| 1 | =encoding utf8 |
| 2 | |
| 3 | =for comment |
| 4 | Consistent formatting of this file is achieved with: |
| 5 | perl ./Porting/podtidy pod/perlgit.pod |
| 6 | |
| 7 | =head1 NAME |
| 8 | |
| 9 | perlgit - Detailed information about git and the Perl repository |
| 10 | |
| 11 | =head1 DESCRIPTION |
| 12 | |
| 13 | This document provides details on using git to develop Perl. If you are |
| 14 | just interested in working on a quick patch, see L<perlhack> first. |
| 15 | This document is intended for people who are regular contributors to |
| 16 | Perl, including those with write access to the git repository. |
| 17 | |
| 18 | =head1 CLONING THE REPOSITORY |
| 19 | |
| 20 | All of Perl's source code is kept centrally in a Git repository at |
| 21 | I<perl5.git.perl.org>. |
| 22 | |
| 23 | You can make a read-only clone of the repository by running: |
| 24 | |
| 25 | % git clone git://perl5.git.perl.org/perl.git perl |
| 26 | |
| 27 | This uses the git protocol (port 9418). |
| 28 | |
| 29 | If you cannot use the git protocol for firewall reasons, you can also |
| 30 | clone via http, though this is much slower: |
| 31 | |
| 32 | % git clone http://perl5.git.perl.org/perl.git perl |
| 33 | |
| 34 | =head1 WORKING WITH THE REPOSITORY |
| 35 | |
| 36 | Once you have changed into the repository directory, you can inspect |
| 37 | it. After a clone the repository will contain a single local branch, |
| 38 | which will be the current branch as well, as indicated by the asterisk. |
| 39 | |
| 40 | % git branch |
| 41 | * blead |
| 42 | |
| 43 | Using the -a switch to C<branch> will also show the remote tracking |
| 44 | branches in the repository: |
| 45 | |
| 46 | % git branch -a |
| 47 | * blead |
| 48 | origin/HEAD |
| 49 | origin/blead |
| 50 | ... |
| 51 | |
| 52 | The branches that begin with "origin" correspond to the "git remote" |
| 53 | that you cloned from (which is named "origin"). Each branch on the |
| 54 | remote will be exactly tracked by theses branches. You should NEVER do |
| 55 | work on these remote tracking branches. You only ever do work in a |
| 56 | local branch. Local branches can be configured to automerge (on pull) |
| 57 | from a designated remote tracking branch. This is the case with the |
| 58 | default branch C<blead> which will be configured to merge from the |
| 59 | remote tracking branch C<origin/blead>. |
| 60 | |
| 61 | You can see recent commits: |
| 62 | |
| 63 | % git log |
| 64 | |
| 65 | And pull new changes from the repository, and update your local |
| 66 | repository (must be clean first) |
| 67 | |
| 68 | % git pull |
| 69 | |
| 70 | Assuming we are on the branch C<blead> immediately after a pull, this |
| 71 | command would be more or less equivalent to: |
| 72 | |
| 73 | % git fetch |
| 74 | % git merge origin/blead |
| 75 | |
| 76 | In fact if you want to update your local repository without touching |
| 77 | your working directory you do: |
| 78 | |
| 79 | % git fetch |
| 80 | |
| 81 | And if you want to update your remote-tracking branches for all defined |
| 82 | remotes simultaneously you can do |
| 83 | |
| 84 | % git remote update |
| 85 | |
| 86 | Neither of these last two commands will update your working directory, |
| 87 | however both will update the remote-tracking branches in your |
| 88 | repository. |
| 89 | |
| 90 | To make a local branch of a remote branch: |
| 91 | |
| 92 | % git checkout -b maint-5.10 origin/maint-5.10 |
| 93 | |
| 94 | To switch back to blead: |
| 95 | |
| 96 | % git checkout blead |
| 97 | |
| 98 | =head2 Finding out your status |
| 99 | |
| 100 | The most common git command you will use will probably be |
| 101 | |
| 102 | % git status |
| 103 | |
| 104 | This command will produce as output a description of the current state |
| 105 | of the repository, including modified files and unignored untracked |
| 106 | files, and in addition it will show things like what files have been |
