fix: remove extra clone from tipset serialization

[akaladarshi]

Summary of changes

Changes introduced in this pull request:

• While serializing the tipset we were cloning the enitre blockheader just to create a struct and then clone again for serialization.
• Changed the field to directly use the HashLotusJson field to avoid cloning.

Reference issue to close (if applicable)

Closes

Other information and links

Change checklist

• I have performed a self-review of my own code,
• I have made corresponding changes to the documentation. All new code adheres to the team's documentation standards,
• I have added tests that prove my fix is effective or that my feature works (if possible),
• I have made sure the CHANGELOG is up-to-date. All user-facing changes should be reflected in this document.

Outside contributions

• I have read and agree to the CONTRIBUTING document.
• I have read and agree to the AI Policy document. I understand that failure to comply with the guidelines will lead to rejection of the pull request.

Summary by CodeRabbit

• Refactor
  • Improved internal JSON serialization handling for Tipset data structures to use consistent type conversion patterns.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

Run ID: 8cf27881-fd36-4f83-a25d-7af9611213e8

📥 Commits

Reviewing files that changed from the base of the PR and between 45c8974 and f39f31a.

📒 Files selected for processing (1)

• src/blocks/tipset.rs

🔗 Linked repositories identified

CodeRabbit considers these linked repositories for cross-repo context during reviews:

• filecoin-project/lotus (manual)

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Walkthrough

Updated Tipset Lotus JSON serialization to use HasLotusJson trait associated types for cids and blocks fields, removing field-level adapter annotations. Deserialization and serialization now employ from_lotus_json() and into_lotus_json() conversions respectively.

Changes

Tipset Lotus JSON Serialization Refactoring

Layer / File(s)	Summary
Tipset Lotus JSON trait-based serialization src/blocks/tipset.rs	TipsetLotusJsonInner field types for cids and blocks change to HasLotusJson associated types, removing explicit serde(with=...)/schemars(with=...) annotations. Deserialization converts blocks via from_lotus_json() before constructing Tipset. Serialization converts tipset.key() and tipset.block_headers() via into_lotus_json() when building TipsetLotusJsonInner.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Possibly related PRs

• ChainSafe/forest#6227: Adds HasLotusJson trait support for Arc<T> and refactors RPC to use Arc<Tipset>, which directly depends on this PR's trait-based serialization plumbing for Tipset.

Suggested reviewers

• LesnyRumcajs
• hanabi1224

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title directly addresses the main change: removing an extra clone from tipset serialization. It accurately summarizes the primary optimization in the changeset.
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.

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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 akaladarshi/fix-tipset-serialization

✨ Simplify code

• Create PR with simplified code
• Commit simplified code in branch akaladarshi/fix-tipset-serialization

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[codecov]

Codecov Report

❌ Patch coverage is 75.00000% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 64.37%. Comparing base (2c1f7e6) to head (f39f31a).
⚠️ Report is 4 commits behind head on main.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
src/blocks/tipset.rs	75.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

Files with missing lines	Coverage Δ
src/blocks/tipset.rs	84.77% <75.00%> (+0.02%)	⬆️

... and 12 files with indirect coverage changes

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