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Python 2 will be replaced with Python 3 in the next RHEL major release

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Re: Python 2 will be replaced with Python 3 in the next RHEL major release

#151

Post by protomyth »

mratzloff wrote: post #106
hyperpallium wrote: post #27

Earlier quoted context omitted.

I think it's the opposite. When other languages make incompatible changes, they have serious problems (e.g perl6). Previous versions of python were back-compatible. Java versions stress back-compatibility. I don't know if HN can find any counter-examples, of a language that thrived through an incompatible, code-breaking upgrade. Python has done everything possible to avoid this fate, by maintaining 2.7. And I'm not e…

I don't know if HN can find any counter-examples, of a language that thrived through an incompatible, code-breaking upgrade. Of course. Swift 3 is one example. Ruby 1.9, as others have pointed out, is another. PHP is yet another, and perhaps more relevant because it is close to contemperaneous. It had its "Python 3 moment" with the migration to PHP 5. Lots of BC breakages.[0] That transition took about 3-4 years for…

Swift is Apple’s baby and has a captive audience. Since Apple cannot even update their example code, I don’t think it proves any points about keeping up with a moving target.

Re: Python 2 will be replaced with Python 3 in the next RHEL major release

#152

Post by simonh »

VeejayRampay wrote: post #111
ceronman wrote: post #23

Earlier quoted context omitted.

What do you mean by double standard? Everyone in the community, including the core developers, acknowledge that the 2 to 3 story was full of mistakes. They have promised not to make it again. And they took some actions to remedy the problems, and that's why Python 3 is finally succeeding. I recommend this presentation by Victor Stinner at FOSDEM 2018 which talks about it: https://fosdem.org/2018/schedule/event/python…

The double standard is that people still stick to Python despite those problems. If we're being honest and all conspiracy aside, imagine the same story for Ruby (a very similar language in terms of capability, features and performance), everyone would be laughing at them and the language would be pulling a Perl right now.

I do not think double standard means what you think it means.

Re: Python 2 will be replaced with Python 3 in the next RHEL major release

#153

Post by paulie_a »

dajonker wrote: post #3

This is good: - Python 2 support officially ends somewhere in 2020 - most popular packages are now compatible with Python 3 - Python 3.7 performs about as well as 2.7 with future release expected to be better Although it still took way too long, if you consider Python 3.0 was released about 10 years ago.

About as well, but in a number of cases signicantly worse. I am not saying people shouldn't upgrade, but it's not without issues.

Re: Python 2 will be replaced with Python 3 in the next RHEL major release

#154

Post by SlowBro »

sametmax wrote: post #130
wiz21c wrote: post #128

Earlier quoted context omitted.

>> It's just that we, as a community, will stop to pay the price for the ones that didn't move. If you want to stay there, you'll pay a commercial actor for it. That's very well put. But I guess this can happen only with big, important, projects where you can afford to loose/upset some users...

No that's just how IT works. Your games don't work in windows XP anymore. Actually, your USB3 mouse doesn't work on windows 7 out of the box. Centos have LTS, but still EOL. Ubuntu init system was changed to upstart. Then to systemd. Also gnome, then unity, then with new menu/notif/systray semantics, then back to gnome (but shell), and soon wayland. It breaks a lot of things. Firefox new addons don't work with some a…

2.X would still be included as an optional package, correct? I couldn’t determine that from the link, but it seems like RedHat’s practice. Or, they could install it from source.

If so, 2.X users still have two years or so to migrate. That’s plenty of time in my opinion, even when all of your code is 2.X. There’s even a library for it.[1]

[1] https://docs.python.org/2/library/2to3.html

Re: Python 2 will be replaced with Python 3 in the next RHEL major release

#155

Post by dagw »

opencl wrote: post #139
sametmax wrote: post #123

Earlier quoted context omitted.

Half of the problem you mention are either: - if you tried to support Python - if you tried to support Python But nobody used 3.0, 1 or 2. And supporting 2.6 is like supporting ruby 1.7 and 1.8 and 1.9. Which nobody did. And it's easy to rewrite libs when really the language started to be used in 2004. Or maybe not, given that "gem install" still regularly crashes on anything other than the top 20 packages, so it's s…

Python 3.0 came out in 2008 and 3.3 came out in 2012. Are you really saying that nobody used Python3 for the first 4 years of its existence? I was certainly using 3.1 and 3.2 back then.

Django never had support for python < 3.3 and numpy and scipy only supported python 3.2 and up. The story is similar for most other packages. So if you where using python with any of its major libraries then python 3 was pretty much useless for you the first 3-4 years.

Re: Python 2 will be replaced with Python 3 in the next RHEL major release

#156

Post by mschuster91 »

sametmax wrote: post #130
wiz21c wrote: post #128

Earlier quoted context omitted.

>> It's just that we, as a community, will stop to pay the price for the ones that didn't move. If you want to stay there, you'll pay a commercial actor for it. That's very well put. But I guess this can happen only with big, important, projects where you can afford to loose/upset some users...