| 107 | staged for the next commit, and usually some useful information about |
| 108 | how to change things. For instance the following: |
| 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 | # |
| 117 | # modified: pod/perlgit.pod |
| 118 | # |
| 119 | # Changed but not updated: |
| 120 | # (use "git add <file>..." to update what will be committed) |
| 121 | # |
| 122 | # modified: pod/perlgit.pod |
| 123 | # |
| 124 | # Untracked files: |
| 125 | # (use "git add <file>..." to include in what will be committed) |
| 126 | # |
| 127 | # deliberate.untracked |
| 128 | |
| 129 | This shows that there were changes to this document staged for commit, |
| 130 | and that there were further changes in the working directory not yet |
| 131 | staged. It also shows that there was an untracked file in the working |
| 132 | directory, and as you can see shows how to change all of this. It also |
| 133 | shows that there is one commit on the working branch C<blead> which has |
| 134 | not been pushed to the C<origin> remote yet. B<NOTE>: that this output |
| 135 | is also what you see as a template if you do not provide a message to |
| 136 | C<git commit>. |
| 137 | |
| 138 | =head2 Patch workflow |
| 139 | |
| 140 | First, please read L<perlhack> for details on hacking the Perl core. |
| 141 | That document covers many details on how to create a good patch. |
| 142 | |
| 143 | If you already have a Perl repository, you should ensure that you're on |
| 144 | the I<blead> branch, and your repository is up to date: |
| 145 | |
| 146 | % git checkout blead |
| 147 | % git pull |
| 148 | |
| 149 | It's preferable to patch against the latest blead version, since this |
| 150 | is where new development occurs for all changes other than critical bug |
| 151 | fixes. Critical bug fix patches should be made against the relevant |
| 152 | maint branches, or should be submitted with a note indicating all the |
| 153 | branches where the fix should be applied. |
| 154 | |
| 155 | Now that we have everything up to date, we need to create a temporary |
| 156 | new branch for these changes and switch into it: |
| 157 | |
| 158 | % git checkout -b orange |
| 159 | |
| 160 | which is the short form of |
| 161 | |
| 162 | % git branch orange |
| 163 | % git checkout orange |
| 164 | |
| 165 | Creating a topic branch makes it easier for the maintainers to rebase |
| 166 | or merge back into the master blead for a more linear history. If you |
| 167 | don't work on a topic branch the maintainer has to manually cherry pick |
| 168 | your changes onto blead before they can be applied. |
| 169 | |
| 170 | That'll get you scolded on perl5-porters, so don't do that. Be Awesome. |
| 171 | |
| 172 | Then make your changes. For example, if Leon Brocard changes his name |
| 173 | to Orange Brocard, we should change his name in the AUTHORS file: |
| 174 | |
| 175 | % perl -pi -e 's{Leon Brocard}{Orange Brocard}' AUTHORS |
| 176 | |
| 177 | You can see what files are changed: |
| 178 | |
| 179 | % git status |
| 180 | # On branch orange |
| 181 | # Changes to be committed: |
| 182 | # (use "git reset HEAD <file>..." to unstage) |
| 183 | # |
| 184 | # modified: AUTHORS |
| 185 | # |
| 186 | |
| 187 | And 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 |
| 194 | @@ -541,7 +541,7 @@ Lars Hecking <lhecking@nmrc.ucc.ie> |
| 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 | |
| 204 | Now commit your change locally: |
| 205 | |
| 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(-) |
| 209 | |
| 210 | The C<-a> option is used to include all files that git tracks that you |
| 211 | have changed. If at this time, you only want to commit some of the |
| 212 | files you have worked on, you can omit the C<-a> and use the command |
| 213 | C<S<git add I<FILE ...>>> before doing the commit. C<S<git add |
| 214 | --interactive>> allows you to even just commit portions of files |
