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Python 2 removed from Debian

bugs.debian.org

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Re: Python 2 removed from Debian

#181

Post by ilyt »

Flimm wrote: post #79

I like Python 3. It eliminated a whole category of encoding/decoding errors. Even Python 2 codebases benefited from it, as libraries were updated to handle Unicode better in an effort to achieve compatibility with Python 3. I didn't experience much pain migrating codebases to it, but I'm just speaking for myself here. Congratulations to Debian on upgrading to Python 3!

> Congratulations to Debian on upgrading to Python 3!

Debian had Py3 for ages. It wasn't upgrade, that happened ages ago, just removing old packages kept for compatibility

Re: Python 2 removed from Debian

#182

Post by maxbond »

andrewstuart wrote: post #178
saila wrote: post #171

Earlier quoted context omitted.

It's not that complicated nor is it a Python specific issue. This is a good article on the topic: https://www.joelonsoftware.com/2003/10/08/the-absolute-minim... A simplistic summary is that you always decode to unicode and always encode to bytes. Another way to think about it is that Unicode is an idealized character model that is reified into a byte encoding, usually UTF-8, for practical usage. It seems to me that…

It’s not that I don’t understand it. The problem is that encode and decode are directional constructs that change depending on context. That’s a poor UI in Python.

Genuinely curious, what would you like it to look like?

Re: Python 2 removed from Debian

#183

Post by seba_dos1 »

mike_hock wrote: post #130
EdwardDiego wrote: post #99

Earlier quoted context omitted.

> 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. That's reading far too much into a tongue in cheek presentation title. Besides, good devs are typically reasonably skeptical of new and shiny. And when you've got a large Python 2.7 codebase, and Python 3 is backwards incompatible, you'd be looking at a lot of work to upg…

> How much Python code in the wild implicitly depends on the behaviour of the GIL? About as much as depended on Python 2-specific features?

A lot of codebases could be converted from Python 2 to Python 3 with just some fairly mechanical work and light refactoring on top. GIL would be a thing of a completely different magnitude.

Re: Python 2 removed from Debian

#184

Post by ilyt »

gspetr wrote: post #56
tgsovlerkhgsel wrote: post #50

Glad this is finally mostly over, but... that was bad. I wonder if the energy that had to be put into this migration by everyone involved was worth what seems to be relatively small improvements. The print-as-a-statement was ugly but convenient and didn't seem like a big deal, the integer division was something that you could live with once you knew about it (and you still need to know what the current behavior is),…

IMO you're oversimplifying things without appreciating the scope of what went into Python 3. Core developer Brett Cannon's talk "Python 3.3: Trust Me, It's Better than 2.7" goes over most of the differences at the time (2013): https://www.youtube.com/watch?v=f_6vDi7ywuA

The changes Python made was made in Perl without breaking compatibility, you just wrote say

    use v5.24
in header to use given feature set (defaulted to something old to not break old stuff)

The Py3 approach was terrible and wasted untold amount of hours just because you had to migrate everything, you couldn't just upgrade codebase piece by piece like in case of Perl.

At the very least they should've just made new one be under .py3 and just make Python3 interpreter transpile Py2 code at runtime

Re: Python 2 removed from Debian

#185

Post by tsimionescu »

asddubs wrote: post #148
hansonkd wrote: post #131

Earlier quoted context omitted.

Well, trying to sell a project to the higher-ups is a lot easier when you can say > Hey our interpreter for our backend code will be eventually deprecated. It is currently version 2 and we need to move to version 3" Then the execs say "we are on 2?? and there is a 3??! what are we waiting for?!" A whole lot easier than trying to say: > Hey, there is a new interpreter out there called COBRA. We need to rewrite our who…

I do like the optimistic worldview of execs being like "version 2?! version 2 sucks!! I want version 3, of that thing you just said"

Oh, I've heard that a lot from execs. What they also say afterwards is - "we expect you to do it without slowing the pace of adding new features and fixing bugs!!"

