4 Consistent formatting of this file is achieved with:
5 perl ./Porting/podtidy pod/perlrepository.pod
9 perlrepository - Using the Perl source repository
13 All of Perl's source code is kept centrally in a Git repository at
14 I<perl5.git.perl.org>. The repository contains many Perl revisions from
15 Perl 1 onwards and all the revisions from Perforce, the version control
16 system we were using previously. This repository is accessible in
19 The full repository takes up about 80MB of disk space. A check out of
20 the blead branch (that is, the main development branch, which contains
21 bleadperl, the development version of perl 5) takes up about 160MB of
22 disk space (including the repository). A build of bleadperl takes up
23 about 200MB (including the repository and the check out).
25 =head1 Getting access to the repository
27 =head2 Read access via the web
29 You may access the repository over the web. This allows you to browse
30 the tree, see recent commits, subscribe to RSS feeds for the changes,
31 search for particular commits and more. You may access it at:
33 http://perl5.git.perl.org/perl.git
35 A mirror of the repository is found at:
37 http://github.com/mirrors/perl
39 =head2 Read access via Git
41 You will need a copy of Git for your computer. You can fetch a copy of
42 the repository using the Git protocol (which uses port 9418):
44 % git clone git://perl5.git.perl.org/perl.git perl-git
46 This clones the repository and makes a local copy in the F<perl-git>
49 If your local network does not allow you to use port 9418, then you can
50 fetch a copy of the repository over HTTP (this is at least 4x slower):
52 % git clone http://perl5.git.perl.org/perl.git perl-http
54 This clones the repository and makes a local copy in the F<perl-http>
57 =head2 Write access to the repository
59 If you are a committer, then you can fetch a copy of the repository
60 that you can push back on with:
62 % git clone ssh://perl5.git.perl.org/perl.git perl-ssh
64 This clones the repository and makes a local copy in the F<perl-ssh>
67 If you cloned using the git protocol, which is faster than ssh, then
68 you will need to modify the URL for the origin remote to enable
69 pushing. To do that edit F<.git/config> with git-config(1) like this:
71 % git config remote.origin.url ssh://perl5.git.perl.org/perl.git
73 You can also set up your user name and e-mail address. Most people do
74 this once globally in their F<~/.gitconfig> by doing something like:
76 % git config --global user.name "Ævar Arnfjörð Bjarmason"
77 % git config --global user.email avarab@gmail.com
79 However if you'd like to override that just for perl then execute then
80 execute something like the following in F<perl-git>:
82 % git config user.email avar@cpan.org
84 It is also possible to keep C<origin> as a git remote, and add a new
85 remote for ssh access:
87 % git remote add camel perl5.git.perl.org:/perl.git
89 This allows you to update your local repository by pulling from
90 C<origin>, which is faster and doesn't require you to authenticate, and
91 to push your changes back with the C<camel> remote:
96 The C<fetch> command just updates the C<camel> refs, as the objects
97 themselves should have been fetched when pulling from C<origin>.
99 =head2 A note on camel and dromedary
101 The committers have SSH access to the two servers that serve
102 C<perl5.git.perl.org>. One is C<perl5.git.perl.org> itself (I<camel>),
103 which is the 'master' repository. The second one is
104 C<users.perl5.git.perl.org> (I<dromedary>), which can be used for
105 general testing and development. Dromedary syncs the git tree from
106 camel every few minutes, you should not push there. Both machines also
107 have a full CPAN mirror in /srv/CPAN, please use this. To share files
108 with the general public, dromedary serves your ~/public_html/ as
109 C<http://users.perl5.git.perl.org/~yourlogin/>
111 These hosts have fairly strict firewalls to the outside. Outgoing, only
112 rsync, ssh and git are allowed. For http and ftp, you can use
113 http://webproxy:3128 as proxy. Incoming, the firewall tries to detect
114 attacks and blocks IP addresses with suspicious activity. This
115 sometimes (but very rarely) has false positives and you might get
116 blocked. The quickest way to get unblocked is to notify the admins.
118 These two boxes are owned, hosted, and operated by booking.com. You can
119 reach the sysadmins in #p5p on irc.perl.org or via mail to
120 C<perl5-porters@perl.org>
122 =head1 Overview of the repository
124 Once you have changed into the repository directory, you can inspect
127 After a clone the repository will contain a single local branch, which
128 will be the current branch as well, as indicated by the asterisk.
