[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On Wed, 4 Mar 2020 at 23:09, Victor Stinner wrote: > By the way, I also added a new "You should check for > DeprecationWarning in your code" section to "What's New In Python 3.9" > document, to strongly advice users to check for deprecation warnings > in their code: >

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

Hi, I proposed a second change to restore the "U" open() mode (universal newlines): https://github.com/python/cpython/pull/18767 Again, it's only kept in Python 3.9 to ease migration from Python 2, but will be removed in Python 3.10. By the way, I also added a new "You should check for

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

> And proposed a first pull request to add again collections.Mapping: https://github.com/python/cpython/pull/18245 FYI, this patch is adding a fixer to handling abstract base classes. It will be helpful for the migration to new changes. I hope someone reviews this. 2020년 2월 18일 (화) 오후 8:44,

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

Hi, I created an issue: "Keep deprecated features in Python 3.9 to ease migration from Python 2.7, but remove in Python 3.10" https://bugs.python.org/issue39674 And proposed a first pull request to add again collections.Mapping: https://github.com/python/cpython/pull/18545 Victor Le jeu. 23

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On 2020-02-04, 01:00 GMT, Brett Cannon wrote: > I think people also forget that prior to worrying about > maintaining backwards-compatibility with Python 2 we > deprecated for a release and then we removed (so an 18 month > deprecation period). But then you mustn’t filter out deprecation

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On 2020-02-04 14:40, Paul Moore wrote: >> The answer to that concern is to not break compatibility in the first place, >> and/or revert it when the mistake is discovered. It happens. > > That sounds to me like an argument for stagnation. We already take > backwards compatibility very seriously.

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On Tue, 4 Feb 2020 at 22:10, Mike Miller wrote: > > On 2020-02-04 12:10, Brett Cannon wrote: > > Please be careful making that claim. Over my 16 years of helping manage > > this project I can tell you that claim is not universally true no matter > > how small and simple you think something is.

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On 2020-02-04 12:10, Brett Cannon wrote: Please be careful making that claim. Over my 16 years of helping manage this project I can tell you that claim is not universally true no matter how small and simple you think something is. The answer to that concern is to not break compatibility in

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

Mike Miller wrote: > On 2020-02-03 17:00, Brett Cannon wrote: > > Until you're being asked to maintain all of that for > > a decade. We paid a major price keeping Python 2 alive for over a decade. > > Now I'm not > > saying it wasn't the right thing to do considering what we changed, but for > >

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On 2020-02-03 17:00, Brett Cannon wrote: Until you're being asked to maintain all of that for a decade. We paid a major price keeping Python 2 alive for over a decade. Now I'm not saying it wasn't the right thing to do considering what we changed, but for the stuff we are talking about

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On 2020-02-04 04:16, Rhodri James wrote: I think that just enables laziness.  "We don't need to worry about the deprecations, nothing is going to happen for years yet," is more or less what happened with the Python2 to Python3 shift.  People naturally enjoy adding shiny new features to their

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On 03/02/2020 22:06, Mike Miller wrote: On 2020-02-03 01:50, Petr Viktorin wrote: When the changes are rolled out gradually across minor releases, those that cause unforeseen trouble in real-world code can be identified in the alphas/betas, and rethought/reverted if necessary. To be clear,

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On 2020-02-03 16:44, Antoine Pitrou wrote: On Mon, 3 Feb 2020 13:18:46 +0100 Petr Viktorin wrote: I agree with the sentiment that gradual deprecations are more easily managed, this statement about Python 3.0 is not true. The unicode transition was never thought to be small, and that's

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

Ethan Furman wrote: > On 2020-01-23 07:20, Victor Stinner wrote: > > Python 3.9 introduces many small incompatible changes > > which broke tons > > On 2020-01-31 19:47, Mike Miller wrote: > > There's a well-known and established way of signaling > > breaking changes in software platforms—it is to

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On 2020-01-23 07:20, Victor Stinner wrote: Python 3.9 introduces many small incompatible changes which broke tons On 2020-01-31 19:47, Mike Miller wrote: There's a well-known and established way of signaling breaking changes in software platforms—it is to increment the major version number.

