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I'm surprised that it doesn't support Python 3.5. I've been a bit out of touch with Python - is there something that changed significantly in subsequent version

I'm surprised that it doesn't support Python 3.5. I've been a bit out of touch with Python - is there something that changed significantly in subsequent versions to justify this?

1f60c 6y ago
3.5 has been EOL for 8 months now. (Source: https://endoflife.date/python https://endoflife.date/python) I’m guessing they want to tell people it’s time to upgrade. And 3.6 brings a lot of niceties that they might want to use, like f-strings.
- kstrauser 6y ago
  That’s what I’ve done on personal projects. The benefits of dropping support for the old version are large enough to outweigh the tiny drawbacks of not supporting it.
- skvark 6y ago
  Many projects are dropping support for old Python versions very fast. It's not surprising given the history of the Python 2 -> 3 transition. No one wants to end up in that situation anymore. For example, NumPy has already dropped 3.6 support (3.6 will be EOL later this year).
  - remram 6y ago
    I don't know about "very fast", Python 3.6 was released in 2016 giving people plenty of time to update from 3.5. Those are backward-compatible too. If you haven't updated in that time, you probably have a systemic problem which shouldn't be blamed on Python moving too fast (in fact I suspect those people don't keep up with bugfixes either, so nudging them to upgrade when they try to update flask/numpy is a good idea).
deleted 6y ago
[deleted]
matusf 6y ago
Python 3.6 added f-strings which are rather popular and they cause syntax error in previous versions of Python.
nicolaslem 6y ago
Python 3.5 is end of life, as it doesn't receive security fixes anymore no one should really use it for production. I imagine that removing it from the supported versions in Flask allows for example to use f-strings.
yuy910616 6y ago
3.6 had a couple of big improvement - f strings, annotation, and if I'm not mistaking, the devs did something to improve the dictionaries; from 3.6 on dicts are ordered. I don't know too much about it but raymond hettinger gave a talk about it. https://www.youtube.com/watch?v=p33CVV29OG8 https://www.youtube.com/watch?v=p33CVV29OG8
- TkTech 6y ago
  -
  - orf 6y ago
    Ordering was stable within a process (and within a given PYTHONHASHSEED value), but not stable across processes. They are now insertion ordered.
    - TkTech 6y ago
      Thank you for the clarification :)
  - deleted 6y ago
    [deleted]
  - morvita 6y ago
    Order-preserving dicts were added as a side effect of an optimization in CPython 3.6 [0]. They were considered an implementation detail of CPython in 3.6, it wasn't until Python 3.7 that is was declared an official part of the language [1]. [0] https://docs.python.org/3/whatsnew/3.6.html#whatsnew36-compactdict https://docs.python.org/3/whatsnew/3.6.html#whatsnew36-compa... [1] https://mail.python.org/pipermail/python-dev/2017-December/151283.html https://mail.python.org/pipermail/python-dev/2017-December/1...
- ehsankia 6y ago
  Considering the last item in the changelog is: - Add type hinting. https://github.com/pallets/flask/pull/3973 https://github.com/pallets/flask/pull/3973 I think it's fair to assume annotations is the big reason.
morvita 6y ago
Python 3.5 was declared end of life in September 2020, so it makes sense for library developers to drop support for it as well. Something like Flask 2.0 may work in Python 3.5 (I haven't tested it myself), but it isn't worth the developers' time to guarantee that support for a language version getting no support upstream. https://www.python.org/downloads/release/python-3510/ https://www.python.org/downloads/release/python-3510/
- ehsankia 6y ago
  Deprecation aside, Flask 2.0 begins adding type annotations, which is 3.6+ https://github.com/pallets/flask/pull/3973 https://github.com/pallets/flask/pull/3973
  - matthiasv 6y ago
    Type annotations started with 3.5, 3.6 added type annotations for variables.
formerly_proven 6y ago
https://www.python.org/dev/peps/pep-0478/ https://www.python.org/dev/peps/pep-0478/
bredren 6y ago
Flask's creator, Armin Ronacher, was asked on the Real Python podcast in July 2020 what specifically he would have done differently. He said he under appreciated how big the community would get but also the number of people who would use it. He faulted himself for not spending time thinking about the transition from him primarily working on it to others. And that he should have been thinking about how things would work when he was not involved. The specific item he was concerned about was that he did not work to build a "community of like minded people" which he says Django did a much better job at doing. At the very end of the comment, he openly considers if there are things he should have done differently: "I probably would feel less detached from it if I would have communicated some of my ideas more. I feel like it is no longer my fight to make it more backwards compatible for instance. The community sees this differently than I do, so that's fine." https://realpython.com/podcasts/rpp/58/#t=1202 https://realpython.com/podcasts/rpp/58/#t=1202
nijave 6y ago
Afaik the Python foundation supports the current and 3 previous Python releases and many developers track CPython interpreter support. Can't find a link to n+3, though (Current is 3.9 so 8,7,6 are also supported)
tusharsadhwani 6y ago
The biggest reason of all would be that 3.5 is already end of life :)

I'm surprised that it doesn't support Python 3.5. I've been a bit out of touch with Python - is there something that changed significantly in subsequent versions to justify this?

