+
+=head2 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/perlrepository.pod
+ #
+ # Changed but not updated:
+ # (use "git add <file>..." to update what will be committed)
+ #
+ # modified: pod/perlrepository.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 C<blead> which has
+not been pushed to the C<origin> remote yet. B<NOTE>: that this output
+is also what you see as a template if you do not provide a message to
+C<git commit>.
+
+Assuming we commit all the mentioned changes above:
+
+ % git commit -a -m'explain git status and stuff about remotes'
+ Created commit daf8e63: explain git status and stuff about remotes
+ 1 files changed, 83 insertions(+), 3 deletions(-)
+
+We can re-run git status and see something like this:
+
+ % git status
+ # On branch blead
+ # Your branch is ahead of 'origin/blead' by 2 commits.
+ #
+ # 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.
+
+=head1 SUBMITTING A PATCH
+
+If you have a patch in mind for Perl, you should first get a copy of
+the repository:
+
+ % git clone git://perl5.git.perl.org/perl.git perl-git
+
+Then change into the directory:
+
+ % cd perl-git
+
+Alternatively, if you already have a Perl repository, you should ensure
+that you're on the I<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
+
+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(-)
+
+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 you should create a patch file for all your local changes:
+
+ % git format-patch origin
+ 0001-Rename-Leon-Brocard-to-Orange-Brocard.patch
+
+You should now send an email to perl5-porters@perl.org with a
+description of your changes, and include this patch file as an
+attachment. (See the next section for how to configure and use git to
+send these emails for you.)
+
+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.
+
+=head2 Using git to send patch emails
+
+In your ~/git/perl repository, set the destination email to the
+perl5-porters mailing list.
+
+ $ git config sendemail.to perl5-porters@perl.org
+
+Then you can use git directly to send your patch emails:
+
+ $ git send-email 0001-Rename-Leon-Brocard-to-Orange-Brocard.patch
+
+You may need to set some configuration variables for your particular
+email service provider. For example, to set your global git config to
+send email via a gmail account:
+
+ $ git config --global sendemail.smtpserver smtp.gmail.com
+ $ git config --global sendemail.smtpssl 1
+ $ git config --global sendemail.smtpuser YOURUSERNAME@gmail.com
+
+With this configuration, you will be prompted for your gmail password
+when you run 'git send-email'. You can also configure
+C<sendemail.smtppass> with your password if you don't care about having
+your password in the .gitconfig file.
+
+=head2 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 C<MANIFEST>.
+
+=for XXX
+
+What should we recommend about binary files now? Do we need anything?
+
+=head2 Getting your patch accepted
+
+The first thing you should include with your patch is a description of
+the problem that the patch corrects. If it is a code patch (rather
+than a documentation patch) you should also include a small test case
+that illustrates the bug (a patch to an existing test file is
+preferred).
+
+If you are submitting a code patch there are several other things that
+you need to do.
+
+=over 4
+
+=item Comments, Comments, Comments
+
+Be sure to adequately comment your code. While commenting every line
+is unnecessary, anything that takes advantage of side effects of
+operators, that creates changes that will be felt outside of the
+function being patched, or that others may find confusing should be
+documented. If you are going to err, it is better to err on the side
+of adding too many comments than too few.
+
+=item Style
+
+In general, please follow the particular style of the code you are
+patching.
+
+In particular, follow these general guidelines for patching Perl
+sources:
+
+ 8-wide tabs (no exceptions!)
+ 4-wide indents for code, 2-wide indents for nested CPP #defines
+ try hard not to exceed 79-columns
+ ANSI C prototypes
+ uncuddled elses and "K&R" style for indenting control constructs
+ no C++ style (//) comments
+ mark places that need to be revisited with XXX (and revisit often!)
+ opening brace lines up with "if" when conditional spans multiple
+ lines; should be at end-of-line otherwise
+ in function definitions, name starts in column 0 (return value is on
+ previous line)
+ single space after keywords that are followed by parens, no space
+ between function name and following paren
+ avoid assignments in conditionals, but if they're unavoidable, use
+ extra paren, e.g. "if (a && (b = c)) ..."
+ "return foo;" rather than "return(foo);"
+ "if (!foo) ..." rather than "if (foo == FALSE) ..." etc.
+
+=item Testsuite
+
+When submitting a patch you should make every effort to also include an
+addition to perl's regression tests to properly exercise your patch.
+Your testsuite additions should generally follow these guidelines
+(courtesy of Gurusamy Sarathy <gsar@activestate.com>):
+
+ Know what you're testing. Read the docs, and the source.
+ Tend to fail, not succeed.
+ Interpret results strictly.
+ Use unrelated features (this will flush out bizarre interactions).
+ Use non-standard idioms (otherwise you are not testing TIMTOWTDI).
+ Avoid using hardcoded test numbers whenever possible (the
+ EXPECTED/GOT found in t/op/tie.t is much more maintainable,
+ and gives better failure reports).
+ Give meaningful error messages when a test fails.
+ Avoid using qx// and system() unless you are testing for them. If you
+ do use them, make sure that you cover _all_ perl platforms.
+ Unlink any temporary files you create.
+ Promote unforeseen warnings to errors with $SIG{__WARN__}.
+ Be sure to use the libraries and modules shipped with the version
+ being tested, not those that were already installed.
+ Add comments to the code explaining what you are testing for.
+ Make updating the '1..42' string unnecessary. Or make sure that
+ you update it.
+ Test _all_ behaviors of a given operator, library, or function:
+ - All optional arguments
+ - Return values in various contexts (boolean, scalar, list, lvalue)
+ - Use both global and lexical variables
+ - Don't forget the exceptional, pathological cases.
