Sergei Shulepov
3c2fb21b93
This PR is a part of https://github.com/paritytech/polkadot/issues/3211. This PR prepares ground for the following runtime changes required for PVF pre-checking. Specifically, we do several changes here: 1. We remove `validation_code_at` and `validation_code_hash_at`. Those functions are not used. They were added in the early days with intent to use it later but turned out that we do not need them. 2. We replace `validation_code_hash_at` with just `current_code_hash` for the case of inclusion and candidate checking. 3. We also replace `last_code_upgrade` with a direct query into `FutureCodeHash` and `UpgradeRestrictionSignal`. Those in conjunction should replace the logic that was used for allowing/disallowing upgrades. This requires special attention of the reviewers. 4. Then we remove the machinery required to support those queries. Specifically the code related to `UseCodeAt`. We do not need it since we do not answer the historical queries. However, we still leave all the data on-chain. At some point we may clean it up, but that would be needed to be done with a dedicated migration which can be done as follow-up. 5. Some now irrelevant tests were removed and/or adapted.
Preamble
This document aims to describe the purpose, functionality, and implementation of the host for Polkadot's parachains functionality - that is, the software which provides security and advancement for constituent parachains. It is not for the implementer of a specific parachain but rather for the implementer of the Parachain Host. In practice, this is for the implementers of Polkadot in general.
There are a number of other documents describing the research in more detail. All referenced documents will be linked here and should be read alongside this document for the best understanding of the full picture. However, this is the only document which aims to describe key aspects of Polkadot's particular instantiation of much of that research down to low-level technical details and software architecture.