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perlgit: standardize verbatims to 2-space indent
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1=encoding utf8
2
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3=for comment
4Consistent formatting of this file is achieved with:
04c692a8 5 perl ./Porting/podtidy pod/perlgit.pod
0549aefb 6
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7=head1 NAME
8
04c692a8 9perlgit - Detailed information about git and the Perl repository
d7dd28b6 10
04c692a8 11=head1 DESCRIPTION
d7dd28b6 12
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13This document provides details on using git to develop Perl. If you are
14just interested in working on a quick patch, see L<perlhack> first.
15This document is intended for people who are regular contributors to
16Perl, including those with write access to the git repository.
184487f0 17
04c692a8 18=head1 CLONING THE REPOSITORY
f6c12373 19
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20All of Perl's source code is kept centrally in a Git repository at
21I<perl5.git.perl.org>.
f6c12373 22
04c692a8 23You can make a read-only clone of the repository by running:
f6c12373 24
04c692a8 25 % git clone git://perl5.git.perl.org/perl.git perl
f6c12373 26
04c692a8 27This uses the git protocol (port 9418).
f6c12373 28
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29If you cannot use the git protocol for firewall reasons, you can also
30clone via http, though this is much slower:
3482f01a 31
04c692a8 32 % git clone http://perl5.git.perl.org/perl.git perl
b47aa495 33
04c692a8 34=head1 WORKING WITH THE REPOSITORY
d7dd28b6 35
6acba58e 36Once you have changed into the repository directory, you can inspect
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37it. After a clone the repository will contain a single local branch,
38which will be the current branch as well, as indicated by the asterisk.
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39
40 % git branch
41 * blead
42
f755e97d 43Using the -a switch to C<branch> will also show the remote tracking
6acba58e 44branches in the repository:
39219fd3 45
d9847473 46 % git branch -a
09081495 47 * blead
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48 origin/HEAD
49 origin/blead
50 ...
51
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52The branches that begin with "origin" correspond to the "git remote"
53that you cloned from (which is named "origin"). Each branch on the
c9d1da35 54remote will be exactly tracked by these branches. You should NEVER do
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55work on these remote tracking branches. You only ever do work in a
56local branch. Local branches can be configured to automerge (on pull)
57from a designated remote tracking branch. This is the case with the
58default branch C<blead> which will be configured to merge from the
59remote tracking branch C<origin/blead>.
39219fd3 60
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61You can see recent commits:
62
c2cf2042 63 % git log
d7dd28b6 64
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65And pull new changes from the repository, and update your local
66repository (must be clean first)
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67
68 % git pull
09081495 69
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70Assuming we are on the branch C<blead> immediately after a pull, this
71command would be more or less equivalent to:
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72
73 % git fetch
74 % git merge origin/blead
75
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76In fact if you want to update your local repository without touching
77your working directory you do:
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78
79 % git fetch
80
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81And if you want to update your remote-tracking branches for all defined
82remotes simultaneously you can do
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83
84 % git remote update
85
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86Neither of these last two commands will update your working directory,
87however both will update the remote-tracking branches in your
88repository.
39219fd3 89
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90To make a local branch of a remote branch:
91
92 % git checkout -b maint-5.10 origin/maint-5.10
93
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94To switch back to blead:
95
96 % git checkout blead
c2cf2042 97
ba336be1 98=head2 Finding out your status
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99
100The most common git command you will use will probably be
101
102 % git status
103
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104This command will produce as output a description of the current state
105of the repository, including modified files and unignored untracked
106files, and in addition it will show things like what files have been
107staged for the next commit, and usually some useful information about
108how to change things. For instance the following:
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109
110 $ git status
111 # On branch blead
112 # Your branch is ahead of 'origin/blead' by 1 commit.
113 #
114 # Changes to be committed:
115 # (use "git reset HEAD <file>..." to unstage)
116 #
04c692a8 117 # modified: pod/perlgit.pod
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118 #
119 # Changed but not updated:
120 # (use "git add <file>..." to update what will be committed)
121 #
04c692a8 122 # modified: pod/perlgit.pod
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123 #
124 # Untracked files:
125 # (use "git add <file>..." to include in what will be committed)
126 #
127 # deliberate.untracked
128
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129This shows that there were changes to this document staged for commit,
130and that there were further changes in the working directory not yet
131staged. It also shows that there was an untracked file in the working
132directory, and as you can see shows how to change all of this. It also
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133shows that there is one commit on the working branch C<blead> which has
134not been pushed to the C<origin> remote yet. B<NOTE>: that this output
135is also what you see as a template if you do not provide a message to
136C<git commit>.