| 215 | instead of all the changes in them. |
| 216 | |
| 217 | The C<-m> option is used to specify the commit message. If you omit it, |
| 218 | git will open a text editor for you to compose the message |
| 219 | interactively. This is useful when the changes are more complex than |
| 220 | the sample given here, and, depending on the editor, to know that the |
| 221 | first line of the commit message doesn't exceed the 50 character legal |
| 222 | maximum. |
| 223 | |
| 224 | Once you've finished writing your commit message and exited your |
| 225 | editor, git will write your change to disk and tell you something like |
| 226 | this: |
| 227 | |
| 228 | Created commit daf8e63: explain git status and stuff about remotes |
| 229 | 1 files changed, 83 insertions(+), 3 deletions(-) |
| 230 | |
| 231 | If you re-run C<git status>, you should see something like this: |
| 232 | |
| 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) |
| 242 | |
| 243 | When in doubt, before you do anything else, check your status and read |
| 244 | it carefully, many questions are answered directly by the git status |
| 245 | output. |
| 246 | |
| 247 | You can examine your last commit with: |
| 248 | |
| 249 | % git show HEAD |
| 250 | |
| 251 | and if you are not happy with either the description or the patch |
| 252 | itself you can fix it up by editing the files once more and then issue: |
| 253 | |
| 254 | % git commit -a --amend |
| 255 | |
| 256 | Now you should create a patch file for all your local changes: |
| 257 | |
| 258 | % git format-patch -M origin.. |
| 259 | 0001-Rename-Leon-Brocard-to-Orange-Brocard.patch |
| 260 | |
| 261 | You should now send an email to to |
| 262 | L<perlbug@perl.org|mailto:perlbug@perl.org> with a description of your |
| 263 | changes, and include this patch file as an attachment. In addition to |
| 264 | being tracked by RT, mail to perlbug will automatically be forwarded to |
| 265 | perl5-porters (with manual moderation, so please be patient). You |
| 266 | should only send patches to |
| 267 | L<perl5-porters@perl.org|mailto:perl5-porters@perl.org> directly if the |
| 268 | patch is not ready to be applied, but intended for discussion. |
| 269 | |
| 270 | See the next section for how to configure and use git to send these |
| 271 | emails for you. |
| 272 | |
| 273 | If you want to delete your temporary branch, you may do so with: |
| 274 | |
| 275 | % git checkout blead |
| 276 | % git branch -d orange |
| 277 | error: The branch 'orange' is not an ancestor of your current HEAD. |
| 278 | If you are sure you want to delete it, run 'git branch -D orange'. |
| 279 | % git branch -D orange |
| 280 | Deleted branch orange. |
| 281 | |
| 282 | =head2 Committing your changes |
| 283 | |
| 284 | Assuming that you'd like to commit all the changes you've made as a |
| 285 | single atomic unit, run this command: |
| 286 | |
| 287 | % git commit -a |
| 288 | |
| 289 | (That C<-a> tells git to add every file you've changed to this commit. |
| 290 | New files aren't automatically added to your commit when you use |
| 291 | C<commit -a> If you want to add files or to commit some, but not all of |
| 292 | your changes, have a look at the documentation for C<git add>.) |
| 293 | |
| 294 | Git will start up your favorite text editor, so that you can craft a |
| 295 | commit message for your change. See L<perlhack/Commit message> for more |
| 296 | information about what makes a good commit message. |
| 297 | |
| 298 | Once you've finished writing your commit message and exited your |
| 299 | editor, git will write your change to disk and tell you something like |
| 300 | this: |
| 301 | |
| 302 | Created commit daf8e63: explain git status and stuff about remotes |
| 303 | 1 files changed, 83 insertions(+), 3 deletions(-) |
| 304 | |
| 305 | If you re-run C<git status>, you should see something like this: |
