Nonce Lowering Improvements

[d4mr]

Summary by CodeRabbit

• Bug Fixes

  • Prevents over-inflated optimistic transaction counts by capping them to the next expected value, improving accuracy and stability when sending transactions.

• Chores

  • Adds a warning log when no inflight budget is available, improving operational visibility.
  • Minor log formatting improvements for better readability.

[coderabbitai]

Walkthrough

Extends validation data for CleanAndGetRecycledNonces to include an optional current_optimistic_tx_count from Redis, updates call sites to destructure the new tuple, and conditionally adjusts the optimistic transaction counter during apply. Adds a warning log when inflight budget is unavailable in send_flow. Minor logging-format changes.

Changes

Cohort / File(s)	Change Summary
EOA submitted store: validation tuple and optimistic count handling executors/src/eoa/store/submitted.rs	ValidationData expanded from (u64, Vec) to (u64, Vec, Option<u64)); validation now fetches and returns current_optimistic_tx_count; apply path conditionally reduces optimistic count to highest_submitted_nonce + 1 when applicable; updated destructuring; minor multiline logging formatting.
EOA worker send: inflight budget logging executors/src/eoa/worker/send.rs	Adds warning log when no inflight budget is available in send_flow; no other behavior changes.

Sequence Diagram(s)

sequenceDiagram
  autonumber
  participant Caller
  participant SubmittedStore
  participant Redis

  rect rgba(230,240,255,0.5)
  note over Caller,SubmittedStore: Validation phase (CleanAndGetRecycledNonces)
  Caller->>SubmittedStore: validate()
  SubmittedStore->>Redis: GET highest_submitted_nonce, recycled_nonces, current_optimistic_tx_count
  Redis-->>SubmittedStore: (u64, Vec<u64>, Option<u64>)
  SubmittedStore-->>Caller: ValidationData(h, recycled, opt_count)
  end

  rect rgba(235,255,235,0.5)
  note over Caller,SubmittedStore: Apply phase (update optimistic counter if needed)
  Caller->>SubmittedStore: apply(h, recycled, opt_count)
  alt opt_count is Some and h+1 < opt_count
    SubmittedStore->>Redis: SET optimistic_tx_count = h + 1
  else No update needed
    SubmittedStore-->>Caller: proceed without changing counter
  end
  SubmittedStore-->>Caller: done
  end

Loading

sequenceDiagram
  autonumber
  participant Worker
  participant Budget

  Worker->>Budget: check_inflight_budget()
  alt budget available
    Worker-->>Worker: proceed to send
  else no budget
    Worker-->>Worker: log warn "No inflight budget, not sending new transactions"
    Worker-->>Worker: skip send
  end

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Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Pre-merge checks and finishing touches

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 16.67% which is insufficient. The required threshold is 80.00%.	You can run @coderabbitai generate docstrings to improve docstring coverage.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title Check	✅ Passed	The title succinctly references the primary change of enhancing nonce-lowering logic by improving how optimistic transaction counts are handled and guarded, accurately summarizing the main update in the pull request.

✨ Finishing touches

• 📝 Generate Docstrings

🧪 Generate unit tests

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch pb/nonce-lowering-fix

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Actionable comments posted: 0

🧹 Nitpick comments (1)

executors/src/eoa/store/submitted.rs (1)

649-656: Harden the optimistic count lowering against overflow

highest_submitted_nonce + 1 will panic in debug builds if we ever reach u64::MAX. It’s astronomically unlikely on Ethereum today, but the saturating form is a zero-cost guard and avoids the panic should we ever roll the counter that far.

-        if let Some(current_optimistic_tx_count) = current_optimistic_tx_count {
-            // if the current optimistic tx count is floating too high, we need to bring it down
-            if highest_submitted_nonce + 1 < current_optimistic_tx_count {
-                pipeline.set(
-                    self.keys.optimistic_transaction_count_key_name(),
-                    highest_submitted_nonce + 1,
-                );
+        if let Some(current_optimistic_tx_count) = current_optimistic_tx_count {
+            // if the current optimistic tx count is floating too high, we need to bring it down
+            let next_nonce = highest_submitted_nonce.saturating_add(1);
+            if next_nonce < current_optimistic_tx_count {
+                pipeline.set(
+                    self.keys.optimistic_transaction_count_key_name(),
+                    next_nonce,
+                );
             }
         }

📜 Review details

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📥 Commits

Reviewing files that changed from the base of the PR and between 6a41959 and 6744794.

📒 Files selected for processing (2)

• executors/src/eoa/store/submitted.rs (5 hunks)
• executors/src/eoa/worker/send.rs (1 hunks)

🧰 Additional context used

🧠 Learnings (1)

📚 Learning: 2025-09-20T06:58:40.230Z

Learnt from: d4mr
PR: thirdweb-dev/engine-core#48
File: executors/src/eoa/store/submitted.rs:229-230
Timestamp: 2025-09-20T06:58:40.230Z
Learning: The diff in executors/src/eoa/store/submitted.rs shows correct brace structure - the first closing brace closes the remove_transaction_from_redis_submitted_zset method and the second closing brace closes the impl CleanSubmittedTransactions block. The change only adds whitespace formatting.

Applied to files:

• executors/src/eoa/store/submitted.rs

🧬 Code graph analysis (1)

executors/src/eoa/store/submitted.rs (3)

executors/src/eoa/store/borrowed.rs (1)

• operation (99-262)

executors/src/eoa/store/atomic.rs (4)

• operation (39-43)
• operation (708-735)
• pipeline (244-245)
• pipeline (362-363)

executors/src/eoa/store/pending.rs (2)

• operation (121-149)
• operation (239-262)

🔇 Additional comments (1)

executors/src/eoa/worker/send.rs (1)

69-73: Appreciate the explicit no-budget warning

The added warn! gives much-needed visibility into why the worker skips the new-tx path, which will help during incident triage. Good call.