[Assets] Call implementation for transfer_all

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

@@ -531,4 +531,14 @@ impl<T: frame_system::Config> pallet_assets::WeightInfo for WeightInfo<T> {
 			.saturating_add(T::DbWeight::get().reads(2))
 			.saturating_add(T::DbWeight::get().writes(1))
 	}
+
+	fn transfer_all() -> Weight {
+		// Proof Size summary in bytes:
+		//  Measured:  `0`
+		//  Estimated: `3593`
+		// Minimum execution time: 46_573_000 picoseconds.
+		Weight::from_parts(47_385_000, 3593)
+			.saturating_add(T::DbWeight::get().reads(1_u64))
+			.saturating_add(T::DbWeight::get().writes(1_u64))
+	}
 }

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

@@ -528,4 +528,14 @@ impl<T: frame_system::Config> pallet_assets::WeightInfo for WeightInfo<T> {
 			.saturating_add(T::DbWeight::get().reads(2))
 			.saturating_add(T::DbWeight::get().writes(1))
 	}
+
+	fn transfer_all() -> Weight {
+		// Proof Size summary in bytes:
+		//  Measured:  `0`
+		//  Estimated: `3593`
+		// Minimum execution time: 46_573_000 picoseconds.
+		Weight::from_parts(47_385_000, 3593)
+			.saturating_add(T::DbWeight::get().reads(1_u64))
+			.saturating_add(T::DbWeight::get().writes(1_u64))
+	}
 }

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

@@ -528,4 +528,14 @@ impl<T: frame_system::Config> pallet_assets::WeightInfo for WeightInfo<T> {
 			.saturating_add(T::DbWeight::get().reads(2))
 			.saturating_add(T::DbWeight::get().writes(1))
 	}
+
+	fn transfer_all() -> Weight {
+		// Proof Size summary in bytes:
+		//  Measured:  `0`
+		//  Estimated: `3593`
+		// Minimum execution time: 46_573_000 picoseconds.
+		Weight::from_parts(47_385_000, 3593)
+			.saturating_add(T::DbWeight::get().reads(1_u64))
+			.saturating_add(T::DbWeight::get().writes(1_u64))
+	}
 }

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

@@ -537,4 +537,14 @@ impl<T: frame_system::Config> pallet_assets::WeightInfo for WeightInfo<T> {
 			.saturating_add(T::DbWeight::get().reads(2))
 			.saturating_add(T::DbWeight::get().writes(1))
 	}
+
+	fn transfer_all() -> Weight {
+		// Proof Size summary in bytes:
+		//  Measured:  `0`
+		//  Estimated: `3593`
+		// Minimum execution time: 46_573_000 picoseconds.
+		Weight::from_parts(47_385_000, 3593)
+			.saturating_add(T::DbWeight::get().reads(1_u64))
+			.saturating_add(T::DbWeight::get().writes(1_u64))
+	}
 }

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

@@ -535,4 +535,14 @@ impl<T: frame_system::Config> pallet_assets::WeightInfo for WeightInfo<T> {
 			.saturating_add(T::DbWeight::get().reads(2))
 			.saturating_add(T::DbWeight::get().writes(1))
 	}
+
+	fn transfer_all() -> Weight {
+		// Proof Size summary in bytes:
+		//  Measured:  `0`
+		//  Estimated: `3593`
+		// Minimum execution time: 46_573_000 picoseconds.
+		Weight::from_parts(47_385_000, 3593)
+			.saturating_add(T::DbWeight::get().reads(1_u64))
+			.saturating_add(T::DbWeight::get().writes(1_u64))
+	}
 }

