Liam Aharon
c4211b6533
Original PR https://github.com/paritytech/substrate/pull/14641 --- Closes https://github.com/paritytech/polkadot-sdk/issues/109 ### Problem Quoting from the above issue: > When adding a pallet to chain after genesis we currently don't set the StorageVersion. So, when calling on_chain_storage_version it returns 0 while the pallet is maybe already at storage version 9 when it was added to the chain. This could lead to issues when running migrations. ### Solution - Create a new trait `BeforeAllRuntimeMigrations` with a single method `fn before_all_runtime_migrations() -> Weight` trait with a noop default implementation - Modify `Executive` to call `BeforeAllRuntimeMigrations::before_all_runtime_migrations` for all pallets before running any other hooks - Implement `BeforeAllRuntimeMigrations` in the pallet proc macro to initialize the on-chain version to the current pallet version if the pallet has no storage set (indicating it has been recently added to the runtime and needs to have its version initialised). ### Other changes in this PR - Abstracted repeated boilerplate to access the `pallet_name` in the pallet expand proc macro. ### FAQ #### Why create a new hook instead of adding this logic to the pallet `pre_upgrade`? `Executive` currently runs `COnRuntimeUpgrade` (custom migrations) before `AllPalletsWithSystem` migrations. We need versions to be initialized before the `COnRuntimeUpgrade` migrations are run, because `COnRuntimeUpgrade` migrations may use the on-chain version for critical logic. e.g. `VersionedRuntimeUpgrade` uses it to decide whether or not to execute. We cannot reorder `COnRuntimeUpgrade` and `AllPalletsWithSystem` so `AllPalletsWithSystem` runs first, because `AllPalletsWithSystem` have some logic in their `post_upgrade` hooks to verify that the on-chain version and current pallet version match. A common use case of `COnRuntimeUpgrade` migrations is to perform a migration which will result in the versions matching, so if they were reordered these `post_upgrade` checks would fail. #### Why init the on-chain version for pallets without a current storage version? We must init the on-chain version for pallets even if they don't have a defined storage version so if there is a future version bump, the on-chain version is not automatically set to that new version without a proper migration. e.g. bad scenario: 1. A pallet with no 'current version' is added to the runtime 2. Later, the pallet is upgraded with the 'current version' getting set to 1 and a migration is added to Executive Migrations to migrate the storage from 0 to 1 a. Runtime upgrade occurs b. `before_all` hook initializes the on-chain version to 1 c. `on_runtime_upgrade` of the migration executes, and sees the on-chain version is already 1 therefore think storage is already migrated and does not execute the storage migration Now, on-chain version is 1 but storage is still at version 0. By always initializing the on-chain version when the pallet is added to the runtime we avoid that scenario. --------- Co-authored-by: Kian Paimani <5588131+kianenigma@users.noreply.github.com> Co-authored-by: Bastian Köcher <git@kchr.de>
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.
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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
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visit the
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