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 F<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 F<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 authenticate, 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
96 After a clone the repository will contain a single local branch, which
97 will be the current branch as well, as indicated by the asterix.
102 Using the -a switch to C<branch> will also show the remote tracking
103 branches in the repository:
111 The branches that begin with "origin" correspond to the "git remote"
112 that you cloned from (which is named "origin"). Each branch on the
113 remote will be exactly tracked by theses branches. You should NEVER do
114 work on these remote tracking branches. You only ever do work in a
115 local branch. Local branches can be configured to automerge (on pull)
116 from a designated remote tracking branch. This is the case with the
117 default branch C<blead> which will be configured to merge from the
118 remote tracking branch C<origin/blead>.
120 You can see recent commits:
124 And pull new changes from the repository, and update your local
125 repository (must be clean first)
129 Assuming we are on the branch C<blead> immediately after a pull, this
130 command would be more or less equivalent to:
133 % git merge origin/blead
135 In fact if you want to update your local repository without touching
136 your working directory you do:
140 And if you want to update your remote-tracking branches for all defined
141 remotes simultaneously you can do
145 Neither of these last two commands will update your working directory,
146 however both will update the remote-tracking branches in your
149 To switch to another branch:
151 % git checkout origin/maint-5.8-dor
153 To make a local branch of a remote branch:
155 % git checkout -b maint-5.10 origin/maint-5.10
157 To switch back to blead:
161 =head2 FINDING OUT YOUR STATUS
163 The most common git command you will use will probably be
167 This command will produce as output a description of the current state
168 of the repository, including modified files and unignored untracked
169 files, and in addition it will show things like what files have been
170 staged for the next commit, and usually some useful information about
171 how to change things. For instance the following:
175 # Your branch is ahead of 'origin/blead' by 1 commit.
177 # Changes to be committed:
178 # (use "git reset HEAD <file>..." to unstage)
180 # modified: pod/perlrepository.pod
182 # Changed but not updated:
183 # (use "git add <file>..." to update what will be committed)
185 # modified: pod/perlrepository.pod
188 # (use "git add <file>..." to include in what will be committed)
190 # deliberate.untracked
192 This shows that there were changes to this document staged for commit,
193 and that there were further changes in the working directory not yet
194 staged. It also shows that there was an untracked file in the working
195 directory, and as you can see shows how to change all of this. It also
196 shows that there is one commit on the working branch C<blead> which
197 has not been pushed to the C<origin> remote yet. B<NOTE>: that this
198 output is also what you see as a template if you do not provide a
199 message to C<git commit>.
201 Assuming we commit all the mentioned changes above:
203 % git commit -a -m'explain git status and stuff about remotes'
204 Created commit daf8e63: explain git status and stuff about remotes
205 1 files changed, 83 insertions(+), 3 deletions(-)
207 We can re-run git status and see something like this:
211 # Your branch is ahead of 'origin/blead' by 2 commits.
214 # (use "git add <file>..." to include in what will be committed)
216 # deliberate.untracked
217 nothing added to commit but untracked files present (use "git add" to track)
220 When in doubt, before you do anything else, check your status and read
221 it carefully, many questions are answered directly by the git status
224 =head1 SUBMITTING A PATCH
226 If you have a patch in mind for Perl, you should first get a copy of
229 % git clone git://perl5.git.perl.org/perl.git perl-git
231 Then change into the directory:
235 Alternatively, if you already have a Perl repository, you should ensure
236 that you're on the I<blead> branch, and your repository is up to date:
241 Now that we have everything up to date, we need to create a temporary
242 new branch for these changes and switch into it:
244 % git checkout -b orange
246 which is the short form of
249 % git checkout orange
251 Then make your changes. For example, if Leon Brocard changes his name
252 to Orange Brocard, we should change his name in the AUTHORS file:
254 % perl -pi -e 's{Leon Brocard}{Orange Brocard}' AUTHORS
256 You can see what files are changed:
260 # Changes to be committed:
261 # (use "git reset HEAD <file>..." to unstage)
266 And you can see the changes:
269 diff --git a/AUTHORS b/AUTHORS
270 index 293dd70..722c93e 100644
273 @@ -541,7 +541,7 @@ Lars Hecking <lhecking@nmrc.ucc.ie>
274 Laszlo Molnar <laszlo.molnar@eth.ericsson.se>
275 Leif Huhn <leif@hale.dkstat.com>
276 Len Johnson <lenjay@ibm.net>
277 -Leon Brocard <acme@astray.com>
278 +Orange Brocard <acme@astray.com>
279 Les Peters <lpeters@aol.net>
280 Lesley Binks <lesley.binks@gmail.com>
281 Lincoln D. Stein <lstein@cshl.org>
283 Now commit your change locally:
286 % git commit -m 'Rename Leon Brocard to Orange Brocard'
287 Created commit 6196c1d: Rename Leon Brocard to Orange Brocard
288 1 files changed, 1 insertions(+), 1 deletions(-)
290 Now you should create a patch file for all your local changes:
292 % git format-patch origin
293 0001-Rename-Leon-Brocard-to-Orange-Brocard.patch
295 You should now send an email to perl5-porters@perl.org with a
296 description of your changes, and attach this patch file as an
299 If you want to delete your temporary branch, you may do so with:
302 % git branch -d orange
303 error: The branch 'orange' is not an ancestor of your current HEAD.
