Assets Events for Deposited and Withdrawn (#4312)

Closes #4308

Polkadot address: 12gMhxHw8QjEwLQvnqsmMVY1z5gFa54vND74aMUbhhwN6mJR

---------

Co-authored-by: command-bot <>
Co-authored-by: Francisco Aguirre <franciscoaguirreperez@gmail.com>

substrate/frame/assets/src/impl_fungibles.rs

@@ -118,6 +118,22 @@ impl<T: Config<I>, I: 'static> fungibles::Balanced<<T as SystemConfig>::AccountI
 {
 	type OnDropCredit = fungibles::DecreaseIssuance<T::AccountId, Self>;
 	type OnDropDebt = fungibles::IncreaseIssuance<T::AccountId, Self>;
+
+	fn done_deposit(
+		asset_id: Self::AssetId,
+		who: &<T as SystemConfig>::AccountId,
+		amount: Self::Balance,
+	) {
+		Self::deposit_event(Event::Deposited { asset_id, who: who.clone(), amount })
+	}
+
+	fn done_withdraw(
+		asset_id: Self::AssetId,
+		who: &<T as SystemConfig>::AccountId,
+		amount: Self::Balance,
+	) {
+		Self::deposit_event(Event::Withdrawn { asset_id, who: who.clone(), amount })
+	}
 }
 
 impl<T: Config<I>, I: 'static> fungibles::Unbalanced<T::AccountId> for Pallet<T, I> {

substrate/frame/assets/src/lib.rs

@@ -571,6 +571,10 @@ pub mod pallet {
 		Touched { asset_id: T::AssetId, who: T::AccountId, depositor: T::AccountId },
 		/// Some account `who` was blocked.
 		Blocked { asset_id: T::AssetId, who: T::AccountId },
+		/// Some assets were deposited (e.g. for transaction fees).
+		Deposited { asset_id: T::AssetId, who: T::AccountId, amount: T::Balance },
+		/// Some assets were withdrawn from the account (e.g. for transaction fees).
+		Withdrawn { asset_id: T::AssetId, who: T::AccountId, amount: T::Balance },
 	}
 
 	#[pallet::error]

substrate/frame/assets/src/tests/sets.rs

@@ -90,6 +90,12 @@ fn deposit_from_set_types_works() {
 		assert_eq!(First::<Assets>::balance((), &account2), 50);
 		assert_eq!(First::<Assets>::total_issuance(()), 100);
 
+		System::assert_has_event(RuntimeEvent::Assets(crate::Event::Deposited {
+			asset_id: asset1,
+			who: account2,
+			amount: 50,
+		}));
+
 		assert_eq!(imb.peek(), 50);
 
 		let (imb1, imb2) = imb.split(30);
@@ -336,6 +342,12 @@ fn withdraw_from_set_types_works() {
 		assert_eq!(First::<Assets>::balance((), &account2), 50);
 		assert_eq!(First::<Assets>::total_issuance(()), 200);
 
+		System::assert_has_event(RuntimeEvent::Assets(crate::Event::Withdrawn {
+			asset_id: asset1,
+			who: account2,
+			amount: 50,
+		}));
+
 		assert_eq!(imb.peek(), 50);
 		drop(imb);
 		assert_eq!(First::<Assets>::total_issuance(()), 150);