From 0a7936a38f0bab1619ee9fe257880a51c9d839d5 Mon Sep 17 00:00:00 2001
From: Carl Meyer <carl@oddbird.net>
Date: Thu, 5 Jan 2023 17:19:40 -0700
Subject: gh-90104: avoid RecursionError on recursive dataclass field repr
 (gh-100756)

Avoid RecursionError on recursive dataclass field repr
---
 Lib/dataclasses.py | 42 +++++++++++++++++++++---------------------
 1 file changed, 21 insertions(+), 21 deletions(-)

(limited to 'Lib/dataclasses.py')

diff --git a/Lib/dataclasses.py b/Lib/dataclasses.py
index b54e16984c..5c0257eba1 100644
--- a/Lib/dataclasses.py
+++ b/Lib/dataclasses.py
@@ -223,6 +223,26 @@ _POST_INIT_NAME = '__post_init__'
 # https://bugs.python.org/issue33453 for details.
 _MODULE_IDENTIFIER_RE = re.compile(r'^(?:\s*(\w+)\s*\.)?\s*(\w+)')
 
+# This function's logic is copied from "recursive_repr" function in
+# reprlib module to avoid dependency.
+def _recursive_repr(user_function):
+    # Decorator to make a repr function return "..." for a recursive
+    # call.
+    repr_running = set()
+
+    @functools.wraps(user_function)
+    def wrapper(self):
+        key = id(self), _thread.get_ident()
+        if key in repr_running:
+            return '...'
+        repr_running.add(key)
+        try:
+            result = user_function(self)
+        finally:
+            repr_running.discard(key)
+        return result
+    return wrapper
+
 class InitVar:
     __slots__ = ('type', )
 
@@ -280,6 +300,7 @@ class Field:
         self.kw_only = kw_only
         self._field_type = None
 
+    @_recursive_repr
     def __repr__(self):
         return ('Field('
                 f'name={self.name!r},'
@@ -403,27 +424,6 @@ def _tuple_str(obj_name, fields):
     return f'({",".join([f"{obj_name}.{f.name}" for f in fields])},)'
 
 
-# This function's logic is copied from "recursive_repr" function in
-# reprlib module to avoid dependency.
-def _recursive_repr(user_function):
-    # Decorator to make a repr function return "..." for a recursive
-    # call.
-    repr_running = set()
-
-    @functools.wraps(user_function)
-    def wrapper(self):
-        key = id(self), _thread.get_ident()
-        if key in repr_running:
-            return '...'
-        repr_running.add(key)
-        try:
-            result = user_function(self)
-        finally:
-            repr_running.discard(key)
-        return result
-    return wrapper
-
-
 def _create_fn(name, args, body, *, globals=None, locals=None,
                return_type=MISSING):
     # Note that we may mutate locals. Callers beware!
-- 
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