fix(consensus): return own mempool on empty-incoming pull

[Shitikyan]

What

Fixes a consensus-liveness bug: a tx submitted to a single node in a multi-validator network is never included.

Root cause

Mempool.receive([]) early-returned { mempool: [] }. The peer "mempool" exchange is push-pull (handleMempool → receive(theirTxs).mempool): an idle validator (empty mempool) pulls a peer by sending [], so the proposer replied [] instead of its own pool. Peers never learned the proposer's txs → the candidate block's tx-set diverged (broadcastBlockHash missingFromThem>0) → block rejected → tx never included.

Fix

On empty incoming, return our own pool (mirrors the unseenTransactions===0 path).

Verified

Local 4-node devnet: before, peers logged "Received 0 transactions from "; after, "Received N". Single-validator sidesteps the bug.

Follow-up (separate scope, NOT in this PR)

Exposed a second layer: peers then reject propagated txs as "Transaction is not coherent" — the submit path hashes via the node @/forks serializer while the worker validates via the SDK demosdk denomination serializer; they diverge post-osDenomination. Serializer-parity fix is its own (likely cross-repo) scope.

🤖 Generated with Claude Code

[coderabbitai]

Important

Draft PR not reviewed

Draft PRs are not automatically reviewed by default.

• Trigger a manual review

To automatically review draft PRs, update your CodeRabbit configuration:

reviews:
  auto_review:
    drafts: true

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}