Provided by: perl-doc_5.34.0-3ubuntu1.3_all bug

NAME

       perlgit - Detailed information about git and the Perl repository

DESCRIPTION

       This document provides details on using git to develop Perl. If you are just interested in
       working on a quick patch, see perlhack first.  This document is intended for people who
       are regular contributors to Perl, including those with write access to the git repository.

CLONING THE REPOSITORY

       All of Perl's source code is kept centrally in a Git repository at github.com.

       You can make a read-only clone of the repository by running:

         % git clone git://github.com/Perl/perl5.git perl

       This uses the git protocol (port 9418).

       If you cannot use the git protocol for firewall reasons, you can also clone via http:

         % git clone https://github.com/Perl/perl5.git perl

WORKING WITH THE REPOSITORY

       Once you have changed into the repository directory, you can inspect it. After a clone the
       repository will contain a single local branch, which will be the current branch as well,
       as indicated by the asterisk.

         % git branch
         * blead

       Using the -a switch to "branch" will also show the remote tracking branches in the
       repository:

         % git branch -a
         * blead
           origin/HEAD
           origin/blead
         ...

       The branches that begin with "origin" correspond to the "git remote" that you cloned from
       (which is named "origin"). Each branch on the remote will be exactly tracked by these
       branches. You should NEVER do work on these remote tracking branches. You only ever do
       work in a local branch. Local branches can be configured to automerge (on pull) from a
       designated remote tracking branch. This is the case with the default branch "blead" which
       will be configured to merge from the remote tracking branch "origin/blead".

       You can see recent commits:

         % git log

       And pull new changes from the repository, and update your local repository (must be clean
       first)

         % git pull

       Assuming we are on the branch "blead" immediately after a pull, this command would be more
       or less equivalent to:

         % git fetch
         % git merge origin/blead

       In fact if you want to update your local repository without touching your working
       directory you do:

         % git fetch

       And if you want to update your remote-tracking branches for all defined remotes
       simultaneously you can do

         % git remote update

       Neither of these last two commands will update your working directory, however both will
       update the remote-tracking branches in your repository.

       To make a local branch of a remote branch:

         % git checkout -b maint-5.10 origin/maint-5.10

       To switch back to blead:

         % git checkout blead

   Finding out your status
       The most common git command you will use will probably be

         % git status

       This command will produce as output a description of the current state of the repository,
       including modified files and unignored untracked files, and in addition it will show
       things like what files have been staged for the next commit, and usually some useful
       information about how to change things. For instance the following:

        % git status
        On branch blead
        Your branch is ahead of 'origin/blead' by 1 commit.

        Changes to be committed:
          (use "git reset HEAD <file>..." to unstage)

              modified:   pod/perlgit.pod

        Changes not staged for commit:
          (use "git add <file>..." to update what will be committed)
          (use "git checkout -- <file>..." to discard changes in working
                                                                     directory)

              modified:   pod/perlgit.pod

        Untracked files:
          (use "git add <file>..." to include in what will be committed)

              deliberate.untracked

       This shows that there were changes to this document staged for commit, and that there were
       further changes in the working directory not yet staged. It also shows that there was an
       untracked file in the working directory, and as you can see shows how to change all of
       this. It also shows that there is one commit on the working branch "blead" which has not
       been pushed to the "origin" remote yet. NOTE: This output is also what you see as a
       template if you do not provide a message to "git commit".

   Patch workflow
       First, please read perlhack for details on hacking the Perl core.  That document covers
       many details on how to create a good patch.

       If you already have a Perl repository, you should ensure that you're on the blead branch,
       and your repository is up to date:

         % git checkout blead
         % git pull

       It's preferable to patch against the latest blead version, since this is where new
       development occurs for all changes other than critical bug fixes. Critical bug fix patches
       should be made against the relevant maint branches, or should be submitted with a note
       indicating all the branches where the fix should be applied.

