various fixups

Author: topper-123

pandas/core/array_algos/masked_reductions.py

@@ -122,10 +122,11 @@ def _minmax(
             return func(values, axis=axis)
     else:
         subset = values[~mask]
-        if not subset.size:
+        if subset.size:
+            return func(values, where=~mask, axis=axis, initial=subset[0])
             # min/max with empty array raise in numpy, pandas returns NA
+        else:
             return libmissing.NA
-        return func(values, where=~mask, axis=axis, initial=subset[0])
 
 
 def min(

pandas/core/arrays/base.py

@@ -1431,7 +1431,7 @@ def _reduce(self, name: str, *, skipna: bool = True, **kwargs):
         See Also
         --------
         ExtensionArray._reduce_with_wrap
-            Calls ``_reduce`` and wraps the result in a ndarray/extensionArray.
+            Calls ``_reduce`` and wraps the result in a ndarray/ExtensionArray.
         """
         meth = getattr(self, name, None)
         if meth is None:

pandas/core/frame.py

@@ -11140,10 +11140,9 @@ def idxmin(
         )
         indices = res._values
 
-        # indices will always be np.ndarray since axis is not None and
+        # indices will always be 1d array since axis is not None and
         # values is a 2d array for DataFrame
-        # error: Item "int" of "Union[int, Any]" has no attribute "__iter__"
-        assert isinstance(indices, (np.ndarray, ExtensionArray))  # for mypy
+        # indices will always be np.ndarray since axis is not N
 
         index = data._get_axis(axis)
         result = [index[i] if i >= 0 else np.nan for i in indices]
@@ -11165,9 +11164,8 @@ def idxmax(
         )
         indices = res._values
 
-        # indices will always be np.ndarray since axis is not None and
+        # indices will always be 1d array since axis is not None and
         # values is a 2d array for DataFrame
-        # error: Item "int" of "Union[int, Any]" has no attribute "__iter__"
         assert isinstance(indices, (np.ndarray, ExtensionArray))  # for mypy
 
         index = data._get_axis(axis)

pandas/core/internals/blocks.py

@@ -340,10 +340,9 @@ def reduce(self, func) -> list[Block]:
 
         if self.values.ndim == 1:
             # TODO(EA2D): special case not needed with 2D EAs
-            if isinstance(result, (np.ndarray, ExtensionArray)):
-                res_values = result
-            else:
-                res_values = np.array([[result]])
+            if not isinstance(result, (np.ndarray, ExtensionArray)):
+                result = np.array([[result]])
+            res_values = result
         else:
             res_values = result.reshape(-1, 1)
 

pandas/tests/extension/test_arrow.py

@@ -62,7 +62,6 @@
 from pandas.core.arrays.arrow.dtype import ArrowDtype  # isort:skip
 
 
-
 @pytest.fixture(params=tm.ALL_PYARROW_DTYPES, ids=str)
 def dtype(request):
     return ArrowDtype(pyarrow_dtype=request.param)