Pin copy.copy and copy.deepcopy guards on dbapi reject classes

The existing pickle-guard test pins ``pickle.dumps`` rejection on
Connection / Cursor / AsyncConnection / AsyncCursor — but copy.copy
and copy.deepcopy are independent surfaces that route through
__reduce_ex__ → __reduce__ as well. Today they pass through to the
same TypeError because the rejection lives on __reduce__, but a
future regression that adds a __copy__ / __deepcopy__ hook would
silently produce a broken duplicate of a class that holds live
transports / asyncio locks.

Pin both copy paths explicitly. Mirrors the SA-adapter and client-
layer pin shape established by prior cycles.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: antoineleclair

tests/test_pickle_guard.py

@@ -47,3 +47,34 @@ def test_connection_error_message_names_actionable_alternative(self) -> None:
         with pytest.raises(TypeError) as excinfo:
             pickle.dumps(conn)
         assert "consumer process" in str(excinfo.value)
+
+
+class TestCopyGuard:
+    """Sibling pin for ``copy.copy`` / ``copy.deepcopy``.
+
+    ``copy.copy(c)`` and ``copy.deepcopy(c)`` route through
+    ``__reduce_ex__`` → ``__reduce__`` (the same path pickle uses), so
+    a class that rejects pickle also rejects copy. Pin both copy paths
+    explicitly — without these, a regression that tightens
+    ``__reduce__`` to refuse pickle but accepts copy via a separate
+    ``__copy__`` / ``__deepcopy__`` hook would silently succeed and
+    produce a broken duplicate of a class that holds live transports
+    / asyncio locks. Mirrors the SA-adapter and client-layer pin
+    shape established by prior cycles.
+    """
+
+    @pytest.mark.parametrize("cls", [Connection, Cursor, AsyncConnection, AsyncCursor])
+    def test_copy_copy_refuses_with_clear_error(self, cls: type) -> None:
+        import copy
+
+        instance = cls.__new__(cls)  # type: ignore[call-overload]
+        with pytest.raises(TypeError, match=f"cannot pickle '{cls.__name__}'"):
+            copy.copy(instance)
+
+    @pytest.mark.parametrize("cls", [Connection, Cursor, AsyncConnection, AsyncCursor])
+    def test_copy_deepcopy_refuses_with_clear_error(self, cls: type) -> None:
+        import copy
+
+        instance = cls.__new__(cls)  # type: ignore[call-overload]
+        with pytest.raises(TypeError, match=f"cannot pickle '{cls.__name__}'"):
+            copy.deepcopy(instance)