304 If you are sure you want to delete it, run 'git branch -D orange'.
305 % git branch -D orange
306 Deleted branch orange.
308 =head1 ACCEPTING A PATCH
310 If you have received a patch file generated using the above section,
311 you should try out the patch.
313 First we need to create a temporary new branch for these changes and
316 % git checkout -b experimental
318 Patches that were formatted by C<git format-patch> are applied with
321 % git am 0001-Rename-Leon-Brocard-to-Orange-Brocard.patch
322 Applying Rename Leon Brocard to Orange Brocard
324 If just a raw diff is provided, it is also possible use this two-step
327 % git apply bugfix.diff
328 % git commit -am "Some fixing" --author="That Guy <that.guy@internets.com>"
330 Now we can inspect the change:
333 commit b1b3dab48344cff6de4087efca3dbd63548ab5e2
334 Author: Leon Brocard <acme@astray.com>
335 Date: Fri Dec 19 17:02:59 2008 +0000
337 Rename Leon Brocard to Orange Brocard
341 diff --git a/AUTHORS b/AUTHORS
342 index 293dd70..722c93e 100644
345 @@ -541,7 +541,7 @@ Lars Hecking <lhecking@nmrc.ucc.ie>
346 Laszlo Molnar <laszlo.molnar@eth.ericsson.se>
347 Leif Huhn <leif@hale.dkstat.com>
348 Len Johnson <lenjay@ibm.net>
349 -Leon Brocard <acme@astray.com>
350 +Orange Brocard <acme@astray.com>
351 Les Peters <lpeters@aol.net>
352 Lesley Binks <lesley.binks@gmail.com>
353 Lincoln D. Stein <lstein@cshl.org>
355 If you are a committer to Perl and you think the patch is good, you can
356 then merge it into blead then push it out to the main repository:
359 % git merge experimental
362 If you want to delete your temporary branch, you may do so with:
365 % git branch -d experimental
366 error: The branch 'experimental' is not an ancestor of your current HEAD.
367 If you are sure you want to delete it, run 'git branch -D experimental'.
368 % git branch -D experimental
369 Deleted branch experimental.
371 =head1 CLEANING A WORKING DIRECTORY
373 The command C<git clean> can with varying arguments be used as a
374 replacement for make-clean.
376 To reset your working directory to a pristine condition you can do:
380 However, be aware this will delete ALL untracked content. You can use
384 to remove all ignored untracked files, such as build and test
385 byproduct, but leave any manually created files alone.
387 If you only want to cancel some uncommitted edits, you can use
388 C<git checkout> and give it a list of files to be reverted.
390 If you want to cancel one or several commits, you can use C<git reset>.
394 C<git> provides a built-in way to determine, with a binary search in
395 the history, which commit should be blamed for introducing a given bug.
397 Suppose that we have a script F<~/testcase.pl> that exits with C<0>
398 when some behaviour is correct, and with C<1> when it's faulty. We need
399 an helper script that automates building C<perl> and running the
405 # If you can use ccache, add -Dcc=ccache\ gcc -Dld=gcc to the Configure line
406 sh Configure -des -Dusedevel -Doptimize="-g" || exit 125
408 ./perl -Ilib ~/testcase.pl
410 This script may return C<125> to indicate that the corresponding commit
411 should be skipped. Otherwise, it returns the status of
414 We first enter in bisect mode with:
418 For example, if the bug is present on C<HEAD> but wasn't in 5.10.0,
419 C<git> will learn about this when you enter:
422 % git bisect good perl-5.10.0
423 Bisecting: 853 revisions left to test after this
425 This results in checking out the median commit between C<HEAD> and
426 C<perl-5.10.0>. We can then run the bisecting process with:
428 % git bisect run ~/run
430 When the first bad commit is isolated, C<git bisect> will tell you so:
432 ca4cfd28534303b82a216cfe83a1c80cbc3b9dc5 is first bad commit
433 commit ca4cfd28534303b82a216cfe83a1c80cbc3b9dc5
434 Author: Dave Mitchell <davem@fdisolutions.com>
435 Date: Sat Feb 9 14:56:23 2008 +0000
437 [perl #49472] Attributes + Unkown Error
442 You can peek into the bisecting process with C<git bisect log> and
443 C<git bisect visualize>. C<git bisect reset> will get you out of bisect
446 Please note that the first C<good> state must be an ancestor of the
447 first C<bad> state. If you want to search for the commit that I<solved>
448 some bug, you have to negate your test case (i.e. exit with C<1> if OK
449 and C<0> if not) and still mark the lower bound as C<good> and the
450 upper as C<bad>. The "first bad commit" has then to be understood as
451 the "first commit where the bug is solved".
453 C<git help bisect> has much more information on how you can tweak your
456 =head1 COMITTING TO MAINTENANCE VERSIONS
458 To commit to a maintenance version of perl, you need to create a local
461 % git checkout --track -b maint-5.005 origin/maint-5.005
463 This creates a local branch named C<maint-5.005>, which tracks the remote
464 branch C<origin/maint-5.005>. Then you can pull, commit, merge and push as
467 You can also cherry-pick commits from blead and another branch, by
468 using the C<git cherry-pick> command. It is recommended to use the B<-x>
469 option to C<git cherry-pick> in order to record the SHA1 of the original
470 commit in the new commit message.
474 The git documentation, accessible via C<git help command>.