This is a live mirror of the Perl 5 development currently hosted at https://github.com/perl/perl5
More info about camel in perlrepository.pod
[perl5.git] / pod / perlrepository.pod
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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
572f57ba 48fetch a copy of the repository over HTTP (this is 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>.
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229
230Assuming we commit all the mentioned changes above:
231
232 % git commit -a -m'explain git status and stuff about remotes'
233 Created commit daf8e63: explain git status and stuff about remotes
234 1 files changed, 83 insertions(+), 3 deletions(-)
235
236We can re-run git status and see something like this:
237
238 % git status
239 # On branch blead
240 # Your branch is ahead of 'origin/blead' by 2 commits.
241 #
242 # Untracked files:
243 # (use "git add <file>..." to include in what will be committed)
244 #
245 # deliberate.untracked
246 nothing added to commit but untracked files present (use "git add" to track)
247
39219fd3 248
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249When in doubt, before you do anything else, check your status and read
250it carefully, many questions are answered directly by the git status
251output.
39219fd3 252
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253=head1 SUBMITTING A PATCH
254
255If you have a patch in mind for Perl, you should first get a copy of
256the repository:
257
258 % git clone git://perl5.git.perl.org/perl.git perl-git
259
260Then change into the directory:
261
262 % cd perl-git
263
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264Alternatively, if you already have a Perl repository, you should ensure
265that you're on the I<blead> branch, and your repository is up to date:
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266
267 % git checkout blead
268 % git pull
269
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270It's preferable to patch against the latest blead version, since this
271is where new development occurs for all changes other than critical bug
272fixes. Critical bug fix patches should be made against the relevant
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273maint branches, or should be submitted with a note indicating all the
274branches where the fix should be applied.
a44f43ac 275
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276Now that we have everything up to date, we need to create a temporary
277new branch for these changes and switch into it:
b1fccde5 278
a9b05323 279 % git checkout -b orange
23f8d33e 280
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281which is the short form of
282
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283 % git branch orange
284 % git checkout orange
285
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286Then make your changes. For example, if Leon Brocard changes his name
287to Orange Brocard, we should change his name in the AUTHORS file:
288
289 % perl -pi -e 's{Leon Brocard}{Orange Brocard}' AUTHORS
290
291You can see what files are changed:
292
293 % git status
f755e97d 294 # On branch orange
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295 # Changes to be committed:
296 # (use "git reset HEAD <file>..." to unstage)
297 #
2699d634 298 # modified: AUTHORS
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299 #
300
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301And you can see the changes:
302
303 % git diff
304 diff --git a/AUTHORS b/AUTHORS
305 index 293dd70..722c93e 100644
306 --- a/AUTHORS
307 +++ b/AUTHORS
7df2e4bc 308 @@ -541,7 +541,7 @@ Lars Hecking <lhecking@nmrc.ucc.ie>
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309 Laszlo Molnar <laszlo.molnar@eth.ericsson.se>
310 Leif Huhn <leif@hale.dkstat.com>
311 Len Johnson <lenjay@ibm.net>
312 -Leon Brocard <acme@astray.com>
313 +Orange Brocard <acme@astray.com>
314 Les Peters <lpeters@aol.net>
315 Lesley Binks <lesley.binks@gmail.com>
316 Lincoln D. Stein <lstein@cshl.org>
317
318Now commit your change locally:
319
dc3c3040 320 % git commit -a -m 'Rename Leon Brocard to Orange Brocard'
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321 Created commit 6196c1d: Rename Leon Brocard to Orange Brocard
322 1 files changed, 1 insertions(+), 1 deletions(-)
323
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324You can examine your last commit with:
325
326 % git show HEAD
327
328and if you are not happy with either the description or the patch
c26da522 329itself you can fix it up by editing the files once more and then issue:
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330
331 % git commit -a --amend
332
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333Now you should create a patch file for all your local changes:
334
2af192ee 335 % git format-patch origin
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336 0001-Rename-Leon-Brocard-to-Orange-Brocard.patch
337
338You should now send an email to perl5-porters@perl.org with a
dc3c3040 339description of your changes, and include this patch file as an
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340attachment. (See the next section for how to configure and use git to
341send these emails for you.)
c2cf2042 342
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343If you want to delete your temporary branch, you may do so with:
344
345 % git checkout blead
346 % git branch -d orange
347 error: The branch 'orange' is not an ancestor of your current HEAD.