| 306 | |
| 307 | % git status |
| 308 | # On branch blead |
| 309 | # Your branch is ahead of 'origin/blead' by 2 commits. |
| 310 | # |
| 311 | # Untracked files: |
| 312 | # (use "git add <file>..." to include in what will be committed) |
| 313 | # |
| 314 | # deliberate.untracked |
| 315 | nothing added to commit but untracked files present (use "git add" to track) |
| 316 | |
| 317 | When in doubt, before you do anything else, check your status and read |
| 318 | it carefully, many questions are answered directly by the git status |
| 319 | output. |
| 320 | |
| 321 | =head2 Using git to send patch emails |
| 322 | |
| 323 | Please read L<perlhack> first in order to figure out where your patches |
| 324 | should be sent. |
| 325 | |
| 326 | In your ~/git/perl repository, set the destination email to perl's bug |
| 327 | tracker: |
| 328 | |
| 329 | $ git config sendemail.to perlbug@perl.org |
| 330 | |
| 331 | Or maybe perl5-porters: |
| 332 | |
| 333 | $ git config sendemail.to perl5-porters@perl.org |
| 334 | |
| 335 | Then you can use git directly to send your patch emails: |
| 336 | |
| 337 | $ git send-email 0001-Rename-Leon-Brocard-to-Orange-Brocard.patch |
| 338 | |
| 339 | You may need to set some configuration variables for your particular |
| 340 | email service provider. For example, to set your global git config to |
| 341 | send email via a gmail account: |
| 342 | |
| 343 | $ git config --global sendemail.smtpserver smtp.gmail.com |
| 344 | $ git config --global sendemail.smtpssl 1 |
| 345 | $ git config --global sendemail.smtpuser YOURUSERNAME@gmail.com |
| 346 | |
| 347 | With this configuration, you will be prompted for your gmail password |
| 348 | when you run 'git send-email'. You can also configure |
| 349 | C<sendemail.smtppass> with your password if you don't care about having |
| 350 | your password in the .gitconfig file. |
| 351 | |
| 352 | =head2 A note on derived files |
| 353 | |
| 354 | Be aware that many files in the distribution are derivative--avoid |
| 355 | patching them, because git won't see the changes to them, and the build |
| 356 | process will overwrite them. Patch the originals instead. Most |
| 357 | utilities (like perldoc) are in this category, i.e. patch |
| 358 | F<utils/perldoc.PL> rather than F<utils/perldoc>. Similarly, don't |
| 359 | create patches for files under $src_root/ext from their copies found in |
| 360 | $install_root/lib. If you are unsure about the proper location of a |
| 361 | file that may have gotten copied while building the source |
| 362 | distribution, consult the C<MANIFEST>. |
| 363 | |
| 364 | =head2 Cleaning a working directory |
| 365 | |
| 366 | The command C<git clean> can with varying arguments be used as a |
| 367 | replacement for C<make clean>. |
| 368 | |
| 369 | To reset your working directory to a pristine condition you can do: |
| 370 | |
| 371 | % git clean -dxf |
| 372 | |
| 373 | However, be aware this will delete ALL untracked content. You can use |
| 374 | |
| 375 | % git clean -Xf |
| 376 | |
| 377 | to remove all ignored untracked files, such as build and test |
| 378 | byproduct, but leave any manually created files alone. |
| 379 | |
| 380 | If you only want to cancel some uncommitted edits, you can use C<git |
| 381 | checkout> and give it a list of files to be reverted, or C<git checkout |
| 382 | -f> to revert them all. |
| 383 | |
| 384 | If you want to cancel one or several commits, you can use C<git reset>. |
| 385 | |
| 386 | =head2 Bisecting |
| 387 | |
| 388 | C<git> provides a built-in way to determine, with a binary search in |
| 389 | the history, which commit should be blamed for introducing a given bug. |
| 390 | |
| 391 | Suppose that we have a script F<~/testcase.pl> that exits with C<0> |
| 392 | when some behaviour is correct, and with C<1> when it's faulty. You |
| 393 | need an helper script that automates building C<perl> and running the |
