PEP 101 -- Doing Python Releases 101

PEP: 101
Title: Doing Python Releases 101
Version: 555b1e389e83
Last-Modified: 2014-10-12 08:59:21 +0200 (Sun, 12 Oct 2014)
Author: Barry Warsaw <barry at>, Guido van Rossum <guido at>
Status: Active
Type: Informational
Created: 22-Aug-2001


    Making a Python release is a thrilling and crazy process.  You've heard
    the expression "herding cats"?  Imagine trying to also saddle those
    purring little creatures up, and ride them into town, with some of their
    buddies firmly attached to your bare back, anchored by newly sharpened
    claws.  At least they're cute, you remind yourself.

    Actually, no that's a slight exaggeration <wink>.  The Python release
    process has steadily improved over the years and now, with the help of our
    amazing community, is really not too difficult.  This PEP attempts to
    collect, in one place, all the steps needed to make a Python release.  It
    is organized as a recipe and you can actually print this out and check
    items off as you complete them.

Things You'll Need

    As a release manager there are a lot of resources you'll need to access.
    Here's a hopefully-complete list.

    * A GPG key.

      Python releases are digitally signed with GPG; you'll need a key,
      which hopefully will be on the "web of trust" with at least one of
      the other release managers.

    * Access to ````, the server that hosts download files.
      You'll be uploading files directly here.

    * Shell access to ````, the Python Mercurial host.  You'll
      have to adapt repository configuration there.

    * Write access to the website SVN repository

      Instructions here:

    * Write access to the PEP repository.

      If you're reading this, you probably already have this--the first
      task of any release manager is to draft the release schedule.  But
      in case you just signed up... sucker!  I mean, uh, congratulations!

    * Posting access to, a Blogger-hosted weblog.
      The RSS feed from this blog is used for the 'Python News' section

How to Make A Release

    Here are the steps taken to make a Python release.  Some steps are more
    fuzzy than others because there's little that can be automated (e.g.
    writing the NEWS entries).  Where a step is usually performed by An
    Expert, the role of that expert is given.  Otherwise, assume the step is
    done by the Release Manager (RM), the designated person performing the
    release.  The roles and their current experts are:

    * RM = Release Manager: Larry Hastings <> (US)
    * WE = Windows: Martin von Loewis <> (Central Europe) and Steve Dower <>
    * ME = Mac: Ned Deily <> (US)
    * DE = Docs: Georg Brandl <> (Central Europe)
    * IE = Idle Expert: ??

    NOTE: It is highly recommended that the RM contact the Experts the day
          before the release.  Because the world is round and everyone lives
          in different timezones, the RM must ensure that the release tag is
          created in enough time for the Experts to cut binary releases.

          You should not make the release public (by updating the website and
          sending announcements) before all experts have updated their bits.
          In rare cases where the expert for Windows or Mac is MIA, you may add
          a message "(Platform) binaries will be provided shortly" and proceed.

    XXX: We should include a dependency graph to illustrate the steps that can
    be taken in parallel, or those that depend on other steps.

    As much as possible, the release steps are automated and guided by the
    release script, which is available in a separate repository:

    We use the following conventions in the examples below.  Where a release
    number is given, it is of the form X.Y.ZaN, e.g. 3.3.0a3 for Python 3.3.0
    alpha 3, where "a" == alpha, "b" == beta, "rc" == release candidate.

    Release tags are named "vX.Y.ZaN".  The branch name for minor release
    maintenance branches is "X.Y".

    This helps by performing several automatic editing steps, and guides you
    to perform some manual editing steps.

  ___ Log into and join the #python-dev channel.

      You probably need to coordinate with other people around the world.
      This IRC channel is where we've arranged to meet.

  ___ Check to see if there are any showstopper bugs.

      Go to and look for any open bugs that can block
      this release.  You're looking at the Priority of the open bugs for the
      release you're making; here are the relevant definitions:

      release blocker - Stops the release dead in its tracks.  You may not
                        make any release with any open release blocker bugs.

      deferred blocker - Doesn't block this release, but it will block a
                         future release.  You may not make a final or
                         candidate release with any open deferred blocker

      critical - Important bugs that should be fixed, but which does not block
                 a release.

