Very obscure edge case with __debug__

[00001H]

If __debug__ is present in globals(), then the globals() value is read instead of the actual __debug__ value. However, the write is still attempted to the real __debug__, which fails. (or maybe it failed early when it detected a write to __debug__)

Python 3.13.0 (tags/v3.13.0:60403a5, Oct  7 2024, 09:38:07) [MSC v.1941 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license()" for more information.
>>> __debug__
True
>>> __debug__ = False
SyntaxError: cannot assign to __debug__
>>> globals()["__debug__"]
Traceback (most recent call last):
  File "<pyshell#2>", line 1, in <module>
    globals()["__debug__"]
KeyError: '__debug__'
>>> globals()["__debug__"] = "Hello"
>>> __debug__
True
>>> __debug__ = 3
SyntaxError: cannot assign to __debug__
>>>

Brython 3.13.0 on Netscape 5.0 (Windows)
Type "help", "copyright", "credits" or "license" for more information.
>>> __debug__
True
>>> __debug__ = False
File "<stdin>", line 1
    __debug__ = False
    ^^^^^^^^^
SyntaxError: cannot assign to __debug__
>>> globals()["__debug__"]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
KeyError: __debug__
>>> globals()["__debug__"] = "Hello"
>>> __debug__
'Hello'
>>> __debug__ = 3
File "<stdin>", line 1
    __debug__ = 3
    ^^^^^^^^^
SyntaxError: cannot assign to __debug__
>>>