			Order::QueryHolding { query_id, dest, assets } => {
-				let assets = Self::reanchored(holding.min(assets.iter()), &dest);
+				let assets = Self::reanchored(holding.min(&assets), &dest);
 				Config::XcmSender::send_xcm(
 					dest,
 					Xcm::QueryResponse { query_id, response: Response::Assets(assets) },
 				)?;
 			},
-			Order::BuyExecution { fees, weight, debt, halt_on_error, xcm } => {
-				// pay for `weight` using up to `fees` of the holding account.
+			Order::BuyExecution { fees, weight, debt, halt_on_error, orders, instructions } => {
+				// pay for `weight` using up to `fees` of the holding register.
 				let purchasing_weight =
 					Weight::from(weight.checked_add(debt).ok_or(XcmError::Overflow)?);
-				let max_fee = holding.try_take(fees).map_err(|()| XcmError::NotHoldingFees)?;
+				let max_fee =
+					holding.try_take(fees.into()).map_err(|_| XcmError::NotHoldingFees)?;
 				let unspent = trader.buy_weight(purchasing_weight, max_fee)?;
-				holding.saturating_subsume_all(unspent);
+				holding.subsume_assets(unspent);
 
 				let mut remaining_weight = weight;
-				for message in xcm.into_iter() {
+				for order in orders.into_iter() {
+					match Self::execute_orders(origin, holding, order, trader) {
+						Err(e) if halt_on_error => return Err(e),
+						Err(_) => {},
+						Ok(surplus) => total_surplus += surplus,
+					}
+				}
+				for instruction in instructions.into_iter() {
 					match Self::do_execute_xcm(
 						origin.clone(),
 						false,
-						message,
+						instruction,
 						&mut remaining_weight,
 						None,
 						trader,
@@ -331,7 +334,9 @@ impl<Config: config::Config> XcmExecutor<Config> {
 						Ok(surplus) => total_surplus += surplus,
 					}
 				}
-				holding.saturating_subsume(trader.refund_weight(remaining_weight));
+				if let Some(w) = trader.refund_weight(remaining_weight) {
+					holding.subsume(w);
+				}
 			},
 			_ => return Err(XcmError::UnhandledEffect)?,
 		}

polkadot/xcm/xcm-executor/src/traits/conversion.rs

@@ -16,7 +16,7 @@
 
 use parity_scale_codec::{Decode, Encode};
 use sp_std::{borrow::Borrow, convert::TryFrom, prelude::*, result::Result};
-use xcm::v0::{MultiLocation, OriginKind};
+use xcm::latest::{MultiLocation, OriginKind};
 
 /// Generic third-party conversion trait. Use this when you don't want to force the user to use default
 /// implementations of `From` and `Into` for the types you wish to convert between.
@@ -139,7 +139,7 @@ impl<T: Clone + Encode + Decode> Convert<Vec<u8>, T> for Decoded {
 /// which is passed to the next convert item.
 ///
 /// ```rust
-/// # use xcm::v0::{MultiLocation, Junction, OriginKind};
+/// # use xcm::latest::{MultiLocation, Junction, OriginKind};
 /// # use xcm_executor::traits::ConvertOrigin;
 /// // A convertor that will bump the para id and pass it to the next one.
 /// struct BumpParaId;

polkadot/xcm/xcm-executor/src/traits/filter_asset_location.rs

@@ -14,7 +14,7 @@
 // You should have received a copy of the GNU General Public License
 // along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.
 
-use xcm::v0::{MultiAsset, MultiLocation};
+use xcm::latest::{MultiAsset, MultiLocation};
 
 /// Filters assets/location pairs.
 ///

polkadot/xcm/xcm-executor/src/traits/matches_fungible.rs

@@ -14,7 +14,7 @@
 // You should have received a copy of the GNU General Public License
 // along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.
 
-use xcm::v0::MultiAsset;
+use xcm::latest::MultiAsset;
 
 pub trait MatchesFungible<Balance> {
 	fn matches_fungible(a: &MultiAsset) -> Option<Balance>;

polkadot/xcm/xcm-executor/src/traits/matches_fungibles.rs

@@ -15,7 +15,7 @@
 // along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.
 
 use sp_std::result;
-use xcm::v0::{Error as XcmError, MultiAsset};
+use xcm::latest::{Error as XcmError, MultiAsset};
 
 /// Errors associated with [`MatchesFungibles`] operation.
 pub enum Error {

polkadot/xcm/xcm-executor/src/traits/on_response.rs

@@ -15,7 +15,7 @@
 // along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.
 
 use frame_support::weights::Weight;
-use xcm::v0::{MultiLocation, Response};
+use xcm::latest::{MultiLocation, Response};
 
 /// Define what needs to be done upon receiving a query response.
 pub trait OnResponse {

polkadot/xcm/xcm-executor/src/traits/should_execute.rs

@@ -16,7 +16,7 @@
 
 use frame_support::weights::Weight;
 use sp_std::result::Result;
-use xcm::v0::{MultiLocation, Xcm};
+use xcm::latest::{MultiLocation, Xcm};
 
 /// Trait to determine whether the execution engine should actually execute a given XCM.
 ///

polkadot/xcm/xcm-executor/src/traits/transact_asset.rs

@@ -16,7 +16,7 @@
 
 use crate::Assets;
 use sp_std::result::Result;
-use xcm::v0::{Error as XcmError, MultiAsset, MultiLocation, Result as XcmResult};
+use xcm::latest::{Error as XcmError, MultiAsset, MultiLocation, Result as XcmResult};
 