      Review the release blockers and either resolve them, bump them down to
      deferred, or stop the release and ask for community assistance.  If
      you're making a final or candidate release, do the same with any open

  ___ Check the stable buildbots.

      Go to

      (the trailing slash is required).  Look at the buildbots for the release
      you're making.  Ignore any that are offline (or inform the community so
      they can be restarted).  If what remains are (mostly) green buildbots,
      you're good to go.  If you have non-offline red buildbots, you may want
      to hold up the release until they are fixed.  Review the problems and
      use your judgement, taking into account whether you are making an alpha,
      beta, or final release.

  ___ Make a release clone.

      Create a local clone of the cpython repository (called the "release
      clone" from now on).

      Also clone the repo at using the
      server-side clone feature.  The name of the new clone should preferably
      have a "releasing/" prefix.  The other experts will use the release
      clone for making the binaries, so it is important that they have access
      to it!

      It's best to set up your local release clone to push to the remote
      release clone by default (by editing .hg/hgrc to that effect).

  ___ Notify all committers by sending email to

      Since we're now working with a distributed version control system, there
      is no need to stop everyone from pushing to the main repo; you'll just
      work in your own clone.  Therefore, there won't be any checkin freezes.

      However, all committers should know the point at which your release
      clone was made, as later commits won't make it into the release without
      extra effort.

  ___ Make sure the current branch of your release clone is the branch you
      want to release from.

  ___ Regenerate Lib/

      cd to the Doc directory and type ``make pydoc-topics``.  Then copy
      ``build/pydoc-topics/`` to ``../Lib/pydoc_data/``.

  ___ Check the docs for markup errors.

      In the Doc directory, type ``make suspicious``.  If any markup errors
      are found, fix them.

  ___ Commit any changes to and the doc sources.

  ___ Make sure the SOURCE_URI in ``Doc/tools/``
      points to the right branch in the hg repository (or ``default`` for
      unstable releases of the default branch).

  ___ Bump version numbers via the release script.

      $ .../release/ --bump X.Y.ZaN

      This automates updating various release numbers, but you will have to
      modify a few files manually.  If your $EDITOR environment variable is
      set up correctly, will pop up editor windows with the files
      you need to edit.

      It is important to update the Misc/NEWS file, however in recent years,
      this has become easier as the community is responsible for most of the
      content of this file.  You should only need to review the text for
      sanity, and update the release date with today's date.

  ___ Make sure all changes have been committed.  (`` --bump``
      doesn't check in its changes for you.)

  ___ Check the years on the copyright notice.  If the last release
      was some time last year, add the current year to the copyright
      notice in several places:

      ___ README
      ___ LICENSE (make sure to change on trunk and the branch)
      ___ Python/getcopyright.c
      ___ Doc/README.txt (at the end)
      ___ Doc/copyright.rst
      ___ Doc/license.rst
      ___ PC/python_nt.rc sets up the DLL version resource for Windows
          (displayed when you right-click on the DLL and select

  ___ Check with the IE (if there is one <wink>) to be sure that
      Lib/idlelib/NEWS.txt has been similarly updated.

  ___ For a final major release, edit the first paragraph of
      Doc/whatsnew/X.Y.rst to include the actual release date; e.g. "Python
      2.5 was released on August 1, 2003."  There's no need to edit this for
      alpha or beta releases.  Note that Andrew Kuchling often takes care of

  ___ Tag the release for X.Y.ZaN.

      $ .../release/ --tag X.Y.ZaN

      NOTE: when forward, i.e. "null" merging your changes to newer branches,
      e.g. 2.6 -> 2.7, do *not* revert your changes to the .hgtags file or you
      will not be able to run the --export command below.  Revert everything
      else but leave .hgtags alone.

  ___ If this is a final major release, branch the tree for X.Y.

      When making a major release (e.g., for 3.2), you must create the
      long-lived maintenance branch.

      ___ Note down the current revision ID of the tree.

          $ hg identify

      ___ First, set the original trunk up to be the next release.

          $ .../release/ --bump 3.3a0

          ___ Edit all version references in the README

          ___ Move any historical "what's new" entries from Misc/NEWS to

          ___ Edit Doc/tutorial/interpreter.rst (2 references to '[Pp]ython3x',
              one to 'Python 3.x', also make the date in the banner consistent).

