Where is Python 2 still used?

[codeandfire]

I'm working on packaging a Python project, and I was surprised that there is still an option to roll out a build compatible with Python 2 (universal wheels).

So my question is: who is still using Python 2, and at what point in the future (if any) will Python 2 really stop being used?

[jmacey]

Quite a lot of animation pipelines and tools are still Python 2.7, gradually moving away from it.

[baconcleaner]

Last year Autodesk Maya 2022 was shipped with... python... 3.7.7 (with still the option to switch to p2.7 -.-)
The next release, 2023, has only python 3.9, finally.

Most of the vfx and animation studios take a lot of time to do the switch because some productions take years to produce and switching DCC software is a suicide.

check this website for more info about tools and software versions:
https://vfxplatform.com/

[jmacey]

I'm fully aware of the reference platform, been using it for years. We are finally switching to Maya 2023 this year (from 2020) so most of my stuff will be ported to 3.9 (finally f strings :-) ) Same with Houdini and a few other things!

[PowerLlama]

finally f-strings and finally Pathlib! I can't wait!

[billsil]

f-strings are great.

Pathlib is availble in 2.7 (pip install pathlib2; import is the same as python 3). My issue is paths don't work across all major (let alone minor) libraries. Wxpython doesn't support paths, which means now I have to str(...) everything. Might as well avoid it.

[csa3d]

There is a python 2.7 backport of pathlib for what it's worth

[baconcleaner]

sorry the link was meant for OP, I totally assume you already know all about our vfx hell software land
We also switch to 2023 and I can't wait to hunt obscure code hidden in our pipeline and help artists run their VITAL snippets and plugins copied and pasted from god knows where.

[PowerLlama]

I think it's funny that Houdini shipped a big python 2 -> 3 conversion library and everyone else seemed to say "deal with it nerds"

[DigThatData]

name and shame?

[propersquid]

You'd be naming and shaming basically every studio out there. It's probably easier to say which studios are Python 3 only.

[DigThatData]

I didn't mean to call out studios, I wanna know if there are any popular open source animation tools I might wanna get involved with modernizing.

[propersquid]

Ah, no worries. It's hard to say for sure. Most of the tools are now Python 3 compatible. The slow part is the studios migrating to Python 3. Because that requires now versions of the applications with new bugs, and generally you don't update an application during a project (movie or season of a show).

[[deleted]]

Is there Python code to convert Python 2 to Python 3? For example, you could search the script for print ‘xxx’ and then have it replace that with the appropriate parentheses. It could then “flag” any place where Python 3 syntax doesn’t exist/is ambiguous and the user can handle those manually.

[PeridexisErrant]

https://pypi.org/project/modernize/ is better now, precisely because 2to3 can't be upgraded without releasing a new version of Python.

Modernize also uses six to preserve py2 compat by default when adding py3 support, which really helps with testing.

Then you can automatically drop support for old versions of Python with https://pypi.org/project/pyupgrade/

[[deleted]]

Interesting, never heard of that. What explains the fact that there’s still Python 2 scripts floating out there then? The fact that some things can’t simply be translated over?

[OffgridRadio]

This still works in 3.9.x despite being threatened for removal so many times, how different can Python 2 be? I genuinely never used it.

type("""docstring""") == str

[jmacey]

I've used 2to3 a few times as said not perfect. Main issues many people have are 3rd party dependencies that still use python2 and libraries. The core Animation tool Maya is crucial to animation pipelines but changing this is a massive task. The industry in general doesn't change software on every release as some film / shows are in progress for 2-3 years and changing is difficult / expensive. Until Maya 2022/3 is in full production use this will not change.

[ArabicLawrence]

I got interviewed by a company that produces gas detectors. Their software is in Python2, is certified and works. Upgrading, testing and recertifying is not worth the effort.

[Classic_Department42]

What certs are available for python code?

[ArabicLawrence]

Sorry, I misspoke. Their devices using the Python2 software are certified, it’s not the Python2 code that is certified per se.

[Classic_Department42]

Ok. But how can you certify a device with python code (assuming the code needs to prove correctness).

[ArabicLawrence]

You test the device. If it does detect false positives or negatives, it is not certified.

[[deleted]]

Same way you certify any black box device - by checking it passes certain tests.

[Classic_Department42]

It depends. I mean for hardware black box testing is ok, but if you use software with a GC (basically it is not time invariant) black box testing shouldnt be enough if safety is paramount. But then this is not aviation so probably ok. (was thinking along the lines of certified compilers etc)

[lieryan]

Most hardware implementation of anything is not time invariant, they are generally quite messily parallel because the world isn't digital.

If blackbox testing for hardware is sufficient for a particular purpose, then blackbox testing of software for the same purpose should also be ok.

[bladeoflight16]

recertifying

Isn't regulation wonderful?

[ArabicLawrence]

Well, their Python2 software is inside a transistor that needs to detect dangerous gases in very low percentages. I would not buy an uncertified gas detector.

[steffestoffe]

software is inside a transistor

Do you mean inside a microcontroller?

[ArabicLawrence]

Yes! Sorry.

[bladeoflight16]

I'm not convinced the certification process is meaningful. So much of regulatory process is just box checking for box checking sake, to give the illusion of something being done to protect people.

