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
72 % git config remote.origin.url ssh://perl5.git.perl.org/perl.git
74 You can also set up your user name and e-mail address. Most people do
75 this once globally in their F<~/.gitconfig> by doing something like:
77 % git config --global user.name "Ævar Arnfjörð Bjarmason"
78 % git config --global user.email avarab@gmail.com
80 However if you'd like to override that just for perl then execute then
81 execute something like the following in F<perl-git>:
83 % git config user.email avar@cpan.org
85 It is also possible to keep C<origin> as a git remote, and add a new
86 remote for ssh access:
88 % git remote add camel perl5.git.perl.org:/perl.git
90 This allows you to update your local repository by pulling from
91 C<origin>, which is faster and doesn't require you to authenticate, and
92 to push your changes back with the C<camel> remote:
97 The C<fetch> command just updates the C<camel> refs, as the objects
98 themselves should have been fetched when pulling from C<origin>.
100 =head2 A note on camel and dromedary
102 The committers have SSH access to the two servers that serve
103 C<perl5.git.perl.org>. One is C<perl5.git.perl.org> itself (I<camel>),
104 which is the 'master' repository. The second one is
105 C<users.perl5.git.perl.org> (I<dromedary>), which can be used for
106 general testing and development. Dromedary syncs the git tree from
107 camel every few minutes, you should not push there. Both machines also
108 have a full CPAN mirror in /srv/CPAN, please use this. To share files
109 with the general public, dromedary serves your ~/public_html/ as
110 C<http://users.perl5.git.perl.org/~yourlogin/>
112 These hosts have fairly strict firewalls to the outside. Outgoing, only
113 rsync, ssh and git are allowed. For http and ftp, you can use
114 http://webproxy:3128 as proxy. Incoming, the firewall tries to detect
115 attacks and blocks IP addresses with suspicious activity. This
116 sometimes (but very rarely) has false positives and you might get
117 blocked. The quickest way to get unblocked is to notify the admins.
119 These two boxes are owned, hosted, and operated by booking.com. You can
120 reach the sysadmins in #p5p on irc.perl.org or via mail to
121 C<perl5-porters@perl.org>
123 =head1 Overview of the repository
125 Once you have changed into the repository directory, you can inspect
128 After a clone the repository will contain a single local branch, which
129 will be the current branch as well, as indicated by the asterisk.
134 Using the -a switch to C<branch> will also show the remote tracking
135 branches in the repository:
143 The branches that begin with "origin" correspond to the "git remote"
144 that you cloned from (which is named "origin"). Each branch on the
145 remote will be exactly tracked by theses branches. You should NEVER do
146 work on these remote tracking branches. You only ever do work in a
147 local branch. Local branches can be configured to automerge (on pull)
148 from a designated remote tracking branch. This is the case with the
149 default branch C<blead> which will be configured to merge from the
150 remote tracking branch C<origin/blead>.
152 You can see recent commits:
156 And pull new changes from the repository, and update your local
157 repository (must be clean first)
161 Assuming we are on the branch C<blead> immediately after a pull, this
162 command would be more or less equivalent to:
165 % git merge origin/blead
167 In fact if you want to update your local repository without touching
168 your working directory you do:
172 And if you want to update your remote-tracking branches for all defined
173 remotes simultaneously you can do
177 Neither of these last two commands will update your working directory,
178 however both will update the remote-tracking branches in your
181 To make a local branch of a remote branch:
183 % git checkout -b maint-5.10 origin/maint-5.10
185 To switch back to blead:
189 =head2 Finding out your status
191 The most common git command you will use will probably be
195 This command will produce as output a description of the current state
196 of the repository, including modified files and unignored untracked
197 files, and in addition it will show things like what files have been
198 staged for the next commit, and usually some useful information about
199 how to change things. For instance the following:
203 # Your branch is ahead of 'origin/blead' by 1 commit.
