5 ms·

You couldn't switch to Python 3 until the middle part of this decade unless the stars aligned with your dependencies, the library support wasn't there. And the

by mantap 7y ago

You couldn't switch to Python 3 until the middle part of this decade unless the stars aligned with your dependencies, the library support wasn't there. And the first releases of Python 3 were glorified betas, the first "usable" version of Python 3 is often considered to be version 3.3 released in 2012.

ensignavenger 7y ago
But you could easily write Python 3 compatible code so that upgrading once your dependacies were ready was easy. You also could have contributed to your dependancies to help them become Python 3 compatible.
- mehrdadn 7y ago
  > But you could easily write Python 3 compatible code so that upgrading once your dependacies were ready was easy. This sounds a bit like telling someone, oh, you could've easily started driving an EV, so that once charging stations were actually out there, you'd have been ready...
  - ericvsmith 7y ago
    > This sounds a bit like telling someone, oh, you could've easily started driving an EV, so that once charging stations were actually out there, you'd have been ready... While car analogies are notoriously bad, it's much more like "I'm going to buy a plug-in hybrid and use gasoline until charging stations are widely available". You can write code that works in Python 2 that takes zero effort to run in Python 3. I (and many others) have been doing this for years. Just look at the number of packages on PyPI that run, unmodified, on 2 and 3. [Edit: gas -> gasoline]
    - mehrdadn 7y ago
      I try to write compatible code myself too, and the only reason it's "zero effort" to run in Python 3 is that I've already invested said effort when making it compatible. Getting strings and paths and stdio to be cross-compatible and working correctly in both 2 and 3 can be quite painful in my experience. Which was kind of my point with the vehicle analogy. It requires a significant investment that you're ignoring, and lack of enough underlying support to justify it during that time.
  - weberc2 7y ago
    Driving an EV without charging stations is (nearly) useless. You can still run Python 2-3 code with a Python 2 interpreter with no significant consequence.
    - WorldMaker 7y ago
      EV drivers don't need charging stations at all if they have an open plug at home or at work. The metaphor still sort of works that Python developers had plenty of time where maybe they didn't have enough charging stations on the wide open highway roads of Production to use Python 3 there, but certainly could have been happy to use an EV to commute from home (hobby projects) to the work parking lot (side projects, automation projects, new projects) and back while they waited for those "charging stations" to be built.
      - weberc2 7y ago
        I don't want to debate the amount of shoehorning necessary to validate the metaphor. We all understand concretely the issue at hand, the metaphor is only obfuscating at this point.
- mikepurvis 7y ago
  Quick: run a shell command, split up the reply by line, run a regex on each line, and save the results to a yaml file— now, does what you wrote work correctly on both Python 2.7 and Python 3.3+? Yeah that's what I thought. It's still hard to get bilingual Python correct today, and it was considerably harder before 3.3.
  - weberc2 7y ago
    No one is arguing that upgrading would be trivial; the argument is that it's necessary work that could have been started 10 years ago. Also, if you run your unit tests on Python 2 and 3, you'll get pretty good pretty fast at writing 2-3 compatible code.
    - mikepurvis 7y ago
      The comment I was specifically replying to asserted that "you could easily write Python 3 compatible code", and could have been doing so 10 years ago. This is simply untrue— there are a dozen small stumbling blocks that mean that writing bilingual code has a real cost. And it's not as easy as just having the right CI setup, especially if it's ten years ago and most of your dependencies haven't migrated.
      - weberc2 7y ago
        Ah, I see the confusion. In this case, "easily" is relative. The assertion "you could easily write Python 3 compatible code" was in response to the (implied?) assertion "you can't do anything to migrate unless your dependencies are migrated". Perhaps "simply" would have been a better word choice than "easily". To your point, writing 2-3 compatible code has a real cost, but to the GP's point, it's the obvious solution to the "can't do anything until deps are migrated" problem.
        logifail 7y ago
        > To your point, writing 2-3 compatible code has a real cost, but to the GP's point, it's the obvious solution to the "can't do anything until deps are migrated" problem Q: Ten years ago how would you have explained to your manager that you needed your team to start writing 2-3 compatible code, which obviously takes considerably more time and effort than sticking with 2 compatible code?
- pfranz 7y ago
  I often hear this, but I just don't see this working in practice. A very similar example I have experience with, I've often worked with people who tried to write code that would be "compatible with Windows" (I primary work in a Linux environment). It makes the code more difficult to read and as soon as you try and run it in Windows it fails spectacularly. You can write code that's compatible with both Python 2 and 3, but I don't think you can expect to be using Python 2 exclusively and write code that works well in Python 3 unless you're constantly running it with Python 3. Especially, if you don't have much firsthand Python 3 experience. This is much easier if your code is isolated from those dependencies and you write tests that run in both Python 2 and 3, but that's quite a bit more of a commitment than you seem to be implying.
  - ensignavenger 7y ago
    There are a ton of open source projects that have done python 2/3 simultaneously in practice. I get your point though about not being able to run full integration tests due to dependencies. Still, if you were making a good effort to keep the code Python 3 compliant, it would make upgrading much easier. Also, my other suggestion- contributing to Python 3 compatibility for modules you depend on! That will give you Python 3 experience :)
oblio 7y ago
2012 was 7 years ago.
- deleted 7y ago
  [deleted]
collinmanderson 7y ago
I feel like there were 3 steps: - 2008-2012 Python 3 becoming usable (byte formatting, six library) - 2012-2016 Libraries (Django, etc) becoming compatible - 2016-today Applications (Trac, Ansible, Chrome[1], etc) becoming compatible. [1] https://bugs.chromium.org/p/chromium/issues/detail?id=942720 https://bugs.chromium.org/p/chromium/issues/detail?id=942720

by mantap 7y ago

ensignavenger 7y ago

But you could easily write Python 3 compatible code so that upgrading once your dependacies were ready was easy. You also could have contributed to your dependancies to help them become Python 3 compatible.