          ___ Edit Doc/tutorial/stdlib.rst and Doc/tutorial/stdlib2.rst, which
              have each one reference to '[Pp]ython3x'.

          ___ Add a new whatsnew/3.x.rst file (with the comment near the top
              and the toplevel sections copied from the previous file) and
              and add it to the toctree in whatsnew/index.rst.

          ___ Update the version number in and re-run autoconf.

          ___ Update the version numbers for the Windows builds in PC/ and
              PCbuild/, which have references to python32.

              $ find PC/ PCbuild/ -type f | xargs sed -i 's/python32/python33/g'
              $ hg mv -f PC/os2emx/python32.def PC/os2emx/python33.def
              $ hg mv -f PC/python32stub.def PC/python33stub.def
              $ hg mv -f PC/ PC/

          ___ Commit these changes to the default branch.

      ___ Now, go back to the previously noted revision and make the
          maintenance branch *from there*.

          $ hg update deadbeef    # revision ID noted down before
          $ hg branch 3.2

      ___ When you want to push back your new branch to the main CPython
          repository, the new branch name must be added to the "allow-branches"
          hook configuration, which protects against stray named branches being
          pushed.  Login to and edit (as the "hg" user)
          ``/data/hg/repos/cpython/.hg/hgrc`` to that effect.

  ___ For a final major release, Doc/tools/static/version_switch.js
      must be updated in all maintained branches, so that the new maintenance
      branch is not "dev" anymore and there is a new "dev" version.

  ___ Push your commits to the remote release clone.

      $ hg push ssh://

  ___ Notify the experts that they can start building binaries.


      At this point you must receive the "green light" from other experts in
      order to create the release.  There are things you can do while you wait
      though, so keep reading until you hit the next STOP.

  ___ The WE builds the Windows helpfile, using (in Doc/)

      > make.bat htmlhelp   (on Windows)

      to create suitable input for HTML Help Workshop in build/htmlhelp. HTML
      Help Workshop is then fired up on the created python33.hhp file, finally
      resulting in an python33.chm file.

  ___ The WE then generates Windows installer files for each Windows
      target architecture (for Python 3.3, this means x86 and AMD64).

      - He has one checkout tree per target architecture, and builds the
        pcbuild.sln project for the appropriate architecture.

      - PC\icons.mak must have been run with nmake.

      - The cmd.exe window in which this is run must have Cygwin/bin in its
        path (at least for x86).

      - The cmd.exe window must have MS compiler tools for the target
        architecture in its path (VS 2010 for Python 3.3).

      - The WE then edits Tools/msi/ (a file only present locally)
        to update full_current_version and sets snapshot to false.  Currently
        for a release looks like

            certname="Python Software Foundation

        The last line is only present for the amd64 checkout.

      - Now he runs with ActivePython or Python with pywin32.

      The WE checksums the files (*.msi, *.chm, *, uploads them to together with gpg signature files, and emails you the
      location and md5sums.

  ___ The ME builds Mac installer packages and uploads them to
      together with gpg signature files.

  ___ Time to build the source tarball.  Be sure to update your clone to the
      correct branch.  E.g.

      $ hg update 3.2

  ___ Do a "hg status" in this directory.

      You should not see any files.  I.e. you better not have any uncommitted
      changes in your working directory.

  ___ Make sure you have an up-to-date Sphinx toolchain installed.

      $ pip install -U Sphinx

      For building the PDF docs, you also need a fairly complete installation
      of a recent TeX distribution such as texlive.

  ___ Use the release script to create the source gzip and xz tarballs,
      documentation tar and zip files, and gpg signature files.

      $ .../release/ --export X.Y.ZaN

      This can take a while for final releases, and it will leave all the
      tarballs and signatures in a subdirectory called 'X.Y.ZaN/src', and the
      built docs in 'X.Y.ZaN/docs' (for final releases).

  ___ scp or rsync all the files to your home directory on

      While you're waiting for the files to finish uploading, you can continue
      on with the remaining tasks.  You can also ask folks on #python-dev
      and/or python-committers to download the files as they finish uploading
      so that they can test them on their platforms as well.