7f6effc7 137
04c692a8 138=head2 Patch workflow
7f6effc7 139
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140First, please read L<perlhack> for details on hacking the Perl core.
141That document covers many details on how to create a good patch.
7f6effc7 142
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143If you already have a Perl repository, you should ensure that you're on
144the I<blead> branch, and your repository is up to date:
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145
146 % git checkout blead
147 % git pull
148
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149It's preferable to patch against the latest blead version, since this
150is where new development occurs for all changes other than critical bug
04c692a8 151fixes. Critical bug fix patches should be made against the relevant
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152maint branches, or should be submitted with a note indicating all the
153branches where the fix should be applied.
a44f43ac 154
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155Now that we have everything up to date, we need to create a temporary
156new branch for these changes and switch into it:
b1fccde5 157
a9b05323 158 % git checkout -b orange
23f8d33e 159
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160which is the short form of
161
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162 % git branch orange
163 % git checkout orange
164
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165Creating a topic branch makes it easier for the maintainers to rebase
166or merge back into the master blead for a more linear history. If you
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167don't work on a topic branch the maintainer has to manually cherry pick
168your changes onto blead before they can be applied.
0c24b290 169
77db6475 170That'll get you scolded on perl5-porters, so don't do that. Be Awesome.
0c24b290 171
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172Then make your changes. For example, if Leon Brocard changes his name
173to Orange Brocard, we should change his name in the AUTHORS file:
174
175 % perl -pi -e 's{Leon Brocard}{Orange Brocard}' AUTHORS
176
177You can see what files are changed:
178
179 % git status
f755e97d 180 # On branch orange
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181 # Changes to be committed:
182 # (use "git reset HEAD <file>..." to unstage)
183 #
2699d634 184 # modified: AUTHORS
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185 #
186
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187And you can see the changes:
188
189 % git diff
190 diff --git a/AUTHORS b/AUTHORS
191 index 293dd70..722c93e 100644
192 --- a/AUTHORS
193 +++ b/AUTHORS
7df2e4bc 194 @@ -541,7 +541,7 @@ Lars Hecking <lhecking@nmrc.ucc.ie>
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195 Laszlo Molnar <laszlo.molnar@eth.ericsson.se>
196 Leif Huhn <leif@hale.dkstat.com>
197 Len Johnson <lenjay@ibm.net>
198 -Leon Brocard <acme@astray.com>
199 +Orange Brocard <acme@astray.com>
200 Les Peters <lpeters@aol.net>
201 Lesley Binks <lesley.binks@gmail.com>
202 Lincoln D. Stein <lstein@cshl.org>
203
04c692a8 204Now commit your change locally:
77471e41 205
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206 % git commit -a -m 'Rename Leon Brocard to Orange Brocard'
207 Created commit 6196c1d: Rename Leon Brocard to Orange Brocard
208 1 files changed, 1 insertions(+), 1 deletions(-)
77471e41 209
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210The C<-a> option is used to include all files that git tracks that you
211have changed. If at this time, you only want to commit some of the
212files you have worked on, you can omit the C<-a> and use the command
213C<S<git add I<FILE ...>>> before doing the commit. C<S<git add
214--interactive>> allows you to even just commit portions of files
215instead of all the changes in them.
77471e41 216
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217The C<-m> option is used to specify the commit message. If you omit it,
218git will open a text editor for you to compose the message
219interactively. This is useful when the changes are more complex than
220the sample given here, and, depending on the editor, to know that the
221first line of the commit message doesn't exceed the 50 character legal
222maximum.
77471e41 223
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224Once you've finished writing your commit message and exited your
225editor, git will write your change to disk and tell you something like
226this:
77471e41 227
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228 Created commit daf8e63: explain git status and stuff about remotes
229 1 files changed, 83 insertions(+), 3 deletions(-)
c2cf2042 230
04c692a8 231If you re-run C<git status>, you should see something like this:
c2cf2042 232
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233 % git status
234 # On branch blead
235 # Your branch is ahead of 'origin/blead' by 2 commits.
