Assorted fixes

Author: WillAyd

pandas/_libs/index.pyx

@@ -140,7 +140,7 @@ cdef class IndexEngine:
 
     cdef readonly:
         ndarray values
-        ndarray mask
+        object mask
         HashTable mapping
         bint over_size_threshold
 

pandas/core/algorithms.py

@@ -16,6 +16,7 @@
 import warnings
 
 import numpy as np
+from pandas_mask import PandasMaskArray
 
 from pandas._libs import (
     algos,
@@ -1173,6 +1174,8 @@ def take(
     ... )
     array([ 10,  10, -10])
     """
+    if isinstance(arr, PandasMaskArray):  # TODO: implement take directly on mask
+        arr = np.array(arr)
     if not isinstance(
         arr,
         (np.ndarray, ABCExtensionArray, ABCIndex, ABCSeries, ABCNumpyExtensionArray),

pandas/core/groupby/ops.py

@@ -324,7 +324,7 @@ def _cython_op_ndim_compat(
             # expand to 2d, dispatch, then squeeze if appropriate
             values2d = values[None, :]
             if mask is not None:
-                mask = mask[None, :]
+                mask = np.array(mask)[None, :]
             if result_mask is not None:
                 result_mask = result_mask[None, :]
             res = self._call_cython_op(