Prefer non-blank transport error keys before fallback

Co-authored-by: Shri Sukhani <shrisukhani@users.noreply.github.com>

Author: cursoragent

hyperbrowser/transport/error_utils.py

@@ -48,8 +48,10 @@ def _fallback_message() -> str:
         for key in ("message", "error", "detail", "errors"):
             message = error_data.get(key)
             if message is not None:
-                extracted_message = _stringify_error_value(message)
-                break
+                candidate_message = _stringify_error_value(message)
+                if candidate_message.strip():
+                    extracted_message = candidate_message
+                    break
         else:
             extracted_message = _stringify_error_value(error_data)
     elif isinstance(error_data, str):

tests/test_transport_error_utils.py

@@ -160,3 +160,12 @@ def test_extract_error_message_extracts_errors_list_messages():
     )
 
     assert message == "first issue; second issue"
+
+
+def test_extract_error_message_skips_blank_message_and_uses_detail():
+    message = extract_error_message(
+        _DummyResponse({"message": "   ", "detail": "useful detail"}),
+        RuntimeError("fallback detail"),
+    )
+
+    assert message == "useful detail"