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

@@ -529,4 +529,14 @@ impl<T: frame_system::Config> pallet_assets::WeightInfo for WeightInfo<T> {
 			.saturating_add(T::DbWeight::get().reads(2))
 			.saturating_add(T::DbWeight::get().writes(1))
 	}
+
+	fn transfer_all() -> Weight {
+		// Proof Size summary in bytes:
+		//  Measured:  `0`
+		//  Estimated: `3593`
+		// Minimum execution time: 46_573_000 picoseconds.
+		Weight::from_parts(47_385_000, 3593)
+			.saturating_add(T::DbWeight::get().reads(1_u64))
+			.saturating_add(T::DbWeight::get().writes(1_u64))
+	}
 }

prdoc/pr_4527.prdoc

@@ -0,0 +1,27 @@
+# Schema: Polkadot SDK PRDoc Schema (prdoc) v1.0.0
+# See doc at https://raw.githubusercontent.com/paritytech/polkadot-sdk/master/prdoc/schema_user.json
+
+title: Call implementation for `transfer_all`
+
+doc:
+  - audience: Runtime Dev
+    description: |
+      This PR introduces the `transfer_all` call for `pallet-assets`.
+      The parameters are analog to the same call in `pallet-balances`.
+      This change shouldn't break the existing APIs.
+      This change requires running benchmarkings to set accurate weights for
+      the call.
+  - audience: Runtime User
+    description: |
+      This PR introduces the `transfer_all` call for `pallet-assets`.
+      The parameters are analog to the same call in `pallet-balances`.
+      When using this call, consider that transferring all funds of an asset
+      account might kill it when setting `keep_alive` as false.
+
+crates:
+  - name: pallet-assets
+    bump: minor
+  - name: asset-hub-rococo-runtime
+    bump: minor
+  - name: asset-hub-westend-runtime
+    bump: minor

substrate/frame/assets/src/benchmarking.rs

@@ -553,5 +553,15 @@ benchmarks_instance_pallet! {
 		assert_last_event::<T, I>(Event::Blocked { asset_id: asset_id.into(), who: caller }.into());
 	}
 
+	transfer_all {
+		let amount = T::Balance::from(100u32);
+		let (asset_id, caller, caller_lookup) = create_default_minted_asset::<T, I>(true, amount);
+		let target: T::AccountId = account("target", 0, SEED);
+		let target_lookup = T::Lookup::unlookup(target.clone());
+	}: _(SystemOrigin::Signed(caller.clone()), asset_id.clone(), target_lookup, false)
+	verify {
+		assert_last_event::<T, I>(Event::Transferred { asset_id: asset_id.into(), from: caller, to: target, amount }.into());
+	}
+
 	impl_benchmark_test_suite!(Assets, crate::mock::new_test_ext(), crate::mock::Test)
 }

substrate/frame/assets/src/lib.rs

@@ -180,7 +180,11 @@ use frame_support::{
 	pallet_prelude::DispatchResultWithPostInfo,
 	storage::KeyPrefixIterator,
 	traits::{
-		tokens::{fungibles, DepositConsequence, WithdrawConsequence},
+		tokens::{
+			fungibles, DepositConsequence, Fortitude,
+			Preservation::{Expendable, Preserve},
+			WithdrawConsequence,
+		},
 		BalanceStatus::Reserved,
 		Currency, EnsureOriginWithArg, ReservableCurrency, StoredMap,
 	},
@@ -1687,6 +1691,49 @@ pub mod pallet {
 			Self::deposit_event(Event::<T, I>::Blocked { asset_id: id, who });
 			Ok(())
 		}
+
+		/// Transfer the entire transferable balance from the caller asset account.
+		///
+		/// NOTE: This function only attempts to transfer _transferable_ balances. This means that
+		/// any held, frozen, or minimum balance (when `keep_alive` is `true`), will not be
+		/// transferred by this function. To ensure that this function results in a killed account,
+		/// you might need to prepare the account by removing any reference counters, storage
+		/// deposits, etc...
+		///
+		/// The dispatch origin of this call must be Signed.
+		///
+		/// - `id`: The identifier of the asset for the account holding a deposit.
+		/// - `dest`: The recipient of the transfer.
+		/// - `keep_alive`: A boolean to determine if the `transfer_all` operation should send all
+		///   of the funds the asset account has, causing the sender asset account to be killed
+		///   (false), or transfer everything except at least the minimum balance, which will
+		///   guarantee to keep the sender asset account alive (true).
+		#[pallet::call_index(32)]
+		#[pallet::weight(T::WeightInfo::refund_other())]
+		pub fn transfer_all(
+			origin: OriginFor<T>,
+			id: T::AssetIdParameter,
+			dest: AccountIdLookupOf<T>,
+			keep_alive: bool,
+		) -> DispatchResult {
+			let transactor = ensure_signed(origin)?;
+			let keep_alive = if keep_alive { Preserve } else { Expendable };
+			let reducible_balance = <Self as fungibles::Inspect<_>>::reducible_balance(
+				id.clone().into(),
+				&transactor,
+				keep_alive,
+				Fortitude::Polite,
+			);
+			let dest = T::Lookup::lookup(dest)?;
+			<Self as fungibles::Mutate<_>>::transfer(
+				id.into(),
+				&transactor,
+				&dest,
+				reducible_balance,
+				keep_alive,
+			)?;
+			Ok(())
+		}
 	}
 