133 Using the -a switch to C<branch> will also show the remote tracking
134 branches in the repository:
142 The branches that begin with "origin" correspond to the "git remote"
143 that you cloned from (which is named "origin"). Each branch on the
144 remote will be exactly tracked by theses branches. You should NEVER do
145 work on these remote tracking branches. You only ever do work in a
146 local branch. Local branches can be configured to automerge (on pull)
147 from a designated remote tracking branch. This is the case with the
148 default branch C<blead> which will be configured to merge from the
149 remote tracking branch C<origin/blead>.
151 You can see recent commits:
155 And pull new changes from the repository, and update your local
156 repository (must be clean first)
160 Assuming we are on the branch C<blead> immediately after a pull, this
161 command would be more or less equivalent to:
164 % git merge origin/blead
166 In fact if you want to update your local repository without touching
167 your working directory you do:
171 And if you want to update your remote-tracking branches for all defined
172 remotes simultaneously you can do
176 Neither of these last two commands will update your working directory,
177 however both will update the remote-tracking branches in your
180 To make a local branch of a remote branch:
182 % git checkout -b maint-5.10 origin/maint-5.10
184 To switch back to blead:
188 =head2 Finding out your status
190 The most common git command you will use will probably be
194 This command will produce as output a description of the current state
195 of the repository, including modified files and unignored untracked
196 files, and in addition it will show things like what files have been
197 staged for the next commit, and usually some useful information about
198 how to change things. For instance the following:
202 # Your branch is ahead of 'origin/blead' by 1 commit.
204 # Changes to be committed:
205 # (use "git reset HEAD <file>..." to unstage)
207 # modified: pod/perlrepository.pod
209 # Changed but not updated:
210 # (use "git add <file>..." to update what will be committed)
212 # modified: pod/perlrepository.pod
215 # (use "git add <file>..." to include in what will be committed)
217 # deliberate.untracked
219 This shows that there were changes to this document staged for commit,
220 and that there were further changes in the working directory not yet
221 staged. It also shows that there was an untracked file in the working
222 directory, and as you can see shows how to change all of this. It also
223 shows that there is one commit on the working branch C<blead> which has
224 not been pushed to the C<origin> remote yet. B<NOTE>: that this output
225 is also what you see as a template if you do not provide a message to
228 Assuming that you'd like to commit all the changes you've just made as
229 a a single atomic unit, run this command:
233 (That C<-a> tells git to add every file you've changed to this commit.
234 New files aren't automatically added to your commit when you use
235 C<commit -a> If you want to add files or to commit some, but not all of
236 your changes, have a look at the documentation for C<git add>.)
238 Git will start up your favorite text editor, so that you can craft a
239 commit message for your change. See L</Commit message> below for more
240 information about what makes a good commit message.
242 Once you've finished writing your commit message and exited your
243 editor, git will write your change to disk and tell you something like
246 Created commit daf8e63: explain git status and stuff about remotes
247 1 files changed, 83 insertions(+), 3 deletions(-)
250 If you re-run C<git status>, you should see something like this:
254 # Your branch is ahead of 'origin/blead' by 2 commits.
257 # (use "git add <file>..." to include in what will be committed)
259 # deliberate.untracked
260 nothing added to commit but untracked files present (use "git add" to track)
263 When in doubt, before you do anything else, check your status and read
264 it carefully, many questions are answered directly by the git status
267 =head1 Submitting a patch
269 If you have a patch in mind for Perl, you should first get a copy of
272 % git clone git://perl5.git.perl.org/perl.git perl-git
274 Then change into the directory:
278 Alternatively, if you already have a Perl repository, you should ensure
279 that you're on the I<blead> branch, and your repository is up to date:
284 It's preferable to patch against the latest blead version, since this
285 is where new development occurs for all changes other than critical bug
286 fixes. Critical bug fix patches should be made against the relevant
287 maint branches, or should be submitted with a note indicating all the
288 branches where the fix should be applied.
290 Now that we have everything up to date, we need to create a temporary
291 new branch for these changes and switch into it:
293 % git checkout -b orange
295 which is the short form of
298 % git checkout orange
300 Creating a topic branch makes it easier for the maintainers to rebase
301 or merge back into the master blead for a more linear history. If you
302 don't work on a topic branch the maintainer has to manually cherry pick
303 your changes onto blead before they can be applied.
