3 perlrepository - Using the Perl source repository
7 All of Perl's source code is kept centrally in a Git repository. The
8 repository contains many Perl revisions from Perl 1 onwards and all the
9 revisions from Perforce, the version control system we were using
10 previously. This repository is accessible in different ways.
12 The full repository takes up about 80MB of disk space. A check out of
13 the blead branch (that is, the master branch, which contains bleadperl,
14 the development version of perl 5) takes up about 160MB of disk space
15 (including the repository). A build of bleadperl takes up about 200MB
16 (including the repository and the check out).
18 =head1 GETTING ACCESS TO THE REPOSITORY
20 =head2 READ ACCESS VIA THE WEB
22 You may access this over the web. This allows you to browse the tree,
23 see recent commits, search for particular commits and more. You may
26 http://perl5.git.perl.org/perl.git
28 =head2 READ ACCESS VIA GIT
30 You will need a copy of Git for your computer. You can fetch a copy of
31 the repository using the Git protocol (which uses port 9418):
33 git clone git://perl5.git.perl.org/perl.git perl-git
35 This clones the repository and makes a local copy in the 'perl-git'
38 If your local network does not allow you to use port 9418, then you can
39 fetch a copy of the repository over HTTP (this is slower):
41 git clone http://perl5.git.perl.org/perl.git perl-http
43 This clones the repository and makes a local copy in the 'perl-http'
46 =head2 WRITE ACCESS TO THE REPOSITORY
48 If you are a committer, then you can fetch a copy of the repository
49 that you can push back on with:
51 git clone ssh://perl5.git.perl.org/gitroot/perl.git perl-ssh
53 This clones the repository and makes a local copy in the 'perl-ssh'
56 If you clone using git, which is faster than ssh, then you will need to
57 modify your config in order to enable pushing. Edit F<.git/config>
58 where you will see something like:
61 url = git://perl5.git.perl.org/perl.git
63 change that to something like this:
66 url = ssh://perl5.git.perl.org/gitroot/perl.git
68 NOTE: there are symlinks set up so that the /gitroot is actually
71 You can also set up your user name and e-mail address. For example
73 % git config user.name "Leon Brocard"
74 % git config user.email acme@astray.com
76 It is also possible to keep C<origin> as a git remote, and add a new
77 remote for ssh access:
79 % git remote add camel user@camel:/gitroot/perl.git
81 This allows you to update your local repository by pulling from
82 C<origin>, which is faster and doesn't require you to authentify, and
83 to push your changes back with the C<camel> remote:
88 The C<fetch> command just updates the C<camel> refs, as the objects
89 themselves should have been fetched when pulling from C<origin>.
91 =head1 OVERVIEW OF THE REPOSITORY
93 Once you have changed into the repository directory, you can inspect
97 After a clone the repository will contain a single local branch, which
98 will be the current branch as well, as indicated by the asterix.
103 Using the -a switch to branch will also show the remote tracking
104 branches in the repository:
112 The branches that begin with "origin" correspond to the "git remote"
113 that you cloned from (which is named "origin"). Each branch on the
114 remote will be exactly tracked by theses branches. You should NEVER do
115 work on these remote tracking branches. You only ever do work in a
116 local branch. Local branches can be configured to automerge (on pull)
117 from a designated remote tracking branch. This is the case with the
118 default branch C<blead> which will be configured to merge from the
119 remote tracking branch C<origin/blead>.
121 You can see recent commits:
125 And pull new changes from the repository, and update your local
126 repository (must be clean first)
130 Assuming we are on the branch C<blead> immediately after a pull, this
131 command would be more or less equivalent to:
134 % git merge origin/blead
136 In fact if you want to update your local repository without touching
137 your working directory you do:
141 And if you want to update your remote-tracking branches for all defined
142 remotes simultaneously you can do
146 Neither of these last two commands will update your working directory,
147 however both will update the remote-tracking branches in your
150 To switch to another branch:
152 % git checkout origin/maint-5.8-dor
154 To switch back to blead:
158 =head2 FINDING OUT YOUR STATUS
160 The most common git command you will use will probably be
164 This command will produce as output a description of the current state
165 of the repository, including modified files and unignored untracked
166 files, and in addition it will show things like what files have been
167 staged for the next commit, and usually some useful information about
168 how to change things. For instance the following:
172 # Your branch is ahead of 'origin/blead' by 1 commit.