205 # Changes to be committed:
206 # (use "git reset HEAD <file>..." to unstage)
208 # modified: pod/perlrepository.pod
210 # Changed but not updated:
211 # (use "git add <file>..." to update what will be committed)
213 # modified: pod/perlrepository.pod
216 # (use "git add <file>..." to include in what will be committed)
218 # deliberate.untracked
220 This shows that there were changes to this document staged for commit,
221 and that there were further changes in the working directory not yet
222 staged. It also shows that there was an untracked file in the working
223 directory, and as you can see shows how to change all of this. It also
224 shows that there is one commit on the working branch C<blead> which has
225 not been pushed to the C<origin> remote yet. B<NOTE>: that this output
226 is also what you see as a template if you do not provide a message to
229 Assuming that you'd like to commit all the changes you've just made as a
230 a single atomic unit, run this command:
234 (That C<-a> tells git to add every file you've changed to this commit.
235 New files aren't automatically added to your commit when you use C<commit
236 -a> If you want to add files or to commit some, but not all of your
237 changes, have a look at the documentation for C<git add>.)
239 Git will start up your favorite text editor, so that you can craft a
240 commit message for your change. See L</Commit message> below for more
241 information about what makes a good commit message.
243 Once you've finished writing your commit message and exited your editor,
244 git will write your change to disk and tell you something like this:
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
303 pick your changes onto blead before they can be applied.
305 That'll get you scolded on perl5-porters, so don't do that. Be
308 Then make your changes. For example, if Leon Brocard changes his name
309 to Orange Brocard, we should change his name in the AUTHORS file:
311 % perl -pi -e 's{Leon Brocard}{Orange Brocard}' AUTHORS
313 You can see what files are changed:
317 # Changes to be committed:
318 # (use "git reset HEAD <file>..." to unstage)
323 And you can see the changes:
326 diff --git a/AUTHORS b/AUTHORS
327 index 293dd70..722c93e 100644
330 @@ -541,7 +541,7 @@ Lars Hecking <lhecking@nmrc.ucc.ie>
331 Laszlo Molnar <laszlo.molnar@eth.ericsson.se>
332 Leif Huhn <leif@hale.dkstat.com>
333 Len Johnson <lenjay@ibm.net>
334 -Leon Brocard <acme@astray.com>
335 +Orange Brocard <acme@astray.com>
336 Les Peters <lpeters@aol.net>
337 Lesley Binks <lesley.binks@gmail.com>
338 Lincoln D. Stein <lstein@cshl.org>
340 Now commit your change locally:
342 % git commit -a -m 'Rename Leon Brocard to Orange Brocard'
343 Created commit 6196c1d: Rename Leon Brocard to Orange Brocard
344 1 files changed, 1 insertions(+), 1 deletions(-)
346 You can examine your last commit with:
350 and if you are not happy with either the description or the patch
351 itself you can fix it up by editing the files once more and then issue:
353 % git commit -a --amend
355 Now you should create a patch file for all your local changes:
357 % git format-patch -M origin..
358 0001-Rename-Leon-Brocard-to-Orange-Brocard.patch
360 You should now send an email to to
361 L<perlbug@perl.org|mailto:perlbug@perl.org> with a description of your
362 changes, and include this patch file as an attachment. In addition to
363 being tracked by RT, mail to perlbug will automatically be forwarded
364 to perl5-porters. You should only send patches to
365 L<perl5-porters@perl.org|mailto:perl5-porters@perl.org> directly if the
366 patch is not ready to be applied, but intended for discussion.
368 See the next section for how to configure and use git to send these
371 If you want to delete your temporary branch, you may do so with:
374 % git branch -d orange
375 error: The branch 'orange' is not an ancestor of your current HEAD.
376 If you are sure you want to delete it, run 'git branch -D orange'.
377 % git branch -D orange
378 Deleted branch orange.
380 =head2 Using git to send patch emails
382 In your ~/git/perl repository, set the destination email to perl's bug
385 $ git config sendemail.to perlbug@perl.org
387 Or maybe perl5-porters (discussed above):
389 $ git config sendemail.to perl5-porters@perl.org
391 Then you can use git directly to send your patch emails:
393 $ git send-email 0001-Rename-Leon-Brocard-to-Orange-Brocard.patch
395 You may need to set some configuration variables for your particular
396 email service provider. For example, to set your global git config to
397 send email via a gmail account:
399 $ git config --global sendemail.smtpserver smtp.gmail.com
400 $ git config --global sendemail.smtpssl 1
401 $ git config --global sendemail.smtpuser YOURUSERNAME@gmail.com
403 With this configuration, you will be prompted for your gmail password
404 when you run 'git send-email'. You can also configure
405 C<sendemail.smtppass> with your password if you don't care about having
406 your password in the .gitconfig file.
