Mailman 3 February 2017 - python-committers

No more notifications of commits (merged PR) on bpo?
by Victor Stinner 27 Feb '17

27 Feb '17

Hi, My PR was merged, but I don't see any notification on bpo: https://github.com/python/cpython/pull/253 http://bugs.python.org/issue27840 A few weeks ago, we got two notifications per commit (hg, git), and now there is zero notification :-) Is it a known issue? Victor

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IMPORTANT: Python 3.6.1 Maintenance Release Release Candidate in 7 days (2017-02-27)
by Ned Deily 26 Feb '17

26 Feb '17

It seems like last year already since the release of 3.6.0. I guess that's because it was last year, 2016-12-22 to be exact! Now we're approaching the end of the first quarter and, according to PEP 494, it's time to start producing the first maintenance release for the 3.6 series. The schedule calls for the release candidate to be produced on Monday 2017-02-27 UTC. As was the case with the 3.6.0 release cycle, the plan is for the release candidate to be the same as the final release, that is, no additional changes go in after the release candidate except for any showstopper critical problems that might be discovered with rc1. So please plan to get any security fixes, bug fixes, and documentation changes you think should be in 3.6.1 merged in before 2017-02-27. I will send out another reminder a couple of days before. The 3.6.1 final is planned for two weeks following rc1, that is, on 2017-03-13. I expect the next 3.6 maintenance release (3.6.2) will follow about 3 months later, so most likely in 2017-06 after PyCon US. 3.6.1 will be the first release using our new GitHub-based development process (thanks, Brett and team!). If you are planning to push something for 3.6.1 and haven't yet tried out the new workflow or are not yet familiar with GitHub pull requests, you should probably give yourself some extra time. As always, the Developer's Guide is the primary reference for the development workflow; not surprisingly, with such a major change, there are likely still some parts of the guide that could use further changes and clarifications. You can help by reviewing the devguide's open issues and pull requests in its repository and adding to them as you work through issues. If you have comments on or improvement suggestions for the new workflow, the place to discuss them is on the core-workflow mailing list. Thanks again for all of your efforts in bringing 3.6.0 into the world and for helping now to make it even better! https://www.python.org/dev/peps/pep-0494/ http://cpython-devguide.readthedocs.io https://mail.python.org/mailman/listinfo/core-workflow -- Ned Deily nad(a)python.org -- []

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PRs now require Travis to be green, don't require a review
by Brett Cannon 25 Feb '17

25 Feb '17

I don't know about the rest of you but I can't believe it's only been two weeks since we moved over to GitHub! Hopefully people are still viewing it in a positive light. :) One complaint I have heard consistently is the required review sign-off on PRs. To do some A/B testing of this, I have switched that requirement off but switched on the requirement that Travis tests be passing. In two weeks I will be starting a conversation about the new workflow to find out what people think we need to tweak, add/create, or remove in the process. At that point we can make a final call if this situation is better than requiring reviews, or if we want both CI and reviews for each PR.

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Date of the Language Summit at Pycon US 2017?
by Victor Stinner 24 Feb '17

24 Feb '17

Hi, I'm going to book my hotel and flight for Pycon US, but I don't know the date of the Language Summit and I would prefer to not miss it if possible :-) Does someone organize it? Victor

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Mercurial commit url is broken
by Victor Stinner 18 Feb '17

18 Feb '17

Hi, I clicked on a Mercurial commit number from: http://bugs.python.org/issue18383#msg249581 It points me to: http://hg.python.org/lookup/c1396d28c440 ... which displays short error message: --- Usage: /lookup/GITHEXHASH or gitGITHEXHASH (10, 11, or 40 hex characters) /lookup/HGHEXNODE or hgHGHEXNODE (12 or 40 hex characters) /lookup/rSVNREVISION --- "c1396d28c440" hash is 12 hex characters long. Victor

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New Roundup notifications on Git commits?
by Victor Stinner 16 Feb '17

16 Feb '17

Hi, I merged my pull request: https://github.com/python/cpython/pull/12 which has a commit message starting with "bpo-29524: ", but the issue wasn't updated (no new comment to mention the comit): http://bugs.python.org/issue29524 The final commit is: https://github.com/python/cpython/commit/c22bfaae83ab5436d008ac0d13e7b47cbe… Is it a known issue? Should I mention the issue number differently? Victor

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Discussions on PRs
by M.-A. Lemburg 14 Feb '17