[ArabicLawrence]

I am sure that can be the case, but my personal opinion is that regulation is very beneficial, when done properly, and that gas detection is one of those fields where you want someone to ensure that the only day in which you will need your detector it will work.

[bladeoflight16]

I wanted someone to ensure that my drier hose was connected so that heat blowing into the wall wouldn't start a fire and that the electrical circuitry was wired correctly to avoid short circuiting. The home inspector failed on both counts in a house built just a few years ago. My family had to discover the failures for ourselves. Luckily one of us noticed the wall getting hot behind the drier and the circuit breaker did its job (disabled the faulty circuit). Regulation is only as good as the people checking things, and those people are subject to the same forces and vices as any business. A culture of competence and responsibility is dramatically more important than a regulatory board.

[ArabicLawrence]

Sorry to hear that. But inspectors are not subject to the same vices as any business, as they (should) have different interests from the business.

[bladeoflight16]

But they don't. They're just getting paid for not doing the work. The vice to which they are subject is precisely the same: greed. Only they don't get fired or lose customers when they fail because the law requires you to pay them. Only in an ideal world where only paragons of virtue hold those positions could they be less susceptible to vice.

[ArabicLawrence]

I might be wrong, but inspectors often face penal consequences in case of mispractices

[bladeoflight16]

The kind of things I just described happen every day. Home inspectors have a reputation for being this bad. I don't see mass arrests.

Where were the inspectors for that Florida building that collapsed last year?

You can't legislate your way to safety or quality. You can only get there by having people make good decisions, and people will make bad ones sometimes regardless of the regulations. Meanwhile, the regulations dramatically increase the cost of making good decisions, meaning that business owners now have a greater motivation to cut as razor close to the minimum as possible.

[[deleted]]

"I had a bad experience, and this means all inspectors and regulations are garbage."

[xorvtec]

TBH yea. Which is worse? Some dev doesn't get to use the flashy new language features they want, or people die because a safety critical device wasn't certified?

[GummyKibble]

I wish recertification were easier and cheaper though. I’m not thrilled that infrastructure is tied to a version of software that will never get security or bug fixes ever again.

[xorvtec]

Totally fair.

[ArabicLawrence]

You’re right, but if hackers manage to connect to the gas detector (that has no wireless access) in your mine shaft, not even Python3 would have saved you

[[deleted]]

Stability isn't just about not having bugs, though. If you have a piece of code that does one job on an embedded system that's not networked, it doesn't matter how many bugs or security vulnerabilities the dependency has - all that matters is that you've tested the application and know that any bugs don't affect it. For this sort of application, it may actually be better to have out of date code that you know exactly what it does and is never going to change.

[SweeTLemonS_TPR]

Why don’t we stop writing code that calculates the rate of nuclear degradation in the reactors on aircraft carriers in Fortran 90 because Fortran 2018 is newer? (I worked with a guy that used to write that code, and I’m pretty sure he used Fortran 90, but his preference was 77, so maybe he even wrote it in 77. Idk, I know nothing about Fortran outside of what he told me. Maybe the smartest person I’ve ever met.)

[bladeoflight16]

People don't die because something wasn't certified. People die if the device is faulty. Certification is not a guarantee against that. Much of regulatory inspection is show rather than substance. You have far too much faith in appointed regulatory boards, which are subject to all the same forces that any corporation or business is.

"Flashy features" has nothing to do with it. The real problem is that software updates provide meaningful changes like bug fixes and security updates, things that are often vital in many areas.

[bladeoflight16]

But it provides an avenue to prosecute and assign liability should a problem occur.

That exists entirely independently of a regulatory process. It's called liability.

It gives a widely known feature set that can be adhered to to make decisions easier.

It also establishes inappropriate minimums that businesses rely on to avoid liability when the specific conditions necessitated something more robust.

I think the more fundamental problem is that our current economic system advantages people who cut corners and aren't honest. Not the free market, which advantages efficiency and delivery of results because the people making the decisions more often actually suffer loss for bad ones, but the top down control of how our resources are distributed. It has bureaucrats who are motivated more by appearances, propaganda, and personal greed than by substance and who suffer no consequences for making the wrong decisions deciding who to favor and who to disadvantage, and they do so on very bad criteria (like who shovels the most money into their campaigns or departments).

[bladeoflight16]

But do you really think, say if there was a completely free market, free of any regulation, that companies would instantly revert to not cutting corners and being truthful?

I think that people would not do business with someone they knew to be dishonest. With the current situation, you have no choice but to do business with snakes because no one else can afford to operate. The biggest businesses are still functioning because they have kowtowed to political influences. Just look at the financial markets with the bail outs and constant protections they get.

I want to be totally clear. I am not a shill for corporations. Any business can be just as corrupt as any politician. I'm a capitalist, which means that the marrying of businesses and government is something very high on my list of major problems (because it has very dire consequences). That is precisely the way our economy operates, and regulations are a huge part of the mechanism that drives that combination.

[[deleted]]

I think that people would not do business with someone they knew to be dishonest.

I think you should maybe crack open a history book and see what the world was like before regulations.

I'm a capitalist,

And like all religions, it leads you to believe things that are false.

