ColumnTransformer with SimpleImputer fails on DataFrame input with “DataFrame object has no attribute dtype” #6183

from cuml.compose import ColumnTransformer
from cuml.preprocessing import SimpleImputer

num_imputer = SimpleImputer(strategy = 'constant', fill_value = 0)
cat_imputer = SimpleImputer(strategy = 'constant', fill_value = 'None', missing_values = pd.NA)
mode_imputer = SimpleImputer(strategy = 'most_frequent', missing_values = pd.NA)

preprocessor = ColumnTransformer(
    transformers = [
        ('num', num_imputer, num_cols_zero),
        ('cat', cat_imputer, cat_cols_none),
        ('mod', mode_imputer, cols_mode)
    ]
)

processed_data = preprocessor.fit_transform(all_data_tofill_copy)

processed_df = pd.DataFrame(processed_data, columns = num_cols_zero + cat_cols_none + cols_mode)

processed_df[num_cols_zero] = processed_df[num_cols_zero].astype('float64')
processed_df[cat_cols_none + cols_mode] = processed_df[cat_cols_none + cols_mode].astype('object')

processed_df.head() 

---------------------------------------------------------------------------
KeyError                                  Traceback (most recent call last)
File ~/.venv/lib/python3.12/site-packages/cudf/utils/utils.py:228, in GetAttrGetItemMixin.__getattr__(self, key)
    227 try:
--> 228     return self[key]
    229 except KeyError:

File ~/.venv/lib/python3.12/site-packages/cudf/utils/performance_tracking.py:51, in _performance_tracking.<locals>.wrapper(*args, **kwargs)
     44     stack.enter_context(
     45         nvtx.annotate(
     46             message=func.__qualname__,
   (...)
     49         )
     50     )
---> 51 return func(*args, **kwargs)

File ~/.venv/lib/python3.12/site-packages/cudf/core/dataframe.py:1347, in DataFrame.__getitem__(self, arg)
   1346 if _is_scalar_or_zero_d_array(arg) or isinstance(arg, tuple):
-> 1347     out = self._get_columns_by_label(arg)
   1348     if is_scalar(arg):

File ~/.venv/lib/python3.12/site-packages/cudf/utils/performance_tracking.py:51, in _performance_tracking.<locals>.wrapper(*args, **kwargs)
     44     stack.enter_context(
     45         nvtx.annotate(
     46             message=func.__qualname__,
   (...)
     49         )
     50     )
---> 51 return func(*args, **kwargs)

File ~/.venv/lib/python3.12/site-packages/cudf/core/frame.py:358, in Frame._get_columns_by_label(self, labels)
    353 """
    354 Returns columns of the Frame specified by `labels`.
    355 
    356 Akin to cudf.DataFrame(...).loc[:, labels]
    357 """
--> 358 return self._from_data_like_self(self._data.select_by_label(labels))

File ~/.venv/lib/python3.12/site-packages/cudf/core/column_accessor.py:401, in ColumnAccessor.select_by_label(self, key)
    400         return self._select_by_label_with_wildcard(key)
--> 401 return self._select_by_label_grouped(key)

File ~/.venv/lib/python3.12/site-packages/cudf/core/column_accessor.py:563, in ColumnAccessor._select_by_label_grouped(self, key)
    562 def _select_by_label_grouped(self, key: abc.Hashable) -> Self:
--> 563     result = self._grouped_data[key]
    564     if isinstance(result, column.ColumnBase):
    565         # self._grouped_data[key] = self._data[key] so skip validation

KeyError: 'dtype'

During handling of the above exception, another exception occurred:

AttributeError                            Traceback (most recent call last)
File ~/.venv/lib/python3.12/site-packages/cudf/pandas/fast_slow_proxy.py:928, in _fast_slow_function_call(func, *args, **kwargs)
    927 fast_args, fast_kwargs = _fast_arg(args), _fast_arg(kwargs)
--> 928 result = func(*fast_args, **fast_kwargs)
    929 if result is NotImplemented:
    930     # try slow path

File ~/.venv/lib/python3.12/site-packages/cudf/pandas/fast_slow_proxy.py:26, in call_operator(fn, args, kwargs)
     25 def call_operator(fn, args, kwargs):
---> 26     return fn(*args, **kwargs)

File ~/.venv/lib/python3.12/site-packages/cudf/utils/utils.py:230, in GetAttrGetItemMixin.__getattr__(self, key)
    229 except KeyError:
--> 230     raise AttributeError(
    231         f"{type(self).__name__} object has no attribute {key}"
    232     )

AttributeError: DataFrame object has no attribute dtype

During handling of the above exception, another exception occurred:

AttributeError                            Traceback (most recent call last)
Cell In[65], line 19
      9 mode_imputer = SimpleImputer(strategy = 'most_frequent', missing_values = pd.NA)
     11 preprocessor = ColumnTransformer(
     12     transformers = [
     13         ('num', num_imputer, num_cols_zero),
   (...)
     16     ]
     17 )
---> 19 processed_data = preprocessor.fit_transform(all_data_tofill_copy)
     21 processed_df = pd.DataFrame(processed_data, columns = num_cols_zero + cat_cols_none + cols_mode)
     23 processed_df[num_cols_zero] = processed_df[num_cols_zero].astype('float64')

File ~/.venv/lib/python3.12/site-packages/cuml/internals/api_decorators.py:188, in _make_decorator_function.<locals>.decorator_function.<locals>.decorator_closure.<locals>.wrapper(*args, **kwargs)
    185     set_api_output_dtype(output_dtype)
    187 if process_return:
--> 188     ret = func(*args, **kwargs)
    189 else:
    190     return func(*args, **kwargs)

File ~/.venv/lib/python3.12/site-packages/cuml/_thirdparty/sklearn/preprocessing/_column_transformer.py:894, in ColumnTransformer.fit_transform(self, X, y)
    891 self._validate_column_callables(X)
...
   6297 ):
   6298     return self[name]
-> 6299 return object.__getattribute__(self, name)

AttributeError: 'DataFrame' object has no attribute 'dtype'