Accept wrote the block, the tip pointer and the height through the version
layer and never committed, so a node that had accepted a thousand blocks came
back from a restart naming genesis — while its peers held it to the tip it had
already told them about. The three writes were also three early returns, so a
failure part-way left the block stored under a tip that named its parent. They
are now one commit with a rollback, alongside the height index that makes
GetBlockIDAtHeight an answer rather than a refusal.
Verify checked only that the parent existed, and only above height one. A
height-one block could name a parent no node has ever seen; any block could
name genesis as the parent of height 500, rewind chain time to revive expired
quantum stamps, or jump forward and expire every stamp in flight. It now sits
on its parent in height and in time, under a skew cap — and BuildBlock never
stamps behind its own parent, so a node whose clock trails a slightly fast peer
does not build blocks it will itself refuse.
Verify held the VM's read lock and then called GetBlock, which takes it again.
Go queues a waiting writer ahead of any later reader, so a build arriving
between the two acquisitions deadlocked the chain with nothing to time out.
The Quasar validator id was the CHAIN id — a field never assigned — so every
node signed as the empty id, each peer's signature arrived as a duplicate of
the first, and no threshold above one could ever be met. It is the node id.
The default threshold was derived from a committee size that had not yet been
defaulted, so a config naming neither got one-of-three. Cleanup released only
FINALIZED entries, which are exactly the ones that do not accumulate. Corona
keyed its PRF off the first 32 bytes of the message, so any shorter message
through StampBlock killed the process; the signature counts were read outside
the lock that appends them.
A transaction whose quantum stamp has aged out never verifies again; left in
the pool it held its slot for good, and enough of them stopped the chain
accepting work. BuildBlock evicts what it could not verify, and re-arms the
builder when the batch limit leaves work behind — the latch holds one signal,
so the remainder had nothing to wake it.
A wire too short to hold the header decoded to height 0, time 0 and the empty
parent rather than failing, so every truncation named one value under as many
ids as an attacker cared to send.
Deleted, all proven unreferenced: the dlopen GPU plugin bridge (a second way to
do what quantum.ParallelVerifyWithThreshold already does through accel), the
stamper package (near-verbatim copy of the signer's accel path, with a
mode-confusion bug the original does not have, and the only reason the tree
needed geth/core), the Q-witness adapter, the NTT helpers (whose inverse did
not invert), and a signature cache that was written and never read — and whose
ids.ToID over a >32-byte input gave every entry the empty id, so all ten
thousand slots were one.
Coverage 20.0% -> 97.0%, with every load-bearing guard mutation-checked.
VMs now live in ONE place: chains/<name>/ owns the full implementation.
Previously split across node/vms/<name>/ (impl) + chains/<name>/main.go
(plugin wrapper). Now consolidated.
New layout:
chains/<name>vm/*.go — package <name>vm (VM code)
chains/<name>vm/cmd/plugin/main.go — package main (plugin binary)
chains/<name>vm/go.mod — module github.com/luxfi/chains/<name>vm
Moved 11 VMs: aivm, bridgevm, dexvm, graphvm, identityvm, keyvm,
oraclevm, quantumvm, relayvm, thresholdvm, zkvm.
External callers now import github.com/luxfi/chains/<name> directly.
zeekay