408 =head2 A note on derived files
410 Be aware that many files in the distribution are derivative--avoid
411 patching them, because git won't see the changes to them, and the build
412 process will overwrite them. Patch the originals instead. Most
413 utilities (like perldoc) are in this category, i.e. patch
414 F<utils/perldoc.PL> rather than F<utils/perldoc>. Similarly, don't create
415 patches for files under $src_root/ext from their copies found in
416 $install_root/lib. If you are unsure about the proper location of a
417 file that may have gotten copied while building the source
418 distribution, consult the C<MANIFEST>.
420 As a special case, several files are regenerated by 'make regen' if
421 your patch alters C<embed.fnc>. These are needed for compilation, but
422 are included in the distribution so that you can build perl without
423 needing another perl to generate the files. You must test with these
424 regenerated files, but it is preferred that you instead note that
425 'make regen is needed' in both the email and the commit message, and
426 submit your patch without them. If you're submitting a series of
427 patches, it might be best to submit the regenerated changes
428 immediately after the source-changes that caused them, so as to have
429 as little effect as possible on the bisectability of your patchset.
433 What should we recommend about binary files now? Do we need anything?
435 =head2 Getting your patch accepted
437 If you are submitting a code patch there are several things that
444 As you craft each patch you intend to submit to the Perl core, it's
445 important to write a good commit message.
447 The first line of the commit message should be a short description and
448 should skip the full stop. It should be no longer than the subject
449 line of an E-Mail, 50 characters being a good rule of thumb.
451 A lot of Git tools (Gitweb, GitHub, git log --pretty=oneline, ..) will
452 only display the first line (cut off at 50 characters) when presenting
455 The commit message should include description of the problem that the
456 patch corrects or new functionality that the patch adds.
458 As a general rule of thumb, your commit message should let a programmer
459 with a reasonable familiarity with the Perl core quickly understand what
460 you were trying to do, how you were trying to do it and why the change
467 Your commit message should describe what part of the Perl core you're
468 changing and what you expect your patch to do.
472 Perhaps most importantly, your commit message should describe why the
473 change you are making is important. When someone looks at your change
474 in six months or six years, your intent should be clear. If you're
475 deprecating a feature with the intent of later simplifying another bit
476 of code, say so. If you're fixing a performance problem or adding a new
477 feature to support some other bit of the core, mention that.
481 While it's not necessary for documentation changes, new tests or
482 trivial patches, it's often worth explaining how your change works.
483 Even if it's clear to you today, it may not be clear to a porter next
488 A commit message isn't intended to take the place of comments in your
489 code. Commit messages should describe the change you made, while code
490 comments should describe the current state of the code. If you've just
491 implemented a new feature, complete with doc, tests and well-commented
492 code, a brief commit message will often suffice. If, however, you've
493 just changed a single character deep in the parser or lexer, you might
494 need to write a small novel to ensure that future readers understand
495 what you did and why you did it.
497 =item Comments, Comments, Comments
499 Be sure to adequately comment your code. While commenting every line
500 is unnecessary, anything that takes advantage of side effects of
501 operators, that creates changes that will be felt outside of the
502 function being patched, or that others may find confusing should be
503 documented. If you are going to err, it is better to err on the side
504 of adding too many comments than too few.
508 In general, please follow the particular style of the code you are
511 In particular, follow these general guidelines for patching Perl
514 8-wide tabs (no exceptions!)
515 4-wide indents for code, 2-wide indents for nested CPP #defines
516 try hard not to exceed 79-columns
518 uncuddled elses and "K&R" style for indenting control constructs
519 no C++ style (//) comments
520 mark places that need to be revisited with XXX (and revisit often!)
521 opening brace lines up with "if" when conditional spans multiple
522 lines; should be at end-of-line otherwise
523 in function definitions, name starts in column 0 (return value is on
525 single space after keywords that are followed by parens, no space
526 between function name and following paren
527 avoid assignments in conditionals, but if they're unavoidable, use
528 extra paren, e.g. "if (a && (b = c)) ..."
529 "return foo;" rather than "return(foo);"
530 "if (!foo) ..." rather than "if (foo == FALSE) ..." etc.