| 394 | testcase: |
| 395 | |
| 396 | % cat ~/run |
| 397 | #!/bin/sh |
| 398 | git clean -dxf |
| 399 | |
| 400 | # If you get './makedepend: 1: Syntax error: Unterminated quoted |
| 401 | # string' when bisecting versions of perl older than 5.9.5 this hack |
| 402 | # will work around the bug in makedepend.SH which was fixed in |
| 403 | # version 96a8704c. Make sure to comment out `git checkout makedepend.SH' |
| 404 | # below too. |
| 405 | git show blead:makedepend.SH > makedepend.SH |
| 406 | |
| 407 | # If you can use ccache, add -Dcc=ccache\ gcc -Dld=gcc to the Configure line |
| 408 | # if Encode is not needed for the test, you can speed up the bisect by |
| 409 | # excluding it from the runs with -Dnoextensions=Encode |
| 410 | sh Configure -des -Dusedevel -Doptimize="-g" |
| 411 | test -f config.sh || exit 125 |
| 412 | # Correct makefile for newer GNU gcc |
| 413 | perl -ni -we 'print unless /<(?:built-in|command)/' makefile x2p/makefile |
| 414 | # if you just need miniperl, replace test_prep with miniperl |
| 415 | make test_prep |
| 416 | [ -x ./perl ] || exit 125 |
| 417 | ./perl -Ilib ~/testcase.pl |
| 418 | ret=$? |
| 419 | [ $ret -gt 127 ] && ret=127 |
| 420 | # git checkout makedepend.SH |
| 421 | git clean -dxf |
| 422 | exit $ret |
| 423 | |
| 424 | This script may return C<125> to indicate that the corresponding commit |
| 425 | should be skipped. Otherwise, it returns the status of |
| 426 | F<~/testcase.pl>. |
| 427 | |
| 428 | You first enter in bisect mode with: |
| 429 | |
| 430 | % git bisect start |
| 431 | |
| 432 | For example, if the bug is present on C<HEAD> but wasn't in 5.10.0, |
| 433 | C<git> will learn about this when you enter: |
| 434 | |
| 435 | % git bisect bad |
| 436 | % git bisect good perl-5.10.0 |
| 437 | Bisecting: 853 revisions left to test after this |
| 438 | |
| 439 | This results in checking out the median commit between C<HEAD> and |
| 440 | C<perl-5.10.0>. You can then run the bisecting process with: |
| 441 | |
| 442 | % git bisect run ~/run |
| 443 | |
| 444 | When the first bad commit is isolated, C<git bisect> will tell you so: |
| 445 | |
| 446 | ca4cfd28534303b82a216cfe83a1c80cbc3b9dc5 is first bad commit |
| 447 | commit ca4cfd28534303b82a216cfe83a1c80cbc3b9dc5 |
| 448 | Author: Dave Mitchell <davem@fdisolutions.com> |
| 449 | Date: Sat Feb 9 14:56:23 2008 +0000 |
| 450 | |
| 451 | [perl #49472] Attributes + Unknown Error |
| 452 | ... |
| 453 | |
| 454 | bisect run success |
| 455 | |
| 456 | You can peek into the bisecting process with C<git bisect log> and |
| 457 | C<git bisect visualize>. C<git bisect reset> will get you out of bisect |
| 458 | mode. |
| 459 | |
| 460 | Please note that the first C<good> state must be an ancestor of the |
| 461 | first C<bad> state. If you want to search for the commit that I<solved> |
| 462 | some bug, you have to negate your test case (i.e. exit with C<1> if OK |
| 463 | and C<0> if not) and still mark the lower bound as C<good> and the |
| 464 | upper as C<bad>. The "first bad commit" has then to be understood as |
| 465 | the "first commit where the bug is solved". |
| 466 | |
| 467 | C<git help bisect> has much more information on how you can tweak your |
| 468 | binary searches. |
| 469 | =head1 Topic branches and rewriting history |
| 470 | |
| 471 | Individual committers should create topic branches under |
| 472 | B<yourname>/B<some_descriptive_name>. Other committers should check |
| 473 | with a topic branch's creator before making any change to it. |
| 474 | |
| 475 | The simplest way to create a remote topic branch that works on all |
| 476 | versions of git is to push the current head as a new branch on the |
| 477 | remote, then check it out locally: |
| 478 | |
| 479 | $ branch="$yourname/$some_descriptive_name" |
| 480 | $ git push origin HEAD:$branch |
| 481 | $ git checkout -b $branch origin/$branch |
| 482 | |
