[Hardik K (hardikkaurani)]

Description

This PR brings HeadersInspectionHandler into full alignment with the middleware patterns and error handling across Kiota HTTP:

1. Null Request Check:
   Validates if request is None: raise TypeError("request cannot be null") matching BodyInspectionHandler, preventing an unexpected AttributeError on invalid requests.
2. Span Lifecycle & Timing:
   Keeps the observability span open over the downstream super().send(request, transport) call and ensures span.end() is invoked within a try ... finally block (mirroring the fix in UrlReplaceHandler and BodyInspectionHandler), ensuring correct timing and preventing dropped spans on transport failures.
3. Per-Request Options Clearing:
   Clears captured request and response headers on each call on whichever option object is active (current_options), preventing headers from previous requests or retry attempts from accumulating when passing custom HeadersInspectionHandlerOption per request.
4. Preserve Multi-Valued Headers:
   Uses request.headers.get_list(header) and response.headers.get_list(header) when feeding into HeadersCollection.add, accurately preserving discrete multi-valued headers (e.g. multiple cookies or accepts) without comma concatenation.

Testing

Added comprehensive unit tests in packages/http/httpx/tests/middleware_tests/test_headers_inspection_handler.py:

• test_send_request_none_raises_type_error
• test_headers_inspection_handler_request_options_isolation_and_clearing
• test_headers_inspection_handler_multi_valued_headers
• test_span_ends_on_transport_failure

cc Vincent Biret (@baywet)

[Copilot]

Copilot was unable to review this pull request because the user who requested the review has reached their quota limit.

[Hardik K (hardikkaurani)]

Hi Vincent Biret (@baywet), I've created this PR to resolve the span lifecycle, per-request option isolation, multi-valued header preservation, and null checks for HeadersInspectionHandler, complete with comprehensive regression unit tests. Ready for your review whenever convenient!

[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