Add a developer check for proxy objects

docs/cudf/source/developer_guide/cudf_pandas.md

@@ -20,6 +20,7 @@ The "wrapped" types/classes are the Pandas and cuDF specific types that have bee
 Wrapped objects and proxy objects are instances of wrapped types and proxy types, respectively.
 In the snippet below `s1` and `s2` are wrapped objects and `s3` is a fast-slow proxy object.
 Also note that the module `xpd` is a wrapped module and contains cuDF and Pandas modules as attributes.
+To check if an object is a proxy type, we can use `cudf.pandas.is_proxy_object`.
   ```python
   import cudf.pandas
   cudf.pandas.install()
@@ -31,6 +32,14 @@ Also note that the module `xpd` is a wrapped module and contains cuDF and Pandas
   s1 = cudf.Series([1,2])
   s2 = pd.Series([1,2])
   s3 = xpd.Series([1,2])
+
+  from cudf.pandas import is_proxy_object
+
+  is_proxy_object(s1) # returns False
+
+  is_proxy_object(s2) # returns False
+
+  is_proxy_object(s3) # returns True
   ```
 
 ```{note}

python/cudf/cudf/pandas/__init__.py

@@ -1,11 +1,12 @@
-# SPDX-FileCopyrightText: Copyright (c) 2023 NVIDIA CORPORATION & AFFILIATES.
+# SPDX-FileCopyrightText: Copyright (c) 2023-2024, NVIDIA CORPORATION & AFFILIATES.
 # All rights reserved.
 # SPDX-License-Identifier: Apache-2.0
 
+from .fast_slow_proxy import is_proxy_object
 from .magics import load_ipython_extension
 from .profiler import Profiler
 
-__all__ = ["Profiler", "load_ipython_extension", "install"]
+__all__ = ["Profiler", "load_ipython_extension", "install", "is_proxy_object"]
 
 
 LOADED = False

python/cudf/cudf/pandas/fast_slow_proxy.py

@@ -1185,6 +1185,20 @@ def _replace_closurevars(
     )
 
 
+def is_proxy_object(obj: Any) -> bool:
+    """Determine if an object is proxy object
+
+    Parameters
+    ----------
+    obj : object
+        Any python object.
+
+    """
+    if _FastSlowProxyMeta in type(type(obj)).__mro__:
+        return True
+    return False
+
+
 NUMPY_TYPES: Set[str] = set(np.sctypeDict.values())
 
 

python/cudf/cudf_pandas_tests/test_cudf_pandas.py

@@ -20,7 +20,7 @@
 from pytz import utc
 
 from cudf.pandas import LOADED, Profiler
-from cudf.pandas.fast_slow_proxy import _Unusable
+from cudf.pandas.fast_slow_proxy import _Unusable, is_proxy_object
 
 if not LOADED:
     raise ImportError("These tests must be run with cudf.pandas loaded")
@@ -1488,3 +1488,17 @@ def mock_mean_none(self, *args, **kwargs):
 
 def test_excelwriter_pathlike():
     assert isinstance(pd.ExcelWriter("foo.xlsx"), os.PathLike)
+
+
+def test_is_proxy_object():
+    np_arr = np.array([1])
+
+    s1 = xpd.Series([1])
+    s2 = pd.Series([1])
+
+    np_arr_proxy = s1.to_numpy()
+
+    assert not is_proxy_object(np_arr)
+    assert is_proxy_object(np_arr_proxy)
+    assert is_proxy_object(s1)
+    assert not is_proxy_object(s2)