236 #
237 # Untracked files:
238 # (use "git add <file>..." to include in what will be committed)
239 #
240 # deliberate.untracked
241 nothing added to commit but untracked files present (use "git add" to track)
2be70973 242
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243When in doubt, before you do anything else, check your status and read
244it carefully, many questions are answered directly by the git status
245output.
2be70973 246
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247You can examine your last commit with:
248
249 % git show HEAD
250
251and if you are not happy with either the description or the patch
c26da522 252itself you can fix it up by editing the files once more and then issue:
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253
254 % git commit -a --amend
255
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256Now you should create a patch file for all your local changes:
257
5df24413 258 % git format-patch -M blead..
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259 0001-Rename-Leon-Brocard-to-Orange-Brocard.patch
260
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261Or for a lot of changes, e.g. from a topic branch:
262
5df24413 263 % git format-patch --stdout -M blead.. > topic-branch-changes.patch
9420b3b3 264
e001c712 265You should now send an email to
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266L<perlbug@perl.org|mailto:perlbug@perl.org> with a description of your
267changes, and include this patch file as an attachment. In addition to
77db6475 268being tracked by RT, mail to perlbug will automatically be forwarded to
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269perl5-porters (with manual moderation, so please be patient). You
270should only send patches to
271L<perl5-porters@perl.org|mailto:perl5-porters@perl.org> directly if the
272patch is not ready to be applied, but intended for discussion.
64a8e22b 273
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274Please do not use git-send-email(1) to send your patch. See L<Sending
275patch emails|/Sending patch emails> for more information.
c2cf2042 276
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277If you want to delete your temporary branch, you may do so with:
278
279 % git checkout blead
280 % git branch -d orange
281 error: The branch 'orange' is not an ancestor of your current HEAD.
282 If you are sure you want to delete it, run 'git branch -D orange'.
283 % git branch -D orange
284 Deleted branch orange.
7df2e4bc 285
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286=head2 Committing your changes
287
6a6d7b97 288Assuming that you'd like to commit all the changes you've made as a
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289single atomic unit, run this command:
290
cc116ce7 291 % git commit -a
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292
293(That C<-a> tells git to add every file you've changed to this commit.
294New files aren't automatically added to your commit when you use
295C<commit -a> If you want to add files or to commit some, but not all of
296your changes, have a look at the documentation for C<git add>.)
297
298Git will start up your favorite text editor, so that you can craft a
299commit message for your change. See L<perlhack/Commit message> for more
300information about what makes a good commit message.
301
302Once you've finished writing your commit message and exited your
303editor, git will write your change to disk and tell you something like
304this:
305
306 Created commit daf8e63: explain git status and stuff about remotes
307 1 files changed, 83 insertions(+), 3 deletions(-)
308
309If you re-run C<git status>, you should see something like this:
310
311 % git status
312 # On branch blead
313 # Your branch is ahead of 'origin/blead' by 2 commits.
314 #
315 # Untracked files:
316 # (use "git add <file>..." to include in what will be committed)
317 #
318 # deliberate.untracked
319 nothing added to commit but untracked files present (use "git add" to track)
320
321When in doubt, before you do anything else, check your status and read
322it carefully, many questions are answered directly by the git status
323output.
324
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325=head2 Sending patch emails
326
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327After you've generated your patch you should sent it
328to perlbug@perl.org (as discussed L<in the previous
f6cce60a 329section|/"Patch workflow">) with a normal mail client as an
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330attachment, along with a description of the patch.
331
332You B<must not> use git-send-email(1) to send patches generated with
333git-format-patch(1). The RT ticketing system living behind
334perlbug@perl.org does not respect the inline contents of E-Mails,
335sending an inline patch to RT guarantees that your patch will be
336destroyed.
337
338Someone may download your patch from RT, which will result in the
339subject (the first line of the commit message) being omitted. See RT
340#74192 and commit a4583001 for an example. Alternatively someone may
341apply your patch from RT after it arrived in their mailbox, by which
342time RT will have modified the inline content of the message. See RT
343#74532 and commit f9bcfeac for a bad example of this failure mode.
