Fix RuntimeError when checking httpx.Response.request property

- Replace unsafe hasattr(response, 'request') check with safe _request attribute check
- httpx.Response.request is a property that raises RuntimeError when _request is None
- Check private _request attribute directly to avoid triggering property getter
- Use minimal error response when response is None, not httpx.Response, or lacks _request
- Fixes test_context_window_exceeded_error_from_litellm_proxy test failure

litellm/exceptions.py

@@ -142,18 +142,17 @@ class BadRequestError(openai.BadRequestError):  # type: ignore
         self.litellm_debug_info = litellm_debug_info
         self.max_retries = max_retries
         self.num_retries = num_retries
+        # Use response if it's a valid httpx.Response with a request, otherwise use minimal error response
+        # Note: We check _request (not .request property) to avoid RuntimeError when _request is None
         if (
             response is not None
             and isinstance(response, httpx.Response)
+            and hasattr(response, "_request")
+            and getattr(response, "_request", None) is not None
         ):
-            # Check if response has a request attribute safely
-            # httpx.Response.request is a property that raises RuntimeError if _request is None
-            # We check the private _request attribute to avoid triggering the property getter
-            if hasattr(response, "_request") and getattr(response, "_request", None) is not None:
-                self.response = response
-            else:
-                # Response doesn't have a valid request, use minimal error response
-                self.response = _get_minimal_error_response()
+            self.response = response
+        else:
+            self.response = _get_minimal_error_response()
         super().__init__(
             self.message, response=self.response, body=body
         )  # Call the base class constructor with the parameters it needs