       Now that we have everything up to date, we need to create a temporary new branch for these
       changes and switch into it:

         % git checkout -b orange

       which is the short form of

         % git branch orange
         % git checkout orange

       Creating a topic branch makes it easier for the maintainers to rebase or merge back into
       the master blead for a more linear history. If you don't work on a topic branch the
       maintainer has to manually cherry pick your changes onto blead before they can be applied.

       That'll get you scolded on perl5-porters, so don't do that. Be Awesome.

       Then make your changes. For example, if Leon Brocard changes his name to Orange Brocard,
       we should change his name in the AUTHORS file:

         % perl -pi -e 's{Leon Brocard}{Orange Brocard}' AUTHORS

       You can see what files are changed:

         % git status
         On branch orange
         Changes to be committed:
           (use "git reset HEAD <file>..." to unstage)

            modified:   AUTHORS

       And you can see the changes:

        % git diff
        diff --git a/AUTHORS b/AUTHORS
        index 293dd70..722c93e 100644
        --- a/AUTHORS
        +++ b/AUTHORS
        @@ -541,7 +541,7 @@    Lars Hecking              <lhecking@nmrc.ucc.ie>
         Laszlo Molnar                  <laszlo.molnar@eth.ericsson.se>
         Leif Huhn                      <leif@hale.dkstat.com>
         Len Johnson                    <lenjay@ibm.net>
        -Leon Brocard                   <acme@astray.com>
        +Orange Brocard                 <acme@astray.com>
         Les Peters                     <lpeters@aol.net>
         Lesley Binks                   <lesley.binks@gmail.com>
         Lincoln D. Stein               <lstein@cshl.org>

       Now commit your change locally:

        % git commit -a -m 'Rename Leon Brocard to Orange Brocard'
        Created commit 6196c1d: Rename Leon Brocard to Orange Brocard
         1 files changed, 1 insertions(+), 1 deletions(-)

       The "-a" option is used to include all files that git tracks that you have changed. If at
       this time, you only want to commit some of the files you have worked on, you can omit the
       "-a" and use the command "git add FILE ..." before doing the commit.
       "git add --interactive" allows you to even just commit portions of files instead of all
       the changes in them.

       The "-m" option is used to specify the commit message. If you omit it, git will open a
       text editor for you to compose the message interactively. This is useful when the changes
       are more complex than the sample given here, and, depending on the editor, to know that
       the first line of the commit message doesn't exceed the 50 character legal maximum. See
       "Commit message" in perlhack for more information about what makes a good commit message.

       Once you've finished writing your commit message and exited your editor, git will write
       your change to disk and tell you something like this:

        Created commit daf8e63: explain git status and stuff about remotes
         1 files changed, 83 insertions(+), 3 deletions(-)

       If you re-run "git status", you should see something like this:

        % git status
        On branch orange
        Untracked files:
          (use "git add <file>..." to include in what will be committed)

              deliberate.untracked

        nothing added to commit but untracked files present (use "git add" to
                                                                         track)

       When in doubt, before you do anything else, check your status and read it carefully, many
       questions are answered directly by the git status output.

       You can examine your last commit with:

         % git show HEAD

       and if you are not happy with either the description or the patch itself you can fix it up
       by editing the files once more and then issue:

         % git commit -a --amend

       Now, create a fork on GitHub to push your branch to, and add it as a remote if you haven't
       already, as described in the GitHub documentation at
       <https://help.github.com/en/articles/working-with-forks>:

         % git remote add fork git@github.com:MyUser/perl5.git

       And push the branch to your fork:

         % git push -u fork orange

       You should now submit a Pull Request (PR) on GitHub from the new branch to blead. For more
       information, see the GitHub documentation at
       <https://help.github.com/en/articles/creating-a-pull-request-from-a-fork>.

       You can also send patch files to perl5-porters@perl.org <mailto:perl5-porters@perl.org>
       directly if the patch is not ready to be applied, but intended for discussion.