174 # Changes to be committed:
175 # (use "git reset HEAD <file>..." to unstage)
177 # modified: pod/perlrepository.pod
179 # Changed but not updated:
180 # (use "git add <file>..." to update what will be committed)
182 # modified: pod/perlrepository.pod
185 # (use "git add <file>..." to include in what will be committed)
187 # deliberate.untracked
189 This shows that there were changes to this document staged for commit,
190 and that there were further changes in the working directory not yet
191 staged. It also shows that there was an untracked file in the working
192 directory, and as you can see shows how to change all of this. It also
193 shows that there is one commit on the working branch C<blead> which
194 has not been pushed to the C<origin> remote yet. B<NOTE>: that this
195 output is also what you see as a template if you do not provide a
196 message to C<git commit>.
198 Assuming we commit all the mentioned changes above:
200 % git commit -a -m'explain git status and stuff about remotes'
201 Created commit daf8e63: explain git status and stuff about remotes
202 1 files changed, 83 insertions(+), 3 deletions(-)
204 We can re-run git status and see something like this:
208 # Your branch is ahead of 'origin/blead' by 2 commits.
211 # (use "git add <file>..." to include in what will be committed)
213 # deliberate.untracked
214 nothing added to commit but untracked files present (use "git add" to track)
217 When in doubt, before you do anything else, check your status and read
218 it carefully, many questions are answered directly by the git status
221 =head1 SUBMITTING A PATCH
223 If you have a patch in mind for Perl, you should first get a copy of
226 % git clone git://perl5.git.perl.org/perl.git perl-git
228 Then change into the directory:
232 Alternatively, if you already have a Perl repository, you should ensure
233 that you're on the I<blead> branch, and your repository is up to date:
238 Now that we have everything up to date, we need to create a temporary
239 new branch for these changes and switch into it:
241 % git checkout -b orange
243 which is the short form of
246 % git checkout orange
248 Then make your changes. For example, if Leon Brocard changes his name
249 to Orange Brocard, we should change his name in the AUTHORS file:
251 % perl -pi -e 's{Leon Brocard}{Orange Brocard}' AUTHORS
253 You can see what files are changed:
257 # Changes to be committed:
258 # (use "git reset HEAD <file>..." to unstage)
263 And you can see the changes:
266 diff --git a/AUTHORS b/AUTHORS
267 index 293dd70..722c93e 100644
270 @@ -541,7 +541,7 @@ Lars Hecking <lhecking@nmrc.ucc.ie>
271 Laszlo Molnar <laszlo.molnar@eth.ericsson.se>
272 Leif Huhn <leif@hale.dkstat.com>
273 Len Johnson <lenjay@ibm.net>
274 -Leon Brocard <acme@astray.com>
275 +Orange Brocard <acme@astray.com>
276 Les Peters <lpeters@aol.net>
277 Lesley Binks <lesley.binks@gmail.com>
278 Lincoln D. Stein <lstein@cshl.org>
280 Now commit your change locally:
283 % git commit -m 'Rename Leon Brocard to Orange Brocard'
284 Created commit 6196c1d: Rename Leon Brocard to Orange Brocard
285 1 files changed, 1 insertions(+), 1 deletions(-)
287 Now you should create a patch file for all your local changes:
289 % git format-patch origin
290 0001-Rename-Leon-Brocard-to-Orange-Brocard.patch
292 You should now send an email to perl5-porters@perl.org with a
293 description of your changes, and attach this patch file as an
296 If you want to delete your temporary branch, you may do so with:
299 % git branch -d orange
300 error: The branch 'orange' is not an ancestor of your current HEAD.
301 If you are sure you want to delete it, run 'git branch -D orange'.
302 % git branch -D orange
303 Deleted branch orange.
305 =head1 ACCEPTING A PATCH
307 If you have received a patch file generated using the above section,
308 you should try out the patch.
