pallet-asset-conversion: Decoupling Native Currency Dependancy (#2031)
closes https://github.com/paritytech/polkadot-sdk/issues/1842 Decoupling Pallet from the Concept of Native Currency Currently, the pallet is intrinsically linked with the concept of native currency, requiring users to provide implementations of the `fungible::*` and `fungibles::*` traits to interact with native and non native assets. This incapsulates some non-related to the pallet complexity and makes it less adaptable in contexts where the native currency concept is absent. With this PR, the dependence on `fungible::*` for liquidity-supplying assets has been removed. Instead, the native and non-native currencies' handling is now overseen by a single type that implements the `fungibles::*` traits. To simplify this integration, types have been introduced to facilitate the creation of a union between `fungible::*` and `fungibles::*` implementations, producing a unified `fungibles::*` type. One of the reasons driving these changes is the ambition to create a more user-friendly API for the `SwapCredit` implementation. Given that it interacts with two distinct credit types from `fungible` and `fungibles`, a unified type was introduced. Clients now manage potential conversion failures for those credit types. In certain contexts, it's vital to guarantee that operations are fail-safe, like in this impl - [PR](https://github.com/paritytech/polkadot-sdk/pull/1845), place in [code](https://github.com/paritytech/polkadot-sdk/blob/20b85a5f /cumulus/primitives/utility/src/lib.rs#L429). Additional Updates: - abstracted the pool ID and its account derivation logic via trait bounds, along with common implementation offerings; - removed `inc_providers` on a pool creation for the pool account; - benchmarks: -- swap complexity is N, not const; -- removed `From<u128> + Into<u128>` bound from `T::Balance`; -- removed swap/liquidity/.. amount constants, resolve them dynamically based on pallet configuration; -- migrated to v2 API; - `OnUnbalanced` handler for the pool creation fee, replacing direct transfers to a specified account ID; - renamed `MultiAssetId` to `AssetKind` aligning with naming across frame crates; related PRs: - (depends) https://github.com/paritytech/polkadot-sdk/pull/1677 - (caused) https://github.com/paritytech/polkadot-sdk/pull/2033 - (caused) https://github.com/paritytech/polkadot-sdk/pull/1876 --------- Co-authored-by: joe petrowski <[email protected]> Co-authored-by: Liam Aharon <[email protected]>