       To create a patch file for all your local changes:

         % git format-patch -M blead..
         0001-Rename-Leon-Brocard-to-Orange-Brocard.patch

       Or for a lot of changes, e.g. from a topic branch:

         % git format-patch --stdout -M blead.. > topic-branch-changes.patch

       If you want to delete your temporary branch, you may do so with:

        % git checkout blead
        % git branch -d orange
        error: The branch 'orange' is not an ancestor of your current HEAD.
        If you are sure you want to delete it, run 'git branch -D orange'.
        % git branch -D orange
        Deleted branch orange.

   A note on derived files
       Be aware that many files in the distribution are derivative--avoid patching them, because
       git won't see the changes to them, and the build process will overwrite them. Patch the
       originals instead. Most utilities (like perldoc) are in this category, i.e. patch
       utils/perldoc.PL rather than utils/perldoc. Similarly, don't create patches for files
       under $src_root/ext from their copies found in $install_root/lib. If you are unsure about
       the proper location of a file that may have gotten copied while building the source
       distribution, consult the MANIFEST.

   Cleaning a working directory
       The command "git clean" can with varying arguments be used as a replacement for "make
       clean".

       To reset your working directory to a pristine condition you can do:

         % git clean -dxf

       However, be aware this will delete ALL untracked content. You can use

         % git clean -Xf

       to remove all ignored untracked files, such as build and test byproduct, but leave any
       manually created files alone.

       If you only want to cancel some uncommitted edits, you can use "git checkout" and give it
       a list of files to be reverted, or "git checkout -f" to revert them all.

       If you want to cancel one or several commits, you can use "git reset".

   Bisecting
       "git" provides a built-in way to determine which commit should be blamed for introducing a
       given bug. "git bisect" performs a binary search of history to locate the first failing
       commit. It is fast, powerful and flexible, but requires some setup and to automate the
       process an auxiliary shell script is needed.

       The core provides a wrapper program, Porting/bisect.pl, which attempts to simplify as much
       as possible, making bisecting as simple as running a Perl one-liner. For example, if you
       want to know when this became an error:

           perl -e 'my $a := 2'

       you simply run this:

           .../Porting/bisect.pl -e 'my $a := 2;'

       Using Porting/bisect.pl, with one command (and no other files) it's easy to find out

       •   Which commit caused this example code to break?

       •   Which commit caused this example code to start working?

       •   Which commit added the first file to match this regex?

       •   Which commit removed the last file to match this regex?

       usually without needing to know which versions of perl to use as start and end revisions,
       as Porting/bisect.pl automatically searches to find the earliest stable version for which
       the test case passes. Run "Porting/bisect.pl --help" for the full documentation, including
       how to set the "Configure" and build time options.

       If you require more flexibility than Porting/bisect.pl has to offer, you'll need to run
       "git bisect" yourself. It's most useful to use "git bisect run" to automate the building
       and testing of perl revisions. For this you'll need a shell script for "git" to call to
       test a particular revision. An example script is Porting/bisect-example.sh, which you
       should copy outside of the repository, as the bisect process will reset the state to a
       clean checkout as it runs. The instructions below assume that you copied it as ~/run and
       then edited it as appropriate.

       You first enter in bisect mode with:

         % git bisect start

       For example, if the bug is present on "HEAD" but wasn't in 5.10.0, "git" will learn about
       this when you enter:

         % git bisect bad
         % git bisect good perl-5.10.0
         Bisecting: 853 revisions left to test after this

       This results in checking out the median commit between "HEAD" and "perl-5.10.0". You can
       then run the bisecting process with:

         % git bisect run ~/run

       When the first bad commit is isolated, "git bisect" will tell you so:

         ca4cfd28534303b82a216cfe83a1c80cbc3b9dc5 is first bad commit
         commit ca4cfd28534303b82a216cfe83a1c80cbc3b9dc5
         Author: Dave Mitchell <davem@fdisolutions.com>
         Date:   Sat Feb 9 14:56:23 2008 +0000

             [perl #49472] Attributes + Unknown Error
             ...

         bisect run success

       You can peek into the bisecting process with "git bisect log" and "git bisect visualize".
       "git bisect reset" will get you out of bisect mode.