| 483 | Users of git 1.7 or newer can do it in a more obvious manner: |
| 484 | |
| 485 | $ branch="$yourname/$some_descriptive_name" |
| 486 | $ git checkout -b $branch |
| 487 | $ git push origin -u $branch |
| 488 | |
| 489 | If you are not the creator of B<yourname>/B<some_descriptive_name>, you |
| 490 | might sometimes find that the original author has edited the branch's |
| 491 | history. There are lots of good reasons for this. Sometimes, an author |
| 492 | might simply be rebasing the branch onto a newer source point. |
| 493 | Sometimes, an author might have found an error in an early commit which |
| 494 | they wanted to fix before merging the branch to blead. |
| 495 | |
| 496 | Currently the master repository is configured to forbid |
| 497 | non-fast-forward merges. This means that the branches within can not be |
| 498 | rebased and pushed as a single step. |
| 499 | |
| 500 | The only way you will ever be allowed to rebase or modify the history |
| 501 | of a pushed branch is to delete it and push it as a new branch under |
| 502 | the same name. Please think carefully about doing this. It may be |
| 503 | better to sequentially rename your branches so that it is easier for |
| 504 | others working with you to cherry-pick their local changes onto the new |
| 505 | version. (XXX: needs explanation). |
| 506 | |
| 507 | If you want to rebase a personal topic branch, you will have to delete |
| 508 | your existing topic branch and push as a new version of it. You can do |
| 509 | this via the following formula (see the explanation about C<refspec>'s |
| 510 | in the git push documentation for details) after you have rebased your |
| 511 | branch: |
| 512 | |
| 513 | # first rebase |
| 514 | $ git checkout $user/$topic |
| 515 | $ git fetch |
| 516 | $ git rebase origin/blead |
| 517 | |
| 518 | # then "delete-and-push" |
| 519 | $ git push origin :$user/$topic |
| 520 | $ git push origin $user/$topic |
| 521 | |
| 522 | B<NOTE:> it is forbidden at the repository level to delete any of the |
| 523 | "primary" branches. That is any branch matching |
| 524 | C<m!^(blead|maint|perl)!>. Any attempt to do so will result in git |
| 525 | producing an error like this: |
| 526 | |
| 527 | $ git push origin :blead |
| 528 | *** It is forbidden to delete blead/maint branches in this repository |
| 529 | error: hooks/update exited with error code 1 |
| 530 | error: hook declined to update refs/heads/blead |
| 531 | To ssh://perl5.git.perl.org/perl |
| 532 | ! [remote rejected] blead (hook declined) |
| 533 | error: failed to push some refs to 'ssh://perl5.git.perl.org/perl' |
| 534 | |
| 535 | As a matter of policy we do B<not> edit the history of the blead and |
| 536 | maint-* branches. If a typo (or worse) sneaks into a commit to blead or |
| 537 | maint-*, we'll fix it in another commit. The only types of updates |
| 538 | allowed on these branches are "fast-forward's", where all history is |
| 539 | preserved. |
| 540 | |
| 541 | Annotated tags in the canonical perl.git repository will never be |
| 542 | deleted or modified. Think long and hard about whether you want to push |
| 543 | a local tag to perl.git before doing so. (Pushing unannotated tags is |
| 544 | not allowed.) |
| 545 | |
| 546 | =head3 Grafts |
| 547 | |
| 548 | The perl history contains one mistake which was not caught in the |
| 549 | conversion: a merge was recorded in the history between blead and |
| 550 | maint-5.10 where no merge actually occurred. Due to the nature of git, |
| 551 | this is now impossible to fix in the public repository. You can remove |
| 552 | this mis-merge locally by adding the following line to your |
| 553 | C<.git/info/grafts> file: |
| 554 | |
| 555 | 296f12bbbbaa06de9be9d09d3dcf8f4528898a49 434946e0cb7a32589ed92d18008aaa1d88515930 |
| 556 | |
| 557 | It is particularly important to have this graft line if any bisecting |