+
+=back
+
+=head1 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 C<git format-patch> are applied with
+C<git am>:
+
+ % git am 0001-Rename-Leon-Brocard-to-Orange-Brocard.patch
+ Applying Rename Leon Brocard to Orange Brocard
+
+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
+
+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.
+
+=head1 CLEANING A WORKING DIRECTORY
+
+The command C<git clean> can with varying arguments be used as a
+replacement for C<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 C<git
+checkout> and give it a list of files to be reverted, or C<git checkout
+-f> to revert them all.
+
+If you want to cancel one or several commits, you can use C<git reset>.
+
+=head1 BISECTING
+
+C<git> provides a built-in way to determine, with a binary search in
+the history, which commit should be blamed for introducing a given bug.
+
+Suppose that we have a script F<~/testcase.pl> that exits with C<0>
+when some behaviour is correct, and with C<1> when it's faulty. We need
+an helper script that automates building C<perl> and running the
+testcase:
+
+ % cat ~/run
+ #!/bin/sh
+ git clean -dxf
+ # If you can use ccache, add -Dcc=ccache\ gcc -Dld=gcc to the Configure line
+ sh Configure -des -Dusedevel -Doptimize="-g"
+ test -f config.sh || exit 125
+ # Correct makefile for newer GNU gcc
+ perl -ni -we 'print unless /<(?:built-in|command)/' makefile x2p/makefile
+ # if you just need miniperl, replace test_prep with miniperl
+ make -j4 test_prep
+ [ -x ./perl ] || exit 125
+ ./perl -Ilib ~/testcase.pl
+ ret=$?
+ [ $ret -gt 127 ] && ret=127
+ git clean -dxf
+ exit $ret
+
+This script may return C<125> to indicate that the corresponding commit
+should be skipped. Otherwise, it returns the status of
+F<~/testcase.pl>.
+
+We first enter in bisect mode with:
+
+ % git bisect start
+
+For example, if the bug is present on C<HEAD> but wasn't in 5.10.0,
+C<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 C<HEAD> and
+C<perl-5.10.0>. We can then run the bisecting process with:
+
+ % git bisect run ~/run
+
+When the first bad commit is isolated, C<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 C<git bisect log> and
+C<git bisect visualize>. C<git bisect reset> will get you out of bisect
+mode.
+
+Please note that the first C<good> state must be an ancestor of the
+first C<bad> state. If you want to search for the commit that I<solved>
+some bug, you have to negate your test case (i.e. exit with C<1> if OK
+and C<0> if not) and still mark the lower bound as C<good> and the
+upper as C<bad>. The "first bad commit" has then to be understood as
+the "first commit where the bug is solved".
+
+C<git help bisect> has much more information on how you can tweak your
+binary searches.
+
+=head1 SUBMITTING A PATCH VIA GITHUB
+
+GitHub is a website that makes it easy to fork and publish projects
+with Git. First you should set up a GitHub account and log in.
+
+Perl's git repository is mirrored on GitHub at this page:
+
+ http://github.com/github/perl/tree/blead
+
+Visit the page and click the "fork" button. This clones the Perl git
+repository for you and provides you with "Your Clone URL" from which
+you should clone:
+
+ % git clone git@github.com:USERNAME/perl.git perl-github
+
+We shall make the same patch as above, creating a new branch:
+
+ % cd perl-github
+ % git remote add upstream git://github.com/github/perl.git
+ % git pull upstream blead
+ % git checkout -b orange
+ % perl -pi -e 's{Leon Brocard}{Orange Brocard}' AUTHORS
+ % git commit -a -m 'Rename Leon Brocard to Orange Brocard'
+ % git push origin orange
+
+The orange branch has been pushed to GitHub, so you should now send an
+email to perl5-porters@perl.org with a description of your changes and
+the following information:
+
+ http://github.com/USERNAME/perl/tree/orange
+ git@github.com:USERNAME/perl.git branch orange
+
+=head1 MERGING FROM A BRANCH VIA GITHUB
+
+If someone has provided a branch via GitHub and you are a committer,
+you should use the following in your perl-ssh directory:
+
+ % git remote add dandv git://github.com/dandv/perl.git
+ % git fetch
+
+Now you can see the differences between the branch and blead:
+
+ % git diff dandv/blead
+
+And you can see the commits:
+
+ % git log dandv/blead
+
+If you approve of a specific commit, you can cherry pick it:
+
+ % git cherry-pick 3adac458cb1c1d41af47fc66e67b49c8dec2323f
+
+Or you could just merge the whole branch if you like it all:
+
+ % git merge dandv/blead
+
+And then push back to the repository:
+
+ % git push
+
+
+=head1 TOPIC BRANCHES AND REWRITING HISTORY
+
+Individual committers should create topic branches under
+B<yourname>/B<some_descriptive_name>. Other committers should check
+with a topic branch's creator before making any change to it.
+
+If you are not the creator of B<yourname>/B<some_descriptive_name>, 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 C<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
+
+B<NOTE:> it is forbidden at the repository level to delete any of the
+"primary" branches. That is any branch matching
+C<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 B<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-forward's", 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 unannotated tags is
+not allowed.)
+
+=head1 COMMITTING TO MAINTENANCE VERSIONS
+
+Maintenance versions should only be altered to add critical bug fixes.
+
+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 C<maint-5.005>, which tracks the
+remote branch C<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 C<git cherry-pick> command. It is recommended to use the
+B<-x> option to C<git cherry-pick> in order to record the SHA1 of the
+original commit in the new commit message.
+
+=head1 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
+C<.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.
+
+=head1 SEE ALSO
+
+The git documentation, accessible via C<git help command>.
+