Harden transport fallback message extraction

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

Author: cursoragent

hyperbrowser/transport/error_utils.py

@@ -164,10 +164,13 @@ def _stringify_error_value(value: Any, *, _depth: int = 0) -> str:
 
 def extract_error_message(response: httpx.Response, fallback_error: Exception) -> str:
     def _fallback_message() -> str:
-        response_text = response.text
+        try:
+            response_text = response.text
+        except Exception:
+            response_text = ""
         if isinstance(response_text, str) and response_text.strip():
             return _truncate_error_message(response_text)
-        return _truncate_error_message(str(fallback_error))
+        return _truncate_error_message(_safe_to_string(fallback_error))
 
     try:
         error_data: Any = response.json()

tests/test_transport_error_utils.py

@@ -148,6 +148,20 @@ def __str__(self) -> str:
         raise RuntimeError("cannot stringify error value")
 
 
+class _UnstringifiableFallbackError(Exception):
+    def __str__(self) -> str:
+        raise RuntimeError("cannot stringify fallback error")
+
+
+class _BrokenFallbackResponse:
+    @property
+    def text(self) -> str:
+        raise RuntimeError("cannot read response text")
+
+    def json(self):
+        raise ValueError("invalid json")
+
+
 def test_extract_request_error_context_uses_unknown_when_request_unset():
     method, url = extract_request_error_context(httpx.RequestError("network down"))
 
@@ -671,6 +685,14 @@ def test_extract_error_message_uses_fallback_error_when_response_text_is_blank()
     assert message == "fallback detail"
 
 
+def test_extract_error_message_handles_broken_fallback_response_text():
+    message = extract_error_message(
+        _BrokenFallbackResponse(), _UnstringifiableFallbackError()
+    )
+
+    assert message == "<unstringifiable _UnstringifiableFallbackError>"
+
+
 def test_extract_error_message_extracts_errors_list_messages():
     message = extract_error_message(
         _DummyResponse({"errors": [{"msg": "first issue"}, {"msg": "second issue"}]}),