14 Feb '17

With the move to Github, I'm seeing a move away from discussions on the issue tracker towards discussions on pull requests. Example: https://github.com/python/cpython/pull/4 Is this something we should encourage or better ask the OPs to open a ticket on the tracker first and reference the PR there ? Discussion on the PRs would then only be for code review aspects. Thanks, -- Marc-Andre Lemburg eGenix.com Professional Python Services directly from the Experts (#1, Feb 13 2017) >>> Python Projects, Coaching and Consulting ... http://www.egenix.com/ >>> Python Database Interfaces ... http://products.egenix.com/ >>> Plone/Zope Database Interfaces ... http://zope.egenix.com/ ________________________________________________________________________ ::: We implement business ideas - efficiently in both time and costs ::: eGenix.com Software, Skills and Services GmbH Pastor-Loeh-Str.48 D-40764 Langenfeld, Germany. CEO Dipl.-Math. Marc-Andre Lemburg Registered at Amtsgericht Duesseldorf: HRB 46611 http://www.egenix.com/company/contact/ http://www.malemburg.com/

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Accept a PR but only push it once tests pass?
by Victor Stinner 14 Feb '17

14 Feb '17

Hi, Would it be possible to modify the workflow of GitHub pull requests to allow to click on Merge, but only merge a PR once tests complete and only if tests pass? If some tests start to become too annoying for the pre-commit CI, we can try to fix them, or even disable them in the CI to only rely on post-commit buildbots. Victor

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Disable Codecov on GitHub pull requests?
by Victor Stinner 13 Feb '17

13 Feb '17

Hi, I don't get the value of code coverage on a CI. I *like* running code coverage sometimes, but I don't like being annoying by "test failed: coverage -0,01%" by a change completely unrelated to code (note: this issue has been fixed be using a threshold of 1%). I'm annoyed by all these Codecov messages. Berker just told me that he even created a Gmail filter to drop all these email notifications... What do you think of keeping this very useful feature, but not use it on pull requests: only run it on the branches (once changes are merged), to not "pollute" pull requests? Victor

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We are now live on GitHub!
by Brett Cannon 12 Feb '17