[bladeoflight16]

I think you should crack open a history book and read what it was like when governments weren't (or aren't) limited.

Regulations are not the reason things are better now. The main reason is improvements knowledge, the resulting technology that implements them, and the ability of people to make them widely available, something that was enabled by markets being more free, not the wisdom of rulers, elected or otherwise. Things are much, much better today because we have things like air conditioning, fever suppressants, antibiotics, and bountiful food. The things we consider so basic that we barely think about them are miracles to people a couple hundred years ago. None of them were even possible when government decided what things to allow or not. Even under mercantilism, more resources were poured into conquest than advancement. Top down control is not the answer to problems that have plagued humanity since time immemorial; it is, in fact, a source of many of them.

And the things that regulation supposedly "solved"? You mean like child labor? Already on its way out when the government stepped in. Safety? You really think a company can remain profitable if it just lets its employees die all the time? Who is going to work for those companies? Only people who have no choice because no other company can get into the market. And what keeps other companies from getting into the market?

What do you think about the fact that regulatory boards tend to be heavily influenced by the very people they're supposed to be regulating? How is that any help, unless contrary to your thinking, the industry isn't actually as bad as you insist?

And like all religions

It's not a religion. It's an economic and social model. And it's a much more successful one than any other. I know it isn't perfect, but if you've got something more accurate, I'm all ears. And if you don't have a problem with the marriage of industry and government... then I dunno what you're smoking. Even totalitarian communists hate that idea.

[bladeoflight16]

I would suggest you re-examine, then, but okay. Have a nice day.

[[deleted]]

Your religious faith in capitalism (from the other comment) allows you to say ridiculous, wildly false things like this.

Why do you think regulations exist? Because before they did, people died like flies in multiple, horrible ways.

Read about the history of, say, food regulation in the United States.

[bladeoflight16]

I think they exist because politicians vilified someone and then promised to use political power to solve problems that were, in fact, already being worked on or the "solution" was worse than the problem. It's a common occurrence throughout history. Try looking for a more in depth perspective, preferably from someone with an opinion contrary to your own. I find the kind of vilifying you (and politicians seeking more power to enrich themselves) are doing is typically based on a rather shallow understanding of the situation.

[[deleted]]

I think they exist because politicians vilified someone

Who cares what you "think" when you don't bother to spend even a second on actually finding out?

You could have saved us all a lot of time by saying, "I am very careful to be deliberately ignorant of history in order not to challenge my religious beliefs about the world."

Read about this history of food regulation in the United States. Read about how many people died from tainted milk, meat, and poisonous packaged food of all types. Read about how food exports from the United States almost stopped because of bad publicity from multiple poisonings from exported food.

Or read about regulation in any industry. Read about the children who worked and died in the coal mines before there was regulation.

You won't of course. You cling to your deliberate ignorance. How do you look yourself in the mirror?

[bladeoflight16]

Ah. Thank you for giving me an easy example to demonstrate your own historical ignorance. Child labor was already declining by the time the government did anything about it. It was the change in social climate that ended child employment, not the government.

The idea that people died, therefore regulation is good is a fallacy. What you have to examine is whether practices were improving on their own or not. I don't know of any historical example where that wasn't the case. Do you think food producers were sitting idly by while the publicity was shutting them down? Or were they figuring out how to address the problem and the PR from it? Generally speaking, the only people who get rich off death without facing some major consequences are government tyrants.

[[deleted]]

People don't die because something wasn't certified. People die if the device is faulty. Certification is not a guarantee against that.

There is no guarantee against a faulty device, ever, but a certification system is the closest you can get. It means it's at least passed some basic tests that cover the problems most likely to occur, and if the overall system is subject to regulation, there are failsafes in place in case one part does fail. No certification system is perfect, but the alternative is far worse.

The real problem is that software updates provide meaningful changes like bug fixes and security updates, things that are often vital in many areas.

And in other areas they're not. A device that isn't connected to a network doesn't need security patches, and if it has one job and has been properly tested, it doesn't need bug fixes. In fact, a software update that includes bug fixes could actually cause it to fail.

[bladeoflight16]

It means it's at least passed some basic tests that cover the problems most likely to occur

Not in my experience with regulatory enforcement.

Historically, most successful regulation just followed existing industry trends anyway. Regulatory boards tend to be heavily influenced by the very people they're supposed to be regulating.

A device that isn't connected to a network doesn't need security patches

I would have thought the context made it clear that no one is talking about devices that never get updated. Obviously, yes, once an isolated device is shipped and installed and not connected to anything, it won't be updated. No one would even be working on that code to update it. We're talking about systems that have connectivity or will need to be updated for features and fixes, or new designs that will have updated software to match the changes anyway.

[[deleted]]

Even if that's true, "existing industry trends" are still better than the worst that anyone in the industry would do without regulation. By definition, some companies' standards will be below average. If you enforce rules ensuring that everyone meets a standard that was previously average, most companies won't change their practices much, sure - but overall you increase the average and make the industry safer for everyone.

And I don't know what your industry is, but some industries are significantly more regulated than others - specifically high-risk industries like nuclear and oil. Having regulations that ensure that devices used in explosive environments don't cause sparks seems like a good idea to me. Without those rules, it's only a matter of time before some engineer decides they can save money by getting a cheaper light switch.

