This is a live mirror of the Perl 5 development currently hosted at https://github.com/perl/perl5
Note that checking out from git via http:// is at least 4x slower than git://
[perl5.git] / pod / perlrepository.pod
CommitLineData
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1=for comment
2Consistent formatting of this file is achieved with:
3 perl ./Porting/podtidy pod/perlrepository.pod
4
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5=head1 NAME
6
7perlrepository - Using the Perl source repository
8
9=head1 SYNOPSIS
10
dc3c3040 11All of Perl's source code is kept centrally in a Git repository at
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12I<perl5.git.perl.org>. The repository contains many Perl revisions from
13Perl 1 onwards and all the revisions from Perforce, the version control
14system we were using previously. This repository is accessible in
15different ways.
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16
17The full repository takes up about 80MB of disk space. A check out of
7f4ffa9d 18the blead branch (that is, the main development branch, which contains
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19bleadperl, the development version of perl 5) takes up about 160MB of
20disk space (including the repository). A build of bleadperl takes up
21about 200MB (including the repository and the check out).
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22
23=head1 GETTING ACCESS TO THE REPOSITORY
24
25=head2 READ ACCESS VIA THE WEB
26
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27You may access the repository over the web. This allows you to browse
28the tree, see recent commits, subscribe to RSS feeds for the changes,
29search for particular commits and more. You may access it at:
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30
31 http://perl5.git.perl.org/perl.git
32
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33A mirror of the repository is found at:
34
35 http://github.com/github/perl
36
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37=head2 READ ACCESS VIA GIT
38
39You will need a copy of Git for your computer. You can fetch a copy of
40the repository using the Git protocol (which uses port 9418):
41
3b8a5fb0 42 git clone git://perl5.git.perl.org/perl.git perl-git
d7dd28b6 43
f755e97d 44This clones the repository and makes a local copy in the F<perl-git>
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45directory.
46
47If your local network does not allow you to use port 9418, then you can
cf5e7595 48fetch a copy of the repository over HTTP (this is at least 4x slower):
d7dd28b6 49
3b8a5fb0 50 git clone http://perl5.git.perl.org/perl.git perl-http
d7dd28b6 51
f755e97d 52This clones the repository and makes a local copy in the F<perl-http>
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53directory.
54
55=head2 WRITE ACCESS TO THE REPOSITORY
56
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57If you are a committer, then you can fetch a copy of the repository
58that you can push back on with:
d7dd28b6 59
3482f01a 60 git clone ssh://perl5.git.perl.org/perl.git perl-ssh
d7dd28b6 61
8f718e95 62This clones the repository and makes a local copy in the F<perl-ssh>
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63directory.
64
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65If you cloned using the git protocol, which is faster than ssh, then
66you will need to modify your config in order to enable pushing. Edit
67F<.git/config> where you will see something like:
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68
69 [remote "origin"]
70 url = git://perl5.git.perl.org/perl.git
71
72change that to something like this:
73
74 [remote "origin"]
3482f01a 75 url = ssh://perl5.git.perl.org/perl.git
d7dd28b6 76
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77You can also set up your user name and e-mail address. For example
78
79 % git config user.name "Leon Brocard"
80 % git config user.email acme@astray.com
81
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82It is also possible to keep C<origin> as a git remote, and add a new
83remote for ssh access:
f6c12373 84
dc3c3040 85 % git remote add camel perl5.git.perl.org:/perl.git
f6c12373 86
6acba58e 87This allows you to update your local repository by pulling from
f755e97d 88C<origin>, which is faster and doesn't require you to authenticate, and
6acba58e 89to push your changes back with the C<camel> remote:
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90
91 % git fetch camel
92 % git push camel
93
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94The C<fetch> command just updates the C<camel> refs, as the objects
95themselves should have been fetched when pulling from C<origin>.