       Please note that the first "good" state must be an ancestor of the first "bad" state. If
       you want to search for the commit that solved some bug, you have to negate your test case
       (i.e. exit with 1 if OK and 0 if not) and still mark the lower bound as "good" and the
       upper as "bad". The "first bad commit" has then to be understood as the "first commit
       where the bug is solved".

       "git help bisect" has much more information on how you can tweak your binary searches.

       Following bisection you may wish to configure, build and test perl at commits identified
       by the bisection process.  Sometimes, particularly with older perls, "make" may fail
       during this process.  In this case you may be able to patch the source code at the older
       commit point.  To do so, please follow the suggestions provided in "Building perl at older
       commits" in perlhack.

   Topic branches and rewriting history
       Individual committers should create topic branches under yourname/some_descriptive_name:

         % branch="$yourname/$some_descriptive_name"
         % git checkout -b $branch
         ... do local edits, commits etc ...
         % git push origin -u $branch

       Should you be stuck with an ancient version of git (prior to 1.7), then "git push" will
       not have the "-u" switch, and you have to replace the last step with the following
       sequence:

         % git push origin $branch:refs/heads/$branch
         % git config branch.$branch.remote origin
         % git config branch.$branch.merge refs/heads/$branch

       If you want to make changes to someone else's topic branch, you should check with its
       creator before making any change to it.

       You might sometimes find that the original author has edited the branch's history. There
       are lots of good reasons for this. Sometimes, an author might simply be rebasing the
       branch onto a newer source point.  Sometimes, an author might have found an error in an
       early commit which they wanted to fix before merging the branch to blead.

       Currently the master repository is configured to forbid non-fast-forward merges. This
       means that the branches within can not be rebased and pushed as a single step.

       The only way you will ever be allowed to rebase or modify the history of a pushed branch
       is to delete it and push it as a new branch under the same name. Please think carefully
       about doing this. It may be better to sequentially rename your branches so that it is
       easier for others working with you to cherry-pick their local changes onto the new
       version. (XXX: needs explanation).

       If you want to rebase a personal topic branch, you will have to delete your existing topic
       branch and push as a new version of it. You can do this via the following formula (see the
       explanation about "refspec"'s in the git push documentation for details) after you have
       rebased your branch:

         # first rebase
         % git checkout $user/$topic
         % git fetch
         % git rebase origin/blead

         # then "delete-and-push"
         % git push origin :$user/$topic
         % git push origin $user/$topic

       NOTE: it is forbidden at the repository level to delete any of the "primary" branches.
       That is any branch matching "m!^(blead|maint|perl)!". Any attempt to do so will result in
       git producing an error like this:

         % git push origin :blead
         *** It is forbidden to delete blead/maint branches in this repository
         error: hooks/update exited with error code 1
         error: hook declined to update refs/heads/blead
         To ssh://perl5.git.perl.org/perl
          ! [remote rejected] blead (hook declined)
          error: failed to push some refs to 'ssh://perl5.git.perl.org/perl'

       As a matter of policy we do not edit the history of the blead and maint-* branches. If a
       typo (or worse) sneaks into a commit to blead or maint-*, we'll fix it in another commit.
       The only types of updates allowed on these branches are "fast-forwards", where all history
       is preserved.

       Annotated tags in the canonical perl.git repository will never be deleted or modified.
       Think long and hard about whether you want to push a local tag to perl.git before doing
       so. (Pushing simple tags is not allowed.)

