When printing some instance of RegexFlag **in the REPL** it fails to print:

>>> import gc
# This prints a ton of objects, including the bad enum RegexFlag one
>>> gc.get_referrers(None) 
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/pablogsal/github/cpython/Lib/enum.py", line 1399, in global_flag_repr
    return "%x" % (module, cls_name, self._value_)
           ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
TypeError: %x format: an integer is required, not str

(Deleted last message because it was incorrect)

Simpler reproducer:

>>> import re
>>> re.RegexFlag(0)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/pablogsal/github/cpython/Lib/enum.py", line 1399, in global_flag_repr
    return "%x" % (module, cls_name, self._value_)
           ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
TypeError: %x format: an integer is required, not str

This looks incorrect:

https://github.com/python/cpython/blob/1512bc21d60f098a9e9f37b44a2f6a9b49a3fd4f/Lib/enum.py#L1399

Ethan, could you take a look at the PR? I added a few failing test methods since `repr` handling for global enum flags wasn't covered and looks unfinished. If you tell us what the expected return values should be, I'll finish the fix.

`_name_` is only None if the entire enum value is outside any named member and `_boundary_` is `KEEP` -- so

    class Example(Flag, boundary=KEEP):
        first = auto()
        second = auto()
        third = auto()

    >>> Example(0)
    module.Example(0)

    >>> Example(8)
    module.Example(8)

No need to backport.

New changeset 24da544014f78e6f1440d5ce5c2d14794a020340 by Pablo Galindo Salgado in branch 'main':
bpo-44929: [Enum] Fix global repr (GH-27789)
https://github.com/python/cpython/commit/24da544014f78e6f1440d5ce5c2d14794a020340

repr(re.RegexFlag(0)) no longer crashes so we can close this.