Candidate for 6.0.5 release - #2416

MINOR: PoPowParams going from case class to a private-constructor class with apply returning Try is a source/binary break in ergo-core's public API (no more direct construction, copy, or unapply). Since ergo-core is the library SPV clients build against, this deserves an explicit entry in the 6.0.5 release notes.

NIT: minChainLength is computed and stored but never read in production code (only one test asserts it). Either drop it or use it in prove's chain.lengthCompare(k + m) check so it earns its place.

MINOR: the self-heal fallbacks (withoutTransaction's full filter, hasUnregisteredTransaction, currentTransaction's orElse scan) are O(n) per mutation once orderedTransactions.size != transactionsRegistry.size, so a corrupted pool under tx flood pays O(n) per admission until healed. The healthy path keeps O(log n) via the size-equality guard, so this is fine as a recovery path — but consider logging when the degraded path triggers, so pool corruption is visible in production instead of silently costing CPU.

NIT: MemPoolStatistics.measurementIntervalMsec = 60 * 1000 is commented "one hour" but is one minute. Pre-existing, but the new elapsed-time cap here now depends on this constant, so worth fixing the comment while in the area.

NIT: MaxBufferedOutboundMessages = 64 and the byte cap are hard-coded. If field tuning ever turns out to be needed (e.g. peers on high-latency links tripping the abort), exposing them under scorex.network would avoid a redeploy — fine to defer.

MINOR: client-visible behavior change worth a release-note entry: modifier/box/token ids with wrong byte length and scan ids outside Short range now return 400 where they were previously accepted, silently truncated (scanIdInt.toShort querying the wrong scan!), or 500'd. Good hardening — just make sure API consumers hear about the stricter validation.

NIT: removal of /openapi.yaml and /.well-known/ai-plugin.json is a deliberate feature removal, but anyone who scripted against those endpoints will notice — one line in the release notes would cover it.

NIT: the lazy val change is right, but it documents that the only OpenAPI conformance test remains ignored (checker image gone) — so the openapi.yaml edits on this branch aren't machine-checked. Worth a tracking issue to restore an OpenAPI validation step.

MAJOR The deferral branch stops the Index() self-loop without scheduling any retry, and while caughtUp = false the actor has no handler for FullBlockApplied (the handler at line 501 requires caughtUp), so the only signal that can resume indexing is a Rollback event.

Consider a near-tip headers-only fork that briefly becomes the best header chain but whose full blocks never win (the losing side of a miner race): the guard at line 481 sees a next header that does not extend the indexed tip and defers. If the original chain then outgrows the fork, the best header chain flips back — but no Rollback is ever published, because the full-block chain never switched. The indexer stays stalled until node restart, silently dropping every subsequent FullBlockApplied.

Suggestion: add case _: FullBlockApplied if !state.caughtUp && !state.rollbackInProgress => self ! Index() so every applied block re-evaluates the deferral condition (or re-schedule Index() with a short delay instead of only logging).

MINOR During catch-up this adds a bestHeaderAtHeight(h + 1) (heightIds index read + full header fetch) per block, and index() then re-reads bestHeaderIdAtHeight(height) at line 381 because headerOpt is None on this path — two redundant storage reads per block on the full-reindex hot path, where they multiply across millions of blocks.

Suggestion: pass the already-fetched nextHeaderOpt into index(state.incrementIndexedHeight, nextHeaderOpt) so both the parent check and indexedHeaderId reuse a single read.

MINOR Removing /openapi.yaml and /.well-known/ai-plugin.json is clearly intentional (ChatGPT-plugin retirement), but it is a breaking removal of public endpoints — anything still fetching them gets a 404 after upgrade. Worth an explicit line in the 6.0.5 release notes.

MINOR The spec's only test remains ignored (the openapi-checker image is gone), so this suite passes CI while providing zero signal — the new comment documents the situation but keeps the dead spec. Consider deleting the spec or reviving the check with a maintained validator image.

MINOR minChainLength is not read anywhere in production code — its only consumer is the assertion in PoPowAlgosSpec. If it is groundwork for the follow-up NiPoPoW parsing work (#2461), fine to keep, but then a short comment saying so would help; otherwise it is a dead field that suggests a validation which does not actually happen yet.

MINOR Validating every header's Autolykos PoW is the right fix, but isValid is evaluated inside ErgoNodeViewSynchronizer's receive (case Success(proof) if proof.isValid around line 1085 of ErgoNodeViewSynchronizer.scala), so a proof chain of hundreds of headers now runs full PoW verification on the synchronizer's dispatcher thread, stalling its mailbox during nipopow bootstrap — and several proofs can arrive back-to-back from the p2pNipopows peers.

Suggestion: run the proof validation in a Future on a dedicated dispatcher and pipeTo the result back, keeping the synchronizer responsive.

NIT The size-equality heuristic takes the fast path on compensating corruption — one duplicate key plus one orphaned entry leaves the sizes equal, so a duplicate would survive withoutTransaction. Fine as best-effort self-healing, but worth extending the comment to note that limitation.

NIT awaitCondition fixes the lock discipline (the old pattern never unlocks after await()), but this test still uses bare lock.lock(); created.await() in two places. Worth finishing the migration to awaitCondition(created) here too.

NIT Question on honest-path headroom: the byte cap is one max frame (~16.4 MB), which the tests show fits 4 in-flight snapshot chunks — but a peer that requested a large block batch can legitimately have several Modifiers responses (up to ~8.4 MB each) queued while its socket is stalled, and two of those already exceed the cap, aborting the connection. Reconnect makes this self-healing, so it may well be acceptable — but worth confirming the serving side never queues more than one large response per request round, or noting that connection churn under full-stall is the intended trade-off.