   Grafts
       The perl history contains one mistake which was not caught in the conversion: a merge was
       recorded in the history between blead and maint-5.10 where no merge actually occurred. Due
       to the nature of git, this is now impossible to fix in the public repository. You can
       remove this mis-merge locally by adding the following line to your ".git/info/grafts"
       file:

        296f12bbbbaa06de9be9d09d3dcf8f4528898a49 434946e0cb7a32589ed92d18008aaa1d88515930

       It is particularly important to have this graft line if any bisecting is done in the area
       of the "merge" in question.

WRITE ACCESS TO THE GIT REPOSITORY

       Once you have write access, you will need to modify the URL for the origin remote to
       enable pushing. Edit .git/config with the git-config(1) command:

         % git config remote.origin.url git@github.com:Perl/perl5.git

       You can also set up your user name and e-mail address. Most people do this once globally
       in their ~/.gitconfig by doing something like:

         % git config --global user.name "Ævar Arnfjörð Bjarmason"
         % git config --global user.email avarab@gmail.com

       However, if you'd like to override that just for perl, execute something like the
       following in perl:

         % git config user.email avar@cpan.org

       It is also possible to keep "origin" as a git remote, and add a new remote for ssh access:

         % git remote add camel git@github.com:Perl/perl5.git

       This allows you to update your local repository by pulling from "origin", which is faster
       and doesn't require you to authenticate, and to push your changes back with the "camel"
       remote:

         % git fetch camel
         % git push camel

       The "fetch" command just updates the "camel" refs, as the objects themselves should have
       been fetched when pulling from "origin".

   Working with Github pull requests
       Pull requests typically originate from outside of the "Perl/perl.git" repository, so if
       you want to test or work with it locally a vanilla "git fetch" from the "Perl/perl5.git"
       repository won't fetch it.

       However Github does provide a mechanism to fetch a pull request to a local branch.  They
       are available on Github remotes under "pull/", so you can use "git fetch
       pull/PRID/head:localname" to make a local copy.  eg.  to fetch pull request 9999 to the
       local branch "local-branch-name" run:

         git fetch origin pull/9999/head:local-branch-name

       and then:

         git checkout local-branch-name

       Note: this branch is not rebased on "blead", so instead of the checkout above, you might
       want:

         git rebase origin/blead local-branch-name

       which rebases "local-branch-name" on "blead", and checks it out.

       Alternatively you can configure the remote to fetch all pull requests as remote-tracking
       branches.  To do this edit the remote in .git/config, for example if your github remote is
       "origin" you'd have:

         [remote "origin"]
                 url = git@github.com:/Perl/perl5.git
                 fetch = +refs/heads/*:refs/remotes/origin/*

       Add a line to map the remote pull request branches to remote-tracking branches:

         [remote "origin"]
                 url = git@github.com:/Perl/perl5.git
                 fetch = +refs/heads/*:refs/remotes/origin/*
                 fetch = +refs/pull/*/head:refs/remotes/origin/pull/*

       and then do a fetch as normal:

         git fetch origin

       This will create a remote-tracking branch for every pull request, including closed
       requests.

       To remove those remote-tracking branches, remove the line added above and prune:

         git fetch -p origin # or git remote prune origin

   Accepting a patch
       If you have received a patch file generated using the above section, you should try out
       the patch.

       First we need to create a temporary new branch for these changes and switch into it:

        % git checkout -b experimental

       Patches that were formatted by "git format-patch" are applied with "git am":

        % git am 0001-Rename-Leon-Brocard-to-Orange-Brocard.patch
        Applying Rename Leon Brocard to Orange Brocard

       Note that some UNIX mail systems can mess with text attachments containing 'From '. This
       will fix them up:

        % perl -pi -e's/^>From /From /' \
                               0001-Rename-Leon-Brocard-to-Orange-Brocard.patch

       If just a raw diff is provided, it is also possible use this two-step process:

        % git apply bugfix.diff
        % git commit -a -m "Some fixing" \
                                   --author="That Guy <that.guy@internets.com>"

       Now we can inspect the change:

        % git show HEAD
        commit b1b3dab48344cff6de4087efca3dbd63548ab5e2
        Author: Leon Brocard <acme@astray.com>
        Date:   Fri Dec 19 17:02:59 2008 +0000

          Rename Leon Brocard to Orange Brocard

        diff --git a/AUTHORS b/AUTHORS
        index 293dd70..722c93e 100644
        --- a/AUTHORS
        +++ b/AUTHORS
        @@ -541,7 +541,7 @@ Lars Hecking                 <lhecking@nmrc.ucc.ie>
         Laszlo Molnar                  <laszlo.molnar@eth.ericsson.se>
         Leif Huhn                      <leif@hale.dkstat.com>
         Len Johnson                    <lenjay@ibm.net>
        -Leon Brocard                   <acme@astray.com>
        +Orange Brocard                 <acme@astray.com>
         Les Peters                     <lpeters@aol.net>
         Lesley Binks                   <lesley.binks@gmail.com>
         Lincoln D. Stein               <lstein@cshl.org>

       If you are a committer to Perl and you think the patch is good, you can then merge it into
       blead then push it out to the main repository:

         % git checkout blead
         % git merge experimental
         % git push origin blead

       If you want to delete your temporary branch, you may do so with:

        % git checkout blead
        % git branch -d experimental
        error: The branch 'experimental' is not an ancestor of your current
        HEAD.  If you are sure you want to delete it, run 'git branch -D
        experimental'.
        % git branch -D experimental
        Deleted branch experimental.

   Committing to blead
       The 'blead' branch will become the next production release of Perl.

       Before pushing any local change to blead, it's incredibly important that you do a few
       things, lest other committers come after you with pitchforks and torches:

       •   Make sure you have a good commit message. See "Commit message" in perlhack for
           details.

       •   Run the test suite. You might not think that one typo fix would break a test file.
           You'd be wrong. Here's an example of where not running the suite caused problems. A
           patch was submitted that added a couple of tests to an existing .t. It couldn't
           possibly affect anything else, so no need to test beyond the single affected .t,
           right?  But, the submitter's email address had changed since the last of their
           submissions, and this caused other tests to fail. Running the test target given in the
           next item would have caught this problem.

       •   If you don't run the full test suite, at least "make test_porting".  This will run
           basic sanity checks. To see which sanity checks, have a look in t/porting.

       •   If you make any changes that affect miniperl or core routines that have different code
           paths for miniperl, be sure to run "make minitest".  This will catch problems that
           even the full test suite will not catch because it runs a subset of tests under
           miniperl rather than perl.

   On merging and rebasing
       Simple, one-off commits pushed to the 'blead' branch should be simple commits that apply
       cleanly.  In other words, you should make sure your work is committed against the current
       position of blead, so that you can push back to the master repository without merging.

       Sometimes, blead will move while you're building or testing your changes.  When this
       happens, your push will be rejected with a message like this:

        To ssh://perl5.git.perl.org/perl.git
         ! [rejected]        blead -> blead (non-fast-forward)
        error: failed to push some refs to 'ssh://perl5.git.perl.org/perl.git'
        To prevent you from losing history, non-fast-forward updates were
        rejected Merge the remote changes (e.g. 'git pull') before pushing
        again.  See the 'Note about fast-forwards' section of 'git push --help'
        for details.

       When this happens, you can just rebase your work against the new position of blead, like
       this (assuming your remote for the master repository is "p5p"):

         % git fetch p5p
         % git rebase p5p/blead

       You will see your commits being re-applied, and you will then be able to push safely.
       More information about rebasing can be found in the documentation for the git-rebase(1)
       command.

