gh-112653: Intern dataclass field names to improve performance

Lib/dataclasses.py

@@ -784,7 +784,7 @@ def _get_field(cls, a_name, a_type, default_kw_only):
         f = field(default=default)
 
     # Only at this point do we know the name and the type.  Set them.
-    f.name = a_name
+    f.name = sys.intern(a_name)
     f.type = a_type
 
     # Assume it's a normal field until proven otherwise.  We're next

Misc/NEWS.d/next/Library/2023-12-03-12-00-38.gh-issue-112653.Q7MK-5.rst

@@ -0,0 +1 @@
+Intern field names of ``dataclass`` to improve performance. Patch by Xuehai Pan.