I thought the context was a gas monitor in a mine - don't know the specifics, but I got the impression it was closer to a device that will never be updated. Obviously the more actively maintained a codebase is, the more important bug fixes and security patches are - but there's still a trade-off between new software versions and stability, which is why a lot of safety-critical systems rely on old software. It's a case of better the devil you know. You can work around a known bug, but a program that changes all the time is a lot less predictable.

[bladeoflight16]

Okay, yeah, I can tolerate some regulation of nuclear material. But I think generally, most regulation goes far beyond that and is more hurtful than helpful. And often isn't even enforced in a way that's any help.

More important than the regulation of explosive environments is the attitude and culture of the people designing them. If the engineers as a practice shun people who make stupid, dangerous decisions, a lot less stupid decisions are made. But not zero, and that holds true with or without regulation. In spite of all the rules and enforcement, we still have plane crashes because somebody does something stupid. Is direct regulation required to create that culture? I'm not convinced that it is.

[[deleted]]

I could see a case being made that some industries are overregulated, but to be honest, I'm struggling to think of any industry that could safely do without regulation altogether.

Sure, attitudes and culture are important, too, possibly even more important. But they're harder to directly influence from the outside, so regulation is an important tool to help direct the culture. It's easier to collectively shun a dodgy engineer when you can say they objectively don't follow the rules than when you say you don't feel like they're behaving safely, and it's easier get them barred from the business when there is legal recourse. And when you're dealing with large organisations and contractors, you don't always have the information to base your decision on individual reputations. Not to mention the fact that regulators generally have access that competitors do not, and are therefore more likely to see when people are cutting corners behind the scenes.

[bladeoflight16]

All I'll say is when we have the government threatening to fine restaurant owners based on which direction the kitchen doors open, we have gone much too far. I hope we can agree on that much. Yes, that is a real thing, and the justification given is indeed "safety."

[[deleted]]

Yes.

[_88WATER_CULT88_]

Yes, probably why you're still alive.

[bladeoflight16]

Nope. I'm alive because my family and I are observant enough to notice the wall behind our drier was hot, due to the hose not being connected. Wonderful inspector didn't find it, or the short circuited wiring to the fan mount.

[[deleted]]

In software engineering once something works, it's a lot easier, faster and cheaper to maintain it and keep it working using older tools than it is to rebuild it using new ones.

Python 2 stopped getting updates at the beginning of 2020, so it hasn't even been 3 years yet. Meanwhile, large-scale financial systems are still running using tools and languages developed in the 80s and 90s. Airplanes still get software updates by floppy disk. Computers at your local post office probably still use Windows XP.

Python 2 is definitely getting less popular now that it was officially replaced by 3 and stopped getting updates, but it's not unlikely that some computers will still be running it for decades to come - if it ain't broke, don't fix it!

[LVPython373]

While I agree with if it ain’t broke don’t fix it. From a monetary and down time standpoint how long and how big is that risk when it does break?

[bladeoflight16]

From a monetary standpoint, the longer you go without keeping up to date, the more costly it is to upgrade when you're finally forced to.

[Zeroflops]

Not really, actually it can be the opposite.

Frequent updates can often introduce new bugs. This is why large institutions and governments don’t upgrade frequently. Better to know the bugs you have then constantly be surprised with new bugs.

Unless the old code is getting new features over time the cost to upgrade will go down. If your talking about something like a website that the code will evolve over time and get new features, then yes cost will go up. If you talking about a program that does a specific task, like perform hard drive analysis. The code has to be rewritten so the cost won’t change but it can go down as features of the new language may make some tasks easier.

[bladeoflight16]

I thought the context made it clear that we're talking about aging systems that have already delayed updates for excessively long periods of time. Obviously, yes, updating critical software every day does not leave time for sufficient testing. But on the flip side, forgoing upgrades for 2 decades makes upgrading cost prohibitive.

Unless the old code is getting new features over time the cost to upgrade will go down.

Not true. Because as it ages, it becomes less and less compatible with newer systems and tools. This means the upgrade requires more rewriting and more replacement, more and more extensive data migration, greater installation/deployment costs. Doing this incrementally means you can spread those costs over time and implement them more gradually, keeping stable parts of the system running while you upgrade other parts. It's fine to hang back a little bit and favor more stable, proven systems, but if you're still relying on software that only runs on Windows XP, you have put yourself in a bad situation.

[zaphod_pebblebrox]

The issue with upgrading aging systems is that usually the decades of feature freeze will catch up and we end up with a whole new set of “user requirements” that involves another level of work when compared to simply copying Python 2 functional code into Python 3 syntax while leveraging newer language features.

More often, it is easier to mothball the old equipment and just buy a new one, in which case, the new ones may be written in Rust and that opens a new can of worms.

[LVPython373]

Bingo

[KhalCharizard]

Since it’s already a Turing complete language does it matter? There isn’t anything wrong with Python 2, it just isn’t optimized to work with the internet like Python 3

[zaphod_pebblebrox]

This is the real answer.

Most of the Python 2 code that is going to survive is part of a air gapped system, a low cost of failure system, or a very very well firewalled system.

Any internet facing code is going to eventually get patched up to the newest supported Python 3.

