zeekayandHanzo Dev
0121536b30
ROOT CAUSE of the C-Chain bootstrap ancestry-descent stall: ParseBlock was STATEFUL.
BlockGasCost is NOT in the RLP block — it is DERIVED from the parent header. UnmarshalBlock
computed it via vm.blockChain.GetHeaderByHash(parent), and SyntacticVerify REQUIRED it non-nil
(errNilBlockGasCostEVM). For a bootstrap descent parsing ancestry blocks AHEAD of the accepted
height the parent is not present, so every such block failed to parse — masked by the ZAP
errorToZAP mapping as the misleading "malformed block id (does not connect to accepted chain)".
The Lux bootstrapper indexes the whole fetched batch by (id,height,parent) up front, so it could
not index the ancestry, never found the frontier tip in the batch, and re-requested forever ->
ErrStalled. Confirmed on devnet: "syntactic block verification failed: nil blockGasCost is
invalid after EVM activation".
FIX — decomplect parse from verify (matches upstream avalanchego coreth: parse decodes, Verify
enforces connectivity):
- block.go: new ensureBlockGasCost() fills BlockGasCost from the parent header WHEN PRESENT
(SetHeaderExtra is hash-keyed, so it persists for a block first parsed while its parent was
absent). Best-effort at parse; authoritative at Verify (AcceptBootstrapBlock calls blk.Verify
only after the contiguity gate height==finalized+1, so the parent is ACCEPTED/present).
- block_verification.go: SyntacticVerify no longer requires BlockGasCost (stateless,
block-intrinsic checks only); keeps the uint64 sanity check when it IS set.
- vm.go UnmarshalBlock: replace the inline parent-lookup with block.ensureBlockGasCost().
SAFETY (parse != accept): parse only decodes + stateless syntactic checks; no non-connecting or
gas-cost-invalid block can be ACCEPTED just because it now parses. Verify/Accept
(InsertBlockManual -> consensus/dummy header verification) recomputes the expected BlockGasCost
from the (present) parent and rejects a mismatch; the bootstrap contiguity gate accepts blocks
oldest-first (parent finalized). A wrong-hash block is rejected off-path by the content-addressed
descent. BlockGasCost is not in the block hash -> no malleability.
evm plugin/evm tests pass.
Co-authored-by: Hanzo Dev <[email protected]>
EVM Package
The EVM package implements the Luxd VM interface.
VM
The VM creates the Ethereum backend and provides basic block building, parsing, and retrieval logic to the consensus engine.
APIs
The VM creates APIs for the node through the function CreateHandlers(). CreateHandlers returns the Service struct to serve EVM specific APIs. Additionally, the Ethereum backend APIs are also returned at the /rpc extension.
Block Handling
The VM implements buildBlock, parseBlock, and getBlock and uses the chain package from Luxd to construct a metered state, which uses these functions to implement an efficient caching layer and maintain the required invariants for blocks that get returned to the consensus engine.
To do this, the VM uses a modified version of the Ethereum RLP block type here and uses the core package's BlockChain type here to handle the insertion and storage of blocks into the chain.
Block
The Block type implements the Luxd ChainVM Block interface. The key functions for this interface are Verify(), Accept(), Reject(), and Status().
The Block type wraps the stateless block type here and implements these functions to allow the consensus engine to verify blocks as valid, perform consensus, and mark them as accepted or rejected. See the documentation in Luxd for the more detailed VM invariants that are maintained here.