mehrdadn 7y ago
> But you could easily write Python 3 compatible code so that upgrading once your dependacies were ready was easy. This sounds a bit like telling someone, oh, you could've easily started driving an EV, so that once charging stations were actually out there, you'd have been ready...
- ericvsmith 7y ago
  > This sounds a bit like telling someone, oh, you could've easily started driving an EV, so that once charging stations were actually out there, you'd have been ready... While car analogies are notoriously bad, it's much more like "I'm going to buy a plug-in hybrid and use gasoline until charging stations are widely available". You can write code that works in Python 2 that takes zero effort to run in Python 3. I (and many others) have been doing this for years. Just look at the number of packages on PyPI that run, unmodified, on 2 and 3. [Edit: gas -> gasoline]
  - mehrdadn 7y ago
    I try to write compatible code myself too, and the only reason it's "zero effort" to run in Python 3 is that I've already invested said effort when making it compatible. Getting strings and paths and stdio to be cross-compatible and working correctly in both 2 and 3 can be quite painful in my experience. Which was kind of my point with the vehicle analogy. It requires a significant investment that you're ignoring, and lack of enough underlying support to justify it during that time.
- weberc2 7y ago
  Driving an EV without charging stations is (nearly) useless. You can still run Python 2-3 code with a Python 2 interpreter with no significant consequence.
  - WorldMaker 7y ago
    EV drivers don't need charging stations at all if they have an open plug at home or at work. The metaphor still sort of works that Python developers had plenty of time where maybe they didn't have enough charging stations on the wide open highway roads of Production to use Python 3 there, but certainly could have been happy to use an EV to commute from home (hobby projects) to the work parking lot (side projects, automation projects, new projects) and back while they waited for those "charging stations" to be built.
    - weberc2 7y ago
      I don't want to debate the amount of shoehorning necessary to validate the metaphor. We all understand concretely the issue at hand, the metaphor is only obfuscating at this point.
mikepurvis 7y ago
Quick: run a shell command, split up the reply by line, run a regex on each line, and save the results to a yaml file— now, does what you wrote work correctly on both Python 2.7 and Python 3.3+? Yeah that's what I thought. It's still hard to get bilingual Python correct today, and it was considerably harder before 3.3.
- weberc2 7y ago
  No one is arguing that upgrading would be trivial; the argument is that it's necessary work that could have been started 10 years ago. Also, if you run your unit tests on Python 2 and 3, you'll get pretty good pretty fast at writing 2-3 compatible code.
  - mikepurvis 7y ago
    The comment I was specifically replying to asserted that "you could easily write Python 3 compatible code", and could have been doing so 10 years ago. This is simply untrue— there are a dozen small stumbling blocks that mean that writing bilingual code has a real cost. And it's not as easy as just having the right CI setup, especially if it's ten years ago and most of your dependencies haven't migrated.
    - weberc2 7y ago
      Ah, I see the confusion. In this case, "easily" is relative. The assertion "you could easily write Python 3 compatible code" was in response to the (implied?) assertion "you can't do anything to migrate unless your dependencies are migrated". Perhaps "simply" would have been a better word choice than "easily". To your point, writing 2-3 compatible code has a real cost, but to the GP's point, it's the obvious solution to the "can't do anything until deps are migrated" problem.
      - logifail 7y ago
        > To your point, writing 2-3 compatible code has a real cost, but to the GP's point, it's the obvious solution to the "can't do anything until deps are migrated" problem Q: Ten years ago how would you have explained to your manager that you needed your team to start writing 2-3 compatible code, which obviously takes considerably more time and effort than sticking with 2 compatible code?
pfranz 7y ago
I often hear this, but I just don't see this working in practice. A very similar example I have experience with, I've often worked with people who tried to write code that would be "compatible with Windows" (I primary work in a Linux environment). It makes the code more difficult to read and as soon as you try and run it in Windows it fails spectacularly. You can write code that's compatible with both Python 2 and 3, but I don't think you can expect to be using Python 2 exclusively and write code that works well in Python 3 unless you're constantly running it with Python 3. Especially, if you don't have much firsthand Python 3 experience. This is much easier if your code is isolated from those dependencies and you write tests that run in both Python 2 and 3, but that's quite a bit more of a commitment than you seem to be implying.
- ensignavenger 7y ago
  There are a ton of open source projects that have done python 2/3 simultaneously in practice. I get your point though about not being able to run full integration tests due to dependencies. Still, if you were making a good effort to keep the code Python 3 compliant, it would make upgrading much easier. Also, my other suggestion- contributing to Python 3 compatibility for modules you depend on! That will give you Python 3 experience :)

oblio 7y ago

2012 was 7 years ago.

deleted 7y ago
[deleted]

collinmanderson 7y ago

I feel like there were 3 steps: - 2008-2012 Python 3 becoming usable (byte formatting, six library) - 2012-2016 Libraries (Django, etc) becoming compatible - 2016-today Applications (Trac, Ansible, Chrome[1], etc) becoming compatible. [1] https://bugs.chromium.org/p/chromium/issues/detail?id=942720 https://bugs.chromium.org/p/chromium/issues/detail?id=942720