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Python 2 removed from Debian

bugs.debian.org

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Re: Python 2 removed from Debian

#271

Post by pixelfarmer »

whirlwin wrote: post #197
pixelfarmer wrote: post #172

Earlier quoted context omitted.

Python 3.0 was released almost 15 years ago and it was clear at that point that Python 2 would be shown the door eventually. My empathy for any complaints regarding that switch is exactly 0, even for open source projects.

There are many core Python projects that predates Python 3. We cannot deny everything that happend before Python 3 was released.

I've had to deal with a lot of stupidity regarding Python, and that started with assuming that /usr/bin/python is Python 2. Why? Because that was the default in distros for just way too long, and some of the problems only got fixed after the distros went with Python 3 as the default. Obviously some people need to get the rug pulled under their feet before they start moving.

Re: Python 2 removed from Debian

#272

Post by [deleted] »

Joeboy wrote: post #190
yen223 wrote: post #122

Earlier quoted context omitted.

I see people saying that the migration was painful, but my own experience with two separate Python 2->3 migrations were so smooth they might as well have been a minor version bumps. I don't know where this discrepancy comes from.

I migrated two significant projects, one of them took about half a day on my own, the other took several months with a team of people contributing.

[deleted]

Re: Python 2 removed from Debian

#273

Post by IgorPartola »

zarzavat wrote: post #209
mananaysiempre wrote: post #199

Earlier quoted context omitted.

> No, it's not even remotely worth the amount of confusion and work it caused. Have you worked with pervasively non-ASCII text in Python 2? Like on a machine where any file might suddenly turn out to be non-ASCII (even if it’s only in a comment), not just data inside a few carefully-patrolled fences? Outside of a few well-behaved libraries (Flask), my experience was that it was utterly impossible. More than half of m…

There is another universe where Python 3 only fixed the unicode strings, and the transition was a huge success and over in a couple of years. The print() function was absolutely not worth all the carnage it caused. They could have just kept the print statement around and introduced a printing function with a different name, for example. The fact that they removed syntax for Python 3 meant that all kinds of scientific…

The print function was the simplest part of the transition. For one you could find and replace all instances of it fairly safely across your codebase and you could quickly discover any places where things broke because of a bad replace. That part took like an hour for a large codebase.

The Unicode handling on the other hand took ages because string handling is not easily searchable and replacing it requires understanding what the piece of code actually does.

So you have it exactly backwards: if the only migration was the print function then it would be a quick and relatively painless process. But fixing the hard thing which was the broken str/byte model was the hard transition.

I am curious if you actually went through this transition or if your opinion on this is more based on observation of others’ work.

Re: Python 2 removed from Debian

#274

Post by rkangel »

onphonenow wrote: post #263
thiht wrote: post #231

I really feel like the community was a difficult pain in the ass during the 2->3 migration. There were breaking changes but I’m sure the Python maintainers didn’t expect the community to react so badly. Are there some valid reasons that made 2->3 migration insanely hard for some projects? I remember seeing blog articles whining about print vs print(), but surely there are some more important stuff.

The python maintainers went out of their way to break things - and were smug about it. That’s what it felt like to the community. A big part of 3 was Unicode strings. In 2 you could mark a string as Unicode with a u””. This would have been a great way to let libraries and code work with both 2 and 3. They banned this, but you had to still use b””. This was the attitude and just one example. The list of stuff that got…

I think this was the right decision for the long run though. What we have now is the right situation where the strings we work with in the language are 'magic' and we don't need to think about representation or encoding or whatever. And then at the periphery we encode/decode based on what the outside world is working on. It has become clear that this is the 'correct' approach for programming languages and is almost universally the approach in new languages. E.g. Rust does something similar (they don't hide that the internal encoding is UTF-8, but it's consistent).

I'm glad that this is what we have for Python now, despite the pain it caused. We'll be using Python for another few decades probably, so we'll reap the benefits.

Re: Python 2 removed from Debian

#275

Post by onphonenow »

simplotek wrote: post #270
onphonenow wrote: post #263

Earlier quoted context omitted.

The python maintainers went out of their way to break things - and were smug about it. That’s what it felt like to the community. A big part of 3 was Unicode strings. In 2 you could mark a string as Unicode with a u””. This would have been a great way to let libraries and code work with both 2 and 3. They banned this, but you had to still use b””. This was the attitude and just one example. The list of stuff that got…

> Migration path was unnecessarily difficult as was compatible code. I feel this take is outright wrong. Python provided it's 2to3 tool[1] which took care of the bulk of the work required to port Python2 code to Python3. The only code that was not supported was eggregious errors in the code that worked by coincidence, such as handling bytes as strings and vice-versa. Porting old code to Python3 is a breeze that consi…

This is totally false - code produced by 2to3 no longer ran on 2. So you ended up w a chicken and egg problem. Things like u would allow folks to keep compatibility with 2 while working in 3.