305 That'll get you scolded on perl5-porters, so don't do that. Be Awesome.
307 Then make your changes. For example, if Leon Brocard changes his name
308 to Orange Brocard, we should change his name in the AUTHORS file:
310 % perl -pi -e 's{Leon Brocard}{Orange Brocard}' AUTHORS
312 You can see what files are changed:
316 # Changes to be committed:
317 # (use "git reset HEAD <file>..." to unstage)
322 And you can see the changes:
325 diff --git a/AUTHORS b/AUTHORS
326 index 293dd70..722c93e 100644
329 @@ -541,7 +541,7 @@ Lars Hecking <lhecking@nmrc.ucc.ie>
330 Laszlo Molnar <laszlo.molnar@eth.ericsson.se>
331 Leif Huhn <leif@hale.dkstat.com>
332 Len Johnson <lenjay@ibm.net>
333 -Leon Brocard <acme@astray.com>
334 +Orange Brocard <acme@astray.com>
335 Les Peters <lpeters@aol.net>
336 Lesley Binks <lesley.binks@gmail.com>
337 Lincoln D. Stein <lstein@cshl.org>
339 Now commit your change locally:
341 % git commit -a -m 'Rename Leon Brocard to Orange Brocard'
342 Created commit 6196c1d: Rename Leon Brocard to Orange Brocard
343 1 files changed, 1 insertions(+), 1 deletions(-)
345 The C<-a> option is used to include all files that git tracks that you have
346 changed. If at this time, you only want to commit some of the files you have
347 worked on, you can omit the C<-a> and use the command C<S<git add I<FILE ...>>>
348 before doing the commit. C<S<git add --interactive>> allows you to even just
349 commit portions of files instead of all the changes in them.
351 The C<-m> option is used to specify the commit message. If you omit it, git
352 will open a text editor for you to compose the message interactively. This
353 is useful when the changes are more complex than the sample given here, and,
354 depending on the editor, to know that the first line of the commit message
355 doesn't exceed the 50 character legal maximum.
357 You can examine your last commit with:
361 and if you are not happy with either the description or the patch
362 itself you can fix it up by editing the files once more and then issue:
364 % git commit -a --amend
366 Now you should create a patch file for all your local changes:
368 % git format-patch -M origin..
369 0001-Rename-Leon-Brocard-to-Orange-Brocard.patch
371 You should now send an email to to
372 L<perlbug@perl.org|mailto:perlbug@perl.org> with a description of your
373 changes, and include this patch file as an attachment. In addition to
374 being tracked by RT, mail to perlbug will automatically be forwarded to
375 perl5-porters. You should only send patches to
376 L<perl5-porters@perl.org|mailto:perl5-porters@perl.org> directly if the
377 patch is not ready to be applied, but intended for discussion.
379 See the next section for how to configure and use git to send these
382 If you want to delete your temporary branch, you may do so with:
385 % git branch -d orange
386 error: The branch 'orange' is not an ancestor of your current HEAD.
387 If you are sure you want to delete it, run 'git branch -D orange'.
388 % git branch -D orange
389 Deleted branch orange.
391 =head2 Using git to send patch emails
393 In your ~/git/perl repository, set the destination email to perl's bug
396 $ git config sendemail.to perlbug@perl.org
398 Or maybe perl5-porters (discussed above):
400 $ git config sendemail.to perl5-porters@perl.org
402 Then you can use git directly to send your patch emails:
404 $ git send-email 0001-Rename-Leon-Brocard-to-Orange-Brocard.patch
406 You may need to set some configuration variables for your particular
407 email service provider. For example, to set your global git config to
408 send email via a gmail account:
410 $ git config --global sendemail.smtpserver smtp.gmail.com
411 $ git config --global sendemail.smtpssl 1
412 $ git config --global sendemail.smtpuser YOURUSERNAME@gmail.com
414 With this configuration, you will be prompted for your gmail password
415 when you run 'git send-email'. You can also configure
416 C<sendemail.smtppass> with your password if you don't care about having
417 your password in the .gitconfig file.
