fix map method, hopefully doesn't break other things...

Author: ngoldbaum

pandas/_libs/lib.pyx

@@ -39,7 +39,9 @@ from cython cimport (
 
 from pandas._config import using_pyarrow_string_dtype
 
-from pandas._libs.missing import check_na_tuples_nonequal
+from pandas._libs.missing import check_na_tuples_nonequal, NA
+
+from pandas.compat.numpy import np_version_gt2
 
 import_datetime()
 
@@ -2625,7 +2627,7 @@ def maybe_convert_objects(ndarray[object] objects,
                 seen.object_ = True
                 break
         elif isinstance(val, str):
-            if convert_non_numeric:
+            if convert_non_numeric or np_version_gt2:
                 seen.str_ = True
                 break
             else:
@@ -2704,6 +2706,9 @@ def maybe_convert_objects(ndarray[object] objects,
 
             dtype = StringDtype()
             return dtype.construct_array_type()._from_sequence(objects, dtype=dtype)
+        elif np_version_gt2:
+            dtype = np.dtypes.StringDType(na_object=NA, coerce=False)
+            return np.array(objects, dtype=dtype)
 
         seen.object_ = True
     elif seen.interval_:

pandas/core/algorithms.py

@@ -35,6 +35,8 @@
 from pandas.util._decorators import doc
 from pandas.util._exceptions import find_stack_level
 
+from pandas.compat.numpy import np_version_gt2
+
 from pandas.core.dtypes.cast import (
     construct_1d_object_array_from_listlike,
     np_find_common_type,
@@ -1645,6 +1647,7 @@ def map_array(
         If the function returns a tuple with more than one element
         a MultiIndex will be returned.
     """
+    from pandas.core.arrays.string_ import StringArray
     if na_action not in (None, "ignore"):
         msg = f"na_action must either be 'ignore' or None, {na_action} was passed"
         raise ValueError(msg)
@@ -1693,6 +1696,7 @@ def map_array(
 
     # we must convert to python types
     values = arr.astype(object, copy=False)
+
     if na_action is None:
         return lib.map_infer(values, mapper)
     else: