6 ms·
If you’re the only one writing it and you’re the only one running it, it’s probably fine. But if I’m putting a file out there that will only work in 3.7, it’d b
by jakear 7y ago
If you’re the only one writing it and you’re the only one running it, it’s probably fine. But if I’m putting a file out there that will only work in 3.7, it’d be nice if any potential users of that file would get a good error message if they try to run it on 3.5, rather than wrong results.
I could potentially assert a version, but do I really want to do that each time I wrote something that might be used somewhere else?
And yes of course I could add a line of documentation, but there is a 100% chance I’d still get bug reports from people on 3.5.
- lonelappde 7y agoIf you write code that doesn't work in 3.5, you should check the version at startup and exit
- jakear 7y agoYes, that would be a good idea. But if you ever run scripts you didn’t write, there’s the potential people didn’t do this, and you have the potential for hard to discover bugs. The language should be designed such that bugs are difficult to encounter, this is an instance where it wasn’t.
- zeulhex 7y agoMost projects use setuptools for package management, which ensures that the environment is as expected.
- orf 7y agoSetuptools solves this, add a python version specifier to your setup.py or pyproject.toml file. If you are just distributing raw python files then congratulations you’ve just realised why packaging is valuable.
- Aachen 7y agoIf I rely on a python version and I expect other people to use it, I add a version if statement on top. I hate those packaging tools that insist on installing stuff in your system and create a frankendebian when really all I want to do is run a single py file standalone once. Often have to do chenanigans like "python3 -c 'from sometool import __app__'". If you want to install it, go ahead and copy or symlink it in your ~/bin or whatever you fancy (that's your personal preference anyway unless I'd specifically package it for some OS like Debian). I don't want to have to use some setup.py that I have no clue where in my OS it installs things.
- orf 7y agoYes, a failure to understand how your tools work or how to use them effectively does indeed make things harder.
- Aachen 7y agoWell I know how my tools work, I don't know how this custom file works that is duplicated and delivered with each project.
- orf 7y ago> I don't know how this custom file works that is duplicated and delivered with each project. It's not duplicated and in most cases it's not even delivered as part of the installation. > If you want to install it, go ahead and copy or symlink it in your ~/bin or whatever you fancy That's exactly what pip will do if invoked with `--user`. > I don't want to have to use some setup.py that I have no clue where in my OS it installs things. It installs it to a single place. Run `python3 -m site` and look at `USER_BASE`. To avoid a lot of this, use pipx[1] to keep things even more isolated. > Often have to do chenanigans like "python3 -c 'from sometool import __app__'". You're doing things wrong because you don't know the tooling. You'd also typically just do `python3 -m sometool`. Things that are distributed as a single file are either so simplistic and have no other dependencies that you can just make do, or written by someone who doesn't know what they are doing and so you're going to have a bad time. 1. https://github.com/pipxproject/pipx https://github.com/pipxproject/pipx
- fctorial 7y ago#!/usr/bin/env python3.7
- gruez 7y agoso now you have to install a specific python version for your script to work?
- fctorial 7y agoOnly if you're using version specific features.
- jakear 7y agoWhat happens when python 3.8 comes out? Everybody needs to go into your script to change the hashbang every time a new release comes?
- sgillen 7y agoyou can just hashbang to python3 which is a symlink to whichever python3.X the user has. If your code won’t work for older versions you can make an explicit check that the version of python is greater than whatever you need.