Re: [python-committers] [Python-Dev] 3.7.2rc1 and 3.6.8rc1 cutoffs ahead, last 3.6.x bugfix release!

2018-12-19 Thread Victor Stinner
Hi,

I am working in the Red Hat "Python-maint" team which is maintaining
Python 3.6 as the main Python interpreter in RHEL 8, which will likely
be supported for at least 10 years. And we have been supporting Python
2.7 in RHEL 7. So obviously, being able to benefit of the upstream
effort and infra to have a Python 3.6 Long Time Support (LTS) would
help us :-)

The question is more who else would benefit from that and is it worth
it? I don't want Python upstream to pay the price of the maintenance
burden of RHEL 8 lifecycle. For example, supporting a version means to
have a working CI (Travis CI, AppVeyor, VSTS, buildbots). I would
suggest to only support a very few platforms for the LTS. I propose to
restrict to Linux. It doesn't mean to break other platforms on
purpose, just to restrict CI to the bare minimum. If Microsoft is
interested, we can also support Windows as well.

RHEL 7 is based on Python 2.7.5 which has been released in 2013 (5
years ago) and there are 150 patches on top of it: it means that
around 30 patches are added per year. I would suggest to have a very
strict policy on which changes are backported into 3.6: only the most
critical bugfixes, but all security fixes obviously.

If we extend Python 3.6 lifetime, do we need a new release manager
when the initial lifetime (usually 5 years) ends? Benjamin Peterson
accepted to be the Python 2.7 release manager for 10 years (instead of
5 years initially). We could ask Ned Deily about Python 3.6 LTS :-) We
would need a group of people reviewing individual 3.6 pull requests to
decide to pick them or not. I would volunteer to review these PRs and
merge them.

The idea isn't new, Nick Coghlan proposed a "ELPython" last year:

   https://github.com/elpython/elpython-meta

The Linux kernel also have multiple LTS kernel which are supported
longer than usual releases: they are now supported for 6 years. See
"Longterm" at:

   https://www.kernel.org/category/releases.html

Victor
--
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Re: [python-committers] [Python-Dev] 3.7.2rc1 and 3.6.8rc1 cutoffs ahead, last 3.6.x bugfix release!

2018-12-19 Thread Serhiy Storchaka

19.12.18 16:01, Victor Stinner пише:

RHEL 7 is based on Python 2.7.5 which has been released in 2013 (5
years ago) and there are 150 patches on top of it: it means that
around 30 patches are added per year.


Unlikely the patch rate was constant. I suppose that more patches were 
created at earlier years. Additional time for fixing bugs in mainstream 
can decrease the number of necessary patches after the end of the 
official support.



I would suggest to have a very
strict policy on which changes are backported into 3.6: only the most
critical bugfixes, but all security fixes obviously.


I think it is better to allow backporting all changes which will be 
backported to 3.7 (but not require this). At this stage we should not 
make risky changes in 3.7.



If we extend Python 3.6 lifetime, do we need a new release manager
when the initial lifetime (usually 5 years) ends?


It would be hard to maintain 3.6 after EOL for 3.7. So I suggest to just 
the same EOL for 3.6 and 3.7 (i.e. add 1.5 years for 3.6 lifetime). 
Fortunately Ned is the release manager of both 3.6 and 3.7.


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Re: [python-committers] [Python-Dev] 3.7.2rc1 and 3.6.8rc1 cutoffs ahead, last 3.6.x bugfix release!

2018-12-19 Thread Brett Cannon
[Dropping python-dev so we don't end up swamping the python-committers
admins -- i.e. me :) -- with posts held for moderation]

On Wed, 19 Dec 2018 at 06:01, Victor Stinner  wrote:

> Hi,
>
> I am working in the Red Hat "Python-maint" team which is maintaining
> Python 3.6 as the main Python interpreter in RHEL 8, which will likely
> be supported for at least 10 years. And we have been supporting Python
> 2.7 in RHEL 7. So obviously, being able to benefit of the upstream
> effort and infra to have a Python 3.6 Long Time Support (LTS) would
> help us :-)
>
> The question is more who else would benefit from that and is it worth
> it? I don't want Python upstream to pay the price of the maintenance
> burden of RHEL 8 lifecycle.


And for me that extends to Ubuntu LTS releases as well.


> For example, supporting a version means to
> have a working CI (Travis CI, AppVeyor, VSTS, buildbots). I would
> suggest to only support a very few platforms for the LTS. I propose to
> restrict to Linux. It doesn't mean to break other platforms on
> purpose, just to restrict CI to the bare minimum. If Microsoft is
> interested, we can also support Windows as well.
>

But that doesn't help someone like me who isn't working on Linux, so it's
still work to support just Linux compared to Windows or macOS. Plus
supporting just Linux in CI and such is still not free either.