2d5f1d01 344
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345=head2 A note on derived files
346
347Be aware that many files in the distribution are derivative--avoid
0549aefb 348patching them, because git won't see the changes to them, and the build
04c692a8 349process will overwrite them. Patch the originals instead. Most
0549aefb 350utilities (like perldoc) are in this category, i.e. patch
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351F<utils/perldoc.PL> rather than F<utils/perldoc>. Similarly, don't
352create patches for files under $src_root/ext from their copies found in
04c692a8 353$install_root/lib. If you are unsure about the proper location of a
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354file that may have gotten copied while building the source
355distribution, consult the C<MANIFEST>.
a44f43ac 356
04c692a8 357=head2 Cleaning a working directory
b0d36535 358
6acba58e 359The command C<git clean> can with varying arguments be used as a
dc3c3040 360replacement for C<make clean>.
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361
362To reset your working directory to a pristine condition you can do:
363
e0b2b458 364 % git clean -dxf
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365
366However, be aware this will delete ALL untracked content. You can use
367
e0b2b458 368 % git clean -Xf
b0d36535 369
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370to remove all ignored untracked files, such as build and test
371byproduct, but leave any manually created files alone.
b0d36535 372
0549aefb 373If you only want to cancel some uncommitted edits, you can use C<git
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374checkout> and give it a list of files to be reverted, or C<git checkout
375-f> to revert them all.
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376
377If you want to cancel one or several commits, you can use C<git reset>.
378
04c692a8 379=head2 Bisecting
d82a90c1 380
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381C<git> provides a built-in way to determine which commit should be blamed
382for introducing a given bug. C<git bisect> performs a binary search of
383history to locate the first failing commit. It is fast, powerful and
384flexible, but requires some setup and to automate the process an auxiliary
385shell script is needed.
386
387The core provides a wrapper program, F<Porting/bisect.pl>, which attempts to
388simplify as much as possible, making bisecting as simple as running a Perl
389one-liner. For example, if you want to know when this became an error:
390
391 perl -e 'my $a := 2'
392
393you simply run this:
394
395 .../Porting/bisect.pl -e 'my $a := 2;'
396
397Using C<bisect.pl>, with one command (and no other files) it's easy to find
398out
399
400=over 4
401
402=item *
403
404Which commit caused this example code to break?
405
406=item *
407
408Which commit caused this example code to start working?
409
410=item *
411
412Which commit added the first file to match this regex?
413
414=item *
415
416Which commit removed the last file to match this regex?
417
418=back
419
420usually without needing to know which versions of perl to use as start and
421end revisions, as F<bisect.pl> automatically searches to find the earliest
422stable version for which the test case passes. Run
423C<Porting/bisect.pl --help> for the full documentation, including how to
424set the C<Configure> and build time options.
425
426If you require more flexibility than F<Porting/bisect.pl> has to offer, you'll
427need to run C<git bisect> yourself. It's most useful to use C<git bisect run>
428to automate the building and testing of perl revisions. For this you'll need
429a shell script for C<git> to call to test a particular revision. An example
430script is F<Porting/bisect-example.sh>, which you should copy B<outside> of
431the repository, as the bisect process will reset the state to a clean checkout
432as it runs. The instructions below assume that you copied it as F<~/run> and
433then edited it as appropriate.
d82a90c1 434
bdaf0bc6 435You first enter in bisect mode with:
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436
437 % git bisect start
438
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439For example, if the bug is present on C<HEAD> but wasn't in 5.10.0,
440C<git> will learn about this when you enter:
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441
442 % git bisect bad
443 % git bisect good perl-5.10.0
444 Bisecting: 853 revisions left to test after this
445
6acba58e 446This results in checking out the median commit between C<HEAD> and
bdaf0bc6 447C<perl-5.10.0>. You can then run the bisecting process with:
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448
449 % git bisect run ~/run
450
451When the first bad commit is isolated, C<git bisect> will tell you so:
452
453 ca4cfd28534303b82a216cfe83a1c80cbc3b9dc5 is first bad commit
454 commit ca4cfd28534303b82a216cfe83a1c80cbc3b9dc5
455 Author: Dave Mitchell <davem@fdisolutions.com>
456 Date: Sat Feb 9 14:56:23 2008 +0000
457
9469eb4a 458 [perl #49472] Attributes + Unknown Error
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459 ...