f6c12373 96
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97=head2 A NOTE ON CAMEL AND DROMEDARY
98
99The committers have SSH access to the two servers that serve
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100C<perl5.git.perl.org>. One is C<perl5.git.perl.org> itself (I<camel>),
101which is the 'master' repository. The second one is
102C<users.perl5.git.perl.org> (I<dromedary>), which can be used for
103general testing and development. Dromedary syncs the git tree from
104camel every few minutes, you should not push there. Both machines also
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105have a full CPAN mirror in /srv/CPAN, please use this. To share files
106with the general public, dromedary serves your ~/public_html/ as
333f8875 107C<http://users.perl5.git.perl.org/~yourlogin/>
b47aa495 108
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109These hosts have fairly strict firewalls to the outside. Outgoing, only
110rsync, ssh and git are allowed. For http and ftp, you can use
111http://webproxy:3128 as proxy. Incoming, the firewall tries to detect
112attacks and blocks IP addresses with suspicious activity. This
113sometimes (but very rarely) has false positives and you might get
114blocked. The quickest way to get unblocked is to notify the admins.
115
116These two boxes are owned, hosted, and operated by booking.com. You can
117reach the sysadmins in #p5p on irc.perl.org or via mail to
118C<perl5-porters@perl.org>
119
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120=head1 OVERVIEW OF THE REPOSITORY
121
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122Once you have changed into the repository directory, you can inspect
123it.
d7dd28b6 124
39219fd3 125After a clone the repository will contain a single local branch, which
50eca761 126will be the current branch as well, as indicated by the asterisk.
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127
128 % git branch
129 * blead
130
f755e97d 131Using the -a switch to C<branch> will also show the remote tracking
6acba58e 132branches in the repository:
39219fd3 133
d9847473 134 % git branch -a
09081495 135 * blead
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136 origin/HEAD
137 origin/blead
138 ...
139
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140The branches that begin with "origin" correspond to the "git remote"
141that you cloned from (which is named "origin"). Each branch on the
142remote will be exactly tracked by theses branches. You should NEVER do
143work on these remote tracking branches. You only ever do work in a
144local branch. Local branches can be configured to automerge (on pull)
145from a designated remote tracking branch. This is the case with the
146default branch C<blead> which will be configured to merge from the
147remote tracking branch C<origin/blead>.
39219fd3 148
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149You can see recent commits:
150
c2cf2042 151 % git log
d7dd28b6 152
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153And pull new changes from the repository, and update your local
154repository (must be clean first)
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155
156 % git pull
09081495 157
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158Assuming we are on the branch C<blead> immediately after a pull, this
159command would be more or less equivalent to:
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160
161 % git fetch
162 % git merge origin/blead
163
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164In fact if you want to update your local repository without touching
165your working directory you do:
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166
167 % git fetch
168
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169And if you want to update your remote-tracking branches for all defined
170remotes simultaneously you can do
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171
172 % git remote update
173
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174Neither of these last two commands will update your working directory,
175however both will update the remote-tracking branches in your
176repository.
39219fd3 177
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178To switch to another branch:
179
180 % git checkout origin/maint-5.8-dor
181
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182To make a local branch of a remote branch:
183
184 % git checkout -b maint-5.10 origin/maint-5.10
185
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186To switch back to blead:
187
188 % git checkout blead
c2cf2042 189
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190=head2 FINDING OUT YOUR STATUS
191
192The most common git command you will use will probably be
193
194 % git status
195
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196This command will produce as output a description of the current state
197of the repository, including modified files and unignored untracked
198files, and in addition it will show things like what files have been
199staged for the next commit, and usually some useful information about
200how to change things. For instance the following:
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201
202 $ git status
203 # On branch blead
204 # Your branch is ahead of 'origin/blead' by 1 commit.
205 #
206 # Changes to be committed:
207 # (use "git reset HEAD <file>..." to unstage)
208 #
209 # modified: pod/perlrepository.pod
210 #
211 # Changed but not updated:
212 # (use "git add <file>..." to update what will be committed)
213 #
214 # modified: pod/perlrepository.pod
215 #
216 # Untracked files:
217 # (use "git add <file>..." to include in what will be committed)
218 #
219 # deliberate.untracked
220
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221This shows that there were changes to this document staged for commit,
222and that there were further changes in the working directory not yet
223staged. It also shows that there was an untracked file in the working
224directory, and as you can see shows how to change all of this. It also
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225shows that there is one commit on the working branch C<blead> which has
226not been pushed to the C<origin> remote yet. B<NOTE>: that this output
227is also what you see as a template if you do not provide a message to
228C<git commit>.
