PEP: 101
Title: Doing Python Releases 101
Version: $Revision$
Last-Modified: $Date$
Author: barry@zope.com (Barry A. Warsaw), guido@python.org (Guido van Rossum)
Status: Active
Type: Informational
Created: 22-Aug-2001
Post-History:


Abstract

    Making a Python release is an arduous processes that takes a
    minimum of half a day's work even for an experienced releaser.
    Until recently, most -- if not all -- of that burden was borne by
    Guido himself.  But several recent releases have been performed by
    other folks, so 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.


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 name of that expert is given.
    Otherwise, assume the step is done by the Release Manager (RM),
    the designated person performing the release.  Almost every place
    the RM is mentioned below, this step can also be done by the BDFL
    of course!

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

    We use the following conventions in the examples below.  Where a
    release number is given, it is of the form X.YaZ, e.g. 2.1a3 for
    Python 2.1 alpha 3, where "a" == alpha, "b" == beta, "rc" ==
    release candidate.  Final releases are named "releaseXY" so the
    branch tag is "releaseXY-branch" and the fork tag on the trunk is
    "releaseXY-fork".  If a micro release number is used, then we'll
    say X.Y.MaZ.

  ___ At noon the day before the release, create a branch for X.YaZ.

      All Python development happens on the trunk.  Making releases
      from a branch allows development by the community to continue
      without impacting what ends up in the release.  There's a
      natural tension here though: branching too soon causes headaches
      when the branch has to be merged back into the trunk, while
      branching too late can cause dependency problems with
      documentation and Windows release steps.

      The compromise is to create the branch at noon, local time, the
      day before the release.  This should give enough time to Fred to
      make the documentation, then for Tim to create the Windows
      installer, both of which need to happen before the release can
      be announced.  It's also short enough that hopefully not too
      many trunk changes will need to be merged into the branch, or
      vice versa.

      Once the branch is made, only the RM or his appointed bots are
      allowed to make commits to the branch.  You can assume that Fred
      is a bot for the Doc/ tree, Tim is a bot for the Windows stuff,
      and Jack is a bot for Mac stuff.

      Anyone can continue to make checkins on the trunk, but if such a
      change should be merged into the branch, the committer must
      indicate this in the checkin message.  It is the responsibility
      of the RM to decide on a case-by-case basis which trunk
      modifications should be merged into the branch.

      To create a branch the following steps are taken:

    ___ Do a CVS update with the -A, -d, and -P flags, e.g.
        % cvs -q update -d -P -A

    ___ CVS tag the trunk with the symbolic name "rXYaZ-fork", e.g.
        % cvs tag r22a3-fork

    ___ Make the branch with the symbolic name "rXYaZ-branch", e.g.
        % cvs tag -b r22a3-branch

    ___ Check out a clean version of the branch into a new directory.
        You'll be doing a lot of work in this directory and you want
        to keep it straight from your trunk working directory.  E.g.
        % cvs -d <cvsroot> -q co -d python-22a3 -r r22a3-branch python/dist/src

  ___ Send an email to python-dev@python.org indicating the fork and
      branch tags you've just created.

  ___ Put a freeze on check ins into the branch.  At this point,
      nobody except the RM should make any commits to the branch (or
      his duly assigned agents, i.e. Guido the BDFL, Fred Drake for
      documentation, or Tim Peters for Windows).  If the RM screwed up
      and some desperate last minute change to the branch is
      necessary, it can mean extra work for Fred and Tim.  So try to
      avoid this!

  ___ In the branch, change Include/patchlevel.h in two places, to
      reflect the new version number you've just created.  You'll want
      to change the PY_VERSION macro, and one or several of the
      version subpart macros just above PY_VERSION, as appropriate.

  ___ If you're changing the version number for Python (e.g. from
      Python 2.1.1 to Python 2.1.2), you also need to update the
      README file, which has a big banner at the top proclaiming its
      identity.  Don't do this if you're just releasing a new alpha or
      beta release, but /do/ do this if you're release a new micro
      release.

  ___ For the next few hours, selectively merge stuff from trunk into
      branch.  For each change you see on the trunk (i.e. via the
      python-checkins mailing list), you need to decide whether the
      change should also be applied to the branch.