534 If your patch changes code (rather than just changing documentation) you
535 should also include one or more test cases which illustrate the bug you're
536 fixing or validate the new functionality you're adding. In general,
537 you should update an existing test file rather than create a new one.
539 Your testsuite additions should generally follow these guidelines
540 (courtesy of Gurusamy Sarathy <gsar@activestate.com>):
542 Know what you're testing. Read the docs, and the source.
543 Tend to fail, not succeed.
544 Interpret results strictly.
545 Use unrelated features (this will flush out bizarre interactions).
546 Use non-standard idioms (otherwise you are not testing TIMTOWTDI).
547 Avoid using hardcoded test numbers whenever possible (the
548 EXPECTED/GOT found in t/op/tie.t is much more maintainable,
549 and gives better failure reports).
550 Give meaningful error messages when a test fails.
551 Avoid using qx// and system() unless you are testing for them. If you
552 do use them, make sure that you cover _all_ perl platforms.
553 Unlink any temporary files you create.
554 Promote unforeseen warnings to errors with $SIG{__WARN__}.
555 Be sure to use the libraries and modules shipped with the version
556 being tested, not those that were already installed.
557 Add comments to the code explaining what you are testing for.
558 Make updating the '1..42' string unnecessary. Or make sure that
560 Test _all_ behaviors of a given operator, library, or function:
561 - All optional arguments
562 - Return values in various contexts (boolean, scalar, list, lvalue)
563 - Use both global and lexical variables
564 - Don't forget the exceptional, pathological cases.
568 =head1 Accepting a patch
570 If you have received a patch file generated using the above section,
571 you should try out the patch.
573 First we need to create a temporary new branch for these changes and
576 % git checkout -b experimental
578 Patches that were formatted by C<git format-patch> are applied with
581 % git am 0001-Rename-Leon-Brocard-to-Orange-Brocard.patch
582 Applying Rename Leon Brocard to Orange Brocard
584 If just a raw diff is provided, it is also possible use this two-step
587 % git apply bugfix.diff
588 % git commit -a -m "Some fixing" --author="That Guy <that.guy@internets.com>"
590 Now we can inspect the change:
593 commit b1b3dab48344cff6de4087efca3dbd63548ab5e2
594 Author: Leon Brocard <acme@astray.com>
595 Date: Fri Dec 19 17:02:59 2008 +0000
597 Rename Leon Brocard to Orange Brocard
599 diff --git a/AUTHORS b/AUTHORS
600 index 293dd70..722c93e 100644
603 @@ -541,7 +541,7 @@ Lars Hecking <lhecking@nmrc.ucc.ie>
604 Laszlo Molnar <laszlo.molnar@eth.ericsson.se>
605 Leif Huhn <leif@hale.dkstat.com>
606 Len Johnson <lenjay@ibm.net>
607 -Leon Brocard <acme@astray.com>
608 +Orange Brocard <acme@astray.com>
609 Les Peters <lpeters@aol.net>
610 Lesley Binks <lesley.binks@gmail.com>
611 Lincoln D. Stein <lstein@cshl.org>
613 If you are a committer to Perl and you think the patch is good, you can
614 then merge it into blead then push it out to the main repository:
617 % git merge experimental
620 If you want to delete your temporary branch, you may do so with:
623 % git branch -d experimental
624 error: The branch 'experimental' is not an ancestor of your current HEAD.
625 If you are sure you want to delete it, run 'git branch -D experimental'.
626 % git branch -D experimental
627 Deleted branch experimental.
629 =head1 Cleaning a working directory
631 The command C<git clean> can with varying arguments be used as a
632 replacement for C<make clean>.
634 To reset your working directory to a pristine condition you can do:
638 However, be aware this will delete ALL untracked content. You can use
642 to remove all ignored untracked files, such as build and test
643 byproduct, but leave any manually created files alone.
645 If you only want to cancel some uncommitted edits, you can use C<git
646 checkout> and give it a list of files to be reverted, or C<git checkout
647 -f> to revert them all.
649 If you want to cancel one or several commits, you can use C<git reset>.
653 C<git> provides a built-in way to determine, with a binary search in
654 the history, which commit should be blamed for introducing a given bug.