7f6effc7 229
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230Assuming that you'd like to commit all the changes you've just made as a
231a single atomic unit, run this command:
232
233 % git commit -a
234
235(That C<-a> tells git to add every file you've changed to this commit.
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236New files aren't automatically added to your commit when you use C<commit
237-a> If you want to add files or to commit some, but not all of your
238changes, have a look at the documentation for C<git add>.)
bdaf0bc6 239
e9360695 240Git will start up your favorite text editor, so that you can craft a
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241commit message for your change. See L</Commit message> below for more
242information about what makes a good commit message.
243
244Once you've finished writing your commit message and exited your editor,
245git will write your change to disk and tell you something like this:
7f6effc7 246
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247 Created commit daf8e63: explain git status and stuff about remotes
248 1 files changed, 83 insertions(+), 3 deletions(-)
249
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250
251If you re-run C<git status>, you should see something like this:
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252
253 % git status
254 # On branch blead
255 # Your branch is ahead of 'origin/blead' by 2 commits.
256 #
257 # Untracked files:
258 # (use "git add <file>..." to include in what will be committed)
259 #
260 # deliberate.untracked
261 nothing added to commit but untracked files present (use "git add" to track)
262
39219fd3 263
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264When in doubt, before you do anything else, check your status and read
265it carefully, many questions are answered directly by the git status
266output.
39219fd3 267
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268=head1 SUBMITTING A PATCH
269
270If you have a patch in mind for Perl, you should first get a copy of
271the repository:
272
273 % git clone git://perl5.git.perl.org/perl.git perl-git
274
275Then change into the directory:
276
277 % cd perl-git
278
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279Alternatively, if you already have a Perl repository, you should ensure
280that you're on the I<blead> branch, and your repository is up to date:
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281
282 % git checkout blead
283 % git pull
284
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285It's preferable to patch against the latest blead version, since this
286is where new development occurs for all changes other than critical bug
287fixes. Critical bug fix patches should be made against the relevant
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288maint branches, or should be submitted with a note indicating all the
289branches where the fix should be applied.
a44f43ac 290
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291Now that we have everything up to date, we need to create a temporary
292new branch for these changes and switch into it:
b1fccde5 293
a9b05323 294 % git checkout -b orange
23f8d33e 295
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296which is the short form of
297
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298 % git branch orange
299 % git checkout orange
300
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301Then make your changes. For example, if Leon Brocard changes his name
302to Orange Brocard, we should change his name in the AUTHORS file:
303
304 % perl -pi -e 's{Leon Brocard}{Orange Brocard}' AUTHORS
305
306You can see what files are changed:
307
308 % git status
f755e97d 309 # On branch orange
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310 # Changes to be committed:
311 # (use "git reset HEAD <file>..." to unstage)
312 #
2699d634 313 # modified: AUTHORS
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314 #
315
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316And you can see the changes:
317
318 % git diff
319 diff --git a/AUTHORS b/AUTHORS
320 index 293dd70..722c93e 100644
321 --- a/AUTHORS
322 +++ b/AUTHORS
7df2e4bc 323 @@ -541,7 +541,7 @@ Lars Hecking <lhecking@nmrc.ucc.ie>
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324 Laszlo Molnar <laszlo.molnar@eth.ericsson.se>
325 Leif Huhn <leif@hale.dkstat.com>
326 Len Johnson <lenjay@ibm.net>
327 -Leon Brocard <acme@astray.com>
328 +Orange Brocard <acme@astray.com>
329 Les Peters <lpeters@aol.net>
330 Lesley Binks <lesley.binks@gmail.com>
331 Lincoln D. Stein <lstein@cshl.org>
332
333Now commit your change locally:
334
dc3c3040 335 % git commit -a -m 'Rename Leon Brocard to Orange Brocard'
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336 Created commit 6196c1d: Rename Leon Brocard to Orange Brocard
337 1 files changed, 1 insertions(+), 1 deletions(-)
338
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339You can examine your last commit with:
340
341 % git show HEAD
342
343and if you are not happy with either the description or the patch
c26da522 344itself you can fix it up by editing the files once more and then issue:
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345
346 % git commit -a --amend
347
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348Now you should create a patch file for all your local changes:
349
2af192ee 350 % git format-patch origin
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351 0001-Rename-Leon-Brocard-to-Orange-Brocard.patch
352
353You should now send an email to perl5-porters@perl.org with a
dc3c3040 354description of your changes, and include this patch file as an
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355attachment. (See the next section for how to configure and use git to
356send these emails for you.)