348 If you are sure you want to delete it, run 'git branch -D orange'.
349 % git branch -D orange
350 Deleted branch orange.
7df2e4bc 351
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352=head2 Using git to send patch emails
353
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354In your ~/git/perl repository, set the destination email to the
355perl5-porters mailing list.
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356
357 $ git config sendemail.to perl5-porters@perl.org
358
359Then you can use git directly to send your patch emails:
360
361 $ git send-email 0001-Rename-Leon-Brocard-to-Orange-Brocard.patch
362
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363You may need to set some configuration variables for your particular
364email service provider. For example, to set your global git config to
365send email via a gmail account:
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366
367 $ git config --global sendemail.smtpserver smtp.gmail.com
368 $ git config --global sendemail.smtpssl 1
369 $ git config --global sendemail.smtpuser YOURUSERNAME@gmail.com
370
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371With this configuration, you will be prompted for your gmail password
372when you run 'git send-email'. You can also configure
373C<sendemail.smtppass> with your password if you don't care about having
374your password in the .gitconfig file.
2d5f1d01 375
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376=head2 A note on derived files
377
378Be aware that many files in the distribution are derivative--avoid
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379patching them, because git won't see the changes to them, and the build
380process will overwrite them. Patch the originals instead. Most
381utilities (like perldoc) are in this category, i.e. patch
382utils/perldoc.PL rather than utils/perldoc. Similarly, don't create
383patches for files under $src_root/ext from their copies found in
384$install_root/lib. If you are unsure about the proper location of a
385file that may have gotten copied while building the source
386distribution, consult the C<MANIFEST>.
a44f43ac 387
6e2cec71 388=for XXX
a44f43ac 389
6e2cec71 390What should we recommend about binary files now? Do we need anything?
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391
392=head2 Getting your patch accepted
393
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394The first thing you should include with your patch is a description of
395the problem that the patch corrects. If it is a code patch (rather
396than a documentation patch) you should also include a small test case
397that illustrates the bug (a patch to an existing test file is
398preferred).
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399
400If you are submitting a code patch there are several other things that
401you need to do.
402
403=over 4
404
405=item Comments, Comments, Comments
406
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407Be sure to adequately comment your code. While commenting every line
408is unnecessary, anything that takes advantage of side effects of
a44f43ac 409operators, that creates changes that will be felt outside of the
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410function being patched, or that others may find confusing should be
411documented. If you are going to err, it is better to err on the side
412of adding too many comments than too few.
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413
414=item Style
415
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416In general, please follow the particular style of the code you are
417patching.
a44f43ac 418
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419In particular, follow these general guidelines for patching Perl
420sources:
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421
422 8-wide tabs (no exceptions!)
423 4-wide indents for code, 2-wide indents for nested CPP #defines
424 try hard not to exceed 79-columns
425 ANSI C prototypes
426 uncuddled elses and "K&R" style for indenting control constructs
427 no C++ style (//) comments
428 mark places that need to be revisited with XXX (and revisit often!)
429 opening brace lines up with "if" when conditional spans multiple
430 lines; should be at end-of-line otherwise
431 in function definitions, name starts in column 0 (return value is on
432 previous line)
433 single space after keywords that are followed by parens, no space
434 between function name and following paren
435 avoid assignments in conditionals, but if they're unavoidable, use
436 extra paren, e.g. "if (a && (b = c)) ..."
437 "return foo;" rather than "return(foo);"
438 "if (!foo) ..." rather than "if (foo == FALSE) ..." etc.
439
440=item Testsuite
441
0549aefb 442When submitting a patch you should make every effort to also include an
2699d634 443addition to perl's regression tests to properly exercise your patch.
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444Your testsuite additions should generally follow these guidelines
445(courtesy of Gurusamy Sarathy <gsar@activestate.com>):
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446
447 Know what you're testing. Read the docs, and the source.
448 Tend to fail, not succeed.
449 Interpret results strictly.
450 Use unrelated features (this will flush out bizarre interactions).
451 Use non-standard idioms (otherwise you are not testing TIMTOWTDI).
452 Avoid using hardcoded test numbers whenever possible (the
453 EXPECTED/GOT found in t/op/tie.t is much more maintainable,
454 and gives better failure reports).
