Fix HTTP redirect handling in urllib instrumentation REPLAY mode

When urllib follows redirects, response.geturl() should return the final
URL after all redirects. The instrumentation now:

- Captures finalUrl in RECORD mode when it differs from request URL
- Uses finalUrl in REPLAY mode so MockHTTPResponse.geturl() returns
  the correct final URL instead of the original request URL

This ensures application code that checks the final URL after redirects
behaves the same in RECORD and REPLAY modes.

Author: sohankshirsagar

drift/instrumentation/urllib/instrumentation.py

@@ -756,7 +756,7 @@ def _create_mock_response(self, mock_data: dict[str, Any], url: str) -> MockHTTP
 
         Args:
             mock_data: Mock response data from CLI
-            url: Request URL
+            url: Request URL (original request URL)
 
         Returns:
             MockHTTPResponse object
@@ -765,6 +765,10 @@ def _create_mock_response(self, mock_data: dict[str, Any], url: str) -> MockHTTP
         reason = mock_data.get("statusMessage", "OK")
         headers = dict(mock_data.get("headers", {}))
 
+        # Use finalUrl from recorded response if present (indicates redirect occurred)
+        # Otherwise fall back to the original request URL
+        response_url = mock_data.get("finalUrl", url)
+
         # Remove content-encoding and transfer-encoding headers since the body
         # was already decompressed when recorded
         headers_to_remove = []
@@ -792,13 +796,13 @@ def _create_mock_response(self, mock_data: dict[str, Any], url: str) -> MockHTTP
         else:
             body_bytes = json.dumps(body).encode("utf-8")
 
-        logger.debug(f"Created mock response: {status_code} for {url}")
+        logger.debug(f"Created mock response: {status_code} for {response_url}")
         return MockHTTPResponse(
             status_code=status_code,
             reason=reason,
             headers=headers,
             body=body_bytes,
-            url=url,
+            url=response_url,
         )
 
     def _raise_http_error_from_mock(self, mock_data: dict[str, Any], url: str) -> None:
@@ -943,12 +947,23 @@ def _finalize_span(
                     response_body_base64 = None
                     response_body_size = 0
 
+                # Capture final URL (important for redirect scenarios)
+                # urllib sets response.url to the final URL after all redirects
+                final_url = getattr(response, "url", None)
+                if callable(final_url):
+                    # Some response objects have geturl() method
+                    final_url = final_url()
+
                 output_value = {
                     "statusCode": response_status,
                     "statusMessage": response_reason,
                     "headers": response_headers,
                 }
 
+                # Store final URL if different from request URL (indicates redirect)
+                if final_url and final_url != url:
+                    output_value["finalUrl"] = final_url
+
                 # Add body fields only if body exists
                 if response_body_base64 is not None:
                     output_value["body"] = response_body_base64