[jmg-duarte]

Description

Places the settlement submission behind a trait to simplify the addition of builders in a follow up PR (and lower the amount of changes). Note that the diff for the mempools.rs file is quite large but mostly whitespace.

Changes

• TransactionReceiver trait. Mempools becomes an Arc<dyn TransactionReceiver>.

How to test

Existing tests

[claude]

Claude finished @jmg-duarte's task in 2m 13s —— View job

---

Review: Put settlement submission behind a Submitter trait

• Read the diff and changed files
• Analyze the Submitter trait refactor
• Check for behavioral/compile regressions
• Post review

This is a clean, mechanical refactor — I didn't find any correctness issues worth a change request, so no inline comments. The pull request CI job (build + tests) is green, which backs that up.

What I checked

• Delegation is faithful. Mempools::execute now forwards to Submitter::execute, and the mempool race (select_ok, inline logging, stats, update_metrics) moves verbatim into impl Submitter for Vec<infra::Mempool>. The extracted free functions (submit, cancel, minimum_replacement_gas_price, update_metrics) just swap self.ethereum/self.mempools for passed-in args — no logic change.
• Clone semantics are safe. Mempools now shares the submitter via Arc<dyn Submitter> instead of deep-cloning Vec<infra::Mempool>. Since infra::Mempool already shares its mutable state (last_submissions: Arc<DashMap<..>>, transport: Web3) across clones, cloned Mempools observe the same submission/nonce state either way — so the Arc wrapping is behaviorally equivalent, not a regression. (Mempools is cloned per-request in api/mod.rs.)
• No dangling references. observe::mempool_submission_result dropping its &Mempool param for &str still compiles — Mempool remains imported/used by mempool_log. update_metrics passes &mempool.to_string(), preserving the old label.
• run.rs factoring hoists accounts out of the per-mempool closure and clone()s it, which is equivalent and slightly cheaper than re-collecting each iteration.

Minor (non-blocking, optional)

• Mempools::execute lost its doc comment (it migrated to the impl Submitter block). The public method is now undocumented — a one-line /// Submits the settlement via the configured submitter. wouldn't hurt.
• The ethereum is held by both Mempools and threaded into Submitter::execute(&self.ethereum, ..). That's a reasonable seam for the follow-up builders PR, just noting the slight redundancy.

Nothing here needs to block the merge. 👍
· branch jmgd/submission-submitter

[MartinquaXD]

Eventually it would be nice to move the trait and the metrics we expect it to populate into a separate file such that the 3 variants (blockbuilder, mempools, private_relay) can then be put into a separate directory nicely.