455 Give meaningful error messages when a test fails.
456 Avoid using qx// and system() unless you are testing for them. If you
457 do use them, make sure that you cover _all_ perl platforms.
458 Unlink any temporary files you create.
459 Promote unforeseen warnings to errors with $SIG{__WARN__}.
460 Be sure to use the libraries and modules shipped with the version
461 being tested, not those that were already installed.
462 Add comments to the code explaining what you are testing for.
463 Make updating the '1..42' string unnecessary. Or make sure that
464 you update it.
465 Test _all_ behaviors of a given operator, library, or function:
466 - All optional arguments
467 - Return values in various contexts (boolean, scalar, list, lvalue)
468 - Use both global and lexical variables
469 - Don't forget the exceptional, pathological cases.
470
471=back
472
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473=head1 ACCEPTING A PATCH
474
475If you have received a patch file generated using the above section,
476you should try out the patch.
477
478First we need to create a temporary new branch for these changes and
479switch into it:
480
a9b05323 481 % git checkout -b experimental
7df2e4bc 482
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483Patches that were formatted by C<git format-patch> are applied with
484C<git am>:
7df2e4bc 485
2af192ee 486 % git am 0001-Rename-Leon-Brocard-to-Orange-Brocard.patch
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487 Applying Rename Leon Brocard to Orange Brocard
488
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489If just a raw diff is provided, it is also possible use this two-step
490process:
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491
492 % git apply bugfix.diff
dc3c3040 493 % git commit -a -m "Some fixing" --author="That Guy <that.guy@internets.com>"
09645c26 494
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495Now we can inspect the change:
496
dc3c3040 497 % git show HEAD
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498 commit b1b3dab48344cff6de4087efca3dbd63548ab5e2
499 Author: Leon Brocard <acme@astray.com>
500 Date: Fri Dec 19 17:02:59 2008 +0000
501
502 Rename Leon Brocard to Orange Brocard
7df2e4bc 503
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504 diff --git a/AUTHORS b/AUTHORS
505 index 293dd70..722c93e 100644
506 --- a/AUTHORS
507 +++ b/AUTHORS
508 @@ -541,7 +541,7 @@ Lars Hecking <lhecking@nmrc.ucc.ie>
509 Laszlo Molnar <laszlo.molnar@eth.ericsson.se>
510 Leif Huhn <leif@hale.dkstat.com>
511 Len Johnson <lenjay@ibm.net>
512 -Leon Brocard <acme@astray.com>
513 +Orange Brocard <acme@astray.com>
514 Les Peters <lpeters@aol.net>
515 Lesley Binks <lesley.binks@gmail.com>
516 Lincoln D. Stein <lstein@cshl.org>
517
518If you are a committer to Perl and you think the patch is good, you can
75fb7651 519then merge it into blead then push it out to the main repository:
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520
521 % git checkout blead
d9847473 522 % git merge experimental
75fb7651 523 % git push
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524
525If you want to delete your temporary branch, you may do so with:
526
527 % git checkout blead
528 % git branch -d experimental
529 error: The branch 'experimental' is not an ancestor of your current HEAD.
530 If you are sure you want to delete it, run 'git branch -D experimental'.
531 % git branch -D experimental
532 Deleted branch experimental.
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533
534=head1 CLEANING A WORKING DIRECTORY
535
6acba58e 536The command C<git clean> can with varying arguments be used as a
dc3c3040 537replacement for C<make clean>.
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538
539To reset your working directory to a pristine condition you can do:
540
541 git clean -dxf
542
543However, be aware this will delete ALL untracked content. You can use
544
545 git clean -Xf
546
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547to remove all ignored untracked files, such as build and test
548byproduct, but leave any manually created files alone.
b0d36535 549
0549aefb 550If you only want to cancel some uncommitted edits, you can use C<git
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551checkout> and give it a list of files to be reverted, or C<git checkout
552-f> to revert them all.
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553
554If you want to cancel one or several commits, you can use C<git reset>.