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On 2020-02-03 01:50, Petr Viktorin wrote: When the changes are rolled out gradually across minor releases, those that cause unforeseen trouble in real-world code can be identified in the alphas/betas, and rethought/reverted if necessary. To be clear, my suggestion was to maintain gradual

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On Mon, 3 Feb 2020 13:18:46 +0100 Petr Viktorin wrote: > > > > I agree with the sentiment that gradual deprecations are more easily > > managed, this statement about Python 3.0 is not true. The unicode > > transition was never thought to be small, and that's *why* 3.0 was such > > a big

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On 2020-02-03 12:55, Thomas Wouters wrote: On Mon, Feb 3, 2020 at 10:53 AM Petr Viktorin > wrote: On 2020-01-31 19:47, Mike Miller wrote: > > On 2020-01-23 07:20, Victor Stinner wrote: >  > Python 3.9 introduces many small incompatible changes

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On Mon, Feb 3, 2020 at 10:53 AM Petr Viktorin wrote: > On 2020-01-31 19:47, Mike Miller wrote: > > > > On 2020-01-23 07:20, Victor Stinner wrote: > > > Python 3.9 introduces many small incompatible changes which broke tons > > > > > > There's a well-known and established way of signaling

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On 2020-01-31 19:47, Mike Miller wrote: On 2020-01-23 07:20, Victor Stinner wrote: > Python 3.9 introduces many small incompatible changes which broke tons There's a well-known and established way of signaling breaking changes in software platforms—it is to increment the major version

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

> We propose to revert 5 changes: > > • Removed tostring/fromstring methods in array.array and base64 modules > • Removed collections aliases to ABC classes > • Removed fractions.gcd() function (which is similar to math.gcd()) > • Remove "U" mode of open(): having to use

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On 2020-01-31 19:58, Ethan Furman wrote: On 01/31/2020 10:47 AM, Mike Miller wrote: On 2020-01-23 07:20, Victor Stinner wrote: Python 3.9 introduces many small incompatible changes which broke tons There's a well-known and established way of signaling breaking changes in software

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On 01/31/2020 10:47 AM, Mike Miller wrote: On 2020-01-23 07:20, Victor Stinner wrote: Python 3.9 introduces many small incompatible changes which broke tons There's a well-known and established way of signaling breaking changes in software platforms—it is to increment the major version

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On 2020-01-23 07:20, Victor Stinner wrote: > Python 3.9 introduces many small incompatible changes which broke tons There's a well-known and established way of signaling breaking changes in software platforms—it is to increment the major version number. Rather than debating the merits of

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

I think this particular mess was caused by the hiding of “DeprecationWarning”s by default: If you don’t see any warnings cropping up in your production code, you don’t know you have to fix something. Some languages handle it like this: 1. Silent deprecation warning (deprecated in docs and/or

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

Dima Tisnek writes: > I thought that collections compatibility was kept up to 3.8 > specifically because py2 was alive. > No that that requirement is gone, so should the shim, right? Python 2 is still very much alive (even in a Python 3 venv :-þ): (analysis.venv) 01 16:56$

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On 2020-01-30 07:12, Dima Tisnek wrote: On Fri, 24 Jan 2020 at 00:27, Victor Stinner wrote: Miro and me consider that Python 3.9 is pushing too much pressure on projects maintainers to either abandon Python 2.7 right now... Let's not conflate py2 EOL with what-should-go-into-py39.

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On Fri, 24 Jan 2020 at 00:27, Victor Stinner wrote: > Miro and me consider that Python 3.9 is pushing too much pressure on > projects maintainers to either abandon Python 2.7 right now... Let's not conflate py2 EOL with what-should-go-into-py39. >

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

Matthias Bussonnier wrote: > Is it possible to change some of those deprecation from Warn-by-default (but > can add a > warning filter to make them error) to error-by-default (but can add a filter > to make them > only warnings). Yes, although it would be a change to how Python functions.

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

Is it possible to change some of those deprecation from Warn-by-default (but can add a warning filter to make them error) to error-by-default (but can add a filter to make them only warnings). That way it is easy to fix large projects (even w/o modifying the source) in only a couple of lines

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

Is it possible to change some of those deprecation from Warn-by-default (but can add a warning filter to make them error) to error-by-default (but can add a filter to make them only warnings). That way it is easy to fix large projects (even w/o modifying the source) in only a couple of lines

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On Jan 27, 2020, at 13:56, Barry Scott wrote: > > Isn't there going to be a final Python 2.7 release in April 2020? Yes, but I’ve been calling it a “celebratory release”. We’re gonna party at Pycon like it’s 2000. -Barry signature.asc Description: Message signed with OpenPGP

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On 1/27/2020 4:56 PM, Barry Scott wrote: On 24 Jan 2020, at 08:40, Victor Stinner wrote: The change is that Python 2.7 is no longer supported (since 2020-01-01). Isn't there going to be a final Python 2.7 release in April 2020? Normal patching has stopped, much as if the final .rc1 release

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On 24. 01. 20 22:54, Serhiy Storchaka wrote: 23.01.20 17:20, Victor Stinner пише: > * Removed collections aliases to ABC classes Adding loud warning was one of largest compatibility breaking changes in 3.8, because many active projects treat warnings in tests as errors. I had doubts about