460
461 bisect run success
462
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463You can peek into the bisecting process with C<git bisect log> and
464C<git bisect visualize>. C<git bisect reset> will get you out of bisect
465mode.
d82a90c1 466
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467Please note that the first C<good> state must be an ancestor of the
468first C<bad> state. If you want to search for the commit that I<solved>
469some bug, you have to negate your test case (i.e. exit with C<1> if OK
470and C<0> if not) and still mark the lower bound as C<good> and the
471upper as C<bad>. The "first bad commit" has then to be understood as
472the "first commit where the bug is solved".
d82a90c1 473
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474C<git help bisect> has much more information on how you can tweak your
475binary searches.
feb5e972 476
99cd8e46 477=head2 Topic branches and rewriting history
9d68b7ed 478
04c692a8 479Individual committers should create topic branches under
04edae75 480B<yourname>/B<some_descriptive_name>:
03050721 481
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482 $ branch="$yourname/$some_descriptive_name"
483 $ git checkout -b $branch
04edae75 484 ... do local edits, commits etc ...
04c692a8 485 $ git push origin -u $branch
03050721 486
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487Should you be stuck with an ancient version of git (prior to 1.7), then
488C<git push> will not have the C<-u> switch, and you have to replace the
489last step with the following sequence:
490
491 $ git push origin $branch:refs/heads/$branch
492 $ git config branch.$branch.remote origin
493 $ git config branch.$branch.merge refs/heads/$branch
494
495If you want to make changes to someone else's topic branch, you should
496check with its creator before making any change to it.
497
498You
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499might sometimes find that the original author has edited the branch's
500history. There are lots of good reasons for this. Sometimes, an author
501might simply be rebasing the branch onto a newer source point.
502Sometimes, an author might have found an error in an early commit which
503they wanted to fix before merging the branch to blead.
c26da522 504
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505Currently the master repository is configured to forbid
506non-fast-forward merges. This means that the branches within can not be
507rebased and pushed as a single step.
c26da522 508
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509The only way you will ever be allowed to rebase or modify the history
510of a pushed branch is to delete it and push it as a new branch under
511the same name. Please think carefully about doing this. It may be
512better to sequentially rename your branches so that it is easier for
513others working with you to cherry-pick their local changes onto the new
514version. (XXX: needs explanation).
c26da522 515
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516If you want to rebase a personal topic branch, you will have to delete
517your existing topic branch and push as a new version of it. You can do
518this via the following formula (see the explanation about C<refspec>'s
519in the git push documentation for details) after you have rebased your
520branch:
c26da522 521
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522 # first rebase
523 $ git checkout $user/$topic
524 $ git fetch
525 $ git rebase origin/blead
c26da522 526
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527 # then "delete-and-push"
528 $ git push origin :$user/$topic
529 $ git push origin $user/$topic
c26da522 530
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531B<NOTE:> it is forbidden at the repository level to delete any of the
532"primary" branches. That is any branch matching
533C<m!^(blead|maint|perl)!>. Any attempt to do so will result in git
534producing an error like this:
c26da522 535
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536 $ git push origin :blead
537 *** It is forbidden to delete blead/maint branches in this repository
538 error: hooks/update exited with error code 1
539 error: hook declined to update refs/heads/blead
540 To ssh://perl5.git.perl.org/perl
541 ! [remote rejected] blead (hook declined)
542 error: failed to push some refs to 'ssh://perl5.git.perl.org/perl'
c26da522 543
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544As a matter of policy we do B<not> edit the history of the blead and
545maint-* branches. If a typo (or worse) sneaks into a commit to blead or
546maint-*, we'll fix it in another commit. The only types of updates
547allowed on these branches are "fast-forward's", where all history is
548preserved.
2bab0636 549
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550Annotated tags in the canonical perl.git repository will never be
551deleted or modified. Think long and hard about whether you want to push
552a local tag to perl.git before doing so. (Pushing unannotated tags is
553not allowed.)
2bab0636 554
feb5e972 555=head2 Grafts
c26da522 556
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557The perl history contains one mistake which was not caught in the
558conversion: a merge was recorded in the history between blead and
559maint-5.10 where no merge actually occurred. Due to the nature of git,
560this is now impossible to fix in the public repository. You can remove
561this mis-merge locally by adding the following line to your
562C<.git/info/grafts> file:
c26da522 563
04c692a8 564 296f12bbbbaa06de9be9d09d3dcf8f4528898a49 434946e0cb7a32589ed92d18008aaa1d88515930
c26da522 565
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566It is particularly important to have this graft line if any bisecting
567is done in the area of the "merge" in question.