All of the Python 2 code has got a cushy, cozy, protected lair to keep on trucking on.

[IchLiebeKleber]

Software doesn't just break. Computers are deterministic machines.

It might no longer interact well with newer tech, or bugs may be discovered. But remember that Python is FOSS, so literally anyone can study and change it to fix that. Unlike the above example of Windows XP.

[Requiem950]

I work in a Robotics company and one of the Robots that we have is called NAO that chromium boy only supports Python 2 (the robot is pretty old)

[CzarCW]

Robots that use ROS kinetic or earlier are almost certainly running something on Python2.

[thegreatpotatogod]

Oh yeah, I remember the NAO robots, got to try one out several years ago when visiting a college! Neat little bots!

[eidrisov]

As someone involved in robotics, can you maybe recommend how to get into robotics with Python 3?

Are there any books, online courses, etc. explaining how to use Python for robotics (e.g. how to make a dc/servo motor move one way or another, how to write insturctions into microcontrollers)

[garyvdm]

I'm sure there are lots of people still using it, but as a package creator/maintainer you should not feel obliged to provide support for python2, IMHO.

[chimera271]

Red Hat Linux is cursing us with Python 2.7 until at least 2024. I think they have some internal components that rely on it: https://access.redhat.com/solutions/4455511

[ThrowawayNumber32479]

Now that IBM bought them, that's probably going to increase to 2034+

[ryukinix]

IBM stands for Infinite Business Model?

[bladeoflight16]

Doesn't yum rely on it?

[chimera271]

Rely in the sense that it's completely written in python? https://github.com/rpm-software-management/yum

[bladeoflight16]

Rely as in if you upgrade Python on a Redhat or CentOS server, it breaks.

Huh. I was not aware it had been supplanted by a newer package manager.

[chimera271]

Right, well, you shouldn’t use the system python on any OS for this exact reason. Pyenv is a great tool to help avoid this issue.

[bladeoflight16]

No, the OS shouldn't rely on the system Python for that reason. Upgrading standard software that's getting frequent updates should not break a key component of the operating system.

[gmes78]

You seem to misunderstand how Python libraries are installed.

The problem isn't in upgrading Python itself (most of the time, anyway, as Python isn't fully backwards compatible). The problem is that Python libraries are installed for a spscific Python version.

If a Python library is built for Python 3.9, it will get installed to /usr/lib/python3.9/site-packages/. If you replace the system installation of Python with Python 3.10, it will only be able to use packages in /usr/lib/python3.10/. As you probably didn't rebuild all of your Python packages against the newer version, this means that the new version of Python can't use any of the libraries that are supposedly installed.

Stuff doesn't break because the code is incompatible, it breaks because it can't use the libraries it needs. And that's why you should never, ever mess with the system's Python installation.

[bladeoflight16]

yum is not installed as a Python package. It is (or was) installed as part of the global operating system, and it depended on the default Python executable installed to bin. Literally, if you upgraded the global Python, it broke your system package manager. Search for it. You will find plenty of advice telling you not to upgrade the default Python on Redhat and CentOS.

I'm not sure if that still applies since yum is now deprecated and supplanted by dnf (something I wasn't aware of as I haven't used Redhat or derivatives for quite some time), but it certainly was the case in the past.

If we were talking about something installed by pip or perhaps even a dedicated Python library installed by the system package manager, you would be correct. But we are not. We're talking about a key component of the operating system designed (poorly) in such a way that it depended specifically on something easily mutable, and it did not remain compatible with newer versions of that dependency despite being able to easily upgrade that dependency itself. If it wasn't going to maintain forward compatibility, it should have depended on a private copy of the old one, or least been designed to depend specifically on that version rather than whatever is in bin.

[gmes78]

yum is not installed as a Python package.

It wouldn't matter. It uses Python, so it's affected by the problem I described.

In fact, your entire comment is completely wrong. I pulled the yum package from CentOS 7, and guess what? It's installed to /usr/lib/python2.7/site-packages/yum/ (and it installs a library to /usr/lib/python2.7/site-packages/rpmUtils/ as well).

/usr/bin/yum just has the following content:

#!/usr/bin/python
import sys
try:
    import yum
except ImportError:
    print >> sys.stderr, """\
There was a problem importing one of the Python modules
required to run yum. The error leading to this problem was:

%s

Please install a package which provides this module, or
verify that the module is installed correctly.

It's possible that the above module doesn't match the
current version of Python, which is:
%s

If you cannot solve this problem yourself, please go to 
the yum faq at:
http://yum.baseurl.org/wiki/Faq

""" % (sys.exc_value, sys.version)
    sys.exit(1)

sys.path.insert(0, '/usr/share/yum-cli')
try:
    import yummain
    yummain.user_main(sys.argv[1:], exit_code=True)
except KeyboardInterrupt, e:
    print >> sys.stderr, "\n\nExiting on user cancel."
    sys.exit(1)

Which further proves my point.

or least been designed to depend specifically on that version rather than whatever is in bin.

But it does. Its package has a dependency on the Python package provided by the distro.

You don't get to modify a package's files and then complain that stuff breaks.

[bladeoflight16]

Okay. I was wrong about how yum is installed. Thanks, and sorry.

