Liam Aharon
46090ff114
Original PR https://github.com/paritytech/substrate/pull/14655 --- Partial https://github.com/paritytech/polkadot-sdk/issues/225 - [x] Adds conformance tests for Unbalanced - [x] Adds conformance tests for Balanced - Several minor fixes to fungible default implementations and the Balances pallet - [x] `Unbalanced::decrease_balance` can reap account when `Preservation` is `Preserve` - [x] `Balanced::pair` can return pairs of imbalances which do not cancel each other out - [x] Balances pallet `active_issuance` 'underflow' - [x] Refactors the conformance test file structure to match the fungible file structure: tests for traits in regular.rs go into a test file named regular.rs, tests for traits in freezes.rs go into a test file named freezes.rs, etc. - [x] Improve doc comments - [x] Simplify macros ## Fixes ### `Unbalanced::decrease_balance` can reap account when called with `Preservation::Preserve` There is a potential issue in the default implementation of `Unbalanced::decrease_balance`. The implementation can delete an account even when it is called with `preservation: Preservation::Preserve`. This seems to contradict the documentation of `Preservation::Preserve`: ```rust /// The account may not be killed and our provider reference must remain (in the context of /// tokens, this means that the account may not be dusted). Preserve, ``` I updated `Unbalanced::decrease_balance` to return `Err(TokenError::BelowMinimum)` when a withdrawal would cause the account to be reaped and `preservation: Preservation::Preserve`. - [ ] TODO Confirm with @gavofyork that this is correct behavior Test for this behavior: https://github.com/paritytech/polkadot-sdk/blob/e5c876dd6b59e2b7dbacaa4538cb42c802db3730/substrate/frame/support/src/traits/tokens/fungible/conformance_tests/regular.rs#L912-L937 ### `Balanced::pair` returning non-canceling pairs `Balanced::pair` is supposed to create a pair of imbalances that cancel each other out. However this is not the case when the method is called with an amount greater than the total supply. In the existing default implementation, `Balanced::pair` creates a pair by first rescinding the balance, creating `Debt`, and then issuing the balance, creating `Credit`. When creating `Debt`, if the amount to create exceeds the `total_supply`, `total_supply` units of `Debt` are created *instead* of `amount` units of `Debt`. This can lead to non-canceling amount of `Credit` and `Debt` being created. To address this, I create the credit and debt directly in the method instead of calling `issue` and `rescind`. Test for this behavior: https://github.com/paritytech/polkadot-sdk/blob/e5c876dd6b59e2b7dbacaa4538cb42c802db3730/substrate/frame/support/src/traits/tokens/fungible/conformance_tests/regular.rs#L1323-L1346 ### `Balances` pallet `active_issuance` 'underflow' This PR resolves an issue in the `Balances` pallet that can lead to odd behavior of `active_issuance`. Currently, the Balances pallet doesn't check if `InactiveIssuance` remains less than or equal to `TotalIssuance` when supply is deactivated. This allows `InactiveIssuance` to be greater than `TotalIssuance`, which can result in unexpected behavior from the perspective of the fungible API. `active_issuance` is derived from `TotalIssuance.saturating_sub(InactiveIssuance)`. If an `amount` is deactivated that causes `InactiveIssuance` to become greater TotalIssuance, `active_issuance` will return 0. However once in that state, reactivating an amount will not increase `active_issuance` by the reactivated `amount` as expected. Consider this test where the last assertion would fail due to this issue: https://github.com/paritytech/polkadot-sdk/blob/e5c876dd6b59e2b7dbacaa4538cb42c802db3730/substrate/frame/support/src/traits/tokens/fungible/conformance_tests/regular.rs#L1036-L1071 To address this, I've modified the `deactivate` function to ensure `InactiveIssuance` never surpasses `TotalIssuance`. --------- Co-authored-by: Muharem <ismailov.m.h@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/contributor/SECURITY.md.
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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.