backend: helm repository error handling and regression test coverage

[Athang69]

Summary

This PR fixes Helm repository/chart handler error behavior by returning early on chart-list failures, mapping repository-not-found deletes to 404, improving repository lock error handling, and adding regression tests for these paths.

Related Issue

Fixes #ISSUE_NUMBER

Changes

• Added/Updated backend Helm handler logic for safer error handling and HTTP status mapping
• Fixed a flow issue where success payload logic could continue after an error
• Added regression tests for:
  • chart list error path (no success payload on failure)
  • repository delete not-found behavior (expects 404)
  • JSON content-type behavior for list endpoints
  • repository internal behaviors via internal test coverage
• Refactored response handling to set JSON Content-Type before writing status for JSON responses
• Increased backend Helm package test coverage from 21.4% to 22.6% (+1.2 percentage points)

Steps to Test

1. From repository root, run:
   • cd backend
   • golangci-lint run ./pkg/helm/...
   • go build ./pkg/helm/...
   • go test ./pkg/helm/... -count=1
2. Verify coverage on feature branch:
   • go test ./pkg/helm -coverprofile=/tmp/helm-after.out -count=1
   • go tool cover -func=/tmp/helm-after.out | tail -n 1
3. (Optional baseline) Compare with main:
   • git checkout main
   • go test ./pkg/helm -coverprofile=/tmp/helm-before.out -count=1
   • go tool cover -func=/tmp/helm-before.out | tail -n 1
   • git checkout backend/helm-repo-error-handling-tests

Notes for the Reviewer

• Scope is intentionally limited to backend Helm package.
• No frontend tests/builds were run.
• Coverage delta is +1.2 percentage points for backend/pkg/helm.

[Copilot]

Pull request overview

This PR tightens backend Helm HTTP handler behavior by preventing success responses after error paths, mapping repository delete “not found” to HTTP 404, and adding regression tests to lock in the intended semantics.

Changes:

• Ensure chart listing returns immediately after an error (no success payload written after http.Error).
• Return 404 for attempts to delete a non-existent Helm repository, backed by an internal error sentinel.
• Set Content-Type: application/json before writing status codes for JSON list endpoints and add regression tests for these cases.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
backend/pkg/helm/repository.go	Adds errRepositoryNotFound, improves lock error handling, fixes JSON header ordering, and maps repo delete not-found to 404.
backend/pkg/helm/charts.go	Returns early on chart list errors and fixes JSON header ordering.
backend/pkg/helm/repository_test.go	Adds handler-level regression tests for delete-not-found (404) and JSON content-type.
backend/pkg/helm/repository_internal_test.go	Adds internal test coverage for RemoveRepository returning the not-found sentinel error.
backend/pkg/helm/charts_test.go	Adds regression test ensuring error responses don’t include a success payload for chart listing.

[Copilot]

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated 3 comments.

[Copilot]

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

[Athang69]

@sniok @skoeva @illume, I’d appreciate your review on this PR
Thanks

[yolossn]

@Athang69 Solid PR, thanks

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: Athang69, yolossn

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• OWNERS [yolossn]

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[yolossn]

/lgtm

[Athang69]

Thanks for review @yolossn