ce2a8773 568
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569=head1 WRITE ACCESS TO THE GIT REPOSITORY
570
571Once you have write access, you will need to modify the URL for the
572origin remote to enable pushing. Edit F<.git/config> with the
573git-config(1) command:
574
575 % git config remote.origin.url ssh://perl5.git.perl.org/perl.git
576
577You can also set up your user name and e-mail address. Most people do
578this once globally in their F<~/.gitconfig> by doing something like:
579
580 % git config --global user.name "Ævar Arnfjörð Bjarmason"
581 % git config --global user.email avarab@gmail.com
582
877637fd 583However, if you'd like to override that just for perl,
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584execute something like the following in F<perl>:
585
586 % git config user.email avar@cpan.org
587
588It is also possible to keep C<origin> as a git remote, and add a new
589remote for ssh access:
590
591 % git remote add camel perl5.git.perl.org:/perl.git
592
593This allows you to update your local repository by pulling from
594C<origin>, which is faster and doesn't require you to authenticate, and
595to push your changes back with the C<camel> remote:
596
597 % git fetch camel
598 % git push camel
599
600The C<fetch> command just updates the C<camel> refs, as the objects
601themselves should have been fetched when pulling from C<origin>.
04baf1ff 602
99cd8e46 603=head2 Accepting a patch
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604
605If you have received a patch file generated using the above section,
606you should try out the patch.
607
608First we need to create a temporary new branch for these changes and
609switch into it:
610
611 % git checkout -b experimental
612
613Patches that were formatted by C<git format-patch> are applied with
614C<git am>:
615
616 % git am 0001-Rename-Leon-Brocard-to-Orange-Brocard.patch
617 Applying Rename Leon Brocard to Orange Brocard
618
619If just a raw diff is provided, it is also possible use this two-step
620process:
621
622 % git apply bugfix.diff
623 % git commit -a -m "Some fixing" --author="That Guy <that.guy@internets.com>"
edcf105d 624
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625Now we can inspect the change:
626
627 % git show HEAD
628 commit b1b3dab48344cff6de4087efca3dbd63548ab5e2
629 Author: Leon Brocard <acme@astray.com>
630 Date: Fri Dec 19 17:02:59 2008 +0000
631
632 Rename Leon Brocard to Orange Brocard
633
634 diff --git a/AUTHORS b/AUTHORS
635 index 293dd70..722c93e 100644
636 --- a/AUTHORS
637 +++ b/AUTHORS
638 @@ -541,7 +541,7 @@ Lars Hecking <lhecking@nmrc.ucc.ie>
639 Laszlo Molnar <laszlo.molnar@eth.ericsson.se>
640 Leif Huhn <leif@hale.dkstat.com>
641 Len Johnson <lenjay@ibm.net>
642 -Leon Brocard <acme@astray.com>
643 +Orange Brocard <acme@astray.com>
644 Les Peters <lpeters@aol.net>
645 Lesley Binks <lesley.binks@gmail.com>
646 Lincoln D. Stein <lstein@cshl.org>
647
648If you are a committer to Perl and you think the patch is good, you can
649then merge it into blead then push it out to the main repository:
650
651 % git checkout blead
652 % git merge experimental
68382b67 653 % git push origin blead
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654
655If you want to delete your temporary branch, you may do so with:
656
657 % git checkout blead
658 % git branch -d experimental
659 error: The branch 'experimental' is not an ancestor of your current HEAD.
660 If you are sure you want to delete it, run 'git branch -D experimental'.
661 % git branch -D experimental
662 Deleted branch experimental.
663
664=head2 Committing to blead
665
666The 'blead' branch will become the next production release of Perl.
edcf105d
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667
668Before pushing I<any> local change to blead, it's incredibly important
669that you do a few things, lest other committers come after you with
670pitchforks and torches:
671
672=over
673
674=item *
675
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676Make sure you have a good commit message. See L<perlhack/Commit
677message> for details.
edcf105d
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678
679=item *
680
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681Run the test suite. You might not think that one typo fix would break a
682test file. You'd be wrong. Here's an example of where not running the
683suite caused problems. A patch was submitted that added a couple of
684tests to an existing .t. It couldn't possibly affect anything else, so
f76a37ee
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685no need to test beyond the single affected .t, right? But, the
686submitter's email address had changed since the last of their
04c692a8 687submissions, and this caused other tests to fail. Running the test
f76a37ee 688target given in the next item would have caught this problem.
