allow list-length-1-with-slice corner case

Author: jorisvandenbossche

pandas/core/arrays/datetimelike.py

@@ -518,14 +518,18 @@ def __getitem__(self, key):
             return type(self)(val, dtype=self.dtype)
 
         if com.is_bool_indexer(key):
-            # first check for boolean, because check_array_indexer doesn't
+            # first convert to boolean, because check_array_indexer doesn't
             # allow object dtype
             key = np.asarray(key, dtype=bool)
             key = check_array_indexer(self, key)
             if key.all():
                 key = slice(0, None, None)
             else:
                 key = lib.maybe_booleans_to_slice(key.view(np.uint8))
+        elif isinstance(key, list) and len(key) == 1 and isinstance(key[0], slice):
+            # see https://github.com/pandas-dev/pandas/issues/31299, need to allow
+            # this for now (would otherwise raise in check_array_indexer)
+            pass
         elif is_list_like(key) and not isinstance(key, tuple):
             key = check_array_indexer(self, key)
 

pandas/core/arrays/interval.py

@@ -496,7 +496,7 @@ def __len__(self) -> int:
         return len(self.left)
 
     def __getitem__(self, value):
-        if is_list_like(value):
+        if is_list_like(value) and not isinstance(value, tuple):
             value = check_array_indexer(self, value)
         left = self.left[value]
         right = self.right[value]

pandas/core/arrays/masked.py

@@ -39,7 +39,7 @@ def __getitem__(self, item):
                 return self.dtype.na_value
             return self._data[item]
 
-        elif is_list_like(item):
+        elif is_list_like(item) and not isinstance(item, tuple):
             item = check_array_indexer(self, item)
 
         return type(self)(self._data[item], self._mask[item])

pandas/core/arrays/numpy_.py

@@ -234,7 +234,7 @@ def __getitem__(self, item):
         if isinstance(item, type(self)):
             item = item._ndarray
 
-        elif is_list_like(item):
+        elif is_list_like(item) and not isinstance(item, tuple):
             item = check_array_indexer(self, item)
 
         result = self._ndarray[item]

pandas/core/arrays/sparse/array.py

@@ -770,7 +770,7 @@ def __getitem__(self, key):
                 else:
                     key = np.asarray(key)
 
-            if is_list_like(key):
+            if is_list_like(key) and not isinstance(key, tuple):
                 key = check_array_indexer(self, key)
 
             if com.is_bool_indexer(key):