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On 24. 01. 20 16:22, Eric V. Smith wrote: On 1/24/2020 9:14 AM, Miro Hrončok wrote: On 24. 01. 20 14:02, Eric V. Smith wrote: I think the concern is that with removing so many deprecated features, we're effectively telling libraries that if they want to support 3.9, they'll have stop

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

See pyfound.blogspot.com/2019/12/python-2-sunset.html for the details. January or April doesn't matter much for this thread, since Python 3.9.0 final is scheduled for October. Victor Le lun. 27 janv. 2020 à 23:13, Barry Scott a écrit : > > > > > On 24 Jan 2020, at 08:40, Victor Stinner wrote:

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

> On 24 Jan 2020, at 08:40, Victor Stinner wrote: > > The change is that Python 2.7 is no longer supported (since 2020-01-01). > Isn't there going to be a final Python 2.7 release in April 2020? I know that Twisted has moved its python 2 removal to match the April 2020 date. Other projects

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On 25Jan.2020 0348, Guido van Rossum wrote: > On Fri, Jan 24, 2020 at 12:12 AM Serhiy Storchaka > wrote: > > I consider breaking unmaintained code is an additional benefit of > removing deprecated features. > > > I'd like to warn against this attitude (even

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

23.01.20 17:20, Victor Stinner пише: > * Removed collections aliases to ABC classes Adding loud warning was one of largest compatibility breaking changes in 3.8, because many active projects treat warnings in tests as errors. I had doubts about removing them. On one side, they were deprecated

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

Le ven. 24 janv. 2020 à 19:35, Brett Cannon a écrit : > I'm also okay with a one-time delay in removals that are problematic for code > trying to get off of Python 2.7 this year and might not quite cut it before > 2021 hits. I'm sure some people will be caught off-guard once 3.9b1 comes out >

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

Le ven. 24 janv. 2020 à 19:28, Brett Cannon a écrit : > (...) otherwise I could be reading most of that email as if you're suggesting > we bring back the print statement or something. ;) By the way, about adding back print statement... nah, I'm just kidding :-D Victor

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

Eric V. Smith wrote: > On 1/24/2020 9:14 AM, Miro Hrončok wrote: > > On 24. 01. 20 14:02, Eric V. Smith wrote: > > I think the concern is that with removing so > > many deprecated > > features, we're effectively telling libraries that if they want to > > support 3.9, they'll have stop supporting

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

Victor Stinner wrote: > Le jeu. 23 janv. 2020 à 20:45, Brett Cannon br...@python.org a écrit : > > Two pieces of feedback on this. One, nose is a bad > > example because that project has been telling people for years to switch to > > nose2 so the > > fact that people have still not switched

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On Fri, Jan 24, 2020 at 12:12 AM Serhiy Storchaka wrote: > I consider breaking unmaintained code is an additional benefit of > removing deprecated features. > I'd like to warn against this attitude (even though in the past I've occasionally said such things). I now think core Python should not

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On 01/24/2020 05:02 AM, Eric V. Smith wrote: On 1/24/2020 5:50 AM, Ivan Levkivskyi wrote: On Fri, 24 Jan 2020 at 10:05, Victor Stinner wrote: The proposal is to give one year to project maintainers to drop Python 2.7 support, since Python 2.7 end of support just happened a few weeks ago

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On Fri, 24 Jan 2020 at 14:14, Miro Hrončok wrote: > > On 24. 01. 20 14:02, Eric V. Smith wrote: > > I think the concern is that with removing so many deprecated features, we're > > effectively telling libraries that if they want to support 3.9, they'll have > > stop supporting 2.7. And many

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On 1/24/2020 9:14 AM, Miro Hrončok wrote: On 24. 01. 20 14:02, Eric V. Smith wrote: I think the concern is that with removing so many deprecated features, we're effectively telling libraries that if they want to support 3.9, they'll have stop supporting 2.7. And many library authors aren't

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On 24. 01. 20 14:02, Eric V. Smith wrote: On 1/24/2020 5:50 AM, Ivan Levkivskyi wrote: On Fri, 24 Jan 2020 at 10:05, Victor Stinner > wrote: The proposal is to give one year to project maintainers to drop Python 2.7 support, since Python 2.7 end of support

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On 1/24/2020 5:50 AM, Ivan Levkivskyi wrote: On Fri, 24 Jan 2020 at 10:05, Victor Stinner > wrote: The proposal is to give one year to project maintainers to drop Python 2.7 support, since Python 2.7 end of support just happened a few weeks ago

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On Fri, 24 Jan 2020 at 10:05, Victor Stinner wrote: > > The proposal is to give one year to project maintainers to drop Python > 2.7 support, since Python 2.7 end of support just happened a few weeks > ago (2020-01-01). > IMO creating this kind of "gray areas" in support and deprecation issues