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689
690=item *
691
692If you don't run the full test suite, at least C<make test_porting>.
693This will run basic sanity checks. To see which sanity checks, have a
694look in F<t/porting>.
695
cd78e84f
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696=item *
697
698If you make any changes that affect miniperl or core routines that have
04baf1ff 699different code paths for miniperl, be sure to run C<make minitest>.
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700This will catch problems that even the full test suite will not catch
701because it runs a subset of tests under miniperl rather than perl.
702
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703=back
704
99cd8e46 705=head2 On merging and rebasing
961bfa8c
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706
707Simple, one-off commits pushed to the 'blead' branch should be simple
708commits that apply cleanly. In other words, you should make sure your
709work is committed against the current position of blead, so that you can
710push back to the master repository without merging.
711
712Sometimes, blead will move while you're building or testing your
713changes. When this happens, your push will be rejected with a message
714like this:
715
716 To ssh://perl5.git.perl.org/perl.git
717 ! [rejected] blead -> blead (non-fast-forward)
718 error: failed to push some refs to 'ssh://perl5.git.perl.org/perl.git'
719 To prevent you from losing history, non-fast-forward updates were rejected
720 Merge the remote changes (e.g. 'git pull') before pushing again. See the
721 'Note about fast-forwards' section of 'git push --help' for details.
722
723When this happens, you can just I<rebase> your work against the new
724position of blead, like this (assuming your remote for the master
725repository is "p5p"):
726
727 $ git fetch p5p
728 $ git rebase p5p/blead
729
730You will see your commits being re-applied, and you will then be able to
c9d1da35 731push safely. More information about rebasing can be found in the
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732documentation for the git-rebase(1) command.
733
734For larger sets of commits that only make sense together, or that would
735benefit from a summary of the set's purpose, you should use a merge
736commit. You should perform your work on a L<topic branch|/Topic
737branches and rewriting history>, which you should regularly rebase
738against blead to ensure that your code is not broken by blead moving.
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739When you have finished your work, please perform a final rebase and
740test. Linear history is something that gets lost with every
741commit on blead, but a final rebase makes the history linear
742again, making it easier for future maintainers to see what has
743happened. Rebase as follows (assuming your work was on the
688cbe00 744branch C<< committer/somework >>):
961bfa8c 745
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746 $ git checkout committer/somework
747 $ git rebase blead
748
749Then you can merge it into master like this:
750
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751 $ git checkout blead
752 $ git merge --no-ff --no-commit committer/somework
753 $ git commit -a
754
755The switches above deserve explanation. C<--no-ff> indicates that even
756if all your work can be applied linearly against blead, a merge commit
757should still be prepared. This ensures that all your work will be shown
758as a side branch, with all its commits merged into the mainstream blead
759by the merge commit.
760
761C<--no-commit> means that the merge commit will be I<prepared> but not
762I<committed>. The commit is then actually performed when you run the
763next command, which will bring up your editor to describe the commit.
764Without C<--no-commit>, the commit would be made with nearly no useful
765message, which would greatly diminish the value of the merge commit as a
766placeholder for the work's description.
767
768When describing the merge commit, explain the purpose of the branch, and
769keep in mind that this description will probably be used by the
770eventual release engineer when reviewing the next perldelta document.
771
04c692a8 772=head2 Committing to maintenance versions
9d68b7ed 773
77db6475
LB
774Maintenance versions should only be altered to add critical bug fixes,
775see L<perlpolicy>.
7f4ffa9d 776
9d68b7ed
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777To commit to a maintenance version of perl, you need to create a local
778tracking branch:
779
780 % git checkout --track -b maint-5.005 origin/maint-5.005
781
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782This creates a local branch named C<maint-5.005>, which tracks the
783remote branch C<origin/maint-5.005>. Then you can pull, commit, merge
784and push as before.
b0d36535 785
f755e97d 786You can also cherry-pick commits from blead and another branch, by
0549aefb
LB
787using the C<git cherry-pick> command. It is recommended to use the
788B<-x> option to C<git cherry-pick> in order to record the SHA1 of the
789original commit in the new commit message.
f755e97d 790
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791Before pushing any change to a maint version, make sure you've
792satisfied the steps in L</Committing to blead> above.
edcf105d 793
04c692a8 794=head2 Merging from a branch via GitHub
bdaf0bc6 795
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796While we don't encourage the submission of patches via GitHub, that
797will still happen. Here is a guide to merging patches from a GitHub
798repository.