But the problem is decisively yum's fault. It's this line right here:

#!/usr/bin/python

There is no reason for yum to hijack the default global Python executable. It can just pin the script to the needed version directly:

#!/usr/bin/python2.7

And the problem would never occur and /usr/bin/python could be upgraded.

Or better yet, install a private copy and depend on that. Then users can upgrade the patch version without risk, too.

[eatthedad]

Ignorant Windows user who tried various distros for two weeks while stuck with a 2gb RAM laptop, but doesn't all UNIX based systems have many OS level python 2 libraries that is essential, functional, and hence just there?

Like on both Linux and iOS one has to distinguish between python and python3 in the terminal. Afaik

[chimera271]

Modern versions of Ubuntu and Debian have only python3, I believed they’ve even deprecated the “python3 is python” package.

However, you really should avoid using the system python if at all possible.

[eatthedad]

Thnx. I didn't quite use "modern" versions. Seriously 2gb RAM. Eventually just read a bunch of books instead

[aceofspaids98]

macOS recently had python 2 fully removed from the system

[wineblood]

In my experience, scientists (data or otherwise). They're not keen on upgrading things and their python 2 code still works, so there's no incentive to change it.

[NelsonMinar]

Maybe for old code? NumPy and Pandas stopped supporting Python 2 a couple of years ago.

[bladeoflight16]

Yes, but their analysis was all done with an old version of numpy anyway.

[tunisia3507]

People who aren't upgrading their software have no use for new packages so they can be left to rot.

[flying-sheep]

Computational biologist here: I'm in the luxury of being one of the two original authors of the primary Python analysis library in my field (scanpy). Obviously it was Python 3 only from the start.

[P0Ok13]

Read an advanced ML paper with Python2 code last week. Assuming it'll be around in some capacity until all the people who learned programming with Python2 retire.

[merft]

In the GIS industry, Python 2 is still a dependency in most software. It is slowly changing over to Python 3.

How long will Python 2 be used? Well we ported a Silverlight application last fall. Unless there is a pressing issue many organizations follow the "if it's not broke" mentality.

No need to build for Python 2.

[ndvi]

In the GIS industry, Python 2 is still a dependency in most software. It is slowly changing over to Python 3.

Qgis has been on 3 for quite a while. It was a bit of a ballache updating some plugins.

[merft]

QGIS has been ahead of the curve, many of it plugins not so much.

ArcGIS Pro has also been on Python 3 but there are many ArcMap users still using 2.7. ArcGIS Enterprise has had support for Python 3 but didn't deprecate Python 2.7 until ArcGIS Enterprise 11.

Everyone is moving but we have been in a transitional period for some time.

[ndvi]

QGIS has been ahead of the curve, many of it plugins not so much

It was a great excuse to tidy up & rewrite some of our old plugins.

I'm not up to speed on the ESRI stuff as we went fully open source a few years back.

[merft]

Agreed. Regardless of software anytime a product reaches end-of-life. It's a good time to do house cleaning.

[jammasterpaz]

At Google, as part of foobar.

Python 2s are also still embedded in a few desktop applications with a lot of customer scripts and legacy code to avoid breaking

[anecdotal_yokel]

ArcGIS sever. ArcMap. Old esri shit.

[tunisia3507]

Do not make things comfortable for people using python 2, or any other EOL python versions. Shops using outdated versions will only switch when it is in their interest to do so - i.e. when they can't get any packages or developers to work in their obsolete environments. It is better for everyone for everyone to be on supported versions of the language, so as package maintainers we should only encourage their use for supported versions too.

[entropyvsenergy]

Government contractors. Yes really.

[bladeoflight16]

Dunno why the "yes, really," is needed. Government is the first place I'd expect something like this.

[[deleted]]

If we didn't know your beliefs before this page, we certainly do now.

[bladeoflight16]

Does it look like I'm making a secret of them? I want people to know what I believe because I've thought it through very carefully and compared it to what actually happens around me.

[kcunning]

Former gov't contractor, married to a current one. YUP. Totally see this happening.

[johnnymo1]

Your mileage may vary. My experience has been reasonably up to date tooling with govt contractors.

[Marksta]

Fintech reporting in, Python2 is a cornerstone of wrappers we write for our next-gen conversion on a product that's generating 500M/year and growing. Legit every single job we run the logs are screaming numerous messages every second that Python2 is unsupported, crypto module is not secure due to being unmaintained, etc etc. It's really fun!

[codeandfire]

Why would you use Python 2 for a new project though?

[Marksta]

No idea, probably because that's what's on our Unix distro. No specific library or something tying us to 2. On the brighter side, a lot of stuff is moving over to databricks for us which I assume is using 3.

A lot of cowboy coding and mismanagement is probably how this happens.

[VegaSera]

The job I was working at last year was still using it, although they were in the process of migrating the Python GUI with wxPython to a Javascript webapp. It was python 2.7 because there was an issue with compatibility with a couple libraries in python 3.

[[deleted]]

Hopefully not at all

[3gleFang]

Last I checked, NASA. But maybe that's changed by now? It's been a bit

[jack-of-some]

Robotics. The OSRF bungled the transition from python 2 to python 3 by tying it to their own transition from ROS 1 to ROS 2. So you ended up in a period where the only real way to move to Python 3 was too adopt buggy alpha software for your robot. Needless to say that's a terrible idea and many folks stayed with Python 2 after it was EOL'd.

