fix(rpc): align Morph transaction and receipt serialization with morph-geth

[panos-xyz]

Summary

Fixes 8 RPC serialization issues discovered during cross-client replay testing against morph-geth.
These were found by running morph-cross-client-tests replay over 12,150 hoodi blocks and the full
268-block mainnet hardfork target set — all 8 fixes are required to reach 0 mismatches.

• fix(rpc): align receipt extension field serialization — Morph receipt fields (l1Fee, feeTokenID, feeRate, tokenScale, feeLimit, version, reference, memo) were missing or mis-typed
• fix(rpc): encode receipt version as quantity — version was emitted as a non-quantity hex
• fix(rpc): derive receipt type from transaction envelope — receipt type was always 0x0 for typed txs
• fix(rpc): remove duplicate transaction extension fields — MorphTx objects emitted version/feeTokenId twice (duplicate JSON keys)
• fix(rpc): emit MorphTx gas as rpc gas field — gas field was omitted from MorphTx transaction objects
• fix(rpc): align MorphTxFields fee token id key — key was feeTokenId in some paths, feeTokenID in others; aligned to feeTokenID
• fix(rpc): omit MorphTx v0 version field — version=0 should be omitted (matches morph-geth behavior)
• fix(rpc): align default priority fee with morph-geth — default gas tip cap diverged from morph-geth's behavior

Test plan

• cargo test -p morph-cct-rpc (existing RPC tests)
• End-to-end replay: 2,000 contiguous hoodi blocks → 0 mismatches
• End-to-end replay: 150-block hardfork-window target set → 0 mismatches
• End-to-end replay: 10,000-block contiguous sweep → 0 mismatches
• Mainnet 268-block hardfork target set (Morph203/Viridian/Emerald/Jade) → 0 mismatches

Summary by CodeRabbit

• New Features

  • Adds a Morph-specific default gas-price suggestion for node startup.

• Bug Fixes

  • RPC receipts now derive their type from the transaction envelope and expose missing numeric metadata as explicit zero values.
  • Transaction/receipt version now appears as a hex-quantity in RPC responses.

• Chores

  • Canonicalized JSON field names and serialization behavior for Morph transactions/receipts; tests updated and a workspace dependency added.

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📝 Walkthrough

Walkthrough

Refactors Morph RPC transaction/receipt serde and types; adds MORPH_DEFAULT_PRIORITY_FEE and applies it to CLI gas price defaults; updates MorphTx JSON naming/omission rules; converts MorphRpcTransaction to a type alias; makes Morph receipt numeric fields use RPC numeric types (explicit nulls when unset); and updates tests and receipt envelope selection logic.

Changes

Morph RPC Serialization and Type Refactoring

Layer / File(s)	Summary
Default Priority Fee Constant and CLI Setup crates/chainspec/src/constants.rs, bin/morph-reth/Cargo.toml, bin/morph-reth/src/main.rs	MORPH_DEFAULT_PRIORITY_FEE constant added and wired into CLI via apply_morph_cli_defaults() to set rpc.gas_price_oracle.default_suggested_fee when missing; alloy-primitives added as a workspace dependency to support U256 usage.
MorphTx Primitive Serialization crates/primitives/src/transaction/morph_transaction.rs	MorphTx serde updated: omit version when zero, canonicalize feeTokenID (accept feeTokenId alias), and serialize gas while accepting gasLimit; adds unit test asserting canonical feeTokenID.
RPC Type Definitions and Serialization crates/rpc/src/types/transaction.rs, crates/rpc/src/types/receipt.rs	MorphRpcTransaction replaced by type MorphRpcTransaction = RpcTransaction<MorphTxEnvelope>; MorphRpcReceipt.version changed to Option<U64> and Morph extension fields no longer skip-serialize so absent fields emit explicit null; tests updated to assert JSON-RPC quantity encoding and presence of nulls.
Receipt Conversion and Envelope Selection crates/rpc/src/eth/receipt.rs	Receipt conversion now derives RPC envelope variant from transaction tx.ty() via morph_tx_type_from_u8; log mapping centralized; numeric Morph receipt metadata defaults to zero for RPC outputs while reference/memo remain null when unset.
Receipt and Transaction Conversion Tests crates/rpc/src/eth/receipt.rs, crates/rpc/src/eth/transaction.rs, crates/node/tests/it/rpc.rs	Tests updated/extended: validate zero-defaulting of numeric Morph fields, ensure historical receipt type follows transaction envelope type, adapt transaction tests to inspect embedded MorphTxEnvelope variants, and change assertions to expect RPC numeric types (hex-quantity strings) for version.

Sequence Diagram(s)

(No additional sequence diagrams generated beyond those embedded in the review stack artifact; primary flows are captured there.)

Estimated code review effort

🎯 4 (Complex) | ⏱️ ~65 minutes

Possibly related PRs

• morph-l2/morph-reth#44: Related serde changes in crates/primitives/src/transaction/morph_transaction.rs for MorphTx field handling.
• morph-l2/morph-reth#36: Related work on TxMorph version handling and encoding.
• morph-l2/morph-reth#56: Overlaps on MorphRpcTransaction conversion and trait delegation changes.