c2cf2042 357
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358If you want to delete your temporary branch, you may do so with:
359
360 % git checkout blead
361 % git branch -d orange
362 error: The branch 'orange' is not an ancestor of your current HEAD.
363 If you are sure you want to delete it, run 'git branch -D orange'.
364 % git branch -D orange
365 Deleted branch orange.
7df2e4bc 366
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367=head2 Using git to send patch emails
368
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369In your ~/git/perl repository, set the destination email to the
370perl5-porters mailing list.
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371
372 $ git config sendemail.to perl5-porters@perl.org
373
374Then you can use git directly to send your patch emails:
375
376 $ git send-email 0001-Rename-Leon-Brocard-to-Orange-Brocard.patch
377
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378You may need to set some configuration variables for your particular
379email service provider. For example, to set your global git config to
380send email via a gmail account:
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381
382 $ git config --global sendemail.smtpserver smtp.gmail.com
383 $ git config --global sendemail.smtpssl 1
384 $ git config --global sendemail.smtpuser YOURUSERNAME@gmail.com
385
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386With this configuration, you will be prompted for your gmail password
387when you run 'git send-email'. You can also configure
388C<sendemail.smtppass> with your password if you don't care about having
389your password in the .gitconfig file.
2d5f1d01 390
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391=head2 A note on derived files
392
393Be aware that many files in the distribution are derivative--avoid
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394patching them, because git won't see the changes to them, and the build
395process will overwrite them. Patch the originals instead. Most
396utilities (like perldoc) are in this category, i.e. patch
397utils/perldoc.PL rather than utils/perldoc. Similarly, don't create
398patches for files under $src_root/ext from their copies found in
399$install_root/lib. If you are unsure about the proper location of a
400file that may have gotten copied while building the source
401distribution, consult the C<MANIFEST>.
a44f43ac 402
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403As a special case, several files are regenerated by 'make regen' if
404your patch alters C<embed.fnc>. These are needed for compilation, but
405are included in the distribution so that you can build perl without
406needing another perl to generate the files. You must test with these
407regenerated files, but it is preferred that you instead note that
408'make regen is needed' in both the email and the commit message, and
409submit your patch without them. If you're submitting a series of
410patches, it might be best to submit the regenerated changes
411immediately after the source-changes that caused them, so as to have
412as little effect as possible on the bisectability of your patchset.
413
6e2cec71 414=for XXX
a44f43ac 415
6e2cec71 416What should we recommend about binary files now? Do we need anything?
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417
418=head2 Getting your patch accepted
419
bdaf0bc6 420If you are submitting a code patch there are several things that
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421you need to do.
422
423=over 4
424
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425=item Commit message
426
427As you craft each patch you intend to submit to the Perl core, it's
428important to write a good commit message.
429
430Your commit message should start with a description of the problem that
431the patch corrects or new functionality that the patch adds.
432
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433As a general rule of thumb, your commit message should let a programmer
434with a reasonable familiarity with the Perl core quickly understand what
435you were trying to do, how you were trying to do it and why the change
436matters to Perl.
437
438=over 4
439
440=item What
441
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442Your commit message should describe what part of the Perl core you're
443changing and what you expect your patch to do.
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444
445=item Why
446
447Perhaps most importantly, your commit message should describe why the
448change you are making is important. When someone looks at your change
449in six months or six years, your intent should be clear. If you're
450deprecating a feature with the intent of later simplifying another bit
451of code, say so. If you're fixing a performance problem or adding a new
452feature to support some other bit of the core, mention that.