| 558 | is done in the area of the "merge" in question. |
| 559 | |
| 560 | =head2 Topic branches and rewriting history |
| 561 | |
| 562 | Individual committers should create topic branches under |
| 563 | B<yourname>/B<some_descriptive_name>. Other committers should check |
| 564 | with a topic branch's creator before making any change to it. |
| 565 | |
| 566 | The simplest way to create a remote topic branch that works on all |
| 567 | versions of git is to push the current head as a new branch on the |
| 568 | remote, then check it out locally: |
| 569 | |
| 570 | $ branch="$yourname/$some_descriptive_name" |
| 571 | $ git push origin HEAD:$branch |
| 572 | $ git checkout -b $branch origin/$branch |
| 573 | |
| 574 | Users of git 1.7 or newer can do it in a more obvious manner: |
| 575 | |
| 576 | $ branch="$yourname/$some_descriptive_name" |
| 577 | $ git checkout -b $branch |
| 578 | $ git push origin -u $branch |
| 579 | |
| 580 | If you are not the creator of B<yourname>/B<some_descriptive_name>, you |
| 581 | might sometimes find that the original author has edited the branch's |
| 582 | history. There are lots of good reasons for this. Sometimes, an author |
| 583 | might simply be rebasing the branch onto a newer source point. |
| 584 | Sometimes, an author might have found an error in an early commit which |
| 585 | they wanted to fix before merging the branch to blead. |
| 586 | |
| 587 | Currently the master repository is configured to forbid |
| 588 | non-fast-forward merges. This means that the branches within can not be |
| 589 | rebased and pushed as a single step. |
| 590 | |
| 591 | The only way you will ever be allowed to rebase or modify the history |
| 592 | of a pushed branch is to delete it and push it as a new branch under |
| 593 | the same name. Please think carefully about doing this. It may be |
| 594 | better to sequentially rename your branches so that it is easier for |
| 595 | others working with you to cherry-pick their local changes onto the new |
| 596 | version. (XXX: needs explanation). |
| 597 | |
| 598 | If you want to rebase a personal topic branch, you will have to delete |
| 599 | your existing topic branch and push as a new version of it. You can do |
| 600 | this via the following formula (see the explanation about C<refspec>'s |
| 601 | in the git push documentation for details) after you have rebased your |
| 602 | branch: |
| 603 | |
| 604 | # first rebase |
| 605 | $ git checkout $user/$topic |
| 606 | $ git fetch |
| 607 | $ git rebase origin/blead |
| 608 | |
| 609 | # then "delete-and-push" |
| 610 | $ git push origin :$user/$topic |
| 611 | $ git push origin $user/$topic |
| 612 | |
| 613 | B<NOTE:> it is forbidden at the repository level to delete any of the |
| 614 | "primary" branches. That is any branch matching |
| 615 | C<m!^(blead|maint|perl)!>. Any attempt to do so will result in git |
| 616 | producing an error like this: |
| 617 | |
| 618 | $ git push origin :blead |
| 619 | *** It is forbidden to delete blead/maint branches in this repository |
| 620 | error: hooks/update exited with error code 1 |
| 621 | error: hook declined to update refs/heads/blead |
| 622 | To ssh://perl5.git.perl.org/perl |
| 623 | ! [remote rejected] blead (hook declined) |
| 624 | error: failed to push some refs to 'ssh://perl5.git.perl.org/perl' |
| 625 | |
| 626 | As a matter of policy we do B<not> edit the history of the blead and |
| 627 | maint-* branches. If a typo (or worse) sneaks into a commit to blead or |
| 628 | maint-*, we'll fix it in another commit. The only types of updates |
| 629 | allowed on these branches are "fast-forward's", where all history is |
| 630 | preserved. |
| 631 | |
| 632 | Annotated tags in the canonical perl.git repository will never be |
| 633 | deleted or modified. Think long and hard about whether you want to push |
| 634 | a local tag to perl.git before doing so. (Pushing unannotated tags is |