419 =head2 A note on derived files
421 Be aware that many files in the distribution are derivative--avoid
422 patching them, because git won't see the changes to them, and the build
423 process will overwrite them. Patch the originals instead. Most
424 utilities (like perldoc) are in this category, i.e. patch
425 F<utils/perldoc.PL> rather than F<utils/perldoc>. Similarly, don't
426 create patches for files under $src_root/ext from their copies found in
427 $install_root/lib. If you are unsure about the proper location of a
428 file that may have gotten copied while building the source
429 distribution, consult the C<MANIFEST>.
431 As a special case, several files are regenerated by 'make regen' if
432 your patch alters C<embed.fnc>. These are needed for compilation, but
433 are included in the distribution so that you can build perl without
434 needing another perl to generate the files. You must test with these
435 regenerated files, but it is preferred that you instead note that 'make
436 regen is needed' in both the email and the commit message, and submit
437 your patch without them. If you're submitting a series of patches, it
438 might be best to submit the regenerated changes immediately after the
439 source-changes that caused them, so as to have as little effect as
440 possible on the bisectability of your patchset.
443 What should we recommend about binary files now? Do we need anything?
445 =head2 Getting your patch accepted
447 If you are submitting a code patch there are several things that you
454 As you craft each patch you intend to submit to the Perl core, it's
455 important to write a good commit message.
457 The first line of the commit message should be a short description and
458 should skip the full stop. It should be no longer than the subject line
459 of an E-Mail, 50 characters being a good rule of thumb.
461 A lot of Git tools (Gitweb, GitHub, git log --pretty=oneline, ..) will
462 only display the first line (cut off at 50 characters) when presenting
465 The commit message should include description of the problem that the
466 patch corrects or new functionality that the patch adds.
468 As a general rule of thumb, your commit message should let a programmer
469 with a reasonable familiarity with the Perl core quickly understand
470 what you were trying to do, how you were trying to do it and why the
471 change matters to Perl.
477 Your commit message should describe what part of the Perl core you're
478 changing and what you expect your patch to do.
482 Perhaps most importantly, your commit message should describe why the
483 change you are making is important. When someone looks at your change
484 in six months or six years, your intent should be clear. If you're
485 deprecating a feature with the intent of later simplifying another bit
486 of code, say so. If you're fixing a performance problem or adding a new
487 feature to support some other bit of the core, mention that.
491 While it's not necessary for documentation changes, new tests or
492 trivial patches, it's often worth explaining how your change works.
493 Even if it's clear to you today, it may not be clear to a porter next
498 A commit message isn't intended to take the place of comments in your
499 code. Commit messages should describe the change you made, while code
500 comments should describe the current state of the code. If you've just
501 implemented a new feature, complete with doc, tests and well-commented
502 code, a brief commit message will often suffice. If, however, you've
503 just changed a single character deep in the parser or lexer, you might
504 need to write a small novel to ensure that future readers understand
505 what you did and why you did it.
507 =item Comments, Comments, Comments
509 Be sure to adequately comment your code. While commenting every line
510 is unnecessary, anything that takes advantage of side effects of
511 operators, that creates changes that will be felt outside of the
512 function being patched, or that others may find confusing should be
513 documented. If you are going to err, it is better to err on the side
514 of adding too many comments than too few.
518 In general, please follow the particular style of the code you are
521 In particular, follow these general guidelines for patching Perl
524 8-wide tabs (no exceptions!)
525 4-wide indents for code, 2-wide indents for nested CPP #defines
526 try hard not to exceed 79-columns
528 uncuddled elses and "K&R" style for indenting control constructs
529 no C++ style (//) comments
530 mark places that need to be revisited with XXX (and revisit often!)
531 opening brace lines up with "if" when conditional spans multiple
532 lines; should be at end-of-line otherwise
533 in function definitions, name starts in column 0 (return value is on
535 single space after keywords that are followed by parens, no space
536 between function name and following paren
537 avoid assignments in conditionals, but if they're unavoidable, use
538 extra paren, e.g. "if (a && (b = c)) ..."
539 "return foo;" rather than "return(foo);"
540 "if (!foo) ..." rather than "if (foo == FALSE) ..." etc.