453
454=item How
455
456While it's not necessary for documentation changes, new tests or
457trivial patches, it's often worth explaining how your change works.
458Even if it's clear to you today, it may not be clear to a porter next
459month or next year.
460
461=back
462
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463A commit message isn't intended to take the place of comments in your
464code. Commit messages should describe the change you made, while code
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465comments should describe the current state of the code. If you've just
466implemented a new feature, complete with doc, tests and well-commented
467code, a brief commit message will often suffice. If, however, you've
468just changed a single character deep in the parser or lexer, you might
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469need to write a small novel to ensure that future readers understand
470what you did and why you did it.
471
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472=item Comments, Comments, Comments
473
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474Be sure to adequately comment your code. While commenting every line
475is unnecessary, anything that takes advantage of side effects of
a44f43ac 476operators, that creates changes that will be felt outside of the
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477function being patched, or that others may find confusing should be
478documented. If you are going to err, it is better to err on the side
479of adding too many comments than too few.
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480
481=item Style
482
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483In general, please follow the particular style of the code you are
484patching.
a44f43ac 485
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486In particular, follow these general guidelines for patching Perl
487sources:
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488
489 8-wide tabs (no exceptions!)
490 4-wide indents for code, 2-wide indents for nested CPP #defines
491 try hard not to exceed 79-columns
492 ANSI C prototypes
493 uncuddled elses and "K&R" style for indenting control constructs
494 no C++ style (//) comments
495 mark places that need to be revisited with XXX (and revisit often!)
496 opening brace lines up with "if" when conditional spans multiple
497 lines; should be at end-of-line otherwise
498 in function definitions, name starts in column 0 (return value is on
499 previous line)
500 single space after keywords that are followed by parens, no space
501 between function name and following paren
502 avoid assignments in conditionals, but if they're unavoidable, use
503 extra paren, e.g. "if (a && (b = c)) ..."
504 "return foo;" rather than "return(foo);"
505 "if (!foo) ..." rather than "if (foo == FALSE) ..." etc.
506
507=item Testsuite
508
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509If your patch changes code (rather than just changing documentation) you
510should also include one or more test cases which illustrate the bug you're
511fixing or validate the new functionality you're adding. In general,
512you should update an existing test file rather than create a new one.
513
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514Your testsuite additions should generally follow these guidelines
515(courtesy of Gurusamy Sarathy <gsar@activestate.com>):
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516
517 Know what you're testing. Read the docs, and the source.
518 Tend to fail, not succeed.
519 Interpret results strictly.
520 Use unrelated features (this will flush out bizarre interactions).
521 Use non-standard idioms (otherwise you are not testing TIMTOWTDI).
522 Avoid using hardcoded test numbers whenever possible (the
523 EXPECTED/GOT found in t/op/tie.t is much more maintainable,
524 and gives better failure reports).
525 Give meaningful error messages when a test fails.
526 Avoid using qx// and system() unless you are testing for them. If you
527 do use them, make sure that you cover _all_ perl platforms.
528 Unlink any temporary files you create.
529 Promote unforeseen warnings to errors with $SIG{__WARN__}.
530 Be sure to use the libraries and modules shipped with the version
531 being tested, not those that were already installed.
532 Add comments to the code explaining what you are testing for.
533 Make updating the '1..42' string unnecessary. Or make sure that
534 you update it.
535 Test _all_ behaviors of a given operator, library, or function:
536 - All optional arguments
537 - Return values in various contexts (boolean, scalar, list, lvalue)
538 - Use both global and lexical variables
539 - Don't forget the exceptional, pathological cases.
540
541=back
542
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543=head1 ACCEPTING A PATCH
544
545If you have received a patch file generated using the above section,
546you should try out the patch.