No that's just how IT works. Your games don't work in windows XP anymore. Actually, your USB3 mouse doesn't work on windows 7 out of the box. Centos have LTS, but still EOL. Ubuntu init system was changed to upstart. Then to systemd. Also gnome, then unity, then with new menu/notif/systray semantics, then back to gnome (but shell), and soon wayland. It breaks a lot of things. Firefox new addons don't work with some a…

> Your games don't work in windows XP anymore.

In fact I can play EarthSiege 2, a game from the 3.11/Win95 era, just fine on Win7 x64 with the only things not working being joystick input (I guess it does some shenanigans with the MIDI/joystick port in addition to using the windows joystick API) and the pause screen which shows your vehicle spinning around spins too fast (probably because its speed is tethered to CPU sppeed).

Microsoft takes, with the exception of drivers, a lot of effort to keep backwards compatibility. And that is why people like it, in contrast to Linux where "Things break" is the norm and even in OS X it's not unheard of. Oh, and also why big enterprises stay as far away as humanly possible from anything NodeJS or more modern than PHP and Java.

Enterprises want and need stability first.

Re: Python 2 will be replaced with Python 3 in the next RHEL major release

#157

Post by dagw »

oblio wrote: post #148
dagw wrote: post #127

Earlier quoted context omitted.

the GIL was not removed or at least a solid parallelism story was not included Not for lack of trying. People have been trying to do this since at least python 1.4. They just haven't found a way of doing it without negatively affecting single threaded performance, which Guido considers an unacceptable trade-off. http://pyparallel.org is probably the most interesting latest experiment in this field, but it never got c…

They were breaking many things, maybe they should have rewritten the C API? From what I remember that's the blocker. That would have broken all C extensions, but it's not like Python 3 at launch was a raving success regarding library porting.

Here's a video and HN thread that covers most of the current problems with removing the GIL:

https://news.ycombinator.com/item?id=11842779

Re: Python 2 will be replaced with Python 3 in the next RHEL major release

#158

Post by consp »

bitL wrote: post #107
dajonker wrote: post #3

This is good: - Python 2 support officially ends somewhere in 2020 - most popular packages are now compatible with Python 3 - Python 3.7 performs about as well as 2.7 with future release expected to be better Although it still took way too long, if you consider Python 3.0 was released about 10 years ago.

You forgot one: - 90% of business code is written in Python 2.x

We've switched from 2.7 to 3.4 (and upwards to 3.5, 3.6) in about a month or so. It delayed some deployments but nothing serious.

If you do it step-by-step it's not that hard. The worst part was str/binary conversions but afterwards everything was a lot easier and better to maintain.

If your company is big enough you should maintain and keep it up-to-date, not "it just works"(TM) and hope for the best after 10 years. The death of 2.7 was already in the air for years.

Re: Python 2 will be replaced with Python 3 in the next RHEL major release

#159

Post by physicsguy »

afarrell wrote: post #87
oblio wrote: post #68

Earlier quoted context omitted.

I tried this a while ago. I think Conda allows installing different versions of Python (good) but it doesn't play well with Pip (bad)? Last I tried it also bundled dependencies in its own particular way (ugly)? I think it was more geared towards SciPy and NumPy and other scientific development than towards general purpose programming.

> I think Conda allows installing different versions of Python (good) Yep. Also allows installing different versions of node or ruby. > Doesn't play well with Pip (bad) You can `pip install` things into a conda environment but I forget how it works with globally pip-installed packages. I don't think it plays nicely with virtualenv. > Last I tried it also bundled dependencies in its own particular way (ugly)? I think…

You can install things with pip but you have to be really careful, because Conda tries to do clever things to avoid downloading multiple copies, which is what you end up with in Virtualenvs. So, if you have two environments both using the same version Jupyter version, installed with 'conda install jupyter' it will only have one copy which is symlinked into the environments.

Problem is, if you do 'pip install' in one of the environments, it will upgrade the existing version, but overwrite the conda installed one, which will break your other environment. Often though the official conda packages are lagging behind those on pip, so you have to do this anyway, or use Conda Forge which gets more regular updates or use pip (but carefully uninstalling all the conda installed stuff in the environment first) if you want the bleeding edge.

Re: Python 2 will be replaced with Python 3 in the next RHEL major release

#160

Post by jamesgeck0 »

VeejayRampay wrote: post #111
ceronman wrote: post #23

Earlier quoted context omitted.

What do you mean by double standard? Everyone in the community, including the core developers, acknowledge that the 2 to 3 story was full of mistakes. They have promised not to make it again. And they took some actions to remedy the problems, and that's why Python 3 is finally succeeding. I recommend this presentation by Victor Stinner at FOSDEM 2018 which talks about it: https://fosdem.org/2018/schedule/event/python…

The double standard is that people still stick to Python despite those problems. If we're being honest and all conspiracy aside, imagine the same story for Ruby (a very similar language in terms of capability, features and performance), everyone would be laughing at them and the language would be pulling a Perl right now.

Ruby had 1.9. It was like the Python 3 situation in miniature, and Matz has said he’s keen to avoid such a mistake again.
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