656 Suppose that we have a script F<~/testcase.pl> that exits with C<0>
657 when some behaviour is correct, and with C<1> when it's faulty. You need
658 an helper script that automates building C<perl> and running the
665 # If you get './makedepend: 1: Syntax error: Unterminated quoted
666 # string' when bisecting versions of perl older than 5.9.5 this hack
667 # will work around the bug in makedepend.SH which was fixed in
668 # version 96a8704c. Make sure to comment out `git checkout makedepend.SH'
670 git show blead:makedepend.SH > makedepend.SH
672 # If you can use ccache, add -Dcc=ccache\ gcc -Dld=gcc to the Configure line
673 # if Encode is not needed for the test, you can speed up the bisect by
674 # excluding it from the runs with -Dnoextensions=Encode
675 sh Configure -des -Dusedevel -Doptimize="-g"
676 test -f config.sh || exit 125
677 # Correct makefile for newer GNU gcc
678 perl -ni -we 'print unless /<(?:built-in|command)/' makefile x2p/makefile
679 # if you just need miniperl, replace test_prep with miniperl
681 [ -x ./perl ] || exit 125
682 ./perl -Ilib ~/testcase.pl
684 [ $ret -gt 127 ] && ret=127
685 # git checkout makedepend.SH
689 This script may return C<125> to indicate that the corresponding commit
690 should be skipped. Otherwise, it returns the status of
693 You first enter in bisect mode with:
697 For example, if the bug is present on C<HEAD> but wasn't in 5.10.0,
698 C<git> will learn about this when you enter:
701 % git bisect good perl-5.10.0
702 Bisecting: 853 revisions left to test after this
704 This results in checking out the median commit between C<HEAD> and
705 C<perl-5.10.0>. You can then run the bisecting process with:
707 % git bisect run ~/run
709 When the first bad commit is isolated, C<git bisect> will tell you so:
711 ca4cfd28534303b82a216cfe83a1c80cbc3b9dc5 is first bad commit
712 commit ca4cfd28534303b82a216cfe83a1c80cbc3b9dc5
713 Author: Dave Mitchell <davem@fdisolutions.com>
714 Date: Sat Feb 9 14:56:23 2008 +0000
716 [perl #49472] Attributes + Unknown Error
721 You can peek into the bisecting process with C<git bisect log> and
722 C<git bisect visualize>. C<git bisect reset> will get you out of bisect
725 Please note that the first C<good> state must be an ancestor of the
726 first C<bad> state. If you want to search for the commit that I<solved>
727 some bug, you have to negate your test case (i.e. exit with C<1> if OK
728 and C<0> if not) and still mark the lower bound as C<good> and the
729 upper as C<bad>. The "first bad commit" has then to be understood as
730 the "first commit where the bug is solved".
732 C<git help bisect> has much more information on how you can tweak your
735 =head1 Submitting a patch via GitHub
737 GitHub is a website that makes it easy to fork and publish projects
738 with Git. First you should set up a GitHub account and log in.
740 Perl's git repository is mirrored on GitHub at this page:
742 http://github.com/mirrors/perl/tree/blead
744 Visit the page and click the "fork" button. This clones the Perl git
745 repository for you and provides you with "Your Clone URL" from which
748 % git clone git@github.com:USERNAME/perl.git perl-github
750 The same patch as above, using github might look like this:
753 % git remote add upstream git://perl5.git.perl.org/perl.git
754 % git pull upstream blead
755 % git checkout -b orange
756 % perl -pi -e 's{Leon Brocard}{Orange Brocard}' AUTHORS
757 % git commit -a -m 'Rename Leon Brocard to Orange Brocard'
758 % git push origin orange
760 The orange branch has been pushed to GitHub, so you should now send an
761 email (see L</Submitting a patch>) with a description of your changes
762 and the following information:
764 http://github.com/USERNAME/perl/tree/orange
765 git://github.com/USERNAME/perl.git branch orange
767 =head1 Merging from a branch via GitHub
769 If someone has provided a branch via GitHub and you are a committer,
770 you should use the following in your perl-ssh directory:
772 % git remote add avar git://github.com/avar/perl.git
775 Now you can see the differences between the branch and blead:
777 % git diff avar/orange
779 And you can see the commits:
781 % git log avar/orange
783 If you approve of a specific commit, you can cherry pick it:
785 % git cherry-pick 0c24b290ae02b2ab3304f51d5e11e85eb3659eae
787 Or you could just merge the whole branch if you like it all:
789 % git merge avar/orange
791 And then push back to the repository:
796 =head1 Topic branches and rewriting history
798 Individual committers should create topic branches under
799 B<yourname>/B<some_descriptive_name>. Other committers should check
800 with a topic branch's creator before making any change to it.
