core/validatorapi: optional committee index param

[KaloyanTanev]

Make the deprecated committee_index query parameter optional on GET /eth/v1/validator/attestation_data, defaulting to 0 — post-gloas spec-compliant validator clients omit it and previously got a 400. Charon's own outgoing requests keep setting it for backwards compatibility with pre-electra forks, with comments noting post-electra beacon nodes ignore it.

category: feature
ticket: #4324

[Copilot]

Pull request overview

Fixes compatibility with post-gloas spec-compliant validator clients by making the deprecated committee_index query parameter optional on Charon’s GET /eth/v1/validator/attestation_data endpoint (defaulting to 0), preventing erroneous 400 responses when the parameter is omitted.

Changes:

• Default committee_index to 0 when omitted on GET /eth/v1/validator/attestation_data.
• Add a router test that asserts the endpoint succeeds without committee_index and passes CommitteeIndex=0 to the provider.
• Add/extend comments documenting why Charon still sets committee_index in outbound BN requests for backwards compatibility.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
core/validatorapi/router.go	Makes committee_index optional and defaults to 0 when absent for attestation data requests.
core/validatorapi/router_internal_test.go	Adds coverage verifying the route works when committee_index is omitted and defaults to 0.
core/fetcher/fetcher.go	Documents continued inclusion of committee index in BN attestation_data requests for backwards compatibility.
testutil/validatormock/attest.go	Documents continued inclusion of committee index in mock VC → BN attestation_data requests for backwards compatibility.

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[Copilot]

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[Copilot]

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated no new comments.

[codecov]

Codecov Report

❌ Patch coverage is 60.00000% with 2 lines in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (gloas@c02d596). Learn more about missing BASE report.

Files with missing lines	Patch %	Lines
core/validatorapi/router.go	60.00%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@           Coverage Diff            @@
##             gloas    #4672   +/-   ##
========================================
  Coverage         ?   58.82%           
========================================
  Files            ?      246           
  Lines            ?    34887           
  Branches         ?        0           
========================================
  Hits             ?    20523           
  Misses           ?    11807           
  Partials         ?     2557           

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