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Python 2 removed from Debian

bugs.debian.org

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Re: Python 2 removed from Debian

#201

Post by xnorswap »

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.

The migration as a whole has been painful.

It's been 14 years and dropping python2 is still controversial.

It's a story of how not to do a major language upgrade.

It's not quite as bad as "Perl 6" which killed off the whole language, but it's up there with massive mistakes which has cost the industry dearly.

Re: Python 2 removed from Debian

#202

Post by solarkraft »

sherr wrote: post #133

It was a bit of a shock when I upgraded my Debian systems to Bullseye (11) from Buster (10) a year or so ago. I discovered that the wiki I've been using for years, Moin Moin, was removed because it didn't support Python 3. I've a lot in the wiki and was in no position to migrate, so I made a wiki only VM and keep it at "oldstable". Since none of it is internet-facing, I can keep it this was forever, even once all sup…

What shocks me is that MoinMoin doesn't support Python 3.

Re: Python 2 removed from Debian

#203

Post by raverbashing »

p-e-w wrote: post #88
gspetr wrote: post #56

Earlier quoted context omitted.

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

> "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…

I think the issue here is that Python 3.3 was more like 3.0-dev-rc3

The first python 3 versions were not great and were missing some things. I think 3.3 didn't even had pip builtin

Re: Python 2 removed from Debian

#204

Post by solarkraft »

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…

Alternative (imo more likely response): Why should I spend money on migrating to 3 when 2 works?

Re: Python 2 removed from Debian

#205

Post by Beltalowda »

tsimionescu wrote: post #179
maxnoe wrote: post #83

Earlier quoted context omitted.

The removal of implicit conversion between bytes and strings via ascii did not introduce bugs, it showed were you already had bugs that you maybe did not yet notice.

That's only true if you ever received Unicode input. There are plenty of uses of strings that never do - enums, DNS domain names, URLs, HTTP parsing, email addresses (from any sane provider) etc.

Strings are still strings in Python 3; if you do 'foo' == EnumValue then that will work fine in Python 2 and 3. If 'foo' is from an unknown source: yeah, you might get a bytes type in Python 3 and an error, but that's the entire point. Turns out that in practice, it can contain >0xff more often than you'd think.

Certainly today DNS domain names, URLs, and email addresses can – and do – contain >0xff input, and for some of these that was the case in 2008 as well (URLs and email addresses – IDN didn't come until a bit later).

The Python 2 situation was untenable and lead to a great many bugs; "decode errors" were something I regularly encountered in Python programs as a user. In hindsight, the migration effort for existing codebases was understated and things could have been done better with greater attention to compatibility, but the problem it addressed was very real.

Re: Python 2 removed from Debian

#207

Post by tinus_hn »

seba_dos1 wrote: post #183
mike_hock wrote: post #130

Earlier quoted context omitted.

> 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.

It’s so trivial! All that needs to happen is someone else putting in the work. And for free, please!

Re: Python 2 removed from Debian

#209

Post by zarzavat »

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…

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 computing code had to be transitioned even if it didn't use any strings!

Re: Python 2 removed from Debian

#210

Post by willis936 »

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…

Breaking changes has been and will continue to be the pythonic way. I avoid it.
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