On Tue, 13 Feb 2024 at 18:21:17 +0100, Andreas Tille wrote: > SyntaxWarning: invalid escape sequence '\.' > 573s CLI_INPUT_RE = re.compile('[a-zA-Z0-9_:\.\-\+; /#%]')
This should be: re.compile(r'[a-zA-Z0-9_:\.\-\+; /#%]') ^ a raw string, where the backslashes are not interpreted by the Python parser, allowing them to be passed through to the re module for parsing; or alternatively re.compile('[a-zA-Z0-9_:\\.\\-\\+; /#%]') ^^ ^^ ^^ like you would have to write in the C equivalent. Reference: """ Regular expressions use the backslash character ('\') to indicate special forms or to allow special characters to be used without invoking their special meaning. This collides with Python’s usage of the same character for the same purpose in string literals; for example, to match a literal backslash, one might have to write '\\\\' as the pattern string, because the regular expression must be \\, and each backslash must be expressed as \\ inside a regular Python string literal. Also, please note that any invalid escape sequences in Python’s usage of the backslash in string literals now generate a SyntaxWarning and in the future this will become a SyntaxError. This behaviour will happen even if it is a valid escape sequence for a regular expression. The solution is to use Python’s raw string notation for regular expression patterns; backslashes are not handled in any special way in a string literal prefixed with 'r'. So r"\n" is a two-character string containing '\' and 'n', while "\n" is a one-character string containing a newline. Usually patterns will be expressed in Python code using this raw string notation. """ —re module docs > which makes me scratching my head what else we should write > for "any kind of space" now in Python3.12. \s continues to be correct for "any kind of space", but Python now complains if you do the backslash-escapes in the wrong layer of syntax. smcv