555
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556=head1 BISECTING
557
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558C<git> provides a built-in way to determine, with a binary search in
559the history, which commit should be blamed for introducing a given bug.
d82a90c1 560
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561Suppose that we have a script F<~/testcase.pl> that exits with C<0>
562when some behaviour is correct, and with C<1> when it's faulty. We need
563an helper script that automates building C<perl> and running the
564testcase:
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565
566 % cat ~/run
567 #!/bin/sh
568 git clean -dxf
569 # If you can use ccache, add -Dcc=ccache\ gcc -Dld=gcc to the Configure line
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570 sh Configure -des -Dusedevel -Doptimize="-g"
571 test -f config.sh || exit 125
572 # Correct makefile for newer GNU gcc
573 perl -ni -we 'print unless /<(?:built-in|command)/' makefile x2p/makefile
574 # if you just need miniperl, replace test_prep with miniperl
575 make -j4 test_prep
68814ba4 576 [ -x ./perl ] || exit 125
d82a90c1 577 ./perl -Ilib ~/testcase.pl
c0d1ef72 578 ret=$?
7930c68b 579 [ $ret -gt 127 ] && ret=127
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580 git clean -dxf
581 exit $ret
d82a90c1 582
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583This script may return C<125> to indicate that the corresponding commit
584should be skipped. Otherwise, it returns the status of
585F<~/testcase.pl>.
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586
587We first enter in bisect mode with:
588
589 % git bisect start
590
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591For example, if the bug is present on C<HEAD> but wasn't in 5.10.0,
592C<git> will learn about this when you enter:
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593
594 % git bisect bad
595 % git bisect good perl-5.10.0
596 Bisecting: 853 revisions left to test after this
597
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598This results in checking out the median commit between C<HEAD> and
599C<perl-5.10.0>. We can then run the bisecting process with:
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600
601 % git bisect run ~/run
602
603When the first bad commit is isolated, C<git bisect> will tell you so:
604
605 ca4cfd28534303b82a216cfe83a1c80cbc3b9dc5 is first bad commit
606 commit ca4cfd28534303b82a216cfe83a1c80cbc3b9dc5
607 Author: Dave Mitchell <davem@fdisolutions.com>
608 Date: Sat Feb 9 14:56:23 2008 +0000
609
9469eb4a 610 [perl #49472] Attributes + Unknown Error
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611 ...
612
613 bisect run success
614
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615You can peek into the bisecting process with C<git bisect log> and
616C<git bisect visualize>. C<git bisect reset> will get you out of bisect
617mode.
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619Please note that the first C<good> state must be an ancestor of the
620first C<bad> state. If you want to search for the commit that I<solved>
621some bug, you have to negate your test case (i.e. exit with C<1> if OK
622and C<0> if not) and still mark the lower bound as C<good> and the
623upper as C<bad>. The "first bad commit" has then to be understood as
624the "first commit where the bug is solved".
d82a90c1 625
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626C<git help bisect> has much more information on how you can tweak your
627binary searches.
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629=head1 SUBMITTING A PATCH VIA GITHUB
630
631GitHub is a website that makes it easy to fork and publish projects
632with Git. First you should set up a GitHub account and log in.
633
634Perl's git repository is mirrored on GitHub at this page:
635
636 http://github.com/github/perl/tree/blead
637
638Visit the page and click the "fork" button. This clones the Perl git
639repository for you and provides you with "Your Clone URL" from which
640you should clone:
641
642 % git clone git@github.com:USERNAME/perl.git perl-github
643
644We shall make the same patch as above, creating a new branch:
645
646 % cd perl-github
647 % git remote add upstream git://github.com/github/perl.git
648 % git pull upstream blead
649 % git checkout -b orange
650 % perl -pi -e 's{Leon Brocard}{Orange Brocard}' AUTHORS
dc3c3040 651 % git commit -a -m 'Rename Leon Brocard to Orange Brocard'
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652 % git push origin orange
653
654The orange branch has been pushed to GitHub, so you should now send an
655email to perl5-porters@perl.org with a description of your changes and
656the following information:
657
658 http://github.com/USERNAME/perl/tree/orange
659 git@github.com:USERNAME/perl.git branch orange
660
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661=head1 MERGING FROM A BRANCH VIA GITHUB
662
663If someone has provided a branch via GitHub and you are a committer,
5c9c28c6 664you should use the following in your perl-ssh directory:
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665
666 % git remote add dandv git://github.com/dandv/perl.git
667 % git fetch
668
669Now you can see the differences between the branch and blead:
670
671 % git diff dandv/blead
672
673And you can see the commits:
674
675 % git log dandv/blead
676
677If you approve of a specific commit, you can cherry pick it:
678
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679 % git cherry-pick 3adac458cb1c1d41af47fc66e67b49c8dec2323f
680
681Or you could just merge the whole branch if you like it all:
682
683 % git merge dandv/blead
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684
685And then push back to the repository:
686
687 % git push
688
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689
690=head1 TOPIC BRANCHES AND REWRITING HISTORY
691
692Individual committers should create topic branches under
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693B<yourname>/B<some_descriptive_name>. Other committers should check
694with a topic branch's creator before making any change to it.