1f60c 6y ago

3.5 has been EOL for 8 months now. (Source: https://endoflife.date/python https://endoflife.date/python) I’m guessing they want to tell people it’s time to upgrade. And 3.6 brings a lot of niceties that they might want to use, like f-strings.

kstrauser 6y ago
That’s what I’ve done on personal projects. The benefits of dropping support for the old version are large enough to outweigh the tiny drawbacks of not supporting it.
skvark 6y ago
Many projects are dropping support for old Python versions very fast. It's not surprising given the history of the Python 2 -> 3 transition. No one wants to end up in that situation anymore. For example, NumPy has already dropped 3.6 support (3.6 will be EOL later this year).
- remram 6y ago
  I don't know about "very fast", Python 3.6 was released in 2016 giving people plenty of time to update from 3.5. Those are backward-compatible too. If you haven't updated in that time, you probably have a systemic problem which shouldn't be blamed on Python moving too fast (in fact I suspect those people don't keep up with bugfixes either, so nudging them to upgrade when they try to update flask/numpy is a good idea).

deleted 6y ago

[deleted]

matusf 6y ago

Python 3.6 added f-strings which are rather popular and they cause syntax error in previous versions of Python.

nicolaslem 6y ago

Python 3.5 is end of life, as it doesn't receive security fixes anymore no one should really use it for production. I imagine that removing it from the supported versions in Flask allows for example to use f-strings.

yuy910616 6y ago

3.6 had a couple of big improvement - f strings, annotation, and if I'm not mistaking, the devs did something to improve the dictionaries; from 3.6 on dicts are ordered. I don't know too much about it but raymond hettinger gave a talk about it. https://www.youtube.com/watch?v=p33CVV29OG8 https://www.youtube.com/watch?v=p33CVV29OG8

TkTech 6y ago
-
- orf 6y ago
  Ordering was stable within a process (and within a given PYTHONHASHSEED value), but not stable across processes. They are now insertion ordered.
  - TkTech 6y ago
    Thank you for the clarification :)
- deleted 6y ago
  [deleted]
- morvita 6y ago
  Order-preserving dicts were added as a side effect of an optimization in CPython 3.6 [0]. They were considered an implementation detail of CPython in 3.6, it wasn't until Python 3.7 that is was declared an official part of the language [1]. [0] https://docs.python.org/3/whatsnew/3.6.html#whatsnew36-compactdict https://docs.python.org/3/whatsnew/3.6.html#whatsnew36-compa... [1] https://mail.python.org/pipermail/python-dev/2017-December/151283.html https://mail.python.org/pipermail/python-dev/2017-December/1...
ehsankia 6y ago
Considering the last item in the changelog is: - Add type hinting. https://github.com/pallets/flask/pull/3973 https://github.com/pallets/flask/pull/3973 I think it's fair to assume annotations is the big reason.

morvita 6y ago

Python 3.5 was declared end of life in September 2020, so it makes sense for library developers to drop support for it as well. Something like Flask 2.0 may work in Python 3.5 (I haven't tested it myself), but it isn't worth the developers' time to guarantee that support for a language version getting no support upstream. https://www.python.org/downloads/release/python-3510/ https://www.python.org/downloads/release/python-3510/

ehsankia 6y ago
Deprecation aside, Flask 2.0 begins adding type annotations, which is 3.6+ https://github.com/pallets/flask/pull/3973 https://github.com/pallets/flask/pull/3973
- matthiasv 6y ago
  Type annotations started with 3.5, 3.6 added type annotations for variables.

formerly_proven 6y ago

https://www.python.org/dev/peps/pep-0478/ https://www.python.org/dev/peps/pep-0478/

bredren 6y ago

Flask's creator, Armin Ronacher, was asked on the Real Python podcast in July 2020 what specifically he would have done differently. He said he under appreciated how big the community would get but also the number of people who would use it. He faulted himself for not spending time thinking about the transition from him primarily working on it to others. And that he should have been thinking about how things would work when he was not involved. The specific item he was concerned about was that he did not work to build a "community of like minded people" which he says Django did a much better job at doing. At the very end of the comment, he openly considers if there are things he should have done differently: "I probably would feel less detached from it if I would have communicated some of my ideas more. I feel like it is no longer my fight to make it more backwards compatible for instance. The community sees this differently than I do, so that's fine." https://realpython.com/podcasts/rpp/58/#t=1202 https://realpython.com/podcasts/rpp/58/#t=1202

nijave 6y ago

Afaik the Python foundation supports the current and 3 previous Python releases and many developers track CPython interpreter support. Can't find a link to n+3, though (Current is 3.9 so 8,7,6 are also supported)

tusharsadhwani 6y ago

The biggest reason of all would be that 3.5 is already end of life :)