On Sat, Mar 16, 2019 at 5:43 AM francismb <[email protected]> wrote: > > On 3/14/19 9:47 PM, Chris Angelico wrote: > > What happens when someone wants to support multiple Python versions? > > "Requires Python 3.5 or newer" is easy. Forcing people to install the > > correct one for each version isn't. > What are the reasons why people want to support multiple Python > versions, on the 3 series? do they really want? or they need to (may > be)? and for how many versions, "from 3.5 or newer" ... forever? will be > reasonable possible? IMHO more versions to support, the harder to support. >
People who care about backward compatibility will usually have some definition of what they support, such as "this app will run on any Python version shipped by a currently-supported Debian release" (which at the moment means supporting Python 3.4, shipped by Debian Jessie), or "we support back as far as isn't too much of a pain" (which usually means committing to support everything starting from the version that introduced some crucial feature). Either way, there's not usually a "forever", but potentially quite a few versions' worth of support. The same is true of books that discuss the language, blog posts giving tips and tricks, Stack Overflow answers, and everything else that incorporates code that people might want to copy and paste. What version of Python do you need? What's the oldest that it still works on, and what's the newest before something breaks it? Backward-incompatible changes make that EXTREMELY hard. Backward-compatible changes make it only a little bit harder, as they set a minimum but not a maximum. You want to see how bad it can be? Go try to find out how to do something slightly unusual with React.js. Stack Overflow answers sometimes have three, four, or even more different code blocks, saying "this if you're on this version, that for some other version". ChrisA _______________________________________________ Python-ideas mailing list [email protected] https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/