802 The simplest way to create a remote topic branch that works on all
803 versions of git is to push the current head as a new branch on the
804 remote, then check it out locally:
806 $ branch="$yourname/$some_descriptive_name"
807 $ git push origin HEAD:$branch
808 $ git checkout -b $branch origin/$branch
810 Users of git 1.7 or newer can do it in a more obvious manner:
812 $ branch="$yourname/$some_descriptive_name"
813 $ git checkout -b $branch
814 $ git push origin -u $branch
816 If you are not the creator of B<yourname>/B<some_descriptive_name>, you
817 might sometimes find that the original author has edited the branch's
818 history. There are lots of good reasons for this. Sometimes, an author
819 might simply be rebasing the branch onto a newer source point.
820 Sometimes, an author might have found an error in an early commit which
821 they wanted to fix before merging the branch to blead.
823 Currently the master repository is configured to forbid
824 non-fast-forward merges. This means that the branches within can not
825 be rebased and pushed as a single step.
827 The only way you will ever be allowed to rebase or modify the history
828 of a pushed branch is to delete it and push it as a new branch under
829 the same name. Please think carefully about doing this. It may be
830 better to sequentially rename your branches so that it is easier for
831 others working with you to cherry-pick their local changes onto the new
832 version. (XXX: needs explanation).
834 If you want to rebase a personal topic branch, you will have to delete
835 your existing topic branch and push as a new version of it. You can do
836 this via the following formula (see the explanation about C<refspec>'s
837 in the git push documentation for details) after you have rebased your
841 $ git checkout $user/$topic
843 $ git rebase origin/blead
845 # then "delete-and-push"
846 $ git push origin :$user/$topic
847 $ git push origin $user/$topic
849 B<NOTE:> it is forbidden at the repository level to delete any of the
850 "primary" branches. That is any branch matching
851 C<m!^(blead|maint|perl)!>. Any attempt to do so will result in git
852 producing an error like this:
854 $ git push origin :blead
855 *** It is forbidden to delete blead/maint branches in this repository
856 error: hooks/update exited with error code 1
857 error: hook declined to update refs/heads/blead
858 To ssh://perl5.git.perl.org/perl
859 ! [remote rejected] blead (hook declined)
860 error: failed to push some refs to 'ssh://perl5.git.perl.org/perl'
862 As a matter of policy we do B<not> edit the history of the blead and
863 maint-* branches. If a typo (or worse) sneaks into a commit to blead or
864 maint-*, we'll fix it in another commit. The only types of updates
865 allowed on these branches are "fast-forward's", where all history is
868 Annotated tags in the canonical perl.git repository will never be
869 deleted or modified. Think long and hard about whether you want to push
870 a local tag to perl.git before doing so. (Pushing unannotated tags is
873 =head1 Committing to maintenance versions
875 Maintenance versions should only be altered to add critical bug
876 fixes, see L<perlpolicy>.
878 To commit to a maintenance version of perl, you need to create a local
881 % git checkout --track -b maint-5.005 origin/maint-5.005
883 This creates a local branch named C<maint-5.005>, which tracks the
884 remote branch C<origin/maint-5.005>. Then you can pull, commit, merge
887 You can also cherry-pick commits from blead and another branch, by
888 using the C<git cherry-pick> command. It is recommended to use the
889 B<-x> option to C<git cherry-pick> in order to record the SHA1 of the
890 original commit in the new commit message.
894 The perl history contains one mistake which was not caught in the
895 conversion: a merge was recorded in the history between blead and
896 maint-5.10 where no merge actually occurred. Due to the nature of git,
897 this is now impossible to fix in the public repository. You can remove
898 this mis-merge locally by adding the following line to your
899 C<.git/info/grafts> file:
901 296f12bbbbaa06de9be9d09d3dcf8f4528898a49 434946e0cb7a32589ed92d18008aaa1d88515930
903 It is particularly important to have this graft line if any bisecting
904 is done in the area of the "merge" in question.
912 The git documentation, accessible via the C<git help> command
916 L<perlpolicy> - Perl core development policy