Your comment is a perfect illustration of the issues. Lots of user blaming. No actual solution. As I said, it did start to get massively better at some point. Instead of condescending lectures on org issues they for example began allowing u”” in 3, which did not mess up Unicode handling in 3

Re: Python 2 removed from Debian

#276

Post by jeltz »

mananaysiempre wrote: post #199
p-e-w wrote: post #88

Earlier quoted context omitted.

> "Python 3.3: Trust Me, It's Better than 2.7" The fact that such a talk exists shows that the improvements aren't worth the switch for most users. If they were, they wouldn't need convincing. Yes, Python 3 is (mostly) better than Python 2. No, it's not even remotely worth the amount of confusion and work it caused. If Python 3 had brought massive performance improvements, or proper support for multiple threads, then…

> No, it's not even remotely worth the amount of confusion and work it caused. Have you worked with pervasively non-ASCII text in Python 2? Like on a machine where any file might suddenly turn out to be non-ASCII (even if it’s only in a comment), not just data inside a few carefully-patrolled fences? Outside of a few well-behaved libraries (Flask), my experience was that it was utterly impossible. More than half of m…

Yes, I have and it was simple but with plenty of footguns for developers who had not groked how you were supposed to work with strings. I am happy we moved away from that but I am not happy with the solution Python 3 picked. I think e.g. Ruby 1.9 came up with a nicer solution to the problem and one which broke much less code.

Re: Python 2 removed from Debian

#277

Post by IgorPartola »

newjersey wrote: post #250
wokwokwok wrote: post #235

Earlier quoted context omitted.

Look, the breaking change to python3 was a disaster. There’s no need to sugar coat it. It was incompetently managed, in a way that made the technical success of the work look like a failure. That’s on them. They screwed up. I lived through it; I feel no particular need to smile and nod and say “it wasn’t that bad”. It was bad. Things are good now! Python 3 is great, it’s well supported and the people involved all lea…

> No one is seriously going back to Python 2 at this point. No, the community is stupid and wrong. My machine learning professor (actual professor, not a teaching assistant) only used Python 2 in 2017. Imagine how many people had their opinions shaped by someone like them. > … it is: never do this. By that standard, we would never get things like angular 2 or Raku. Would it be better if we renamed Python 3 to some ot…

IMO Angular 2 was a huge fail in usability. Angular 1 was a joy to use and 2 was a disaster in terms of writing code in it.

However, I am firmly in the Python 3 camp. It is a better language (all the newfangled bullshit notwithstanding).

Re: Python 2 removed from Debian

#278

Post by EdwardDiego »

Beltalowda wrote: post #237
EdwardDiego wrote: post #114

Earlier quoted context omitted.

That was a 3.8 change I think? It moved from collections to collections.abc, IIRC.

In the 3.9 release notes it says "Aliases to Abstract Base Classes in the collections module, like collections.Mapping alias to collections.abc.Mapping, are kept for one last release for backward compatibility. They will be removed from Python 3.10" but the 3.10 release notes don't really mention it. Apparently it's been emitting a DeprecationWarning since Python 3.3 (2012), but still... I like to have things "just w…

Oh definitely, I agree, it struck me as a rather unnecessary API change.

Re: Python 2 removed from Debian

#279

Post by EdwardDiego »

TylerE wrote: post #137
EdwardDiego wrote: post #108

Earlier quoted context omitted.

It won't be fragmented indefinitely, that claim might've carried some weight five years ago, but these days I see very few Python libraries that still support Python 2.7. And, if they do, it strongly implies that they've not been maintained for some time. (See also, a dependency on six) - with the caveat that sometimes you don't need to continually upgrade a library that fills its desired niche perfectly. Hell, if yo…

The people it lost are going to things other than python3.

Not disagreeing.

Re: Python 2 removed from Debian

#280

Post by jeltz »

thiht wrote: post #234
Nullabillity wrote: post #212

Earlier quoted context omitted.

How does print-as-function help anyone remove the GIL?

Damn, get over it. Who cares that print is a function now?

While that specific example is stupid the general question is very valid. I can't see what paved the way. The most invasive change was the unicode one and even that seems irrelevant to eg the GIL.
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