      There is a tension here.  Announcing the branch often jogs
      people's natural tendency to procrastinate so some very useful
      patches end up getting checked in at the last moment.  But the
      Windows and Docs releases tend to be built many hours before the
      source release, and changes to the branch can force a lot of
      wasted effort to rebuild them.  The best advice is to be
      judicious and to consult Fred and Tim before adding anything
      big.  You really want to avoid skew between the various platform
      releases.

      Note that committers of changes to the trunk SHOULD include in
      the checkin message, a note indicating the suitability of their
      patch for the branch.

      If so, it's fairly easy to apply the change by diff'ing the file
      and patching it manually.  You can also sometimes get away with
      just copying the file from the trunk directory to the branch
      directory, but be careful so you don't lose changes that only
      exist in the branch!

  ___ After creating the branch, the most important thing to do next
      is to update the Misc/NEWS file.  Tim will need this in order to
      do the Windows release and he likes to stay up late.  This step
      can be pretty tedious, so it's best to get to it immediately
      after making the branch, or even before you've made the branch.
      The sooner the better (but again, watch for new checkins up
      until the release is made!)

      Add high level items new to this release.  E.g. if we're
      releasing 2.2a3, there must be a section at the top of the file
      explaining "What's new in Python 2.2a3".  It will be followed by
      a section entitled "What's new in Python 2.2a2".

      Note that you /hope/ that as developers add new features to the
      trunk, they've updated the NEWS file accordingly.  You can't be
      positive, so double check.  If you're a Unix weenie, it helps to
      verify with Tim Peters about changes on Windows, and Jack Jansen
      about changes on the Mac.

      This command should help you:

      % cvs log -rr22a1: | python Tools/scripts/logmerge.py > /tmp/news.txt

      IOW, you're printing out all the cvs log entries from the
      previous release until now.  You can then troll through the
      news.txt file looking for interesting things to add to NEWS.

  ___ Check your NEWS changes into the branch and into the trunk.

  ___ Once the branch is frozen, Fred Drake needs to create the HTML
      from the documentation.  He does this and uploads the file to
      www.python.org.  Then he tells Tim Peters where this file is.
      This may generate some last minute changes on the branch.  Once
      Fred is done, there can be no further checkins on the branch in
      the Doc/ directory -- not even by the RM.  For final releases,
      Fred also sends email to Milan Zamazal for conversion to the GNU
      Info format, and to Hernan M. Foffani for conversion to HTML
      Help.

      Note that Fred is responsible both for merging doc changes from
      the trunk to the branch AND for merging any branch changes from
      the branch to the trunk during the cleaning up phase.
      Basically, if it's in Doc/, Fred will take care of it.

  ___ Tim Peters grabs the HTML and uses this to build the Windows
      installer.

  ___ Tim performs his Windows magic, generating an installer
      executable.  He uploads this file to python.org, and then sends
      the RM a notice which includes the location and MD5 checksum of
      the Windows executable.

      Note that Tim's creation of the Windows executable may generate
      a few more commits on the branch.  Tim will be responsible for
      merging Windows-specific changes from trunk to branch, and from
      branch to trunk.

  ___ It's Noon!

      Now, you're ready to build the source tarball.  First cd to your
      working directory for the branch.  E.g.
      % cd .../python-22a3

  ___ Do a "cvs update" in this directory.  Do NOT include the -A flag!

      You should not see any "M" files, but you may see several "P"
      files.  I.e. you better not have any uncommitted changes in your
      working directory, but you may pick up some of Fred's or Tim's
      last minute changes.

  ___ Now tag the branch using a symbolic name like "rXYaZ",
      e.g. r22a3
      % cvs tag r22a3

  ___ Change to a neutral directory, i.e. one in which you can do a
      fresh, virgin, cvs export of the branch.  You will be creating a
      new directory at this location, to be named "Python-X.YaZ".  Do
      a CVS export of the tagged branch.

      % cd ~
      % cvs -d <cvsroot> export -rr22a3 -d Python-2.2a3 python/dist/src

  ___ Generate the tarball.  Note that we're not using the `z' option
      on the tar command because 1) that's only supported by GNU tar
      as far as we know, and 2) we're going to max out the compression
      level, which isn't a supported option.
      % tar cf - Python-2.2a2 | gzip -9 > Python-2.2a2.tgz

  ___ Calculate the MD5 checksum of the tgz file you just created
      % md5sum Python-2.2a2.tgz

      Note that if you don't have the md5sum program, there is a
      Python replacement in the Tools/scripts/md5sum.py file.