547
548First we need to create a temporary new branch for these changes and
549switch into it:
550
a9b05323 551 % git checkout -b experimental
7df2e4bc 552
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553Patches that were formatted by C<git format-patch> are applied with
554C<git am>:
7df2e4bc 555
2af192ee 556 % git am 0001-Rename-Leon-Brocard-to-Orange-Brocard.patch
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557 Applying Rename Leon Brocard to Orange Brocard
558
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559If just a raw diff is provided, it is also possible use this two-step
560process:
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561
562 % git apply bugfix.diff
dc3c3040 563 % git commit -a -m "Some fixing" --author="That Guy <that.guy@internets.com>"
09645c26 564
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565Now we can inspect the change:
566
dc3c3040 567 % git show HEAD
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568 commit b1b3dab48344cff6de4087efca3dbd63548ab5e2
569 Author: Leon Brocard <acme@astray.com>
570 Date: Fri Dec 19 17:02:59 2008 +0000
571
572 Rename Leon Brocard to Orange Brocard
7df2e4bc 573
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574 diff --git a/AUTHORS b/AUTHORS
575 index 293dd70..722c93e 100644
576 --- a/AUTHORS
577 +++ b/AUTHORS
578 @@ -541,7 +541,7 @@ Lars Hecking <lhecking@nmrc.ucc.ie>
579 Laszlo Molnar <laszlo.molnar@eth.ericsson.se>
580 Leif Huhn <leif@hale.dkstat.com>
581 Len Johnson <lenjay@ibm.net>
582 -Leon Brocard <acme@astray.com>
583 +Orange Brocard <acme@astray.com>
584 Les Peters <lpeters@aol.net>
585 Lesley Binks <lesley.binks@gmail.com>
586 Lincoln D. Stein <lstein@cshl.org>
587
588If you are a committer to Perl and you think the patch is good, you can
75fb7651 589then merge it into blead then push it out to the main repository:
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590
591 % git checkout blead
d9847473 592 % git merge experimental
75fb7651 593 % git push
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594
595If you want to delete your temporary branch, you may do so with:
596
597 % git checkout blead
598 % git branch -d experimental
599 error: The branch 'experimental' is not an ancestor of your current HEAD.
600 If you are sure you want to delete it, run 'git branch -D experimental'.
601 % git branch -D experimental
602 Deleted branch experimental.
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603
604=head1 CLEANING A WORKING DIRECTORY
605
6acba58e 606The command C<git clean> can with varying arguments be used as a
dc3c3040 607replacement for C<make clean>.
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608
609To reset your working directory to a pristine condition you can do:
610
611 git clean -dxf
612
613However, be aware this will delete ALL untracked content. You can use
614
615 git clean -Xf
616
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617to remove all ignored untracked files, such as build and test
618byproduct, but leave any manually created files alone.
b0d36535 619
0549aefb 620If you only want to cancel some uncommitted edits, you can use C<git
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621checkout> and give it a list of files to be reverted, or C<git checkout
622-f> to revert them all.
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623
624If you want to cancel one or several commits, you can use C<git reset>.
625
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626=head1 BISECTING
627
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628C<git> provides a built-in way to determine, with a binary search in
629the history, which commit should be blamed for introducing a given bug.
d82a90c1 630
6acba58e 631Suppose that we have a script F<~/testcase.pl> that exits with C<0>
bdaf0bc6 632when some behaviour is correct, and with C<1> when it's faulty. You need
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633an helper script that automates building C<perl> and running the
634testcase:
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635
636 % cat ~/run
637 #!/bin/sh
638 git clean -dxf
639 # If you can use ccache, add -Dcc=ccache\ gcc -Dld=gcc to the Configure line
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640 # if Encode is not needed for the test, you can speed up the bisect by
641 # excluding it from the runs with -Dnoextensions=Encode
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642 sh Configure -des -Dusedevel -Doptimize="-g"
643 test -f config.sh || exit 125
644 # Correct makefile for newer GNU gcc
645 perl -ni -we 'print unless /<(?:built-in|command)/' makefile x2p/makefile
646 # if you just need miniperl, replace test_prep with miniperl
647 make -j4 test_prep
68814ba4 648 [ -x ./perl ] || exit 125
d82a90c1 649 ./perl -Ilib ~/testcase.pl
c0d1ef72 650 ret=$?
