Python3 erroneously calls r'\' a syntax error

[greg1lutz]

The Python 3.11.3 interpreter, upon seeing the expression
r'\'
emits the message
SyntaxError: unterminated string literal

[hauntsaninja]

Thanks, but this isn't a bug.

This is documented at this FAQ: https://docs.python.org/3/faq/programming.html#can-i-end-a-raw-string-with-an-odd-number-of-backslashes

It's also mentioned at https://docs.python.org/3/reference/lexical_analysis.html#string-and-bytes-literals

(we recently improved the docs for this in #94768 )

[terryjreedy]

@greg1lutz Please ask whether behaviors are bugs on the discuss help channel.

[hauntsaninja]

Oh one more note is that I'd opened #100446 to explore ways to improve the error message