Hi, > Currently, the ``bytes`` and ``bytearray`` constructors accept an integer > argument and interpret it as meaning to create a zero-initialised sequence > of the given size:: > (...) > This PEP proposes to deprecate that behaviour in Python 3.6, and remove it > entirely in Python 3.7.
I'm opposed to this change (presented like that). Please stop breaking the backward compatibility in minor versions. I'm porting Python 2 code to Python 3 for longer than 2 years. First, Python 3 only proposed to immediatly drop Python 2 support using the 2to3 tool. It simply doesn't work because you must port incrementally all dependencies, so you must write code working with Python 2 and Python 3 using the same code base. A few people tried to duplicate repositories, projects, project name, etc. to have one version for Python 2 and one version for Python 3, but IMHO it's even worse. It's very difficult to handle dependencies using that. It took a few years until six was widely used and that pip was popular enough to be able to add six as a *dependency* (and not put an old copy in the project). Basically, you propose to introduce a backward incompatible change for free (I fail to see the benefit of replacing bytes(n) with bytes.zeros(n)) and without obvious way to write code compatible with Python <= 3.6 and Python >= 3.7. Moreover, a single cycle is way too short to port all code in the wild. It's common that users complain that Python core developers like breaking the compatibility at each release. Recently, I saw a list of applications which need to be ported to Python 3.5, while they work perfectly on Python 3.4. *If* you still want to deprecate bytes(n), you must introduce an helper working on *all* Python versions. Obviously, the helper must be avaialble and work for Python 2.7. Maybe it can be the six module. Maybe something else. In Perl 5, there is a nice "use 5.12;" pragma to explicitly ask to keep the compatiiblity with Perl 5.12. This pragma allows to change the language more easily, since you can port code file by file. I don't know if it's technically possible in Python, maybe not for all kinds of backward incompatible changes. Victor _______________________________________________ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