  ___ Now you want to perform the very important step of checking the
      tarball you just created, to make sure a completely clean,
      virgin build passes the regression test.  Here are the best
      steps to take:

      $ cd /tmp
      $ tar xvf ~/Python-3.2rc2.tgz
      $ cd Python-3.2rc2
      $ ls
      (Do things look reasonable?)
      $ ls Lib
      (Are there stray .pyc files?)
      $ ./configure
      (Loads of configure output)
      $ make test
      (Do all the expected tests pass?)

      If you're feeling lucky and have some time to kill, or if you are making
      a release candidate or final release, run the full test suite:

      $ make testall

      If the tests pass, then you can feel good that the tarball is
      fine.  If some of the tests fail, or anything else about the
      freshly unpacked directory looks weird, you better stop now and
      figure out what the problem is.

  ___ Now you need to go to and move all the files in
      place over there.  Our policy is that every Python version gets its own
      directory, but each directory contains all releases of that version.

      ___ On, cd /srv/ creating
          it if necessary.  Make sure it is owned by group 'downloads' and

      ___ Move the release .tgz, and .tar.xz files into place, as well as the
          .asc GPG signature files.  The Win/Mac binaries are usually put there
          by the experts themselves.

          Make sure they are world readable.  They should also be group
          writable, and group-owned by downloads.

      ___ Use `gpg --verify` to make sure they got uploaded intact.

      ___ If this is a final release: Move the doc zips and tarballs to
          /srv/, creating the directory
          if necessary, and adapt the "current" symlink in .../doc to point to
          that directory.  Note though that if you're releasing a maintenance
          release for an older version, don't change the current link.

      ___ If this is a final release (even a maintenance release), also unpack
          the HTML docs to /srv/ on
 Make sure the files are in group "docs".  If it
          is a release of a security-fix-only version, tell the DE to build a
          version with the "version switcher" and put it there.

      ___ Let the DE check if the docs are built and work all right.

      ___ If this is a final major release: Tell the DE to adapt redirects for
 in the Apache config for, update
          the script Doc/tools/ to point to the right
          stable/development branches, and to install it and make the initial
          checkout.  The Doc's version_switcher.js script also needs to be

      ___ Note both the documentation and downloads are behind a caching CDN. If
          you change archives after downloading them through the website, you'll
          need to purge the stale data in the CDN like this:

          $ curl -X PURGE

  ___ For the extra paranoid, do a completely clean test of the release.
      This includes downloading the tarball from

      Make sure the md5 checksums match.  Then unpack the tarball,
      and do a clean make test.

      $ make distclean
      $ ./configure
      $ make test

      To ensure that the regression test suite passes.  If not, you
      screwed up somewhere!

  Now it's time to twiddle the web site.

  To do these steps, you must have the permission to edit the website.  If you
  don't have that, ask someone on for the proper
  permissions.  It's insane for you not to have it.

  XXX This is completely out of date for Django based

  This page will probably come in handy:

  None of the web site updates are automated by

  ___ Build the basic site.

      In the top directory, do an `svn update` to get the latest code.  In the
      build subdirectory, do `make` to build the site.  Do `make serve` to
      start service the pages on localhost:8005.  Hit that url to see the site
      as it is right now.  At any time you can re-run `make` to update the
      local site.  You don't have to restart the server.

      Don't `svn commit` until you're all done!

  ___ If this is the first release for this version (even a new patch
      version), you'll need to create a subdirectory inside download/releases
      to hold the new version files.  It's probably a good idea to copy an
      existing recent directory and twiddle the files in there for the new
      version number.

  ___ Update the version specific pages.

      ___ cd to `download/releases/X.Y.Z`
      ___ Edit the version numbers in
      ___ Update the md5 checksums

      ___ Comment out the "This is a preview release" or the "This is a
          production release" paragraph as appropriate

      Note, you don't have to copy any release files into this directory;
      they only live on in the ftp directory.

  ___ Edit `download/releases/` to update the version numbers for
      this release.  There are a bunch of places you need to touch:

      ___ The subdirectory name as the first element in the Nav rows.
      ___ Possibly the Releases section, and possibly in the experimental
          releases section if this is an alpha, beta or release candidate.

  ___ Update the download page, editing `download/`.  Pre-releases are
      added only to the "Testing versions" list.

  ___ If this is a final release...

      ___ Update the 'Quick Links' section on the front page.  Edit the
          top-level `` file.

      ___ For X.Y.Z, edit all the previous X.Y releases' page to
          point to the new release.

      ___ Update `doc/` to indicate the new current documentation
          version, and remove the current version from any 'in development'
          section. Update the version in the "What's New" link.