310 First we need to create a temporary new branch for these changes and
313 % git checkout -b experimental
315 Patches that were formatted by C<git format-patch> are applied with
318 % git am 0001-Rename-Leon-Brocard-to-Orange-Brocard.patch
319 Applying Rename Leon Brocard to Orange Brocard
321 If just a raw diff is provided, it is also possible use this two-step
324 % git apply bugfix.diff
325 % git commit -am "Some fixing" --author="That Guy <that.guy@internets.com>"
327 Now we can inspect the change:
330 commit b1b3dab48344cff6de4087efca3dbd63548ab5e2
331 Author: Leon Brocard <acme@astray.com>
332 Date: Fri Dec 19 17:02:59 2008 +0000
334 Rename Leon Brocard to Orange Brocard
338 diff --git a/AUTHORS b/AUTHORS
339 index 293dd70..722c93e 100644
342 @@ -541,7 +541,7 @@ Lars Hecking <lhecking@nmrc.ucc.ie>
343 Laszlo Molnar <laszlo.molnar@eth.ericsson.se>
344 Leif Huhn <leif@hale.dkstat.com>
345 Len Johnson <lenjay@ibm.net>
346 -Leon Brocard <acme@astray.com>
347 +Orange Brocard <acme@astray.com>
348 Les Peters <lpeters@aol.net>
349 Lesley Binks <lesley.binks@gmail.com>
350 Lincoln D. Stein <lstein@cshl.org>
352 If you are a committer to Perl and you think the patch is good, you can
353 then merge it into blead then push it out to the main repository:
356 % git merge experimental
359 If you want to delete your temporary branch, you may do so with:
362 % git branch -d experimental
363 error: The branch 'experimental' is not an ancestor of your current HEAD.
364 If you are sure you want to delete it, run 'git branch -D experimental'.
365 % git branch -D experimental
366 Deleted branch experimental.
368 =head1 CLEANING A WORKING DIRECTORY
370 The command C<git clean> can with varying arguments be used as a
371 replacement for make-clean.
373 To reset your working directory to a pristine condition you can do:
377 However, be aware this will delete ALL untracked content. You can use
381 to remove all ignored untracked files, such as build and test
382 byproduct, but leave any manually created files alone.
386 C<git> provides a built-in way to determine, with a binary search in
387 the history, which commit should be blamed for introducing a given bug.
389 Suppose that we have a script F<~/testcase.pl> that exits with C<0>
390 when some behaviour is correct, and with C<1> when it's faulty. We need
391 an helper script that automates building C<perl> and running the
397 # If you can use ccache, add -Dcc=ccache\ gcc -Dld=gcc to the Configure line
398 sh Configure -des -Dusedevel -Doptimize="-g" || exit 125
400 ./perl -Ilib ~/testcase.pl
402 This script may return C<125> to indicate that the corresponding commit
403 should be skipped. Otherwise, it returns the status of
406 We first enter in bisect mode with:
410 For example, if the bug is present on C<HEAD> but wasn't in 5.10.0,
411 C<git> will learn about this when you enter:
414 % git bisect good perl-5.10.0
415 Bisecting: 853 revisions left to test after this
417 This results in checking out the median commit between C<HEAD> and
418 C<perl-5.10.0>. We can then run the bisecting process with:
420 % git bisect run ~/run
422 When the first bad commit is isolated, C<git bisect> will tell you so:
424 ca4cfd28534303b82a216cfe83a1c80cbc3b9dc5 is first bad commit
425 commit ca4cfd28534303b82a216cfe83a1c80cbc3b9dc5
426 Author: Dave Mitchell <davem@fdisolutions.com>
427 Date: Sat Feb 9 14:56:23 2008 +0000
429 [perl #49472] Attributes + Unkown Error
434 You can peek into the bisecting process with C<git bisect log> and
435 C<git bisect visualize>. C<git bisect reset> will get you out of bisect
438 Please note that the first C<good> state must be an ancestor of the
439 first C<bad> state. If you want to search for the commit that I<solved>
440 some bug, you have to negate your test case (i.e. exit with C<1> if OK
441 and C<0> if not) and still mark the lower bound as C<good> and the
442 upper as C<bad>. The "first bad commit" has then to be understood as
443 the "first commit where the bug is solved".
445 C<git help bisect> has much more information on how you can tweak your
448 =head1 COMITTING TO MAINTENANCE VERSIONS
450 To commit to a maintenance version of perl, you need to create a local
453 % git checkout --track -b maint-5.005 origin/maint-5.005
455 This creates a local branch named maint-5.005, which tracks the remote
456 branch origin/maint-5.005. Then you can pull, commit, merge and push as