Normalize transport error text from string subclasses

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

Author: cursoragent

hyperbrowser/transport/error_utils.py

@@ -51,13 +51,15 @@ def _safe_to_string(value: Any) -> str:
         normalized_value = str(value)
     except Exception:
         return f"<unstringifiable {type(value).__name__}>"
-    if not isinstance(normalized_value, str):
+    if type(normalized_value) is not str:
         return f"<{type(value).__name__}>"
     try:
         sanitized_value = "".join(
             "?" if ord(character) < 32 or ord(character) == 127 else character
             for character in normalized_value
         )
+        if type(sanitized_value) is not str:
+            return f"<{type(value).__name__}>"
         if sanitized_value.strip():
             return sanitized_value
     except Exception:
@@ -189,7 +191,13 @@ def _truncate_error_message(message: str) -> str:
 
 def _normalize_response_text_for_error_message(response_text: Any) -> str:
     if isinstance(response_text, str):
-        return response_text
+        try:
+            normalized_response_text = "".join(character for character in response_text)
+            if type(normalized_response_text) is not str:
+                raise TypeError("normalized response text must be a string")
+            return normalized_response_text
+        except Exception:
+            return _safe_to_string(response_text)
     if isinstance(response_text, (bytes, bytearray, memoryview)):
         try:
             return memoryview(response_text).tobytes().decode("utf-8")
@@ -202,7 +210,13 @@ def _stringify_error_value(value: Any, *, _depth: int = 0) -> str:
     if _depth > 10:
         return _safe_to_string(value)
     if isinstance(value, str):
-        return value
+        try:
+            normalized_value = "".join(character for character in value)
+            if type(normalized_value) is not str:
+                raise TypeError("normalized error value must be a string")
+            return normalized_value
+        except Exception:
+            return _safe_to_string(value)
     if isinstance(value, Mapping):
         for key in ("message", "error", "detail", "errors", "msg", "title", "reason"):
             try:

tests/test_transport_error_utils.py

@@ -304,6 +304,18 @@ def __str__(self) -> str:
         return self._BrokenString("broken\tfallback\nvalue")
 
 
+class _StringifiesToStringSubclass:
+    class _StringSubclass(str):
+        pass
+
+    def __str__(self) -> str:
+        return self._StringSubclass("subclass fallback value")
+
+
+class _MessageStringSubclass(str):
+    pass
+
+
 def test_extract_request_error_context_uses_unknown_when_request_unset():
     method, url = extract_request_error_context(httpx.RequestError("network down"))
 
@@ -972,31 +984,31 @@ def test_extract_error_message_sanitizes_control_characters_in_fallback_error_te
     assert message == "bad?fallback?text"
 
 
-def test_extract_error_message_falls_back_when_message_strip_fails():
+def test_extract_error_message_normalizes_message_values_when_strip_fails():
     message = extract_error_message(
         _DummyResponse({"message": _BrokenStripString("broken message")}),
         RuntimeError("fallback detail"),
     )
 
-    assert message == "fallback detail"
+    assert message == "broken message"
 
 
-def test_extract_error_message_falls_back_when_message_length_check_fails():
+def test_extract_error_message_normalizes_message_values_when_length_check_fails():
     message = extract_error_message(
         _DummyResponse({"message": _BrokenLenString("broken message")}),
         RuntimeError("fallback detail"),
     )
 
-    assert message == "fallback detail"
+    assert message == "broken message"
 
 
-def test_extract_error_message_falls_back_when_response_text_strip_fails():
+def test_extract_error_message_normalizes_response_text_values_when_strip_fails():
     message = extract_error_message(
         _DummyResponse("   ", text=_BrokenStripString("response body")),
         RuntimeError("fallback detail"),
     )
 
-    assert message == "fallback detail"
+    assert message == "response body"
 
 
 def test_extract_error_message_handles_response_text_sanitization_iteration_failures():
@@ -1033,6 +1045,24 @@ def test_extract_error_message_handles_fallback_errors_with_broken_string_subcla
     assert message == "<_StringifiesToBrokenSubclass>"
 
 
+def test_extract_error_message_handles_fallback_errors_with_string_subclass_results():
+    message = extract_error_message(
+        _DummyResponse("   ", text="   "),
+        _StringifiesToStringSubclass(),
+    )
+
+    assert message == "<_StringifiesToStringSubclass>"
+
+
+def test_extract_error_message_normalizes_string_subclass_message_values():
+    message = extract_error_message(
+        _DummyResponse({"message": _MessageStringSubclass("detail from subclass")}),
+        RuntimeError("fallback detail"),
+    )
+
+    assert message == "detail from subclass"
+
+
 def test_extract_error_message_sanitizes_control_characters_in_json_message():
     message = extract_error_message(
         _DummyResponse({"message": "bad\tjson\nmessage"}),