 /// Facility for asset transacting.
 ///
@@ -89,7 +89,7 @@ pub trait TransactAsset {
 	/// Move an `asset` `from` one location in `to` another location.
 	///
 	/// Attempts to use `transfer_asset` and if not available then falls back to using a two-part withdraw/deposit.
-	fn teleport_asset(
+	fn beam_asset(
 		asset: &MultiAsset,
 		from: &MultiLocation,
 		to: &MultiLocation,
@@ -111,7 +111,7 @@ impl TransactAsset for Tuple {
 	fn can_check_in(origin: &MultiLocation, what: &MultiAsset) -> XcmResult {
 		for_tuples!( #(
 			match Tuple::can_check_in(origin, what) {
-				Err(XcmError::AssetNotFound | XcmError::Unimplemented) => (),
+				Err(XcmError::AssetNotFound) | Err(XcmError::Unimplemented) => (),
 				r => return r,
 			}
 		)* );
@@ -139,7 +139,7 @@ impl TransactAsset for Tuple {
 	fn deposit_asset(what: &MultiAsset, who: &MultiLocation) -> XcmResult {
 		for_tuples!( #(
 			match Tuple::deposit_asset(what, who) {
-				Err(XcmError::AssetNotFound | XcmError::Unimplemented) => (),
+				Err(XcmError::AssetNotFound) | Err(XcmError::Unimplemented) => (),
 				r => return r,
 			}
 		)* );
@@ -155,7 +155,7 @@ impl TransactAsset for Tuple {
 	fn withdraw_asset(what: &MultiAsset, who: &MultiLocation) -> Result<Assets, XcmError> {
 		for_tuples!( #(
 			match Tuple::withdraw_asset(what, who) {
-				Err(XcmError::AssetNotFound | XcmError::Unimplemented) => (),
+				Err(XcmError::AssetNotFound) | Err(XcmError::Unimplemented) => (),
 				r => return r,
 			}
 		)* );
@@ -175,7 +175,7 @@ impl TransactAsset for Tuple {
 	) -> Result<Assets, XcmError> {
 		for_tuples!( #(
 			match Tuple::transfer_asset(what, from, to) {
-				Err(XcmError::AssetNotFound | XcmError::Unimplemented) => (),
+				Err(XcmError::AssetNotFound) | Err(XcmError::Unimplemented) => (),
 				r => return r,
 			}
 		)* );
@@ -193,6 +193,7 @@ impl TransactAsset for Tuple {
 #[cfg(test)]
 mod tests {
 	use super::*;
+	use MultiLocation::Here;
 
 	pub struct UnimplementedTransactor;
 	impl TransactAsset for UnimplementedTransactor {}
@@ -272,7 +273,7 @@ mod tests {
 			(UnimplementedTransactor, NotFoundTransactor, UnimplementedTransactor);
 
 		assert_eq!(
-			MultiTransactor::deposit_asset(&MultiAsset::All, &MultiLocation::Null),
+			MultiTransactor::deposit_asset(&(Here, 1).into(), &Here),
 			Err(XcmError::AssetNotFound)
 		);
 	}
@@ -281,7 +282,7 @@ mod tests {
 	fn unimplemented_and_not_found_continue_iteration() {
 		type MultiTransactor = (UnimplementedTransactor, NotFoundTransactor, SuccessfulTransactor);
 
-		assert_eq!(MultiTransactor::deposit_asset(&MultiAsset::All, &MultiLocation::Null), Ok(()));
+		assert_eq!(MultiTransactor::deposit_asset(&(Here, 1).into(), &Here), Ok(()));
 	}
 
 	#[test]
@@ -289,7 +290,7 @@ mod tests {
 		type MultiTransactor = (OverflowTransactor, SuccessfulTransactor);
 
 		assert_eq!(
-			MultiTransactor::deposit_asset(&MultiAsset::All, &MultiLocation::Null),
+			MultiTransactor::deposit_asset(&(Here, 1).into(), &Here),
 			Err(XcmError::Overflow)
 		);
 	}
@@ -298,6 +299,6 @@ mod tests {
 	fn success_stops_iteration() {
 		type MultiTransactor = (SuccessfulTransactor, OverflowTransactor);
 
-		assert_eq!(MultiTransactor::deposit_asset(&MultiAsset::All, &MultiLocation::Null), Ok(()));
+		assert_eq!(MultiTransactor::deposit_asset(&(Here, 1).into(), &Here), Ok(()));
 	}
 }

polkadot/xcm/xcm-executor/src/traits/weight.rs

@@ -17,7 +17,7 @@
 use crate::Assets;
 use frame_support::weights::Weight;
 use sp_std::result::Result;
-use xcm::v0::{Error, MultiAsset, MultiLocation, Xcm};
+use xcm::latest::{Error, MultiAsset, MultiLocation, Xcm};
 
 /// Determine the weight of an XCM message.
 pub trait WeightBounds<Call> {
@@ -71,8 +71,8 @@ pub trait WeightTrader: Sized {
 	/// purchased using `buy_weight`.
 	///
 	/// Default implementation refunds nothing.
-	fn refund_weight(&mut self, _weight: Weight) -> MultiAsset {
-		MultiAsset::None
+	fn refund_weight(&mut self, _weight: Weight) -> Option<MultiAsset> {
+		None
 	}
 }