12 Feb '17

[rendered version: https://paper.dropbox.com/doc/CPython-workflow-changes-mx1k8G6M0rg5JLy80F1r6 ] # CPython workflow changes After more than two years, our new GitHub workflow is ready to accept changes (you can look back to my first “[vision statement]( https://mail.python.org/pipermail/python-dev/2014-December/137472.html)” on changing our workflow to see how things have changed since I started working on this)! I hope you are all excited to see this finished; I know my wife is very excited as she’s tired of listening to me talk about it for a third of our marriage. ;) # Thanks First and foremost, I want to thank everyone who helped with this. Thanks to Donald and Barry for writing the initial PEPs proposing [GitHub]( https://www.python.org/dev/peps/pep-0481/) and [GitLab]( https://www.python.org/dev/peps/pep-0507/) and Nick [pre-proposing RhodeCode](https://www.python.org/dev/peps/pep-0474/). Thanks to everyone on [core-workflow](https://mail.python.org/mailman/listinfo/core-workflow) for helping out with various discussion (and which will continue to host discussions on future improvements on our workflow). Thanks to Ezio, Maciej, and Anish Shah for helping with the changes required to bugs.python.org in order to keep the issue tracker around. Thanks to the infrastructure team for helping deal with the migration of the [peps]( https://github.com/python/peps) and [devguide]( https://github.com/python/devguide) repos (especially Donald and Ernest). Thanks to Senthil for doing the conversion of the repo itself. Thanks to Benjamin for helping with hg.python.org stuff. Thanks to Zach for helping with the buildbots (and the devguide). Thanks to Mariatta, Carol Willing, Berker, Oleg, and Stéphane Wirtel for helping with the devguide. There are also plenty of other people who have provided feedback over the past 2 years on mailing lists and in-person. # What has changed The documentation in the [devguide](https://cpython-devguide.readthedocs.io) should be up-to-date, so don’t worry about keeping this around as a reference. Consider this more of an announcement letter to get people quickly up-to-speed and excited about the new workflow. ## The location of the code repository CPython’s code now lives at https://github.com/python/cpython . hg.python.org/cpython is and will stay read-only (no determination has been made as to how long the Mercurial repository will be kept running). It should also be mentioned that we are doing squash commits and not rebased commits or merge commits as some projects on GitHub do. This basically means we will continue to have a single contribution lead to a single commit, keeping our history linear and compact. To up the bus factor on the new repository, I have set up a team for [Python release managers]( https://github.com/orgs/python/teams/python-release-managers) and made them administrators on the repository. I don’t necessarily expect RMs to use this power, but it’s there in case any of them need to change a setting in order to get a release out (to be upfront about it, I’m also in the team as its creator, but I have administrative privileges for the [Python team]( https://github.com/python) on GitHub so it doesn’t change what I’m able to do). ## Specifying issue numbers Traditionally we have specified issues as “Issue #NNNN”. The problem with this format is that [GitHub automatically links]( https://help.github.com/articles/autolinked-references-and-urls/#issues-and…) text in this format to GitHub issues and pull requests. While our repository will initially have no issues or PRs to automatically link to, this might not be true long-term (GitHub does the automatic linking eagerly at push time, so there’s no worry for older commit messages; we actually almost mutated the history to match the new format but in the end I made the decision not to as I didn’t consult with python-committers prior to the migration to make sure such a change was acceptable to everyone). To avoid this issue we are going to start specifying issues as “bpo-NNNN”. This clearly delineates that issue numbers directly relate to bugs.python.org since “[namespaces are one honking great idea]( https://www.python.org/dev/peps/pep-0020/)”. This is also a format that GitHub supports — “GH-NNNN” — as well as JIRA who [lets you specify the prefix]( https://confluence.atlassian.com/adminjiraserver072/changing-the-project-ke…), so there’s precedent for choosing it. This change applies both to `[Misc/NEWS]( https://cpython-devguide.readthedocs.io/committing.html#what-s-new-and-news… and in [commit messages]( https://cpython-devguide.readthedocs.io/committing.html#commit-messages). Mentioning an issue this way in a pull request title or comment will connect the PR to the corresponding issue on bugs.python.org. Mentioning an issue this way in a commit message will cause a comment to show up in the issue relating to the commit. ## Cherry-picking instead of merging When a patch has spanned more than one version/branch we have always done a forward merge. The common issue with this, though, is it leads to racing with other committers from when you make to your initial commit in the oldest version/branch to pushing to hg.python.org on the newest version/branch. There was also the problem of having to remember that Python 2.7 is a special branch which was never merged forward. To deal with these issues we will use [cherry-picking]( https://cpython-devguide.readthedocs.io/committing.html#backporting-changes…) going forward. This allows changes to be pulled into other branches as independent commits. This prevents any commit races with other core developers as we have traditionally needed to deal with when doing forward merges that span e.g. three branches. It also allows using CI to easily verify a change works if each cherry-pick is done as a separate pull request. The Python 2.7 branch also stops being a special case when backporting. It also prevents potential issues stemming from contributors submitting pull requests against the master branch by default and not the oldest branch a change should be applied to. Finally, this also removes the discussion of whether a change should be backported or not from blocking the commit into master to begin with. Labels will be provided for people to use to help track any cherry-picking that needs to occur for a pull request (e.g. “backport to 3.6”). I also left the “bug” and “enhancement” labels to help classify PRs (adding more labels is easy so we can do that as our experience and workflow organically converge towards common practices). ## Protected branches All feature branches have been marked as [protected]( https://help.github.com/articles/about-protected-branches/). This means that feature branches cannot be deleted nor can they be pushed to directly. The latter will be the biggest change as it means all changes must go through a pull request. This helps make sure that there are no accidental breakage of code (I know I have done this multiple times when in a rush and I didn’t take my time when preparing a commit). This also means that all core developers follow the same development workflow as any other contributor. This not only allows all core developers to be able