544 If your patch changes code (rather than just changing documentation)
545 you should also include one or more test cases which illustrate the bug
546 you're fixing or validate the new functionality you're adding. In
547 general, you should update an existing test file rather than create a
550 Your testsuite additions should generally follow these guidelines
551 (courtesy of Gurusamy Sarathy <gsar@activestate.com>):
553 Know what you're testing. Read the docs, and the source.
554 Tend to fail, not succeed.
555 Interpret results strictly.
556 Use unrelated features (this will flush out bizarre interactions).
557 Use non-standard idioms (otherwise you are not testing TIMTOWTDI).
558 Avoid using hardcoded test numbers whenever possible (the
559 EXPECTED/GOT found in t/op/tie.t is much more maintainable,
560 and gives better failure reports).
561 Give meaningful error messages when a test fails.
562 Avoid using qx// and system() unless you are testing for them. If you
563 do use them, make sure that you cover _all_ perl platforms.
564 Unlink any temporary files you create.
565 Promote unforeseen warnings to errors with $SIG{__WARN__}.
566 Be sure to use the libraries and modules shipped with the version
567 being tested, not those that were already installed.
568 Add comments to the code explaining what you are testing for.
569 Make updating the '1..42' string unnecessary. Or make sure that
571 Test _all_ behaviors of a given operator, library, or function:
572 - All optional arguments
573 - Return values in various contexts (boolean, scalar, list, lvalue)
574 - Use both global and lexical variables
575 - Don't forget the exceptional, pathological cases.
579 =head1 Accepting a patch
581 If you have received a patch file generated using the above section,
582 you should try out the patch.
584 First we need to create a temporary new branch for these changes and
587 % git checkout -b experimental
589 Patches that were formatted by C<git format-patch> are applied with
592 % git am 0001-Rename-Leon-Brocard-to-Orange-Brocard.patch
593 Applying Rename Leon Brocard to Orange Brocard
595 If just a raw diff is provided, it is also possible use this two-step
598 % git apply bugfix.diff
599 % git commit -a -m "Some fixing" --author="That Guy <that.guy@internets.com>"
601 Now we can inspect the change:
604 commit b1b3dab48344cff6de4087efca3dbd63548ab5e2
605 Author: Leon Brocard <acme@astray.com>
606 Date: Fri Dec 19 17:02:59 2008 +0000
608 Rename Leon Brocard to Orange Brocard
610 diff --git a/AUTHORS b/AUTHORS
611 index 293dd70..722c93e 100644
614 @@ -541,7 +541,7 @@ Lars Hecking <lhecking@nmrc.ucc.ie>
615 Laszlo Molnar <laszlo.molnar@eth.ericsson.se>
616 Leif Huhn <leif@hale.dkstat.com>
617 Len Johnson <lenjay@ibm.net>
618 -Leon Brocard <acme@astray.com>
619 +Orange Brocard <acme@astray.com>
620 Les Peters <lpeters@aol.net>
621 Lesley Binks <lesley.binks@gmail.com>
622 Lincoln D. Stein <lstein@cshl.org>
624 If you are a committer to Perl and you think the patch is good, you can
625 then merge it into blead then push it out to the main repository:
628 % git merge experimental
631 If you want to delete your temporary branch, you may do so with:
634 % git branch -d experimental
635 error: The branch 'experimental' is not an ancestor of your current HEAD.
636 If you are sure you want to delete it, run 'git branch -D experimental'.
637 % git branch -D experimental
638 Deleted branch experimental.
640 =head1 Cleaning a working directory
642 The command C<git clean> can with varying arguments be used as a
643 replacement for C<make clean>.
645 To reset your working directory to a pristine condition you can do:
649 However, be aware this will delete ALL untracked content. You can use
653 to remove all ignored untracked files, such as build and test
654 byproduct, but leave any manually created files alone.
656 If you only want to cancel some uncommitted edits, you can use C<git
657 checkout> and give it a list of files to be reverted, or C<git checkout
658 -f> to revert them all.
660 If you want to cancel one or several commits, you can use C<git reset>.
664 C<git> provides a built-in way to determine, with a binary search in
665 the history, which commit should be blamed for introducing a given bug.
