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ambiguous-unicode-character-string (RUF001)#

What it does#

Checks for ambiguous Unicode characters in strings.

Why is this bad?#

Some Unicode characters are visually similar to ASCII characters, but have different code points. For example, GREEK CAPITAL LETTER ALPHA (U+0391) is visually similar, but not identical, to the ASCII character A.

The use of ambiguous Unicode characters can confuse readers, cause subtle bugs, and even make malicious code look harmless.

In preview, this rule will also flag Unicode characters that are confusable with other, non-preferred Unicode characters. For example, the spec recommends GREEK CAPITAL LETTER OMEGA over OHM SIGN.

You can omit characters from being flagged as ambiguous via the allowed-confusables setting.


print("Ηello, world!")  # "Η" is the Greek eta (`U+0397`).

Use instead:

print("Hello, world!")  # "H" is the Latin capital H (`U+0048`).