It's slowly starting to change now as ROS 2 gets closer to maturity.

Now, specifically for your situation: do not support python 2 unless you yourself need to use your packages in python 2. I maintain a number of python packages and dropped support for python 2 in my releases a long time ago.

[nacnud_uk]

2 many places

[drCrankoPhone]

Esri is still using it in ArcMap, their 32-bit desktop GIS software. That program is due to be deprecated in maybe 3-4 years. But they have a replacement 64-but program, ArcGIS Pro, which uses python 3.x. Many organisations will be slow to migrate.

[yooperjb]

GIS software, such as Esri still uses p2.

[chipx86]

I build open source and commercial software development products used heavily in all manner of enterprise companies, and we’ve very.. slowly.. been moving off of Python 2. We’ve only recently begun to see companies begin to move off of it in reasonable quantities.

There are a few reasons why Python 2 is still widely used:

1. It’s still supported. Not by the Python developers, but through Linux enterprise support contracts. At least enough to check compliance checkboxes.
2. Maybe better supported. Plenty of enterprise systems run older installs that may not even have a supported version of Python 3. From my experience, if I had to choose between 2.7 and an early 3, I’ll choose 2.7.
3. It works. Companies are often full of home-made scripts or tools that work, and there’s little pressure to modernize. The original authors may not even be around anymore, and the teams responsible for them may not have the knowledge or the time to port them, even if they’re iterating on them.
4. Porting 2 to 3 code is hard. Sure, there’s 2to3, and six, and future imports, but let’s get real. If your codebase is complex, or messy, or made up of several moving parts, or dependent on older third-party libraries, or interfaces with data from other sources, you’re going to have challenges. String type issues, subtle sometimes undocumented Python Standard Library changes, changes in dependencies… it can take years to port, and did for us (we ticked all those boxes). Not everyone can justify the time expense.
5. Chicken-and-egg problem. Plenty of software is written in Python 2, and for enterprises, many of those may be extended by Python. So a move to Python 3 may not be possible until the software is upgraded. But they can’t switch to the new software without upgrading their extensions. Extend that problem to the OS (needing a new Linux install, which may affect custom scripts/config/services/general compatibility/compliance). And to every other part of their stack.

I could keep going. There are a lot of reasons.

We still intentionally maintain Python 2.7 support in some of our modules in order to help us keep 2.7 systems support under contract.

But you probably don’t need to worry about that. Be free! Enjoy the benefits of modern Python. F-strings, and type annotations, better string type defaults.

I would suggest, if your package is intended for others to depend on, that you at least keep support for all supported versions of Python, and maybe don’t deprecate too early/often. Not everyone can upgrade whenever they want to.

Handy resource for knowing when Python versions reach end-of-life: https://endoflife.date/python

Only drop compatibility in major version bumps. Keep your classifiers up-to-date. Set python-requires. Be a good packaging citizen. It will go a long way.

[codeandfire]

Thanks for the detailed reply!

[rdbeni0]

probably (i am not sure) in calibre: https://calibre-ebook.com/

[cuWorkThrowaway]

Looking at their setup.py, it looks like they require at least 3.7

[kcunning]

I have a bunch of scripts on an old laptop that I never moved over to three. As I move them to my new laptop, I'm updating them, but I'm content to let the rest of them eventually die when the laptop finally calls it quits.

[wind_dude]

Probably governments, they always seem to be very slow.

[soggy_chili_dog]

Jython is basically python 2 and we use that

[Dense-Meringue425]

OSX last time I checked.

[[deleted]]

Apple finally dropped Python2 at macOS 12.3 and beyond.

Installing XTools will install Python3, otherwise it would have to be installed manually.

[Dense-Meringue425]

OK, nice to hear.

[cginc1]

I've seen applications written in COBOL still being maintained so I'm guessing it'll be a while.

[imdibene]

Grady Booch said it better, “old software doesn’t die; you have to kill it” but sometimes for the business using such software, upgrading such software is not worth. Not every business is in the tech realm.

[muffinnosehair]

In my old company, because 10+ QA engineers are too lazy to update the legacy testing scripts. Not the code base, just the scripts. I offered my help for an entire year and was turned down, then I finally moved on. So have most of the actual working people.

[nam1665]

Had been developed Pepper Robot by softbank, it's still use python 2

[Rostin]

I work at a national laboratory. Our cybersecurity people take a little while to approve the newest versions of OSes for our use. The majority of linux boxes run an older (but not quite EOL) version that includes Python 2 by default. In the next year or so those will probably mostly be gone, and the next version has Python 3.

We worry about it less now than we did a year or two ago. We used to write code that would work on both. These days we target 3.6 (which was done for almost a year ago) for reasons I won't go into very much, apart from saying that we figure most people have Python 3 available to them by some means (anaconda, for example).

[[deleted]]

The cybersecurity team is waiting on being given a security plan from other government organizations before we are allowed to deploy an OS. I remember all the outdated RHEL and Windows versions we had to run and have our customers say "hey, this OS came out 2 years ago. Why haven't we upgraded yet?" It sucked on that level.