667 Suppose that we have a script F<~/testcase.pl> that exits with C<0>
668 when some behaviour is correct, and with C<1> when it's faulty. You
669 need an helper script that automates building C<perl> and running the
676 # If you get './makedepend: 1: Syntax error: Unterminated quoted
677 # string' when bisecting versions of perl older than 5.9.5 this hack
678 # will work around the bug in makedepend.SH which was fixed in
679 # version 96a8704c. Make sure to comment out `git checkout makedepend.SH'
681 git show blead:makedepend.SH > makedepend.SH
683 # If you can use ccache, add -Dcc=ccache\ gcc -Dld=gcc to the Configure line
684 # if Encode is not needed for the test, you can speed up the bisect by
685 # excluding it from the runs with -Dnoextensions=Encode
686 sh Configure -des -Dusedevel -Doptimize="-g"
687 test -f config.sh || exit 125
688 # Correct makefile for newer GNU gcc
689 perl -ni -we 'print unless /<(?:built-in|command)/' makefile x2p/makefile
690 # if you just need miniperl, replace test_prep with miniperl
692 [ -x ./perl ] || exit 125
693 ./perl -Ilib ~/testcase.pl
695 [ $ret -gt 127 ] && ret=127
696 # git checkout makedepend.SH
700 This script may return C<125> to indicate that the corresponding commit
701 should be skipped. Otherwise, it returns the status of
704 You first enter in bisect mode with:
708 For example, if the bug is present on C<HEAD> but wasn't in 5.10.0,
709 C<git> will learn about this when you enter:
712 % git bisect good perl-5.10.0
713 Bisecting: 853 revisions left to test after this
715 This results in checking out the median commit between C<HEAD> and
716 C<perl-5.10.0>. You can then run the bisecting process with:
718 % git bisect run ~/run
720 When the first bad commit is isolated, C<git bisect> will tell you so:
722 ca4cfd28534303b82a216cfe83a1c80cbc3b9dc5 is first bad commit
723 commit ca4cfd28534303b82a216cfe83a1c80cbc3b9dc5
724 Author: Dave Mitchell <davem@fdisolutions.com>
725 Date: Sat Feb 9 14:56:23 2008 +0000
727 [perl #49472] Attributes + Unknown Error
732 You can peek into the bisecting process with C<git bisect log> and
733 C<git bisect visualize>. C<git bisect reset> will get you out of bisect
736 Please note that the first C<good> state must be an ancestor of the
737 first C<bad> state. If you want to search for the commit that I<solved>
738 some bug, you have to negate your test case (i.e. exit with C<1> if OK
739 and C<0> if not) and still mark the lower bound as C<good> and the
740 upper as C<bad>. The "first bad commit" has then to be understood as
741 the "first commit where the bug is solved".
743 C<git help bisect> has much more information on how you can tweak your
746 =head1 Submitting a patch via GitHub
748 GitHub is a website that makes it easy to fork and publish projects
749 with Git. First you should set up a GitHub account and log in.
751 Perl's git repository is mirrored on GitHub at this page:
753 http://github.com/mirrors/perl/tree/blead
755 Visit the page and click the "fork" button. This clones the Perl git
756 repository for you and provides you with "Your Clone URL" from which
759 % git clone git@github.com:USERNAME/perl.git perl-github
761 The same patch as above, using github might look like this:
764 % git remote add upstream git://perl5.git.perl.org/perl.git
765 % git pull upstream blead
766 % git checkout -b orange
767 % perl -pi -e 's{Leon Brocard}{Orange Brocard}' AUTHORS
768 % git commit -a -m 'Rename Leon Brocard to Orange Brocard'
769 % git push origin orange
771 The orange branch has been pushed to GitHub, so you should now send an
772 email (see L</Submitting a patch>) with a description of your changes
773 and the following information:
775 http://github.com/USERNAME/perl/tree/orange
776 git://github.com/USERNAME/perl.git branch orange
778 =head1 Merging from a branch via GitHub
780 If someone has provided a branch via GitHub and you are a committer,
781 you should use the following in your perl-ssh directory:
783 % git remote add avar git://github.com/avar/perl.git
786 Now you can see the differences between the branch and blead:
788 % git diff avar/orange
790 And you can see the commits:
792 % git log avar/orange
794 If you approve of a specific commit, you can cherry pick it:
796 % git cherry-pick 0c24b290ae02b2ab3304f51d5e11e85eb3659eae
798 Or you could just merge the whole branch if you like it all:
800 % git merge avar/orange
802 And then push back to the repository:
807 =head1 Topic branches and rewriting history
809 Individual committers should create topic branches under
810 B<yourname>/B<some_descriptive_name>. Other committers should check
811 with a topic branch's creator before making any change to it.