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

Adding Python 3.9 and dropping Python 2.7 support are two different things, but Python 3.9 somehow "enforces" to do both at the same time. The proposal is to give one year to project maintainers to drop Python 2.7 support, since Python 2.7 end of support just happened a few weeks ago

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On Fri, 24 Jan 2020 at 08:54, Victor Stinner wrote: > > The change is that Python 2.7 is no longer supported (since 2020-01-01). However the assertion here seems to be that some people are unprepared for this (which seems to me like it's their problem, not ours). Features getting deprecated in

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On Fri, Jan 24, 2020 at 7:40 PM Victor Stinner wrote: > > The change is that Python 2.7 is no longer supported (since 2020-01-01). > Which means that it's now okay to remove things, correct? Starting with 3.9, it's no longer necessary to maintain compatibility with 2.7? ChrisA

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

The change is that Python 2.7 is no longer supported (since 2020-01-01). Victor Le ven. 24 janv. 2020 à 09:19, Chris Angelico a écrit : > > On Fri, Jan 24, 2020 at 7:05 PM Victor Stinner wrote: > > We kept a compatibility layer with Python 2 on purpose, PEP 4 says: > > > > "In order to

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On 24.01.2020 11:08, Serhiy Storchaka wrote: 23.01.20 17:20, Victor Stinner пише: Incompatible changes which require "if : (...) else: (...)" or "try: except (...): ": * Removed tostring/fromstring methods in array.array and base64 modules * Removed collections aliases to ABC classes *

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

24.01.20 01:36, Barry Warsaw пише: Given that we’ve changed the release cadence to one major release per year, it doesn’t seem that much of a burden to revert and carry these changes forward into Python 3.10. And if it helps with the migration off of Python 2.7, then +1 from me. There are

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On Fri, Jan 24, 2020 at 7:05 PM Victor Stinner wrote: > We kept a compatibility layer with Python 2 on purpose, PEP 4 says: > > "In order to facilitate writing code that works in both Python 2 & 3 > simultaneously, any module that exists in both Python 3.5 and Python > 2.7 will not be removed

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

23.01.20 17:20, Victor Stinner пише: Incompatible changes which require "if : (...) else: (...)" or "try: except (...): ": * Removed tostring/fromstring methods in array.array and base64 modules * Removed collections aliases to ABC classes * Removed fractions.gcd() function (which is similar

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

Le ven. 24 janv. 2020 à 08:37, Miro Hrončok a écrit : > No, the motivation to pospone the changes to 3.10 are projects that alrady > support both 2 and 3 at the same time, with or without compatibility libraries > like six. Before they had anough time to make the necessary actions to abandon >

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On 24. 01. 20 5:59, Ethan Furman wrote: My understanding is that this postponement of removals is aimed at those who have just migrated to Python 3, not those who have already done it nor those who have 2/3 straddling code bases. No, the motivation to pospone the changes to 3.10 are projects

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On 01/23/2020 07:02 PM, Robert Collins wrote: On Fri, 24 Jan 2020 at 14:46, Ethan Furman mailto:et...@stoneleaf.us>> wrote: On 01/23/2020 03:36 PM, Barry Warsaw wrote: > On Jan 23, 2020, at 14:03, Victor Stinner wrote: >> It's not only about specific changes, but more a

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On Fri, 24 Jan 2020 at 14:46, Ethan Furman wrote: > On 01/23/2020 03:36 PM, Barry Warsaw wrote: > > On Jan 23, 2020, at 14:03, Victor Stinner wrote: > > >> It's not only about specific changes, but more a discussion about a > >> general policy to decide if a deprecated feature should stay until

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On 01/23/2020 03:36 PM, Barry Warsaw wrote: On Jan 23, 2020, at 14:03, Victor Stinner wrote: It's not only about specific changes, but more a discussion about a general policy to decide if a deprecated feature should stay until 3.10, or if it's ok to remove it in 3.9. Given that we’ve

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On Jan 23, 2020, at 14:03, Victor Stinner wrote: > > I'm not sure of the meaning of "buried" here. What do you mean? We > propose to revert 5 changes: > > * Removed tostring/fromstring methods in array.array and base64 modules > * Removed collections aliases to ABC classes > * Removed

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

Le jeu. 23 janv. 2020 à 20:45, Brett Cannon a écrit : > Two pieces of feedback on this. One, nose is a bad example because that > project has been telling people for years to switch to nose2 so the fact that > people have still not switched something that should mostly be a direct swap > after

[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

Two pieces of feedback on this. One, nose is a bad example because that project has been telling people for years to switch to nose2 so the fact that people have still not switched something that should mostly be a direct swap after years of being asked to does not motivate in wanting to