>
> RHEL 7 is based on Python 2.7.5 which has been released in 2013 (5
> years ago) and there are 150 patches on top of it: it means that
> around 30 patches are added per year. I would suggest to have a very
> strict policy on which changes are backported into 3.6: only the most
> critical bugfixes, but all security fixes obviously.
>
> If we extend Python 3.6 lifetime, do we need a new release manager
> when the initial lifetime (usually 5 years) ends? Benjamin Peterson
> accepted to be the Python 2.7 release manager for 10 years (instead of
> 5 years initially). We could ask Ned Deily about Python 3.6 LTS :-) We
> would need a group of people reviewing individual 3.6 pull requests to
> decide to pick them or not. I would volunteer to review these PRs and
> merge them.
>
> The idea isn't new, Nick Coghlan proposed a "ELPython" last year:
>
>https://github.com/elpython/elpython-meta


Was that when


>
>
> The Linux kernel also have multiple LTS kernel which are supported
> longer than usual releases: they are now supported for 6 years. See
> "Longterm" at:
>
>https://www.kernel.org/category/releases.html


The LKM has plenty of paid, full-time employees to keep those LTS kernels
running upstream while we have nothing close to that. Even if we said "no
one is expected to manage 3.6 changes" to let paid core devs keep 3.6
going, that still adds overhead to other core devs who have no interest in
keeping 3.6 alive for Canonical or RH's benefit (yes, the community gets
benefits as well, but I would argue the pay-off isn't high enough for
volunteers to be involved). Now if downstream vendors wanted to get
together to pool their resources to make 3.6 a LTS-like release in a
separate repo then I would be fine with that.

I also think this puts Ned in a tough position to say "no" to the request
if people start saying "I would love more free support!" ;) .
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Re: [python-committers] [Python-Dev] 3.7.2rc1 and 3.6.8rc1 cutoffs ahead, last 3.6.x bugfix release!

2018-12-19 Thread Gregory P. Smith
Ned - and any release manager in this situation in the future - has a
default valid answer to this request: No.

If we're ever going to do an "EL" or "LTS" Python, that should be decided
and agreed upon *long before the end of its existing planned maintenance
cycle* instead of right as it is ending.  Ideally before the first x.y.0
with agreement of the release manager.  Though it'd likely be fine to have
that conversation about 3.7 as it is still young, the RM gets final say
into if or how that would work.

I know that I won't be bothering with 3.6 backport/review work myself
anymore outside of special circumstances.

-gps


On Wed, Dec 19, 2018 at 9:46 AM Brett Cannon  wrote:

> [Dropping python-dev so we don't end up swamping the python-committers
> admins -- i.e. me :) -- with posts held for moderation]
>
> On Wed, 19 Dec 2018 at 06:01, Victor Stinner  wrote:
>
>> Hi,
>>
>> I am working in the Red Hat "Python-maint" team which is maintaining
>> Python 3.6 as the main Python interpreter in RHEL 8, which will likely
>> be supported for at least 10 years. And we have been supporting Python
>> 2.7 in RHEL 7. So obviously, being able to benefit of the upstream
>> effort and infra to have a Python 3.6 Long Time Support (LTS) would
>> help us :-)
>>
>> The question is more who else would benefit from that and is it worth
>> it? I don't want Python upstream to pay the price of the maintenance
>> burden of RHEL 8 lifecycle.
>
>
> And for me that extends to Ubuntu LTS releases as well.
>
>
>> For example, supporting a version means to
>> have a working CI (Travis CI, AppVeyor, VSTS, buildbots). I would
>> suggest to only support a very few platforms for the LTS. I propose to
>> restrict to Linux. It doesn't mean to break other platforms on
>> purpose, just to restrict CI to the bare minimum. If Microsoft is
>> interested, we can also support Windows as well.
>>
>
> But that doesn't help someone like me who isn't working on Linux, so it's
> still work to support just Linux compared to Windows or macOS. Plus
> supporting just Linux in CI and such is still not free either.
>
>
>>
>> RHEL 7 is based on Python 2.7.5 which has been released in 2013 (5
>> years ago) and there are 150 patches on top of it: it means that
>> around 30 patches are added per year. I would suggest to have a very
>> strict policy on which changes are backported into 3.6: only the most
>> critical bugfixes, but all security fixes obviously.
>>
>> If we extend Python 3.6 lifetime, do we need a new release manager
>> when the initial lifetime (usually 5 years) ends? Benjamin Peterson
>> accepted to be the Python 2.7 release manager for 10 years (instead of
>> 5 years initially). We could ask Ned Deily about Python 3.6 LTS :-) We
>> would need a group of people reviewing individual 3.6 pull requests to
>> decide to pick them or not. I would volunteer to review these PRs and
>> merge them.
>>
>> The idea isn't new, Nick Coghlan proposed a "ELPython" last year:
>>
>>https://github.com/elpython/elpython-meta
>
>
> Was that when
>
>
>>
>>
>> The Linux kernel also have multiple LTS kernel which are supported
>> longer than usual releases: they are now supported for 6 years. See
>> "Longterm" at:
>>
>>https://www.kernel.org/category/releases.html
>
>
> The LKM has plenty of paid, full-time employees to keep those LTS kernels
> running upstream while we have nothing close to that. Even if we said "no
> one is expected to manage 3.6 changes" to let paid core devs keep 3.6
> going, that still adds overhead to other core devs who have no interest in
> keeping 3.6 alive for Canonical or RH's benefit (yes, the community gets
> benefits as well, but I would argue the pay-off isn't high enough for
> volunteers to be involved). Now if downstream vendors wanted to get
> together to pool their resources to make 3.6 a LTS-like release in a
> separate repo then I would be fine with that.
>
> I also think this puts Ned in a tough position to say "no" to the request
> if people start saying "I would love more free support!" ;) .
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Re: [python-committers] Extending 3.6 [was: 3.7.2rc1 and 3.6.8rc1 cutoffs ahead, last 3.6.x bugfix release!]

