feat(evmrpc): configurable batch request limit and batch response size

[amir-deris]

Describe your changes and provide context

Adds two new EVM JSON-RPC config fields to bound the size of batched JSON-RPC calls (PLT-703):

• evm.batch_request_limit — maximum number of requests allowed in a single JSON-RPC batch. Default 1000.
• evm.batch_response_max_size — maximum number of bytes returned from a batched JSON-RPC call. Default 25MB (25 * 1000 * 1000).

Both apply to HTTP and WebSocket endpoints, and both can be set to 0 to disable the limit. The values are wired through to go-ethereum's batchItemLimit / batchResponseSizeLimit on the HTTP and WebSocket server configs in evmrpc/server.go.

Changes:

• evmrpc/config/config.go — new Config fields, defaults, flag names, ReadConfig parsing, and app.toml template entries with documentation.
• evmrpc/server.go — populate batchItemLimit / batchResponseSizeLimit for both the HTTP and WebSocket servers.

Testing performed to validate your change

• evmrpc/config/config_test.go:
  • Added bad-type cases to TestReadConfig for both new fields.
  • Added TestReadConfigBatchLimits covering defaults flowing through and custom values (including 0 to disable) being parsed.
• go test ./evmrpc/config/...

[cursor]

PR Summary

Low Risk
Operational RPC hardening with conservative defaults; misconfiguration could reject large batches but does not change consensus or auth paths.

Overview
Adds configurable caps on JSON-RPC batch traffic for EVM HTTP and WebSocket: evm.batch_request_limit (default 1000 sub-requests per batch) and evm.batch_response_max_size (default 25MB). Either can be set to 0 to turn the limit off.

New fields are defined on EVM RPC config with app.toml template/docs, loaded via ReadConfig, and passed into go-ethereum’s SetBatchLimits through batchItemLimit / batchResponseSizeLimit on both HTTP and WS server setup in server.go.

Config tests cover bad types, defaults when unset, and custom values including 0 to disable.

^{Reviewed by Cursor Bugbot for commit a1ed39b. Bugbot is set up for automated code reviews on this repo. Configure here.}

[github-actions]

The latest Buf updates on your PR. Results from workflow Buf / buf (pull_request).

Build	Format	Lint	Breaking	Updated (UTC)
✅ passed	✅ passed	✅ passed	✅ passed	Jun 24, 2026, 4:35 PM

[codecov]

Codecov Report

❌ Patch coverage is 91.66667% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 58.15%. Comparing base (197fe21) to head (a1ed39b).

Files with missing lines	Patch %	Lines
evmrpc/server.go	83.33%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3636      +/-   ##
==========================================
- Coverage   59.03%   58.15%   -0.88%     
==========================================
  Files        2252     2176      -76     
  Lines      185682   176902    -8780     
==========================================
- Hits       109625   102885    -6740     
+ Misses      66248    64930    -1318     
+ Partials     9809     9087     -722     

Flag	Coverage Δ
sei-chain-pr	67.50% <91.66%> (?)
sei-db	70.41% <ø> (ø)
sei-db-state-db	?

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
evmrpc/config/config.go	72.93% <100.00%> (+1.96%)	⬆️
evmrpc/server.go	88.78% <83.33%> (+0.26%)	⬆️

... and 78 files with indirect coverage changes

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