fix: shallow copy issue of ConjureHTTPError (#167)

Author: psyclaudeZ

conjure_python_client/_http/requests_client.py

@@ -294,6 +294,31 @@ def __init__(self, http_error: HTTPError) -> None:
             message, request=http_error.request, response=http_error.response
         )
 
+    def __copy__(self):
+        """The fact that ConjureHTTPError is a BaseException but its __init__
+        has a different signature causes a subtle issue for shallow copying.
+        During copy.copy(), __init__ will be called with args defined by
+        BaseException.__reduce_, which corresponds to default __init__. Since
+        they're inconsistent, what http_error receives is actually message,
+        hence an error.
+
+        By defining a __copy__ method, we give instructions to the intepreter
+        on how to reconstruct a ConjureHTTPError instance. Alternatively, we
+        could also fix it by changing the _init__ signature of this class.
+        Although cleaner, unfortunately it will be a breaking change.
+        """
+
+        # Create a shell object without calling __init__
+        new_obj = type(self).__new__(type(self))
+
+        for attr, value in self.__dict__.items():
+            setattr(new_obj, attr, value)
+
+        # Exception args are not actually a part of __dict__...
+        new_obj.args = self.args
+
+        return new_obj
+
     @property
     def cause(self) -> Optional[HTTPError]:
         """The wrapped ``HTTPError`` that was the direct cause of

test/_http/test_requests_client.py

@@ -1,11 +1,14 @@
+import copy
 import pickle
 import sys
 
 from conjure_python_client._http.requests_client import (
+    ConjureHTTPError,
     SOCKET_KEEP_ALIVE,
     SOCKET_KEEP_INTVL,
     TransportAdapter,
 )
+from requests.exceptions import HTTPError
 
 if sys.platform != "darwin":
     from conjure_python_client._http.requests_client import SOCKET_KEEP_IDLE
@@ -58,3 +61,19 @@ def test_transport_adapter_can_be_unpickled_from_old_pickle():
     }
     adapter = pickle.loads(pickle.dumps(TransportAdapter()))
     assert adapter._enable_keep_alive is False
+
+def test_shallow_copying_conjure_http_error():
+    class MockResponse:
+        def __init__(self):
+            self.headers = {"X-B3-TraceId": "test"}
+
+        def json(self):
+            return {}
+
+    response = MockResponse()
+    http_error = HTTPError("HTTP 500 Server Error", response=response)
+    original_error = ConjureHTTPError(http_error)
+
+    copied_error = copy.copy(original_error)
+    assert type(original_error) is type(copied_error)
+    assert str(original_error) == str(copied_error)