New submission from Bob Kline <bkl...@rksystems.com>:
We are attempting to convert a large Python 2 code base. Following the guidance of the official documentation (https://docs.python.org/2/library/functions.html#basestring) we created tests in many, many places that look like this: if isinstance(value, basestring): if not isinstance(value, unicode): value = value.decode(encoding) else: some other code It seems that the 2to3 tool is unaware that replacing basestring with str in such cases will break the software. Here's an example. $ 2to3 repro.py ... --- repro.py (original) +++ repro.py (refactored) @@ -1,8 +1,8 @@ from frobnitz import transform def foo(value, encoding=None): - if isinstance(value, basestring): - if not isinstance(value, unicode): + if isinstance(value, str): + if not isinstance(value, str): value = value.decode(encoding or "utf-8") return value else: Help me understand how this "fix" results in the correct behavior. ---------- components: 2to3 (2.x to 3.x conversion tool) messages: 350964 nosy: bkline priority: normal severity: normal status: open title: Incorrect "fixing" of isinstance tests for basestring type: behavior versions: Python 3.7 _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue38003> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
