From d0fd2660031b92a3896db3ea47e65f6f8af9a9ae Mon Sep 17 00:00:00 2001 From: Muharem Date: Mon, 23 Oct 2023 19:14:52 +0200 Subject: [PATCH] Resolve Credit to Account impls of `OnUnbalanced` trait (#1876) Implements the `OnUnbalanced` trait to resolve received credits to the specified account. Credits that fail to resolve are dropped. ### Motivation Throughout the codebase, several types implement the trait with the same behavior. While some currently utilize older currency trait, a migration to the new fungible/s is anticipated for all. Examples: [1](https://github.com/paritytech/polkadot-sdk/blob/1b34571c0c423115813034783ddf524aac257bf5/cumulus/parachains/common/src/impls.rs#L37), [2](https://github.com/paritytech/polkadot-sdk/blob/1b34571c0c423115813034783ddf524aac257bf5/polkadot/runtime/common/src/impls.rs#L36), [3](https://github.com/paritytech/polkadot-sdk/blob/1b34571c0c423115813034783ddf524aac257bf5/substrate/bin/node/runtime/src/impls.rs#L40), [4](https://github.com/paritytech/polkadot-sdk/blob/1b34571c0c423115813034783ddf524aac257bf5/substrate/bin/node/runtime/src/lib.rs#L1969), [5](https://github.com/paritytech/polkadot-sdk/blob/1b34571c0c423115813034783ddf524aac257bf5/substrate/frame/broker/src/mock.rs#L198), [6](https://github.com/paritytech/polkadot-sdk/blob/1b34571c0c423115813034783ddf524aac257bf5/substrate/frame/society/src/lib.rs#L2031), [7](https://github.com/paritytech/polkadot-sdk/blob/1b34571c0c423115813034783ddf524aac257bf5/substrate/frame/treasury/src/lib.rs#L1118) --- .../support/src/traits/tokens/imbalance.rs | 2 +- .../traits/tokens/imbalance/on_unbalanced.rs | 30 ++++++++++++++++++- 2 files changed, 30 insertions(+), 2 deletions(-) diff --git a/substrate/frame/support/src/traits/tokens/imbalance.rs b/substrate/frame/support/src/traits/tokens/imbalance.rs index e487b81223..9dd8531324 100644 --- a/substrate/frame/support/src/traits/tokens/imbalance.rs +++ b/substrate/frame/support/src/traits/tokens/imbalance.rs @@ -25,7 +25,7 @@ use sp_std::ops::Div; mod on_unbalanced; mod signed_imbalance; mod split_two_ways; -pub use on_unbalanced::OnUnbalanced; +pub use on_unbalanced::{OnUnbalanced, ResolveAssetTo, ResolveTo}; pub use signed_imbalance::SignedImbalance; pub use split_two_ways::SplitTwoWays; diff --git a/substrate/frame/support/src/traits/tokens/imbalance/on_unbalanced.rs b/substrate/frame/support/src/traits/tokens/imbalance/on_unbalanced.rs index 27bfe46e18..ecb8de8841 100644 --- a/substrate/frame/support/src/traits/tokens/imbalance/on_unbalanced.rs +++ b/substrate/frame/support/src/traits/tokens/imbalance/on_unbalanced.rs @@ -17,7 +17,9 @@ //! Trait for handling imbalances. -use crate::traits::misc::TryDrop; +use frame_support::traits::{fungible, fungibles, misc::TryDrop}; +use sp_core::TypedGet; +use sp_std::marker::PhantomData; /// Handler for when some currency "account" decreased in balance for /// some reason. @@ -53,3 +55,29 @@ pub trait OnUnbalanced { } impl OnUnbalanced for () {} + +/// Resolves received asset credit to account `A`, implementing [`OnUnbalanced`]. +/// +/// Credits that cannot be resolved to account `A` are dropped. This may occur if the account for +/// address `A` does not exist and the existential deposit requirement is not met. +pub struct ResolveTo(PhantomData<(A, F)>); +impl> OnUnbalanced> + for ResolveTo +{ + fn on_nonzero_unbalanced(credit: fungible::Credit) { + let _ = F::resolve(&A::get(), credit).map_err(|c| drop(c)); + } +} + +/// Resolves received asset credit to account `A`, implementing [`OnUnbalanced`]. +/// +/// Credits that cannot be resolved to account `A` are dropped. This may occur if the account for +/// address `A` does not exist and the existential deposit requirement is not met. +pub struct ResolveAssetTo(PhantomData<(A, F)>); +impl> OnUnbalanced> + for ResolveAssetTo +{ + fn on_nonzero_unbalanced(credit: fungibles::Credit) { + let _ = F::resolve(&A::get(), credit).map_err(|c| drop(c)); + } +}