Adrian Catangiu
18257373b3
## Motivation `pallet-xcm` is the main user-facing interface for XCM functionality, including assets manipulation functions like `teleportAssets()` and `reserve_transfer_assets()` calls. While `teleportAsset()` works both ways, `reserve_transfer_assets()` works only for sending reserve-based assets to a remote destination and beneficiary when the reserve is the _local chain_. ## Solution This PR enhances `pallet_xcm::(limited_)reserve_withdraw_assets` to support transfers when reserves are other chains. This will allow complete, **bi-directional** reserve-based asset transfers user stories using `pallet-xcm`. Enables following scenarios: - transferring assets with local reserve (was previously supported iff asset used as fee also had local reserve - now it works in all cases), - transferring assets with reserve on destination, - transferring assets with reserve on remote/third-party chain (iff assets and fees have same remote reserve), - transferring assets with reserve different than the reserve of the asset to be used as fees - meaning can be used to transfer random asset with local/dest reserve while using DOT for fees on all involved chains, even if DOT local/dest reserve doesn't match asset reserve, - transferring assets with any type of local/dest reserve while using fees which can be teleported between involved chains. All of the above is done by pallet inner logic without the user having to specify which scenario/reserves/teleports/etc. The correct scenario and corresponding XCM programs are identified, and respectively, built automatically based on runtime configuration of trusted teleporters and trusted reserves. #### Current limitations: - while `fees` and "non-fee" `assets` CAN have different reserves (or fees CAN be teleported), the remaining "non-fee" `assets` CANNOT, among themselves, have different reserve locations (this is also implicitly enforced by `MAX_ASSETS_FOR_TRANSFER=2`, but this can be safely increased in the future). - `fees` and "non-fee" `assets` CANNOT have **different remote** reserves (this could also be supported in the future, but adds even more complexity while possibly not being worth it - we'll see what the future holds). Fixes https://github.com/paritytech/polkadot-sdk/issues/1584 Fixes https://github.com/paritytech/polkadot-sdk/issues/2055 --------- Co-authored-by: Francisco Aguirre <franciscoaguirreperez@gmail.com> Co-authored-by: Branislav Kontur <bkontur@gmail.com>
NOTE: We have recently made significant changes to our repository structure. In order to streamline our development process and foster better contributions, we have merged three separate repositories Cumulus, Substrate and Polkadot into this repository. Read more about the changes here.
Polkadot SDK
The Polkadot SDK repository provides all the resources needed to start building on the Polkadot network, a multi-chain blockchain platform that enables different blockchains to interoperate and share information in a secure and scalable way. The Polkadot SDK comprises three main pieces of software:
Polkadot
Implementation of a node for the https://polkadot.network in Rust, using the Substrate framework. This directory
currently contains runtimes for the Polkadot, Kusama, Westend, and Rococo networks. In the future, these will be
relocated to the runtimes repository.
Substrate
Substrate is the primary blockchain SDK used by developers to create the parachains that make up the Polkadot network. Additionally, it allows for the development of self-sovereign blockchains that operate completely independently of Polkadot.
Cumulus
Cumulus is a set of tools for writing Substrate-based Polkadot parachains.
Upstream Dependencies
Below are the primary upstream dependencies utilized in this project:
Security
The security policy and procedures can be found in docs/SECURITY.md.
Contributing & Code of Conduct
Ensure you follow our contribution guidelines. In every interaction and contribution, this project adheres to the Contributor Covenant Code of Conduct.
Additional Resources
- For monitoring upcoming changes and current proposals related to the technical implementation of the Polkadot network,
visit the
Requests for Comment (RFC)repository. While it's maintained by the Polkadot Fellowship, the RFC process welcomes contributions from everyone.