[New-bugs-announce] [issue33705] Unicode is normalised after keywords are checked for

[Steven D'Aprano]

New submission from Steven D'Aprano <steve+python at pearwood.info>:

There is a loophole in the Unicode normalisation which allows the creation of names matching keywords.

class Spam:
    locals()['if'] = 1

Spam.𝐢𝐟    # U+1D422 U+1D41F
# returns 1

Those two characters are 'MATHEMATICAL BOLD SMALL I' and 'MATHEMATICAL BOLD SMALL F'. They ought to be normalised to "if", which is a keyword.

Of course Spam.if is a syntax error, and I believe Spam.𝐢𝐟 ought to be as well.

Another example:

py> globals()['for'] = 2
py> 𝐟or
2



I also asked about this here:

https://mail.python.org/pipermail/python-dev/2018-May/153619.html

----------
components: Interpreter Core, Unicode
messages: 318250
nosy: ezio.melotti, steven.daprano, vstinner
priority: normal
severity: normal
status: open
title: Unicode is normalised after keywords are checked for
type: behavior

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue33705>
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