fix(rpc): Update expensive migration check

[sudo-shashank]

Summary of changes

Changes introduced in this pull request:

• Port fix(eth): serve eth_call at the epoch after an expensive migration filecoin-project/lotus#13644

Reference issue to close (if applicable)

Follow up PR #7192

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

Release Notes

• Bug Fixes
  • Improved eth_call, eth_estimateGas, eth_getCode, and eth_getStorageAt behavior during expensive network-upgrade migrations: requests are refused only at the upgrade epoch, and eth_getCode/eth_getStorageAt now retry on expensive-fork conditions.
  • Enhanced eth_estimateGas to re-execute the call after a gas estimation failure to surface accurate revert details when applicable.
  • Standardized expensive-fork JSON-RPC errors with code -32002, including the fork epoch in the response data.

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Walkthrough

Error::ExpensiveFork is changed from a unit variant to a struct variant carrying epoch: ChainEpoch. ChainConfig gains expensive_fork_between returning the lowest matching fork epoch in a half-open interval. call_raw, apply_message, eth_getCode, eth_getStorageAt, and StateCall::run are updated to use the new epoch-carrying variant, and the JSON-RPC layer maps it to error code -32002 with the epoch in the data field.

Changes

Expensive Fork Epoch Payload and ETH RPC Retry

Layer / File(s)	Summary
Error::ExpensiveFork epoch payload and ChainConfig::expensive_fork_between src/state_manager/errors.rs, src/networks/mod.rs	Error::ExpensiveFork gains epoch: ChainEpoch payload. ChainConfig adds expensive_fork_between(parent, height) -> Option<ChainEpoch> returning the minimum matching fork epoch in [parent, height), and has_expensive_fork_between delegates to it. Unit tests verify the new method on calibnet.
JSON-RPC -32002 error code and ServerError mapping src/rpc/error.rs	Adds EXPENSIVE_FORK_CODE = -32002 constant. Extends From<anyhow::Error> for ServerError to downcast ExpensiveFork { epoch } and produce a ServerError with the new code and epoch as JSON data.
call_raw expensive-fork detection src/state_manager/message_simulation.rs	Replaces parent-tipset-load + has_expensive_fork_between with a fork_floor/fork_height range derived from whether state_cid is provided, then returns Error::ExpensiveFork { epoch } when chain_config.expensive_fork_between finds a match.
ETH RPC apply_message guard, retry loops, and eth_estimateGas src/rpc/methods/eth.rs	apply_message guard switches to ts.epoch()-based check returning ExpensiveFork { epoch: ts.epoch() }. eth_getCode and get_storage_at replace iteration-based retries with loops that hold state_root fixed and rewind ts to its parent on ExpensiveFork. eth_estimateGas error path retries via apply_message to surface ExecutionReverted errors.
StateCall::run pattern match update src/rpc/methods/state.rs	Updates the ExpensiveFork match arm to Error::ExpensiveFork { .. } for the new struct variant; refines comments describing the parent→tipset window.
CHANGELOG and API filter list updates CHANGELOG.md, scripts/tests/api_compare/filter-list*	CHANGELOG documents updated refusal behavior and the -32002 error code. API comparison filter lists exclude StateGetNetworkParams, EthGetBlockByHash, EthGetBlockByNumber, and EthGetTransactionByHashLimited.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

Possibly related PRs

• ChainSafe/forest#7061: Directly modifies StateManager::call_raw in src/state_manager/message_simulation.rs to return an ExpensiveFork refusal that drives higher-level RPC retry/error behavior, the same code path updated in this PR.

Suggested reviewers

• akaladarshi
• hanabi1224

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 46.67% 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 'fix(rpc): Update expensive migration check' directly and clearly describes the main change across the PR—updating the expensive migration/fork check logic in the RPC layer.
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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• Create PR with unit tests
• Commit unit tests in branch shashank/update-expensive-migration-check

✨ Simplify code

• Create PR with simplified code
• Commit simplified code in branch shashank/update-expensive-migration-check

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🧹 Nitpick comments (1)

scripts/tests/api_compare/filter-list (1)

4-6: ⚡ Quick win

Add upstream references for new ignored RPCs.

Please add short comments (issue/PR links) next to these new exclusions to make re-enabling trackable and avoid permanent blind spots.

Suggested update

 !Filecoin.StateGetNetworkParams
 !Filecoin.EthGetBlockByHash
 !Filecoin.EthGetBlockByNumber
+# https://github.com/filecoin-project/lotus/pull/13640
+!Filecoin.StateGetNetworkParams
+# https://github.com/filecoin-project/lotus/pull/13618
+!Filecoin.EthGetBlockByHash
+!Filecoin.EthGetBlockByNumber

🤖 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 `@scripts/tests/api_compare/filter-list` around lines 4 - 6, The three newly
ignored RPC methods (Filecoin.StateGetNetworkParams, Filecoin.EthGetBlockByHash,
and Filecoin.EthGetBlockByNumber) in the filter-list file are missing upstream
reference comments. Add short comments with issue or PR links next to each of
these three exclusions to document why they are being ignored and make it
possible to track when they can be re-enabled in the future, ensuring these are
not permanently blindspotted.

🤖 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 `@scripts/tests/api_compare/filter-list`:
- Around line 4-6: The three newly ignored RPC methods
(Filecoin.StateGetNetworkParams, Filecoin.EthGetBlockByHash, and
Filecoin.EthGetBlockByNumber) in the filter-list file are missing upstream
reference comments. Add short comments with issue or PR links next to each of
these three exclusions to document why they are being ignored and make it
possible to track when they can be re-enabled in the future, ensuring these are
not permanently blindspotted.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Repository UI

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Run ID: 08983cce-b48e-4e93-87f7-acc3394e68e6

📥 Commits

Reviewing files that changed from the base of the PR and between 31d6ec3 and d065adf.

📒 Files selected for processing (7)

• scripts/devnet/.env
• scripts/tests/api_compare/filter-list
• scripts/tests/api_compare/filter-list-gateway
• scripts/tests/api_compare/filter-list-offline
• scripts/tests/bootstrapper/.env
• scripts/tests/snapshot_parity/.env
• src/rpc/methods/state.rs

🔗 Linked repositories identified

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

• filecoin-project/lotus (manual)

✅ Files skipped from review due to trivial changes (3)

• scripts/tests/snapshot_parity/.env
• scripts/tests/api_compare/filter-list-offline
• scripts/tests/bootstrapper/.env

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

• src/rpc/methods/state.rs

[codecov]

Codecov Report

❌ Patch coverage is 62.50000% with 27 lines in your changes missing coverage. Please review.
✅ Project coverage is 64.37%. Comparing base (d1cb4f8) to head (5e97c29).
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
src/rpc/methods/eth.rs	41.17%	20 Missing ⚠️
src/rpc/error.rs	33.33%	4 Missing ⚠️
src/state_manager/message_simulation.rs	66.66%	1 Missing and 2 partials ⚠️

Additional details and impacted files

Files with missing lines	Coverage Δ
src/networks/mod.rs	89.84% <100.00%> (+0.58%)	⬆️
src/rpc/methods/state.rs	44.40% <ø> (ø)
src/state_manager/errors.rs	40.00% <ø> (ø)
src/state_manager/message_simulation.rs	77.59% <66.66%> (-0.19%)	⬇️
src/rpc/error.rs	37.83% <33.33%> (-0.40%)	⬇️
src/rpc/methods/eth.rs	64.95% <41.17%> (-0.15%)	⬇️

... and 9 files with indirect coverage changes

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