Re: Python 2 removed from Debian

#186

Post by ilyt »

lifthrasiir wrote: post #55
whirlwin wrote: post #44

As mentioned by several people already, the migration process from 2 to 3 was really painful. It will be easier for the Python core maintainers, but introducing a breaking change with the intent that that version 2 will be deprecated has probably caused more distress overall, especially maintainers of other open source projects which rely on a specific python version. Let's never have the same kind of breaking change…

> It will be easier for the Python core maintainers, [...] It wasn't not even that easy, to be frank. 2to3 is not a small project [1] and they had (alas, incorrectly) assumed that there were enough people to have enough tests to be benefited from 2to3, only to be found massively wrong. In hindsight no one had a good idea about language evolution; the modern concensus is a single interpreter supporting multiple parall…

> In hindsight no one had a good idea about language evolution; the modern concensus is a single interpreter supporting multiple parallel versions, also called "editions", but (EDIT: to my knowledge) the first major language with this approach was ECMAScript 2009 (5th ed.) with `use strict` and Python 3 predated it.

Perl did it since ages. You just put

    use v5.24
in header and interpreter enabled those language features on file by file basis

Re: Python 2 removed from Debian

#187

Post by ilyt »

masklinn wrote: post #89
kasabali wrote: post #62

Earlier quoted context omitted.

> first major language with this approach was ECMAScript 2009 (5th ed.) Not that I've any proof but I kind of find it hard to believe there were no other examples before

Python had that long before js, with __future__ imports. But editions & friends are for syntax. Python 3 changed semantics all around. Editions are not an option when you’re changing the langage’s entire text model, especially without static typing.

Could just transpile Py2 to Py3 at runtime.

Re: Python 2 removed from Debian

#188

Post by ilyt »

hansonkd wrote: post #131
psychphysic wrote: post #94

2to3 really showed that Python didn't understand their audience. If they had started a new project called COBRA and just eventually had it over take python the world would be all over it. But massive breaking changes going from 2 to 3 was a disaster for their audience. Worse still you could hear the acrimony in Pythons communications on the topic.

Well, trying to sell a project to the higher-ups is a lot easier when you can say > Hey our interpreter for our backend code will be eventually deprecated. It is currently version 2 and we need to move to version 3" Then the execs say "we are on 2?? and there is a 3??! what are we waiting for?!" A whole lot easier than trying to say: > Hey, there is a new interpreter out there called COBRA. We need to rewrite our who…

> Then the execs say "we are on 2?? and there is a 3??! what are we waiting for?!" A whole lot easier than trying to say:

Nope, the real life conversation would be "Is 2 still supported ? Yes ? Well then we will migrate when it won't"

Re: Python 2 removed from Debian

#189

Post by mnau »

pjmlp wrote: post #118

Meanwhile we are still living our Python 2 like moments in .NET and JVM ecosystems, with the huge amount of projects stuck in .NET Framework and Java 8, with no end in sight of them ever moving forward.

Yeah, I hoped MS would be more supportive of .NET Standard 2.0 during transition period.

I am stuck on .NET48 at least for another two years (because of webforms frontend) and the last version of EF Core that supports .NET Standard 2.0 is 3.1. They dropped .NET Standard 2.0 like a rock... for what? Few default interface implementations.

Or nullability attributes that are missing in .NET Fx, they could also be defined externally, like R# does. Nope, sucks to be you.

Re: Python 2 removed from Debian

#190

Post by Joeboy »

yen223 wrote: post #122
whirlwin wrote: post #44

As mentioned by several people already, the migration process from 2 to 3 was really painful. It will be easier for the Python core maintainers, but introducing a breaking change with the intent that that version 2 will be deprecated has probably caused more distress overall, especially maintainers of other open source projects which rely on a specific python version. Let's never have the same kind of breaking change…

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.
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