to help any other contributors with our workflow, but it also helps make sure we are aware of any sticking points in the contributor process so that we can all work towards resolving them for everyone’s benefit. (If experience shows that this is too much overhead we can turn this off.) All feature branches that are in security-only mode are locked down so that only [Python release managers]( https://github.com/orgs/python/teams/python-release-managers) can approve pull requests to them. For all branches that have reached EOL, no one is able to push to them. I expect that RMs will also use this feature when they are ready to gate all commits to a branch on their approval (e.g. when a release reaches RC, maybe even beta if they choose to go that far). # What has improved ## Accepting PRs through GitHub’s web UI While using hg.python.org, all commits had to be done through Mercurial’s CLI. With the move to GitHub we gain the ability to accept pull requests through a web UI. While this will only accept the change into the branch it was submitted against (which can be changed in the web UI), for situations where a change does not need to be backported it will allow for easier acceptance of a change. (When a change does need to be backported this is when you need to cherry-pick and that requires using the git CLI). If a change does need to be cherry-picked into an older branch you can either wait to accept the PR when you have a clone to work with or accept the change into master now and then cherry-pick later when you have a clone available. ## Continuous integration Previously changes required running the test suite manually along with verifying various other things like the documentation building. Moving to GitHub allows us to leverage the Travis continuous integration service to test several things in parallel automatically for each pull request: 1. Debug build under gcc 2. Debug build under clang 3. Documentation is valid and has no stale links 4. Python.h C++ compatibility While this doesn’t solve all testing scenarios (e.g. this doesn’t test a macOS or Windows-related change due to the added hours it take for a PR to be “green” when run on Travis for macOS or AppVeyor for Windows), it does help with the common case of a cross-platform change. (There is an [open issue](https://github.com/python/core-workflow/issues/14) to add some code so that these tests only run when appropriate files have changed so that e.g. fixing a spelling mistake doesn’t run the test suite.) It should be mentioned that status checks on issues are **not** required prior to committing a pull request. While this may be a good idea long-term, until we know that our test suite is stable enough to not have regular flaky tests this would be more trouble than it’s worth (GitHub does visibly show, though, when not all status checks have passed so you won’t easily ignore this situation either). ## Code coverage Traditionally the code coverage of our tests was only known when someone ran the test suite manually under something like [coverage.py]( https://coverage.readthedocs.io). Even when someone did generate a coverage report it was generally not shared with other developers, and so it wasn’t widely known if a pull request increased or lowered test coverage. With the move to GitHub we are able to use [Codecov](https://codecov.io/) to calculate code coverage for each pull request. This also implicitly tests a non-debug build as that’s used to make the coverage results run faster. It should be noted, though, that some tests are skipped due to them holding up the coverage run from completing. (There is an [open issue]( https://github.com/python/core-workflow/issues/18) to use coverage.py’s fullcoverage hack so that the coverage report can even be accurate for modules imported during interpreter startup.) ## CLA enforcement To tell if someone has signed the PSF contributor license agreement you have to look to see if they have an asterisk by their name on the issue tracker. Unfortunately this is a passive thing to need to check for and is easily forgotten. Thanks to GitHub’s webhook events and developer API we now have a bot which checks if the contributor(s) to a pull request have signed the CLA, adding an appropriate label to the PR to signal the CLA signing status (the bot is named [The Knights Who Say Ni]( https://github.com/python/the-knights-who-say-ni)). If the contributor(s) have not signed the CLA then a message is left on the PR explaining how to rectify the issue (it’s either they need to connect their GitHub account to their bugs.python.org account or they need to sign the CLA; there’s also is an easter egg that occasionally appears in the message). If a contributor does end up fixing the issue that leads to the bot thinking the contributor had not signed the CLA, you can remove the “CLA not signed” label and the bot will recheck the PR and add the appropriate label (this also happens automatically if any code changes are made to the PR). If for some the reason the bot has a hiccup then no label will be applied (this is to act as a safeguard against false-negatives and to make it easy to spot when something has gone wrong due to the absence of either a “CLA signed” or “CLA not signed” label). To trigger the bot again you can simply apply the “CLA not signed” label and then remove it. ## Contribution guidelines There is now a `[.github/CONTRIBUTING.rst]( https://github.com/python/cpython/blob/master/.github/CONTRIBUTING.rst)` file which gives general info on contributing. Primarily it has all the various build status badges and links, link to the devguide and an overview of how we differ from most GitHub projects, and a mention of the CoC. For core devs I suspect the badge list for all active branches will be useful to know when something is broken (I am only listing the test coverage for the master branch to prevent encouraging people spending time trying to increase test coverage for bugfix-only branches) . # The future This isn’t here for discussion per-se, but to let people know what I am thinking should change next. If you want to help or discuss anything in this section, please subscribe to core-workflow and participate there. Ideas are also tracked on the [core-workflow issue tracker]( https://github.com/python/core-workflow/issues) (where there are other ideas for improvements beyond the two listed below). First, we need to solve the Misc/NEWS problem. The [plan]( https://github.com/python/core-workflow/issues/6) is to move to individual files per NEWS entry and then have a script to roll them all up into the NEWS file at release time. This will do away with merge conflicts which has always been the biggest hassle when a change spanned versions. Second, we will probably develop some solution to [automatically generate cherry-picking PRs](https://github.com/python/core-workflow/issues/8). This plus the Misc/NEWS solution should be enough to allow most patches to be accepted through the web UI entirely. All the other changes are nice-to-have, but I think these two will lead to the greatest improvement to our workflow and get us far beyond the workflow we had on hg.python.org.

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