fix(txpool): enforce hardfork activation for EIP-7702 and MorphTx

[panos-xyz]

Summary

Adds txpool-level validation to reject transaction types that are not yet active based on hardfork timestamps:

• EIP-7702 (type 0x04): Rejected before Viridian hardfork (PRAGUE SpecId)
• MorphTx (type 0x7F): Rejected before Emerald hardfork

This aligns morph-reth's txpool with go-ethereum's MakeSigner, which only registers these transaction types after their respective hardfork activation.

Test plan

• cargo check -p morph-txpool passes
• Existing unit tests pass
• Verify EIP-7702 tx rejected when Viridian not active
• Verify MorphTx rejected when Emerald not active

Summary by CodeRabbit

• New Features
  • Transaction validation now rejects EIP7702 transactions when Viridian hardfork is inactive
  • Transaction validation now rejects MorphTx transactions when Emerald hardfork is inactive

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 578a8837-e4a5-4713-b259-87c11db81612

📥 Commits

Reviewing files that changed from the base of the PR and between c991f05 and 1e744d7.

📒 Files selected for processing (1)

• crates/txpool/src/validator.rs

📝 Walkthrough

Walkthrough

The PR adds early rejection logic in the transaction validator to mark EIP-7702 transactions as unsupported when Viridian is inactive and MorphTx transactions as unsupported when Emerald is inactive, before proceeding with standard validation.

Changes

Cohort / File(s)	Summary
Transaction Validator Hardfork Checks crates/txpool/src/validator.rs	Added early rejection logic for EIP-7702 and MorphTx transactions based on hardfork activation status (Viridian and Emerald respectively) before standard validation.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

Possibly related PRs

• refactor: simplify logic across crates #56 — Modifies the same validator file and alters MorphTransactionValidator::validate_one with related validation logic.

Suggested reviewers

• chengwenxi

Poem

🐰✨ A hop through the hardfork gates,

Viridian and Emerald now validate!

Early rejections quick and neat,

Make the validation flow complete. 🌿💫

🚥 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 'enforce hardfork activation for EIP-7702 and MorphTx' directly and clearly describes the main changes: adding validation to reject EIP-7702 transactions before Viridian and MorphTx before Emerald based on hardfork activation status.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

_{✏️ 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/txpool-hardfork-activation

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[anylots]

For MorphTx transactions, is_morph_tx() is called twice — at line 261 and line 273. It is recommended to change let is_morph_tx = is_morph_tx(&transaction) at line 273 to reuse the result from the earlier check.

[panos-xyz]

For MorphTx transactions, is_morph_tx() is called twice — at line 261 and line 273. It is recommended to change let is_morph_tx = is_morph_tx(&transaction) at line 273 to reuse the result from the earlier check.

good catch