bdaf0bc6 799
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800 % git remote add avar git://github.com/avar/perl.git
801 % git fetch avar
041325d6 802
04c692a8 803Now you can see the differences between the branch and blead:
705c800c 804
04c692a8 805 % git diff avar/orange
705c800c 806
04c692a8 807And you can see the commits:
041325d6 808
04c692a8 809 % git log avar/orange
f755e97d 810
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811If you approve of a specific commit, you can cherry pick it:
812
813 % git cherry-pick 0c24b290ae02b2ab3304f51d5e11e85eb3659eae
814
815Or you could just merge the whole branch if you like it all:
816
817 % git merge avar/orange
818
819And then push back to the repository:
820
68382b67 821 % git push origin blead
04c692a8 822
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823=head2 Using a smoke-me branch to test changes
824
825Sometimes a change affects code paths which you cannot test on the OSes
826which are directly available to you and it would be wise to have users
827on other OSes test the change before you commit it to blead.
828
829Fortunately, there is a way to get your change smoke-tested on various
830OSes: push it to a "smoke-me" branch and wait for certain automated
831smoke-testers to report the results from their OSes.
832
833The procedure for doing this is roughly as follows (using the example of
834of tonyc's smoke-me branch called win32stat):
835
836First, make a local branch and switch to it:
837
838 % git checkout -b win32stat
839
840Make some changes, build perl and test your changes, then commit them to
841your local branch. Then push your local branch to a remote smoke-me
842branch:
843
844 % git push origin win32stat:smoke-me/tonyc/win32stat
845
846Now you can switch back to blead locally:
847
848 % git checkout blead
849
850and continue working on other things while you wait a day or two,
851keeping an eye on the results reported for your smoke-me branch at
852L<http://perl.develop-help.com/?b=smoke-me/tonyc/win32state>.
853
854If all is well then update your blead branch:
855
856 % git pull
857
858then checkout your smoke-me branch once more and rebase it on blead:
859
860 % git rebase blead win32stat
861
862Now switch back to blead and merge your smoke-me branch into it:
863
864 % git checkout blead
865 % git merge win32stat
866
867As described earlier, if there are many changes on your smoke-me branch
868then you should prepare a merge commit in which to give an overview of
869those changes by using the following command instead of the last
870command above:
871
872 % git merge win32stat --no-ff --no-commit
873
874You should now build perl and test your (merged) changes one last time
875(ideally run the whole test suite, but failing that at least run the
876F<t/porting/*.t> tests) before pushing your changes as usual:
877
878 % git push origin blead
879
880Finally, you should then delete the remote smoke-me branch:
881
882 % git push origin :smoke-me/tonyc/win32stat
883
884(which is likely to produce a warning like this, which can be ignored:
885
1dcc3c19
DG
886 remote: fatal: ambiguous argument 'refs/heads/smoke-me/tonyc/win32stat':
887 unknown revision or path not in the working tree.
3afc3118
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888 remote: Use '--' to separate paths from revisions
889
890) and then delete your local branch:
891
892 % git branch -d win32stat
893
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894=head2 A note on camel and dromedary
895
896The committers have SSH access to the two servers that serve
897C<perl5.git.perl.org>. One is C<perl5.git.perl.org> itself (I<camel>),
898which is the 'master' repository. The second one is
899C<users.perl5.git.perl.org> (I<dromedary>), which can be used for
900general testing and development. Dromedary syncs the git tree from
901camel every few minutes, you should not push there. Both machines also
902have a full CPAN mirror in /srv/CPAN, please use this. To share files
903with the general public, dromedary serves your ~/public_html/ as
904C<http://users.perl5.git.perl.org/~yourlogin/>
905
906These hosts have fairly strict firewalls to the outside. Outgoing, only
907rsync, ssh and git are allowed. For http and ftp, you can use
908http://webproxy:3128 as proxy. Incoming, the firewall tries to detect
909attacks and blocks IP addresses with suspicious activity. This
910sometimes (but very rarely) has false positives and you might get
911blocked. The quickest way to get unblocked is to notify the admins.
912
913These two boxes are owned, hosted, and operated by booking.com. You can
914reach the sysadmins in #p5p on irc.perl.org or via mail to
915C<perl5-porters@perl.org>.