7930c68b 651 [ $ret -gt 127 ] && ret=127
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652 git clean -dxf
653 exit $ret
d82a90c1 654
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655This script may return C<125> to indicate that the corresponding commit
656should be skipped. Otherwise, it returns the status of
657F<~/testcase.pl>.
d82a90c1 658
bdaf0bc6 659You first enter in bisect mode with:
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660
661 % git bisect start
662
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663For example, if the bug is present on C<HEAD> but wasn't in 5.10.0,
664C<git> will learn about this when you enter:
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665
666 % git bisect bad
667 % git bisect good perl-5.10.0
668 Bisecting: 853 revisions left to test after this
669
6acba58e 670This results in checking out the median commit between C<HEAD> and
bdaf0bc6 671C<perl-5.10.0>. You can then run the bisecting process with:
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672
673 % git bisect run ~/run
674
675When the first bad commit is isolated, C<git bisect> will tell you so:
676
677 ca4cfd28534303b82a216cfe83a1c80cbc3b9dc5 is first bad commit
678 commit ca4cfd28534303b82a216cfe83a1c80cbc3b9dc5
679 Author: Dave Mitchell <davem@fdisolutions.com>
680 Date: Sat Feb 9 14:56:23 2008 +0000
681
9469eb4a 682 [perl #49472] Attributes + Unknown Error
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683 ...
684
685 bisect run success
686
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687You can peek into the bisecting process with C<git bisect log> and
688C<git bisect visualize>. C<git bisect reset> will get you out of bisect
689mode.
d82a90c1 690
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691Please note that the first C<good> state must be an ancestor of the
692first C<bad> state. If you want to search for the commit that I<solved>
693some bug, you have to negate your test case (i.e. exit with C<1> if OK
694and C<0> if not) and still mark the lower bound as C<good> and the
695upper as C<bad>. The "first bad commit" has then to be understood as
696the "first commit where the bug is solved".
d82a90c1 697
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698C<git help bisect> has much more information on how you can tweak your
699binary searches.
9d68b7ed 700
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701=head1 SUBMITTING A PATCH VIA GITHUB
702
703GitHub is a website that makes it easy to fork and publish projects
704with Git. First you should set up a GitHub account and log in.
705
706Perl's git repository is mirrored on GitHub at this page:
707
708 http://github.com/github/perl/tree/blead
709
710Visit the page and click the "fork" button. This clones the Perl git
711repository for you and provides you with "Your Clone URL" from which
712you should clone:
713
714 % git clone git@github.com:USERNAME/perl.git perl-github
715
bdaf0bc6 716The same patch as above, using github might look like this:
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717
718 % cd perl-github
719 % git remote add upstream git://github.com/github/perl.git
720 % git pull upstream blead
721 % git checkout -b orange
722 % perl -pi -e 's{Leon Brocard}{Orange Brocard}' AUTHORS
dc3c3040 723 % git commit -a -m 'Rename Leon Brocard to Orange Brocard'
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724 % git push origin orange
725
726The orange branch has been pushed to GitHub, so you should now send an
727email to perl5-porters@perl.org with a description of your changes and
728the following information:
729
730 http://github.com/USERNAME/perl/tree/orange
731 git@github.com:USERNAME/perl.git branch orange
732
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733=head1 MERGING FROM A BRANCH VIA GITHUB
734
735If someone has provided a branch via GitHub and you are a committer,
5c9c28c6 736you should use the following in your perl-ssh directory:
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737
738 % git remote add dandv git://github.com/dandv/perl.git
739 % git fetch
740
741Now you can see the differences between the branch and blead:
742
743 % git diff dandv/blead
744
745And you can see the commits:
746
747 % git log dandv/blead
748
749If you approve of a specific commit, you can cherry pick it:
750
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751 % git cherry-pick 3adac458cb1c1d41af47fc66e67b49c8dec2323f
752
753Or you could just merge the whole branch if you like it all:
754
755 % git merge dandv/blead
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756
757And then push back to the repository:
758
759 % git push
760
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761
762=head1 TOPIC BRANCHES AND REWRITING HISTORY
763
764Individual committers should create topic branches under
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765B<yourname>/B<some_descriptive_name>. Other committers should check
766with a topic branch's creator before making any change to it.
