BUG: fix index validation in algos.take (#27079)

Author: jbrockmendel

pandas/core/algorithms.py

@@ -1526,7 +1526,7 @@ def take(arr, indices, axis=0, allow_fill=False, fill_value=None):
 
     if allow_fill:
         # Pandas style, -1 means NA
-        validate_indices(indices, len(arr))
+        validate_indices(indices, arr.shape[axis])
         result = take_1d(arr, indices, axis=axis, allow_fill=True,
                          fill_value=fill_value)
     else:

pandas/core/arrays/sparse.py

@@ -1868,15 +1868,6 @@ def _maybe_to_dense(obj):
     return obj
 
 
-def _maybe_to_sparse(array):
-    """
-    array must be SparseSeries or SparseArray
-    """
-    if isinstance(array, ABCSparseSeries):
-        array = array.array.copy()
-    return array
-
-
 def make_sparse(arr, kind='block', fill_value=None, dtype=None, copy=False):
     """
     Convert ndarray to sparse format

pandas/tests/test_take.py

@@ -420,6 +420,11 @@ def test_take_axis_1(self):
         expected = np.array([[0, 0], [3, 0], [6, 0], [9, 0]])
         tm.assert_numpy_array_equal(result, expected)
 
+        # GH#26976 make sure we validate along the correct axis
+        with pytest.raises(IndexError, match="indices are out-of-bounds"):
+            algos.take(arr, [0, 3], axis=1, allow_fill=True,
+                       fill_value=0)
+
 
 class TestExtensionTake:
     # The take method found in pd.api.extensions