      ___ Add the new version to `doc/versions/`.

  ___ Add a news section item to the front page by editing newsindex.yml.  The
      format should be pretty self evident.

  ___ When everything looks good, `svn commit` in the data directory.  This
      will trigger the live site to update itself, and at that point the
      release is live.

  ___ If this is a final release, create a new Apache alias
      (or ask pydotorg to do so for you).

  Now it's time to write the announcement for the mailing lists.  This is the
  fuzzy bit because not much can be automated.  You can use an earlier
  announcement as a template, but edit it for content!


      ___ Have you gotten the green light from the WE?

      ___ Have you gotten the green light from the DE?

  ___ Once the announcement is ready, send it to the following

  ___ Also post the announcement to <>.

  Now it's time to do some cleaning up.  These steps are very important!

  ___ Do the guided post-release steps with the release script.

      $ .../release/ --done X.Y.ZaN

      Review and commit these changes.

  ___ Merge your release clone into the main development repo:

      $ cd ../cpython                         # your clone of the main repo
      $ hg pull ssh://   # update from remote first
      $ hg pull ../cpython-releaseX.Y         # now pull from release clone

      Now merge your release clone's changes in every branch you touched
      (usually only one, except if you made a new maintenance release).
      Easily resolvable conflicts may appear in Misc/NEWS.

      If releasing from other than the default branch, remember to carefully
      merge any touched branches with higher level branches, up to default.  For

      $ hg update -C default
      $ hg resolve --list
      $ hg merge --tool "internal:fail" 3.4

      ... here, revert changes that are not relevant for the default branch...

      $ hg resolve --mark

      Commit and push to the main repo.

  ___ You can delete the remote release clone, or simply reuse it for the next

  ___ Send email to python-committers informing them that the release has been

  ___ Update any release PEPs (e.g. 361) with the release dates.

  ___ Update the tracker at

      ___ Flip all the deferred blocker issues back to release blocker
          for the next release.

      ___ Add version X.Y+1 as when version X.Y enters alpha.

      ___ Change non-doc RFEs to version X.Y+1 when version X.Y enters beta.

      ___ Update 'behavior' issues from versions that your release make
          unsupported to the next supported version.

      ___ Review open issues, as this might find lurking showstopper bugs,
          besides reminding people to fix the easy ones they forgot about.

What Next?

  ___ Verify!  Pretend you're a user: download the files from, and
      make Python from it. This step is too easy to overlook, and on several
      occasions we've had useless release files.  Once a general server problem
      caused mysterious corruption of all files; once the source tarball got
      built incorrectly; more than once the file upload process on SF truncated
      files; and so on.

  ___ Rejoice.  Drink.  Be Merry.  Write a PEP like this one.  Or be
      like unto Guido and take A Vacation.

  You've just made a Python release!

Windows Notes

    Windows has a MSI installer, various flavors of Windows have
    "special limitations", and the Windows installer also packs
    precompiled "foreign" binaries (Tcl/Tk, expat, etc).  So Windows
    testing is tiresome but very necessary.

    Concurrent with uploading the installer, the WE installs Python
    from it twice: once into the default directory suggested by the
    installer, and later into a directory with embedded spaces in its
    name.  For each installation, he runs the full regression suite
    from a DOS box, and both with and without -0. For maintenance
    release, he also tests whether upgrade installations succeed.

    He also tries *every* shortcut created under Start -> Menu -> the
    Python group.  When trying IDLE this way, you need to verify that
    Help -> Python Documentation works.  When trying pydoc this way
    (the "Module Docs" Start menu entry), make sure the "Start
    Browser" button works, and make sure you can search for a random
    module (like "random" <wink>) and then that the "go to selected"
    button works.

    It's amazing how much can go wrong here -- and even more amazing
    how often last-second checkins break one of these things.  If
    you're "the Windows geek", keep in mind that you're likely the
    only person routinely testing on Windows, and that Windows is
    simply a mess.

    Repeat the testing for each target architecture.  Try both an
    Admin and a plain User (not Power User) account.


    This document has been placed in the public domain.


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