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767
768If you are not the creator of B<yourname>/B<some_descriptive_name>, you
769might sometimes find that the original author has edited the branch's
770history. There are lots of good reasons for this. Sometimes, an author
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771might simply be rebasing the branch onto a newer source point.
772Sometimes, an author might have found an error in an early commit which
773they wanted to fix before merging the branch to blead.
ce2a8773 774
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775Currently the master repository is configured to forbid
776non-fast-forward merges. This means that the branches within can not
777be rebased and pushed as a single step.
ce2a8773 778
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779The only way you will ever be allowed to rebase or modify the history
780of a pushed branch is to delete it and push it as a new branch under
781the same name. Please think carefully about doing this. It may be
782better to sequentially rename your branches so that it is easier for
783others working with you to cherry-pick their local changes onto the new
784version. (XXX: needs explanation).
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785
786If you want to rebase a personal topic branch, you will have to delete
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787your existing topic branch and push as a new version of it. You can do
788this via the following formula (see the explanation about C<refspec>'s
789in the git push documentation for details) after you have rebased your
790branch:
791
792 # first rebase
793 $ git checkout $user/$topic
794 $ git fetch
795 $ git rebase origin/blead
796
797 # then "delete-and-push"
798 $ git push origin :$user/$topic
799 $ git push origin $user/$topic
800
801B<NOTE:> it is forbidden at the repository level to delete any of the
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802"primary" branches. That is any branch matching
803C<m!^(blead|maint|perl)!>. Any attempt to do so will result in git
804producing an error like this:
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805
806 $ git push origin :blead
807 *** It is forbidden to delete blead/maint branches in this repository
808 error: hooks/update exited with error code 1
809 error: hook declined to update refs/heads/blead
333f8875 810 To ssh://perl5.git.perl.org/perl
2699d634 811 ! [remote rejected] blead (hook declined)
333f8875 812 error: failed to push some refs to 'ssh://perl5.git.perl.org/perl'
2699d634 813
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814As a matter of policy we do B<not> edit the history of the blead and
815maint-* branches. If a typo (or worse) sneaks into a commit to blead or
816maint-*, we'll fix it in another commit. The only types of updates
817allowed on these branches are "fast-forward's", where all history is
818preserved.
2699d634 819
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820Annotated tags in the canonical perl.git repository will never be
821deleted or modified. Think long and hard about whether you want to push
822a local tag to perl.git before doing so. (Pushing unannotated tags is
2699d634 823not allowed.)
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9469eb4a 825=head1 COMMITTING TO MAINTENANCE VERSIONS
9d68b7ed 826
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827Maintenance versions should only be altered to add critical bug fixes.
828
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829To commit to a maintenance version of perl, you need to create a local
830tracking branch:
831
832 % git checkout --track -b maint-5.005 origin/maint-5.005
833
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834This creates a local branch named C<maint-5.005>, which tracks the
835remote branch C<origin/maint-5.005>. Then you can pull, commit, merge
836and push as before.
b0d36535 837
f755e97d 838You can also cherry-pick commits from blead and another branch, by
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839using the C<git cherry-pick> command. It is recommended to use the
840B<-x> option to C<git cherry-pick> in order to record the SHA1 of the
841original commit in the new commit message.
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843=head1 GRAFTS
844
845The perl history contains one mistake which was not caught in the
ac036724 846conversion: a merge was recorded in the history between blead and
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847maint-5.10 where no merge actually occurred. Due to the nature of git,
848this is now impossible to fix in the public repository. You can remove
849this mis-merge locally by adding the following line to your
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850C<.git/info/grafts> file:
851
852 296f12bbbbaa06de9be9d09d3dcf8f4528898a49 434946e0cb7a32589ed92d18008aaa1d88515930
853
854It is particularly important to have this graft line if any bisecting
855is done in the area of the "merge" in question.
856
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857
858
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859=head1 SEE ALSO
860
861The git documentation, accessible via C<git help command>.
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