Harden transport error payload stringification

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

Author: cursoragent

hyperbrowser/transport/error_utils.py

@@ -45,6 +45,13 @@
 }
 
 
+def _safe_to_string(value: Any) -> str:
+    try:
+        return str(value)
+    except Exception:
+        return f"<unstringifiable {type(value).__name__}>"
+
+
 def _normalize_request_method(method: Any) -> str:
     raw_method = method
     if isinstance(raw_method, bool):
@@ -121,7 +128,7 @@ def _truncate_error_message(message: str) -> str:
 
 def _stringify_error_value(value: Any, *, _depth: int = 0) -> str:
     if _depth > 10:
-        return str(value)
+        return _safe_to_string(value)
     if isinstance(value, str):
         return value
     if isinstance(value, dict):
@@ -152,7 +159,7 @@ def _stringify_error_value(value: Any, *, _depth: int = 0) -> str:
     try:
         return json.dumps(value, sort_keys=True)
     except (TypeError, ValueError, RecursionError):
-        return str(value)
+        return _safe_to_string(value)
 
 
 def extract_error_message(response: httpx.Response, fallback_error: Exception) -> str:

tests/test_transport_error_utils.py

@@ -143,6 +143,11 @@ def json(self):
         return self._json_value
 
 
+class _UnstringifiableErrorValue:
+    def __str__(self) -> str:
+        raise RuntimeError("cannot stringify error value")
+
+
 def test_extract_request_error_context_uses_unknown_when_request_unset():
     method, url = extract_request_error_context(httpx.RequestError("network down"))
 
@@ -631,6 +636,15 @@ def test_extract_error_message_handles_recursive_dict_payloads():
     assert message
 
 
+def test_extract_error_message_handles_unstringifiable_message_values():
+    message = extract_error_message(
+        _DummyResponse({"message": _UnstringifiableErrorValue()}),
+        RuntimeError("fallback detail"),
+    )
+
+    assert message == "<unstringifiable _UnstringifiableErrorValue>"
+
+
 def test_extract_error_message_uses_fallback_for_blank_dict_message():
     message = extract_error_message(
         _DummyResponse({"message": "   "}), RuntimeError("fallback detail")