       For larger sets of commits that only make sense together, or that would benefit from a
       summary of the set's purpose, you should use a merge commit.  You should perform your work
       on a topic branch, which you should regularly rebase against blead to ensure that your
       code is not broken by blead moving.  When you have finished your work, please perform a
       final rebase and test.  Linear history is something that gets lost with every commit on
       blead, but a final rebase makes the history linear again, making it easier for future
       maintainers to see what has happened.  Rebase as follows (assuming your work was on the
       branch "committer/somework"):

         % git checkout committer/somework
         % git rebase blead

       Then you can merge it into master like this:

         % git checkout blead
         % git merge --no-ff --no-commit committer/somework
         % git commit -a

       The switches above deserve explanation.  "--no-ff" indicates that even if all your work
       can be applied linearly against blead, a merge commit should still be prepared.  This
       ensures that all your work will be shown as a side branch, with all its commits merged
       into the mainstream blead by the merge commit.

       "--no-commit" means that the merge commit will be prepared but not committed.  The commit
       is then actually performed when you run the next command, which will bring up your editor
       to describe the commit.  Without "--no-commit", the commit would be made with nearly no
       useful message, which would greatly diminish the value of the merge commit as a
       placeholder for the work's description.

       When describing the merge commit, explain the purpose of the branch, and keep in mind that
       this description will probably be used by the eventual release engineer when reviewing the
       next perldelta document.

   Committing to maintenance versions
       Maintenance versions should only be altered to add critical bug fixes, see perlpolicy.

       To commit to a maintenance version of perl, you need to create a local tracking branch:

         % git checkout --track -b maint-5.005 origin/maint-5.005

       This creates a local branch named "maint-5.005", which tracks the remote branch
       "origin/maint-5.005". Then you can pull, commit, merge and push as before.

       You can also cherry-pick commits from blead and another branch, by using the "git
       cherry-pick" command. It is recommended to use the -x option to "git cherry-pick" in order
       to record the SHA1 of the original commit in the new commit message.

       Before pushing any change to a maint version, make sure you've satisfied the steps in
       "Committing to blead" above.

   Using a smoke-me branch to test changes
       Sometimes a change affects code paths which you cannot test on the OSes which are directly
       available to you and it would be wise to have users on other OSes test the change before
       you commit it to blead.

       Fortunately, there is a way to get your change smoke-tested on various OSes: push it to a
       "smoke-me" branch and wait for certain automated smoke-testers to report the results from
       their OSes.  A "smoke-me" branch is identified by the branch name: specifically, as seen
       on github.com it must be a local branch whose first name component is precisely
       "smoke-me".

       The procedure for doing this is roughly as follows (using the example of tonyc's smoke-me
       branch called win32stat):

       First, make a local branch and switch to it:

         % git checkout -b win32stat

       Make some changes, build perl and test your changes, then commit them to your local
       branch. Then push your local branch to a remote smoke-me branch:

         % git push origin win32stat:smoke-me/tonyc/win32stat

       Now you can switch back to blead locally:

         % git checkout blead

       and continue working on other things while you wait a day or two, keeping an eye on the
       results reported for your smoke-me branch at
       <http://perl.develop-help.com/?b=smoke-me/tonyc/win32state>.

       If all is well then update your blead branch:

         % git pull

       then checkout your smoke-me branch once more and rebase it on blead:

         % git rebase blead win32stat

       Now switch back to blead and merge your smoke-me branch into it:

         % git checkout blead
         % git merge win32stat

       As described earlier, if there are many changes on your smoke-me branch then you should
       prepare a merge commit in which to give an overview of those changes by using the
       following command instead of the last command above:

         % git merge win32stat --no-ff --no-commit

       You should now build perl and test your (merged) changes one last time (ideally run the
       whole test suite, but failing that at least run the t/porting/*.t tests) before pushing
       your changes as usual:

         % git push origin blead

       Finally, you should then delete the remote smoke-me branch:

         % git push origin :smoke-me/tonyc/win32stat

       (which is likely to produce a warning like this, which can be ignored:

        remote: fatal: ambiguous argument
                                         'refs/heads/smoke-me/tonyc/win32stat':
        unknown revision or path not in the working tree.
        remote: Use '--' to separate paths from revisions

       ) and then delete your local branch:

         % git branch -d win32stat