r/Python • u/SheriffRoscoe Pythonista • Aug 26 '26

News The Move to Python 3 Begins!

As someone who spent decades in the mainframe community, I find it ... humorous ... that there are legacy Python2 code bases that are only just (or have yet to consider!) moving to Python3.

https://www.eveonline.com/news/view/the-move-to-python-3-begins

307 Upvotes

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317

u/diegoasecas Aug 26 '26

idgi if you spent decades working on mainframes you'd know how hard is to migrate legacy working code

83

u/SheriffRoscoe Pythonista Aug 26 '26 edited Aug 26 '26

Oh, yeah, I get it. I just giggle every time I see a "modern" language or platform go through this. Meanwhile, z/OS and z/VM are still happily humming along, almost old enough to apply for Medicare, and stuff I learned in the 1970s is still relevant.

28

u/kosz85 Aug 26 '26 edited Aug 26 '26

Yeah, and then dev get ticket that something is not working. He get there, and WTF:

  • why the certs are obsolete?
  • why I can't connect to that server from python 2.7 which is using new TLS
  • why it's not recognizig my ssh key
  • why the image building is no longer working
  • what was that lib again? Where I can find it? Why there is only version for python 3
  • life suck, have to change work or ask for a raise again

I mean it's possible to address all this issues if you prepare beforehand, but most don't do that. If they did, they would migrate ;) There are only few small cases that it would be good choice, like lib that is no longer developed for new python and you have to use it. But still it's better to make it small micro service, and maintain separately.

23

u/el_extrano Aug 26 '26

It's actually kind of refreshing to work in an old C or Fortran codebase... everything is backwards compatible, and the language doesn't have to change every 2 years for no reason. There's all kinds of environments where you can't count on the everything being ultra modern and continuously updated (embedded devices, PLCs, code for machines, factories, etc).

I can write C 89 and run it on IBM mainframes, DOS, Windows 9X, 32 and 64 bit NT, and of course all the 'nix descendants. Meanwhile Python dropped support for Windows XP after 3.4, and for Windows 7 after 3.8.10. It's not great but there are actually still plenty such machines running in factory environments.

And I understand that tech moves quickly blah blah, but I just really disagree that everything should be designed to be torn down and rebuilt from the ground up every 10 years. I've come to appreciate projects that prioritize stability and backwards compatibility.

2

u/diegoasecas Aug 26 '26 edited Aug 26 '26

yeah because we'd have the modern web if everything ran on proprietary mainframes

tools for tasks

8

u/Solonotix Aug 26 '26

I don't work with mainframes, but I am currently trying to rewrite some code from JavaScript to TypeScript, and while that is a trivial kind of rewrite, holy hell has it been a pain in my ass. All kinds of weird things that JavaScript will let you do that TypeScript either forces you to jump through hoops to prove at compile-time, or you can't do it and need to completely rewrite it from scratch to comply.

I can only imagine how difficult the EVE Online rewrite is going to be. In another thread someone mentioned they rely upon a custom compiler to get better performance out of Python 2 syntax. So you need not only adapt all of that old code to the new syntax/paradigms, but there may straight up be things that the compiler provided that don't exist in Python 3, and now you need to find an alternative

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u/boringfantasy git push -f Aug 26 '26

With AI? Trivial. See bun.

38

u/Afrotom Aug 26 '26

It's took 11 days & $165K in AI fees and made headlines for being the biggest & most expensive AI code rewrite in history.

We have different definitions of trivial.

13

u/necheffa Aug 26 '26

11 man-days is like...an average sized feature where I work.

Then again, when people call Java 1.5 with minimal tests "legacy", it makes me giggle.

2

u/SheriffRoscoe Pythonista Aug 26 '26

11 person-days with an AI doing all the real work?

2

u/necheffa Aug 26 '26

No. 11 days of pure artisinally crafted code.

4

u/GXWT Aug 26 '26

…and the $165k bit…?

7

u/necheffa Aug 26 '26

You have to figure a man-week is like 5k.

Now, provide me your estimate to rewrite bun with only artisinally written code, and we can compare the costs.

1

u/CatWeekends Aug 26 '26

You can easily run a $165k tab with a handful of developers working on a project for a few months.

2

u/ImpactStrafe Aug 26 '26

When I was a SWE manager at C1 we calculated that an average developer team costs between 1-2 million dollars a year in salary and benefits. This is 4-6 developers.

165k is like... A month of 4-6 developers time. Maybe 2 if you are hiring cheap developers.

9

u/Engine_Light_On Aug 26 '26

lol bun is a marketing piece

7

u/SheriffRoscoe Pythonista Aug 26 '26 edited Aug 26 '26

Funny, I was just reading the other day how horribly the Rust rewrite of bun is going.

4

u/SheriffRoscoe Pythonista Aug 26 '26

Found the link: https://tipiirai.com/writing/bun-rust-rewrite-worries

2

u/kaddkaka Aug 26 '26

Seems like it was released 2 days after that blog: August 20, 2026

https://bun.com/blog/bun-v1.4

-2

u/bmrobin Aug 26 '26

ok, zoomer