keep string instead of large_string for ArrowDtype

Author: jorisvandenbossche

pandas/_libs/parsers.pyx

@@ -10,7 +10,10 @@ import warnings
 
 from pandas.util._exceptions import find_stack_level
 
-from pandas import StringDtype
+from pandas import (
+    ArrowDtype,
+    StringDtype,
+)
 from pandas.core.arrays import (
     ArrowExtensionArray,
     BooleanArray,
@@ -43,7 +46,6 @@ from libc.string cimport (
     strncpy,
 )
 
-
 import numpy as np
 
 cimport numpy as cnp
@@ -1452,7 +1454,13 @@ def _maybe_upcast(
 
     elif arr.dtype == np.object_:
         if use_dtype_backend:
-            dtype = StringDtype()
+            if dtype_backend == "pyarrow":
+                # using the StringDtype below would use large_string by default
+                # keep here to pyarrow's default of string
+                import pyarrow as pa
+                dtype = ArrowDtype(pa.string())
+            else:
+                dtype = StringDtype()
             cls = dtype.construct_array_type()
             arr = cls._from_sequence(arr, dtype=dtype)