 	/// Implements [`AccountTouch`] trait.

substrate/frame/assets/src/tests.rs

@@ -795,6 +795,50 @@ fn transferring_to_blocked_account_should_not_work() {
 	});
 }
 
+#[test]
+fn transfer_all_works_1() {
+	new_test_ext().execute_with(|| {
+		// setup
+		assert_ok!(Assets::force_create(RuntimeOrigin::root(), 0, 0, true, 100));
+		assert_ok!(Assets::mint(RuntimeOrigin::signed(0), 0, 1, 200));
+		assert_ok!(Assets::mint(RuntimeOrigin::signed(0), 0, 2, 100));
+		// transfer all and allow death
+		assert_ok!(Assets::transfer_all(Some(1).into(), 0, 2, false));
+		assert_eq!(Assets::balance(0, &1), 0);
+		assert_eq!(Assets::balance(0, &2), 300);
+	});
+}
+
+#[test]
+fn transfer_all_works_2() {
+	new_test_ext().execute_with(|| {
+		// setup
+		assert_ok!(Assets::force_create(RuntimeOrigin::root(), 0, 0, true, 100));
+		assert_ok!(Assets::mint(RuntimeOrigin::signed(0), 0, 1, 200));
+		assert_ok!(Assets::mint(RuntimeOrigin::signed(0), 0, 2, 100));
+		// transfer all and allow death
+		assert_ok!(Assets::transfer_all(Some(1).into(), 0, 2, true));
+		assert_eq!(Assets::balance(0, &1), 100);
+		assert_eq!(Assets::balance(0, &2), 200);
+	});
+}
+
+// /// TODO: Cover this case once #3951 is merged
+// #[test]
+// fn transfer_all_works_3() {
+// 	new_test_ext().execute_with(|| {
+// 		// setup
+// 		assert_ok!(Assets::force_create(RuntimeOrigin::root(), 0, 0, true, 100));
+//		assert_ok!(Assets::mint(RuntimeOrigin::signed(0), 0, 1, 200));
+// 		assert_ok!(AssetFreezer::set_frozen(&TestId::Foo, 0, &1, 10));
+// 		assert_ok!(Assets::mint(RuntimeOrigin::signed(0), 0, 2, 100));
+// 		// transfer all and allow death w/ reserved
+// 		assert_ok!(Assets::transfer_all(Some(1).into(), 0, 2, true));
+// 		assert_eq!(Assets::balance(0, &1), 110);
+// 		assert_eq!(Assets::balance(0, &2), 200);
+// 	});
+// }
+
 #[test]
 fn origin_guards_should_work() {
 	new_test_ext().execute_with(|| {