2018-12-19 Thread Ned Deily
On Dec 19, 2018, at 04:14, Serhiy Storchaka  wrote:
> Can we revise our policy and prolong the bug fixing mode for 3.6? 3.6 is
> the default Python in Ubuntu 18.04 LTS and RHEL 8. And due to several
> important syntax features it can be a minimal required version for long
> time.

We could but we are not going to now for multiple reasons.

> I merged several PRs before releasing 3.6.8rc1, but there are still less
> trivial bugfix PRs which need more time for reviewing, and there are bugs
> for which no PR is created yet. There is also a number of documentation
> PRs. I propose to allow backporting bugfixes to 3.6 if they do not need
> excessive work, but stop to fix 3.6 only bugs. After migrating to GitHab,
> backporting became less painful, most of backports to 3.6 can be done
> automatically from master or from 3.7.

There are always going to be bugs that remain unfixed when a release
branch moves from bugfix mode to security-fix only mode. That has been
true for all previous Python branches.

So what, if anything, is different about 3.6?

I see two possibly significant differences:

- 3.6 is clearly the most widely adopted Python 3 release to date and is
likely to be in the field longer than previous 3.x releases.

- As Serhiy notes, it is now easier for core developers to port changes to
other branches.

What hasn't changed in 3.6?

- We have had many discussions about Python 3 release cycles in a number
of different venues, e.g. in the mailing lists, at PyCon Language Summits,
at Core Developer Sprints, etc. People have made many different arguments
for how long a release cycle should be and how long we should maintain a
release branch. In the end, we made a plan that started 3.5 years ago, one
that we have been following and one that we have set expectations for us
and for our downstream users, big and small.

- While the act of backporting a fix is obviously an important part of
producing a maintenance release, it is not the only part. As Victor noted,
there is the CI infrastructure that needs to be monitored and maintained,
primarily our CI platforms and buildbots. And Victor knows better than
almost anyone that those things require constant attention, even if the
number of supported platforms and level of activity were somehow reduced.
This activity is exhausting and has led to more than one case of core
developer (near-)burnout. Besides that, there are less visible but very
important activities that are part of our release process: monitoring of
release activity, manufacturing releases, encouraging and monitoring
downstream testing by third-party developers, distributors, and users, etc.

So, extending the bugfix support window of a release affects and is asking
for significant commitments from core developers, release teams,
infrastructure support, third-party users and distributors. It is not
something to be taken lightly - especially when most of the people
involved in these activities are volunteers and largely unpaid.

On Dec 19, 2018, at 13:24, Gregory P. Smith  wrote:
> Ned - and any release manager in this situation in the future - has a
> default valid answer to this request: No.
> 
> If we're ever going to do an "EL" or "LTS" Python, that should be decided
> and agreed upon *long before the end of its existing planned maintenance
> cycle* instead of right as it is ending. Ideally before the first x.y.0
> with agreement of the release manager. Though it'd likely be fine to have
> that conversation about 3.7 as it is still young, the RM gets final say
> into if or how that would work.
> 
> I know that I won't be bothering with 3.6 backport/review work myself
> anymore outside of special circumstances.

I think Greg says it better than I could - thanks!

We have had several years to discuss this. There have been a number of
proposals but none have resulted in a reviewed, approved PEP. Literally
one day before the final bugfix release is not the time to make such a big
change in our plans. It certainly is legitimate and necessary to consider
such changes in the future when we have our new governance process in
place and, at that time, we can consider revising our plans for 3.7 which
is still relatively early in its bugfix phase. And, if there were concrete
proposals with funding sources for co-ordinating extended support for 3.6,
we should consider them. I think a reasonable target is to have a final
discussion and decision made by the next Language Summit upcoming in May;
there is plenty of work to be done before then, i.e. start new or revise
exiting PEPs.

But in the absence of any of that at the moment, it would be a disservice
to all to consider making such major changes and commitments now. And it's
not something that I as release manager or any of us individually as core
developers can or should do.

--Ned

P.S. Thanks for bringing this up, Serihy, and thanks for everyone's
thoughtful responses.

-- Ned Deily
   [email protected] -- []

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