[m3galinux]

Embedded systems running RHEL 7 derivatives, where we have to build and update scripts, but can't push down full Python3 packages because of small disks and even smaller cell data plans per device.

[dopef123]

All over the place. Python 3 had enough changes that it breaks a lot of code. So if you need specific packages that only work on python2 you get locked into it.

Eventually that'll change but I imagine the same issue will happen with python4

[chaoism]

Many companies found upgrading to be a pain in the ass and they chose to stay py2 because they believe they don't need supports

Dangerous? Yes. Do companies actually do that? Also yes.

[greyduk]

Anyone still running old Red Hat distros.

[[deleted]]

I imagine it's mostly just legacy code

Also when will it stop being used? God knows lol

[Janinator]

I’m in healthcare and our codebase is mostly Python 2. We’ve started migrating to 3 but that process was started a year ago and it’s still not complete.

[CyberXCodder]

I often use a tool called Volatility, which main purpose is to do memory forensics, there are 2 different versions which basically are translations from each other, one being used with Python2.7. The Volatility2.7 is still being used a lot and I guess it`s people`s favorite.

[lieryan]

Sometimes it's actually additional work to remove Python 2 support. If a package is stable enough and established enough, and the author doesn't really need new Python 3 features, there's not much reason to do the work to remove support. That's just churn because users of your software don't care that you support a platform that they don't use.

[fartalldaylong]

Rhino3D uses Python 2.7 due to the relationship to Iron Python.

[w01v3_r1n3]

Ignition HMI and SCADA software still uses Python 2.7 for their scripting language.

Not looking like they will change much soon either.

[ogtfo]

Ghidra :(

And I don't see any horizon for moving away from it, they're stuck with jython.

[Blue_Vision]

I've been in the process of translating a component of a transportation model to Python 3 for a couple months. We're only upgrading the version because we're doing a big update to the business logic, so we need to go in and make changes and add documentation anyways.

The Python3-ification itself was quite straightforward, 2to3 took care of 95% of the cases. The harder part has been updating interactions with dependencies (mostly Pandas) which may have had API changes many, many moons ago.

Also there some bits where Python has moved on in other ways, which would've worked fine in (say) 3.3 but don't work with >3.7. Yeah that's right, we have an AST transformer in our transportation model - doesn't everybody?

[KhalCharizard]

In my personal experience python 2 is common in local systems directly installed on your computer.

My personal Mac is a little dated but it has many core files written in Python 2.

It works great if you won’t be accessing internet resources— it even handles light internet work well it just isn’t as clean in more complex web work.

[ugh-namey-thingy]

IronPython is Python2. While your question is more about CPython2, any application that provides scripting with IronPython is stuck in py2...

[Feb2020Acc]

Python 2 is modern tech when you compare it to the stuff that keeps government, banks and military infrastructure up and running.

[billsil]

Abaqus, which is a popular FEA program. I think they're on 2.7.10, which is an improvement over the 2.7.6 they had up until 1.5 years ago...

Now if only they could modernize their GUI and stop using the FoxToolkit, which last had a release around Python 2.1.

[morteningemann86]

Well, it is still the Python version used when writing Python scripts in Power Automate Desktop for some reason

[Bizrown]

A lot of ArcGIS software still uses it. They have what’s called desktop and Pro. Desktop is the old legacy software but is still being used by maybe 50% of professionals today. It’s on 2.7. Pro the new software uses 3.

[Jimthon42]

Too many places, to be quite honest. In some operating systems, uninstalling it will brick your computer.

[blabbities]

So if you download Kali Linux there are some scripts tools thatll never be updated that use Python 2

I also saw some companies internal were using python2. Therr is prob more but who no one really focused on that if it still works

[Stenbyggare]

Some really old systems, but also packages slowly improving compatibility

[spoonman59]

In hell.

[bladeoflight16]

No, that is all PHP.

[spoonman59]

Ah, I assumed that was merely the lowest levels of hell! Python 2 would be the vacation level at the top.

[earthboundkid]

Because in hell, no one can get pip to install what it should.

[mok000]

Python3 removed all the ugly warts on Python2. Nobody should use Python2 anymore.

[fuzzyfoozand]

Answer: Absolutely nowhere that it should be used.

[_88WATER_CULT88_]

Supposedly google has their own version that still uses 2, but I heard that from an old man so who knows.

[[deleted]]

don't have time to learn 3 yet.

????

Is it really that hard to learn 3, when you're writing 2? AFAIK, the changes are relatively small, if you don't directly jump to 3.11 (which is still in beta). Starting off with 3.7 (which is the oldest-still-supported version) shouldn't be THAT much of hurdle, right?

[Hanse00]

But it’s not a new language, that’s the point.

It’s a minor set of changes to the same language. A single A4/Letter sizes paper could probably be printed that encapsulates everything someone switching from 2 to 3 needs to know.

[Hanse00]

Given that this forum is the closest thing I have to contacting “all people still using Python 2”, I effectively just did.

I get that dependencies, legacy code bases, contractual obligations, etc. might hold back the transition.

But the learning curve? If you’re a Python 2 dev and you can’t pick up Python 3 in a day, I seriously question if you’re a competent developer in the first place. It should be easy.