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695
696If you are not the creator of B<yourname>/B<some_descriptive_name>, you
697might sometimes find that the original author has edited the branch's
698history. There are lots of good reasons for this. Sometimes, an author
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699might simply be rebasing the branch onto a newer source point.
700Sometimes, an author might have found an error in an early commit which
701they wanted to fix before merging the branch to blead.
ce2a8773 702
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703Currently the master repository is configured to forbid
704non-fast-forward merges. This means that the branches within can not
705be rebased and pushed as a single step.
ce2a8773 706
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707The only way you will ever be allowed to rebase or modify the history
708of a pushed branch is to delete it and push it as a new branch under
709the same name. Please think carefully about doing this. It may be
710better to sequentially rename your branches so that it is easier for
711others working with you to cherry-pick their local changes onto the new
712version. (XXX: needs explanation).
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713
714If you want to rebase a personal topic branch, you will have to delete
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715your existing topic branch and push as a new version of it. You can do
716this via the following formula (see the explanation about C<refspec>'s
717in the git push documentation for details) after you have rebased your
718branch:
719
720 # first rebase
721 $ git checkout $user/$topic
722 $ git fetch
723 $ git rebase origin/blead
724
725 # then "delete-and-push"
726 $ git push origin :$user/$topic
727 $ git push origin $user/$topic
728
729B<NOTE:> it is forbidden at the repository level to delete any of the
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730"primary" branches. That is any branch matching
731C<m!^(blead|maint|perl)!>. Any attempt to do so will result in git
732producing an error like this:
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733
734 $ git push origin :blead
735 *** It is forbidden to delete blead/maint branches in this repository
736 error: hooks/update exited with error code 1
737 error: hook declined to update refs/heads/blead
333f8875 738 To ssh://perl5.git.perl.org/perl
2699d634 739 ! [remote rejected] blead (hook declined)
333f8875 740 error: failed to push some refs to 'ssh://perl5.git.perl.org/perl'
2699d634 741
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742As a matter of policy we do B<not> edit the history of the blead and
743maint-* branches. If a typo (or worse) sneaks into a commit to blead or
744maint-*, we'll fix it in another commit. The only types of updates
745allowed on these branches are "fast-forward's", where all history is
746preserved.
2699d634 747
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748Annotated tags in the canonical perl.git repository will never be
749deleted or modified. Think long and hard about whether you want to push
750a local tag to perl.git before doing so. (Pushing unannotated tags is
2699d634 751not allowed.)
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9469eb4a 753=head1 COMMITTING TO MAINTENANCE VERSIONS
9d68b7ed 754
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755Maintenance versions should only be altered to add critical bug fixes.
756
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757To commit to a maintenance version of perl, you need to create a local
758tracking branch:
759
760 % git checkout --track -b maint-5.005 origin/maint-5.005
761
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762This creates a local branch named C<maint-5.005>, which tracks the
763remote branch C<origin/maint-5.005>. Then you can pull, commit, merge
764and push as before.
b0d36535 765
f755e97d 766You can also cherry-pick commits from blead and another branch, by
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767using the C<git cherry-pick> command. It is recommended to use the
768B<-x> option to C<git cherry-pick> in order to record the SHA1 of the
769original commit in the new commit message.
f755e97d 770
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771=head1 GRAFTS
772
773The perl history contains one mistake which was not caught in the
774conversion -- a merge was recorded in the history between blead and
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775maint-5.10 where no merge actually occurred. Due to the nature of git,
776this is now impossible to fix in the public repository. You can remove
777this mis-merge locally by adding the following line to your
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778C<.git/info/grafts> file:
779
780 296f12bbbbaa06de9be9d09d3dcf8f4528898a49 434946e0cb7a32589ed92d18008aaa1d88515930
781
782It is particularly important to have this graft line if any bisecting
783is done in the area of the "merge" in question.
784
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785=head1 SEE ALSO
786
787The git documentation, accessible via C<git help command>.
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