  ___ 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 zxvf ~/Python-2.2a3.tgz
      % cd Python-2.2a3
      % ls
      (Do things look reasonable?)
      % ./configure
      (Loads of configure output)
      % make test
      (Do all the expected tests pass?)

      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.

  ___ Upload the tgz file to creosote.python.org.  Tim will have
      already uploaded the exe file to creosote, but if not, you'll
      need to do that too.  These steps can take a long time depending
      on your network bandwidth.  scp both files from your own machine
      to creosote.

  ___ While you're waiting, you can start twiddling the web pages to
      include the announcement.

    ___ If necessary, and if you have the right permissions (the
        python.org sysadmins must set this up for you), check out the
        web site CVS tree by doing:

        % cvs -d :ext:<you>@creosote.python.org:/usr/local/cvsroot co pydotorg

    ___ In the python.org web site CVS tree, cd to the X.Y
        subdirectory, and copy index.ht to new-index.ht.  Be sure to
        do a "cvs update" first!

        % cd .../pydotorg
        % cvs -q up -P -d
        % cd 2.2
        % cp index.ht new-index.ht

    ___ Edit the file for content: usually you can globally replace
        X.Ya(Z-1) with X.YaZ.  However, you'll need to think about the
        "What's New?" section.

    ___ Copy the Misc/NEWS file to NEWS.txt in the X.Y directory for
        python.org; this contains the "full scoop" of changes to
        Python since the previous release for this version of Python.

    ___ Also, update the MD5 checksums.

    ___ Preview the web page by doing a "make" -- NOT a "make install".
        View the page via a file: url.

    ___ Similarly, edit the ../index.ht file, i.e. the python.org home
        page.  In the Big Blue Announcement Block, move the paragraph
        for the new version up to the top and boldify the phrase
        "Python X.YaZ is out".  Edit for content, and preview as
        above.  Do NOT do a "make install" yet!

  ___ Now we're waiting for the scp to creosote to finish.  Da de da,
      da de dum, hmm, hmm, dum de dum.

  ___ Now you need to go to creosote.python.org and move all the files
      in place over there.  Our policy is that every Python version
      gets its own directory, but each directory may contain several
      releases.  We keep all old releases, moving them into a "prev"
      subdirectory when we have a new release.

      So, there's a directory called "2.2" which contains
      Python-2.2a2.exe and Python-2.2a2.tgz, along with a "prev"
      subdirectory containing Python-2.2a1.exe and Python-2.2a1.tgz.

      So...

    ___ On creosote, cd to ~ftp/pub/python/X.Y creating it if
        necessary.

    ___ Move the previous release files to a directory called "prev"
        creating the directory if necessary (make sure the directory
        has g+ws bits on).  If this is the first alpha release of a
        new Python version, skip this step.

    ___ Move the .tgz file and the .exe file to this directory.  Make
        sure they are world readable.  They should also be group
        writable, and group-owned by webmaster.

    ___ md5sum the files and make sure they got uploaded intact.


  ___ Update the X.Y/bugs.ht file if necessary.  It is best to get
      BDFL input for this step.

  ___ Now preview the new-index.ht file once more.  IMPORTANT: follow
      every link on the page to make sure it goes where you expect it
      to go, and that what you expect to be there is there.

  ___ If everything looks good, move new-index.ht to index.ht and do a
      "make install" in this directory.  Go up to the parent directory
      (i.e. the root of the web page hierarchy) and do a "make
      install" there too.  You're release is now live!

  ___ 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 one of Guido's earlier announcements as a template, but
      please edit it for content!

      Once the announcement is ready, send it to the following
      addresses:

      python-list@python.org
      python-announce@python.org
      python-dev@python.org

  ___ Send a SourceForge News Item about the release.  From the
      project's "menu bar", select the "News" link; once in News,
      select the "Submit" link.  Type a suitable subject (e.g. "Python
      2.2c1 released" :-) in the Subject box, add some text to the
      Details box (at the very least including the release URL at
      www.python.org and the fact that you're happy with the release)
      and click the SUBMIT button.