813 The simplest way to create a remote topic branch that works on all
814 versions of git is to push the current head as a new branch on the
815 remote, then check it out locally:
817 $ branch="$yourname/$some_descriptive_name"
818 $ git push origin HEAD:$branch
819 $ git checkout -b $branch origin/$branch
821 Users of git 1.7 or newer can do it in a more obvious manner:
823 $ branch="$yourname/$some_descriptive_name"
824 $ git checkout -b $branch
825 $ git push origin -u $branch
827 If you are not the creator of B<yourname>/B<some_descriptive_name>, you
828 might sometimes find that the original author has edited the branch's
829 history. There are lots of good reasons for this. Sometimes, an author
830 might simply be rebasing the branch onto a newer source point.
831 Sometimes, an author might have found an error in an early commit which
832 they wanted to fix before merging the branch to blead.
834 Currently the master repository is configured to forbid
835 non-fast-forward merges. This means that the branches within can not
836 be rebased and pushed as a single step.
838 The only way you will ever be allowed to rebase or modify the history
839 of a pushed branch is to delete it and push it as a new branch under
840 the same name. Please think carefully about doing this. It may be
841 better to sequentially rename your branches so that it is easier for
842 others working with you to cherry-pick their local changes onto the new
843 version. (XXX: needs explanation).
845 If you want to rebase a personal topic branch, you will have to delete
846 your existing topic branch and push as a new version of it. You can do
847 this via the following formula (see the explanation about C<refspec>'s
848 in the git push documentation for details) after you have rebased your
852 $ git checkout $user/$topic
854 $ git rebase origin/blead
856 # then "delete-and-push"
857 $ git push origin :$user/$topic
858 $ git push origin $user/$topic
860 B<NOTE:> it is forbidden at the repository level to delete any of the
861 "primary" branches. That is any branch matching
862 C<m!^(blead|maint|perl)!>. Any attempt to do so will result in git
863 producing an error like this:
865 $ git push origin :blead
866 *** It is forbidden to delete blead/maint branches in this repository
867 error: hooks/update exited with error code 1
868 error: hook declined to update refs/heads/blead
869 To ssh://perl5.git.perl.org/perl
870 ! [remote rejected] blead (hook declined)
871 error: failed to push some refs to 'ssh://perl5.git.perl.org/perl'
873 As a matter of policy we do B<not> edit the history of the blead and
874 maint-* branches. If a typo (or worse) sneaks into a commit to blead or
875 maint-*, we'll fix it in another commit. The only types of updates
876 allowed on these branches are "fast-forward's", where all history is
879 Annotated tags in the canonical perl.git repository will never be
880 deleted or modified. Think long and hard about whether you want to push
881 a local tag to perl.git before doing so. (Pushing unannotated tags is
884 =head1 Committing to maintenance versions
886 Maintenance versions should only be altered to add critical bug fixes,
889 To commit to a maintenance version of perl, you need to create a local
892 % git checkout --track -b maint-5.005 origin/maint-5.005
894 This creates a local branch named C<maint-5.005>, which tracks the
895 remote branch C<origin/maint-5.005>. Then you can pull, commit, merge
898 You can also cherry-pick commits from blead and another branch, by
899 using the C<git cherry-pick> command. It is recommended to use the
900 B<-x> option to C<git cherry-pick> in order to record the SHA1 of the
901 original commit in the new commit message.
905 The perl history contains one mistake which was not caught in the
906 conversion: a merge was recorded in the history between blead and
907 maint-5.10 where no merge actually occurred. Due to the nature of git,
908 this is now impossible to fix in the public repository. You can remove
909 this mis-merge locally by adding the following line to your
910 C<.git/info/grafts> file:
912 296f12bbbbaa06de9be9d09d3dcf8f4528898a49 434946e0cb7a32589ed92d18008aaa1d88515930
914 It is particularly important to have this graft line if any bisecting
915 is done in the area of the "merge" in question.
923 The git documentation, accessible via the C<git help> command
927 L<perlpolicy> - Perl core development policy