zeekayandHanzo Dev
da70f3d430
Two defects, both fatal, both on the C<->D atomic settlement path. 1. Accept handed the versiondb batch to sm.Apply unconditionally. The C-Chain EVM is an out-of-process plugin, so its SharedMemory is the ZAP client, and that client refuses any batch — a database.Batch cannot cross a process boundary. Every block staging an atomic op would have failed Accept, which is fatal. Commit the versiondb first, then Apply with no batch. Without a shared batch exactly-once is unreachable; the choice is at-most-once or at-least-once, and replay is unsound here (a duplicate put is fatal, and after the peer consumes the object it re-creates it). A skipped op is survivable: C's settlement replay guard is EVM state, not the Remove, and a skipped intent Put is refunded by reclaimIntent. The residual single-node cost is stated in the code. 2. The settle path read the object from shared memory DURING EVM execution while the consuming Remove landed at Accept. A node re-executing that block — bootstrapping, state-syncing, re-tracing — found the object gone, computed a reverted receipt where the network computed a successful one, and died on the receipt root. The seam settled live and wedged every node that tried to sync past it. Execution now binds to the object bytes the transaction carries and declares the consumption in its logs; this adds the block-level rule that proves the declaration against shared memory at Verify, on both the consensus path and the producer's own pre-proposal verify, so a forged object costs a block rather than forking a receipt root. The check is gated on the bootstrap frontier, which the shared-memory layer requires of any chain consuming cross-chain state. Co-authored-by: Hanzo Dev <[email protected]>
Core Package
The core package maintains the backend for the blockchain, transaction pool, and maintains the required indexes for blocks, transactions, logs, and transaction receipts.
Blockchain
The BlockChain struct handles the insertion of blocks into the maintained chain. It maintains a "canonical chain", which is essentially the preferred chain (the chain that ends with the block preferred by the Luxd consensus engine).
When the consensus engine verifies blocks as they are ready to be issued into consensus, it calls Verify() on the ChainVM Block interface implemented here. This calls InsertBlockManual on the BlockChain struct implemented in this package, which is the first entrypoint of a block into the blockchain.
InsertBlockManual verifies the block, inserts it into the state manager to track the merkle trie for the block, and adds it to the canonical chain if it extends the currently preferred chain.
EVM adds functions for Accept and Reject, which take care of marking a block as finalized and performing garbage collection where possible.
The consensus engine can also call SetPreference on a VM to tell the VM that a specific block is preferred by the consensus engine to be accepted. This triggers a call to reorg the blockchain and set the newly preferred block as the preferred chain.
Transaction Pool
The transaction pool maintains the set of transactions that need to be issued into a new block. The VM exposes APIs that allow clients to issue transactions into the transaction pool and also performs gossip across the network in order to send and receive pending transactions that need to be issued into a new block. The transaction pool asynchronously follows the preferred block of the BlockChain struct by subscribing to new head events and updating its state accordingly. When the transaction pool updates, it ensures that any transactions it contains are still valid to be issued on top of the new preferred block.
State Manager
The State Manager manages the TrieDB. The TrieDB tracks a merkle forest of all of the merkle tries for the last accepted block and processing blocks. When a block is processed, the state transition results in a new merkle trie added to the merkle forest. The State Manager can operate in either archival or pruning mode.
Archival Mode
In archival mode, every merkle trie is written to disk so that the node maintains a complete history of all the blocks that it has processed.
Pruning Mode
In pruning mode, the State Manager keeps a reference to merkle tries of processing blocks. When a block gets accepted, it stays in memory. When a block gets rejected, the state manager can dereference and clean up the no longer needed merkle trie. The State Manager does not immediately write the merkle trie to disk of a block when it gets accepted. Instead, at a regular interval (~4096 blocks) it writes the merkle trie to disk, so that it does not add the overhead of storing every accepted block's merkle trie to disk.