Suggested reviewers

• chengwenxi

Poem

🐰 A rabbit hops through RPC types and keys,
Serde trims a field and names align with ease,
Defaults fill zeros where silence used to be,
Hex quantities sparkle in the RPC sea,
Morph's JSON hums a tidy, cheerful breeze.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately describes the main objective of the PR: fixing RPC serialization issues for Morph transactions and receipts to align with morph-geth behavior.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/rpc-morph-serialization

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@crates/primitives/src/transaction/morph_transaction.rs`:
- Around line 46-49: The serde attribute for the fee token field only renames to
"feeTokenID" and thus drops older "feeTokenId" inputs; update the serde
attributes that currently have rename = "feeTokenID" to also include alias =
"feeTokenId" (e.g. serde(default, with = "alloy_serde::quantity", rename =
"feeTokenID", alias = "feeTokenId")) for the fee field(s) referenced in the file
(the same attribute block around the fee field at the top and the similar block
at lines ~140-143) so deserialization accepts the old spelling while continuing
to emit "feeTokenID".

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 3f28872c-372d-4357-a749-35bb4af3fa17

📥 Commits

Reviewing files that changed from the base of the PR and between 18e7961 and 5f8878d.

⛔ Files ignored due to path filters (1)

• Cargo.lock is excluded by !**/*.lock

📒 Files selected for processing (8)

• bin/morph-reth/Cargo.toml
• bin/morph-reth/src/main.rs
• crates/chainspec/src/constants.rs
• crates/primitives/src/transaction/morph_transaction.rs
• crates/rpc/src/eth/receipt.rs
• crates/rpc/src/eth/transaction.rs
• crates/rpc/src/types/receipt.rs
• crates/rpc/src/types/transaction.rs

[coderabbitai]

🧹 Nitpick comments (1)

crates/rpc/src/eth/receipt.rs (1)

116-126: 💤 Low value

Consider adding a comment about the EIP-4844 fallback behavior.

Type 3 (EIP-4844 blob transactions) is not explicitly matched and falls through to Legacy. Since Morph doesn't support blob transactions, this is functionally correct, but a brief comment would clarify intent for future readers.

💡 Suggested clarification

 fn morph_tx_type_from_u8(tx_type: u8) -> MorphTxType {
     match tx_type {
         0 => MorphTxType::Legacy,
         1 => MorphTxType::Eip2930,
         2 => MorphTxType::Eip1559,
         4 => MorphTxType::Eip7702,
         L1_TX_TYPE_ID => MorphTxType::L1Msg,
         MORPH_TX_TYPE_ID => MorphTxType::Morph,
+        // EIP-4844 (type 3) and other unknown types fall back to Legacy.
+        // Morph does not support blob transactions.
         _ => MorphTxType::Legacy,
     }
 }

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@crates/rpc/src/eth/receipt.rs` around lines 116 - 126, The match in
morph_tx_type_from_u8 does not handle EIP-4844 (type 3) explicitly and currently
falls back to MorphTxType::Legacy; add a brief inline comment near the match arm
(or above the function) stating that type 3 (EIP-4844 blob transactions)
intentionally falls back to Legacy because Morph does not support blob
transactions, and mention the EIP-4844 type id (3) and that L1_TX_TYPE_ID and
MORPH_TX_TYPE_ID remain explicit to avoid confusion when inspecting MorphTxType,
MorphTxType::Legacy, L1_TX_TYPE_ID, and MORPH_TX_TYPE_ID.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Nitpick comments:
In `@crates/rpc/src/eth/receipt.rs`:
- Around line 116-126: The match in morph_tx_type_from_u8 does not handle
EIP-4844 (type 3) explicitly and currently falls back to MorphTxType::Legacy;
add a brief inline comment near the match arm (or above the function) stating
that type 3 (EIP-4844 blob transactions) intentionally falls back to Legacy
because Morph does not support blob transactions, and mention the EIP-4844 type
id (3) and that L1_TX_TYPE_ID and MORPH_TX_TYPE_ID remain explicit to avoid
confusion when inspecting MorphTxType, MorphTxType::Legacy, L1_TX_TYPE_ID, and
MORPH_TX_TYPE_ID.

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: ab21fc56-187a-48bb-bd05-2400128c7c61

📥 Commits

Reviewing files that changed from the base of the PR and between 736f04a and 11443be.

⛔ Files ignored due to path filters (1)

• Cargo.lock is excluded by !**/*.lock

📒 Files selected for processing (9)

• bin/morph-reth/Cargo.toml
• bin/morph-reth/src/main.rs
• crates/chainspec/src/constants.rs
• crates/node/tests/it/rpc.rs
• crates/primitives/src/transaction/morph_transaction.rs
• crates/rpc/src/eth/receipt.rs
• crates/rpc/src/eth/transaction.rs
• crates/rpc/src/types/receipt.rs
• crates/rpc/src/types/transaction.rs

✅ Files skipped from review due to trivial changes (1)

• bin/morph-reth/Cargo.toml