Valid Unicode identifier can be used as field name but not as kwargs

[serge-sans-paille]

Simple reproducer:

>>> import attrs
>>> A = attrs.make_class('A', ['Ŀ椁楮潴桶'])
>>> A(Ŀ椁楮潴桶=1)  # this is fine
A(Ŀ椁楮潴桶=1)
>>> A(**{'Ŀ椁楮潴桶':1})  # this is not fine
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: A.__init__() got an unexpected keyword argument 'Ŀ椁楮潴桶'

This was raised by fuzzing when setting up google/oss-fuzz#13009

[hynek]

Thanks, but this is out of scope. I've added a warning in 5820ce7, though.

[serge-sans-paille]

Thanks for your reply ! I did check that

>>> 'Ŀ椁楮潴桶'.isidentifier()
True

though, so why would that be out of scope?

[serge-sans-paille]

@hynek : I've digged a bit because I found it quite strange that attrs fails with such class name while the name is a valid Python identifier.
It turns out that all Python identifiers are converted to so called "normal form NFKC" while parsing, as stated in https://docs.python.org/3.14/reference/lexical_analysis.html#identifiers.
As a consequence supporting all valid Python identifiers in attrs is just a matter of normalizing the parameters of make_class. The diff is very simple:

diff --git a/src/attr/_make.py b/src/attr/_make.py
index e3e31ff..ef3ced0 100644
--- a/src/attr/_make.py
+++ b/src/attr/_make.py
@@ -13,6 +13,7 @@ import linecache
 import sys
 import types
 import typing
+import unicodedata
 
 from operator import itemgetter
 
@@ -2908,10 +2909,15 @@ def make_class(
     .. versionchanged:: 18.1.0 If *attrs* is ordered, the order is retained.
     .. versionchanged:: 23.2.0 *class_body*
     """
+    # All identifiers are converted into the normal form NFKC while parsing
+    name = unicodedata.normalize('NFKC', name)
+
     if isinstance(attrs, dict):
         cls_dict = attrs
+        attrs = {unicodedata.normalize('NFKC', k): v for k, v in attrs}
     elif isinstance(attrs, (list, tuple)):
         cls_dict = {a: attrib() for a in attrs}
+        attrs = [unicodedata.normalize('NFKC', k) for k in attrs]
     else:
         msg = "attrs argument must be a dict or a list."
         raise TypeError(msg)

[hynek]

would you mind opening a PR, then?

[serge-sans-paille]

Done in #1406