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Docs: note requirement to normalise unicode identifiers passed to globals() and locals() #86846
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outofculture commented
on Dec 19, 2020 outofculturemannequinMannequinAuthorThis behavior is best described by the code below:
>>> meow = 1 >>> 'meow' in globals() True >>> µmeow = 1e-6 >>> 'µmeow' in globals() False >>> globals()['woof'] = 1 >>> woof 1 >>> globals()['µwoof'] = 1e-6 >>> µwoof Traceback (most recent call last): File "<stdin>", line 1, in <module> NameError: name 'μwoof' is not defined >>> import sys >>> sys.getdefaultencoding() 'utf-8' >>> [(k, bytes(k, 'utf-8')) for k in globals()] ..., ('μmeow', b'\xce\xbcmeow'), ('µwoof', b'\xc2\xb5woof')] >>> 'µ'.encode('utf-8') b'\xc2\xb5'Testing was done on linux and windows, variously using 3.6.12, 3.7.6, 3.8.6 and 3.9.0+.
outofculture commented
on Dec 19, 2020 outofculturemannequinMannequinAuthorOh, I just gave a cursory using
locals(), and the same misbehavior is present.A workaround, for anyone needing to assign or access unicode globals, is to use
exec, e.g.exec("µmeow = 1e-6", globals()).I'm pretty sure this is not a bug, but is working as designed.
The interpreter normalises unicode identifiers, but key lookup in the dict does not.
Sorry, I don't have time right now to give a more detailed answer, but there are two distinct mu characters:
μ U+03BC µ U+00B5and my prediction is that the identifier is normalised to the first, the actual Greek mu, but you are looking up the second, the micro sign.
(I'll be able to give a longer response in a couple of hours, if still needed.)
outofculture commented
on Dec 19, 2020 outofculturemannequinMannequinAuthorAh! So then the proper code for me would be e.g.:
>>> globals()[unicodedata.normalize("NFKC", "µmeow")] 1e-06Yes, it's clear when I read https://www.python.org/dev/peps/pep-3131/ that the normalization is going to happen. Is it also worth adding a note in the documentation for
globals()andlocals()? That's the first place I looked to try to find out what was wrong.I think documenting this with globals() and locals() is a good idea. That's the place this is most likely to trip someone up.
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Updated issue title and labels to reflect the previous discussion.
- marked Unicode is normalised after keywords are checked for #77886 as a duplicate of this issue
on Sep 26, 2025 - linked a pull request that will close this issuegh-135676: Simplify docs on lexing names #140464
on Oct 22, 2025 Documented as a note in https://docs.python.org/3.15/reference/lexical_analysis.html#non-ascii-characters-in-names
I think that's the proper place, as that where Python does the normalization.
globals()itself is perfectly fine with non-normalized keys:>>> fix = False >>> globals()['fix'] False >>> globals()['fix'] = True >>> globals()['fix'] TrueLet's reopen if someone disagrees.
Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.
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