      Feel free to remove any old news items.

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

  ___ Merge the branch back into the trunk!  Now that we've released
      this branch, we don't need it any more.  We've already tagged it
      so we can always reproduce it.  Note that merging branches is a
      bit of a black art, but here's what's worked for us.

    ___ Check out a completely clean, virgin working directory of the
        trunk, by doing this in the directory that is the parent of
        your branch working directory python-XYaZ:
        % cvs -d <cvsroot> co -d python-clean python/dist/src

    ___ Run a diff against your branch by doing this in the common
        parent directory containing both python-clean and python-XYaZ:
        % diff -r python-clean python-22a2 | grep ^diff | grep -v CVS \
            > /tmp/diffcmd.sh

    ___ Edit diffcmd.sh to get rid of files that you know don't have
        important changes.  You're looking for files that have updates
        in the branch that haven't made it to the trunk.

        Generally you can ignore any changes to the Doc or Mac
        subdirectories, or any changes to Windows related files.  The
        sub-RMs for those parts will take care of any necessary merges
        from the branch to the trunk.

        If you've been diligent about merging changes from the trunk
        into the branch, there shouldn't be many of these files.

    ___ Edit /tmp/diffcmd.sh, changing all the -r's into -u's.  Run
        the /tmp/diffcmd.sh command like so:
        % sh /tmp/diffcmd.sh > /tmp/pydiff.txt

    ___ Attempt to patch your python-clean working directory.  Do this
        first, noting that --dry-run does not actually apply any
        patches, it just makes sure that the patch command runs
        successfully to completion:
        % patch -p1 --dry-run < /tmp/pydiff.txt

    ___ If this goes well, run it again, taking out the --dry-run
        option.  If this fails, or if it prompts you for a file to
        patch, try using -p0 instead of -p1.  Otherwise, your diff
        command was messed up, so try again.

    ___ cd to python-clean and do a "cvs commit".  Use as your log
        message something like "Merging the rXYaZ-branch tag back into
        the trunk".

    ___ Edit the file Include/patchlevel.h so that the PY_VERSION
        string says something like "X.YaZ+".  Note the trailing `+'
        indicating that the trunk is going to be moving forward with
        development.  E.g. the line should look like:

        #define PY_VERSION              "2.2a2+"

        Make sure that the other PY_ version macros contain the
        correct values.  Commit this change.

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

    ___ 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!

    Step 5 ...

    Verify!  This can be interleaved with Step 4.  Pretend you're a
    user: download the files from python.org, 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.


What Next?

    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!

    Actually, there is one more step.  You should turn over ownership
    of the branch to Jack Jansen.  All this means is that now he will
    be responsible for making commits to the branch.  He's going to
    use this to build the MacOS versions.  He may send you information
    about the Mac release that should be merged into the informational
    pages on www.python.org.  When he's done, he'll tag the branch
    something like "rX.YaZ-mac".  He'll also be responsible for
    merging any Mac-related changes back into the trunk.


Final Release Notes

    The Final release of any major release, e.g. Python 2.2 final, has
    special requirements, specifically because it will be one of the
    longest lived releases (i.e. betas don't last more than a couple
    of weeks, but final releases can last for years!).

    For this reason we want to have a higher coordination between the
    three major releases: Windows, Mac, and source.  The Windows and
    source releases benefit from the close proximity of the respective
    release-bots.  But the Mac-bot, Jack Jansen, is 6 hours away.  So
    we add this extra step to the release process for a final
    release:

    ___ Hold up the final release until Jack approves, or until we
        lose patience <wink>.


Windows Notes

    Windows has a GUI 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, Tim 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.

    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 (Tim uses "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 all of the above on at least one flavor of Win9x, and one
    of NT/2000.  On NT/2000, try both an Admin and a plain User (not
    Power User) account.

    WRT Step 5 above (verify the release media), since by the time
    release files are ready to download Tim has generally run many
    Windows tests on the installer he uploaded, he usually doesn't do
    anything for Step 5 except a full byte-comparison ("fc /b" if
    using a Windows shell) of the downloaded file against the file he
    uploaded.


Copyright

    This document has been placed in the public domain.



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