Openapi change impact report

Build OpenAPI Change Impact Report

1. Gather Inputs

1. Require a baseline OpenAPI or Swagger source.
2. Require a current OpenAPI or Swagger source.
3. Require docs/testing/test-mapping-report.md when test-impact mapping is needed.

2. Choose The Files

1. Prefer docs/testing/openapi-change-impact-report.md.
2. When the user wants a human-friendly report, also generate docs/testing/html/openapi-change-impact-report.html.

3. Build The Comparison

1. Compare operation existence first.
2. Compare operation metadata second: tags, summary, security, parameters, request body, and response codes.
3. Classify each difference as Added, Removed, Breaking change, Non-breaking change, or No change.
4. When a traceability report exists, map changed operations back to affected tests and documentation references.
5. Keep the report useful even when there is no change.

4. Output Shape

1. Start from openapi-change-impact-report-template.md.
2. Keep the exact section headings stable.
3. Run python scripts/generate_openapi_change_impact_report.py --baseline <baseline> --current <current> --mapping <mapping-md> --output-md <impact-md> --output-html <impact-html>.

5. Keep It Actionable

1. Explain which changed operations need test updates first.
2. Separate breaking changes from additive changes.
3. Update the session-state artifact after generating or changing the report.

6. Examples

1. Input: Show what changed between these two OpenAPI files and which tests are affected. Output: Create docs/testing/openapi-change-impact-report.md and the paired HTML report.
2. Input: Compare the live contract to the repo contract. Output: Produce a change-impact report, even if the final result is No change.

7. Troubleshooting

1. Problem: The two sources use different file formats. Fix: Normalize both sources before comparison; YAML vs JSON is not itself a change.
2. Problem: There are no contract changes. Fix: Still generate the report and state No change explicitly.