fix(payload): serialize nextL1MessageIndex as bare uint64, not hex string

[panos-xyz]

Summary

• ExecutableL2Data.nextL1MessageIndex was decorated with #[serde(with = "alloy_serde::quantity")], causing it to serialize as a hex string ("0xa")
• morph-geth's gen_l2_ed.go declares NextL1MessageIndex as bare uint64 (not hexutil.Uint64), so it expects a plain JSON number (10)
• morphnode would fail with: json: cannot unmarshal string into Go struct field ExecutableL2Data.nextL1MessageIndex of type uint64

Fix: Remove the quantity serde attribute. All other numeric fields (number, gasLimit, gasUsed, timestamp) correctly use hex encoding because morph-geth uses hexutil.Uint64 for those — NextL1MessageIndex is the sole exception.

Reference: morph/go-ethereum/eth/catalyst/gen_l2_ed.go line 31

Test plan

• Existing serde round-trip test updated: "nextL1MessageIndex": "0xa" → "nextL1MessageIndex": 10
• cargo test -p morph-payload-types passes

Summary by CodeRabbit

• Bug Fixes

  • Numeric message index values now serialize/deserialize as standard JSON numbers instead of hexadecimal strings.

• Documentation

  • Clarified field-level documentation describing the message index serialization format.

• Tests

  • Updated serialization tests/fixtures to use numeric literals for message index values.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: b800d64d-b026-4b19-ae8c-d360b840e970

📥 Commits

Reviewing files that changed from the base of the PR and between 4160111 and 7cf1999.

📒 Files selected for processing (1)

• crates/payload/types/src/executable_l2_data.rs

🚧 Files skipped from review as they are similar to previous changes (1)

• crates/payload/types/src/executable_l2_data.rs

---

📝 Walkthrough

Walkthrough

Removed hex-quantity serde for ExecutableL2Data.next_l1_message_index, so it now serializes/deserializes as a plain JSON u64. Updated tests' camelCase fixture to use numeric literal and added field-level documentation noting morph-geth format. No public API signatures changed.

Changes

Cohort / File(s)	Summary
ExecutableL2Data Serde & Tests crates/payload/types/src/executable_l2_data.rs	Removed #[serde(with = "alloy_serde::quantity")] from next_l1_message_index, making it a bare JSON u64; updated camelCase serde test fixture from hex string to numeric literal; added field documentation referencing morph-geth serialization.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

Poem

🐰 I swapped a hex for plain delight,
Numbers now wake in morning light,
Tests adjusted, docs sing true,
A cleaner field, a clearer view,
Hoppity code — small change, big bite!

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title directly and accurately describes the main change: removing hex-quantity serialization from nextL1MessageIndex and making it serialize as a bare uint64 number instead.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/engine-api-gaps

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[coderabbitai]

🧹 Nitpick comments (2)

crates/payload/types/src/executable_l2_data.rs (2)

68-72: Avoid hardcoded external line numbers in docs.

gen_l2_ed.go line 31 can drift quickly. Prefer symbol/path-only reference or a permalink to a specific commit.

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@crates/payload/types/src/executable_l2_data.rs` around lines 68 - 72, The doc
comment references an external file by a hardcoded line number ("gen_l2_ed.go
line 31") which can drift; update the comment on the next_l1_message_index field
to remove the line number and instead point to a stable identifier — e.g.,
reference the source file and symbol or a commit permalink (for example
"morph/go-ethereum/eth/catalyst/gen_l2_ed.go, see the GenL2ED
function/serialization logic" or a specific commit URL) so readers can locate
the exact code without relying on a line number.

---

191-253: Add explicit test to verify nextL1MessageIndex serializes as a JSON number.

The code comment (lines 68-71) emphasizes that nextL1MessageIndex must serialize as a bare JSON number, unlike other numeric fields. Current tests verify deserialization and roundtrip equality but do not explicitly assert the serialization format using is_number(). The proposed test would protect against accidental changes that could introduce hex serialization.

Proposed test addition

+#[test]
+fn test_next_l1_message_index_serializes_as_number() {
+    let data = ExecutableL2Data {
+        next_l1_message_index: 10,
+        ..Default::default()
+    };
+
+    let json = serde_json::to_value(&data).expect("serialize");
+    assert_eq!(json["nextL1MessageIndex"], serde_json::json!(10));
+    assert!(json["nextL1MessageIndex"].is_number());
+}

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@crates/payload/types/src/executable_l2_data.rs` around lines 191 - 253, Add a
unit test that builds an ExecutableL2Data with a known next_l1_message_index
value, serializes it with serde_json::to_value or to_string, parses to
serde_json::Value and asserts the nextL1MessageIndex field exists and
value.is_number() is true; place the test near the other serde tests (e.g., name
it test_next_l1_message_index_serializes_as_number) and reference
ExecutableL2Data and the JSON key "nextL1MessageIndex" to ensure the field is
not emitted as a hex/string.

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Nitpick comments:
In `@crates/payload/types/src/executable_l2_data.rs`:
- Around line 68-72: The doc comment references an external file by a hardcoded
line number ("gen_l2_ed.go line 31") which can drift; update the comment on the
next_l1_message_index field to remove the line number and instead point to a
stable identifier — e.g., reference the source file and symbol or a commit
permalink (for example "morph/go-ethereum/eth/catalyst/gen_l2_ed.go, see the
GenL2ED function/serialization logic" or a specific commit URL) so readers can
locate the exact code without relying on a line number.
- Around line 191-253: Add a unit test that builds an ExecutableL2Data with a
known next_l1_message_index value, serializes it with serde_json::to_value or
to_string, parses to serde_json::Value and asserts the nextL1MessageIndex field
exists and value.is_number() is true; place the test near the other serde tests
(e.g., name it test_next_l1_message_index_serializes_as_number) and reference
ExecutableL2Data and the JSON key "nextL1MessageIndex" to ensure the field is
not emitted as a hex/string.

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 84a4d90f-7521-466f-9280-d9c3830c4f58

📥 Commits

Reviewing files that changed from the base of the PR and between 6ea9660 and 4160111.

📒 Files selected for processing (1)

• crates/payload/types/src/executable_l2_data.rs

[chengwenxi]

LGTM. Correct fix — matches Go's gen_l2_ed.go where NextL1MessageIndex is plain uint64 (not hexutil.Uint64). Removing alloy_serde::quantity switches serde to bare JSON number, fixing the interop bug. Minor nit: the hardcoded line number in the doc comment (line 31) is brittle — consider a permalink or just the symbol name.