Robert Habermeier
74baed8b39
* crate skeleton and type definitions * add ChainSelectionMessage * add error type * run loop * fix overseer * simplify determine_new_blocks API * write an overlay struct and fetch new blocks * add new function to overlay * more flow * add leaves to overlay and add a strong type around leaves-set * add is_parent_viable * implement block import, ignoring reversions * add stagnant-at to overlay * add stagnant * add revert consensus log * flow for reversions * extract and import block reversions * recursively update viability * remove redundant parameter from WriteBlockEntry * do some removal of viable leaves * address grumbles * refactor * address grumbles * add comment about non-monotonicity * extract backend to submodule * begin the hunt for viable leaves * viability pivots for updating the active leaves * remove LeafSearchFrontier * partially -> explicitly viable and untwist some booleans * extract tree to submodule * implement block finality update * Implement block approval routine * implement stagnant detection * ensure blocks pruned on finality are removed from the active leaves set * write down some planned test cases * floww * leaf loading * implement best_leaf_containing * write down a few more tests to do * remove dependence of tree on header * guide: ChainApiMessage::BlockWeight * node: BlockWeight ChainAPI * fix compile issue * note a few TODOs for the future * fetch block weight using new BlockWeight ChainAPI * implement unimplemented * sort leaves by block number after weight * remove warnings and add more TODOs * create test module * storage for test backend * wrap inner in mutex * add write waker query to test backend * Add OverseerSignal -> FromOverseer conversion * add test harnes * add no-op test * add some more test helpers * the first test * more progress on tests * test two subtrees * determine-new-blocks: cleaner genesis avoidance and tighter ancestry requests * don't make ancestry requests when asking for one block * add a couple more tests * add to AllMessages in guide * remove bad spaces from bridge * compact iterator * test import with gaps * more reversion tests * test finalization pruning subtrees * fixups * test clobbering and fix bug in overlay * exhaustive backend state after finalizaiton tested * more finality tests * leaf tests * test approval * test ChainSelectionMessage::Leaves thoroughly * remove TODO * avoid Ordering::is_ne so CI can build * comment algorithmic complexity * Update node/core/chain-selection/src/lib.rs Co-authored-by: Bernhard Schuster <bernhard@ahoi.io> Co-authored-by: Bernhard Schuster <bernhard@ahoi.io>
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.