pylint #104571 warn about backslash escape [validation pending]

Martin Pool on python-projects:

We were recently debugging some code like this:

re.compile('\\/')

This is legal Python (equivalent to r'\/') but possibly buggy. It would be safer and clearer to say r'\/' if that's what you want - and the 're' manual highly recommends you should use raw strings here.

In Python (unlike C, Perl, Python REs and most unix tools) backslashes followed by a non-special character in a string literal are passed through as backslashes, which in my small survey surprised many people.