| 635 | not allowed.) |
| 636 | |
| 637 | =head1 WRITE ACCESS TO THE GIT REPOSITORY |
| 638 | |
| 639 | Once you have write access, you will need to modify the URL for the |
| 640 | origin remote to enable pushing. Edit F<.git/config> with the |
| 641 | git-config(1) command: |
| 642 | |
| 643 | % git config remote.origin.url ssh://perl5.git.perl.org/perl.git |
| 644 | |
| 645 | You can also set up your user name and e-mail address. Most people do |
| 646 | this once globally in their F<~/.gitconfig> by doing something like: |
| 647 | |
| 648 | % git config --global user.name "Ævar Arnfjörð Bjarmason" |
| 649 | % git config --global user.email avarab@gmail.com |
| 650 | |
| 651 | However if you'd like to override that just for perl then execute then |
| 652 | execute something like the following in F<perl>: |
| 653 | |
| 654 | % git config user.email avar@cpan.org |
| 655 | |
| 656 | It is also possible to keep C<origin> as a git remote, and add a new |
| 657 | remote for ssh access: |
| 658 | |
| 659 | % git remote add camel perl5.git.perl.org:/perl.git |
| 660 | |
| 661 | This allows you to update your local repository by pulling from |
| 662 | C<origin>, which is faster and doesn't require you to authenticate, and |
| 663 | to push your changes back with the C<camel> remote: |
| 664 | |
| 665 | % git fetch camel |
| 666 | % git push camel |
| 667 | |
| 668 | The C<fetch> command just updates the C<camel> refs, as the objects |
| 669 | themselves should have been fetched when pulling from C<origin>. |
| 670 | =head1 Accepting a patch |
| 671 | |
| 672 | If you have received a patch file generated using the above section, |
| 673 | you should try out the patch. |
| 674 | |
| 675 | First we need to create a temporary new branch for these changes and |
| 676 | switch into it: |
| 677 | |
| 678 | % git checkout -b experimental |
| 679 | |
| 680 | Patches that were formatted by C<git format-patch> are applied with |
| 681 | C<git am>: |
| 682 | |
| 683 | % git am 0001-Rename-Leon-Brocard-to-Orange-Brocard.patch |
| 684 | Applying Rename Leon Brocard to Orange Brocard |
| 685 | |
| 686 | If just a raw diff is provided, it is also possible use this two-step |
| 687 | process: |
| 688 | |
| 689 | % git apply bugfix.diff |
| 690 | % git commit -a -m "Some fixing" --author="That Guy <that.guy@internets.com>" |
| 691 | |
| 692 | Now we can inspect the change: |
| 693 | |
| 694 | % git show HEAD |
| 695 | commit b1b3dab48344cff6de4087efca3dbd63548ab5e2 |
| 696 | Author: Leon Brocard <acme@astray.com> |
| 697 | Date: Fri Dec 19 17:02:59 2008 +0000 |
| 698 | |
| 699 | Rename Leon Brocard to Orange Brocard |
| 700 | |
| 701 | diff --git a/AUTHORS b/AUTHORS |
| 702 | index 293dd70..722c93e 100644 |
| 703 | --- a/AUTHORS |
| 704 | +++ b/AUTHORS |
| 705 | @@ -541,7 +541,7 @@ Lars Hecking <lhecking@nmrc.ucc.ie> |
| 706 | Laszlo Molnar <laszlo.molnar@eth.ericsson.se> |
| 707 | Leif Huhn <leif@hale.dkstat.com> |
| 708 | Len Johnson <lenjay@ibm.net> |
| 709 | -Leon Brocard <acme@astray.com> |
| 710 | +Orange Brocard <acme@astray.com> |
| 711 | Les Peters <lpeters@aol.net> |
| 712 | Lesley Binks <lesley.binks@gmail.com> |
| 713 | Lincoln D. Stein <lstein@cshl.org> |
| 714 | |
| 715 | If you are a committer to Perl and you think the patch is good, you can |
| 716 | then merge it into blead then push it out to the main repository: |
| 717 | |
| 718 | % git checkout blead |
| 719 | % git merge experimental |
| 720 | % git push |
| 721 | |
| 722 | If you want to delete your temporary branch, you may do so with: |
| 723 | |
| 724 | % git checkout blead |
| 725 | % git branch -d experimental |
| 726 | error: The branch 'experimental' is not an ancestor of your current HEAD. |
| 727 | If you are sure you want to delete it, run 'git branch -D experimental'. |
| 728 | % git branch -D experimental |
| 729 | Deleted branch experimental. |
| 730 | |
| 731 | =head2 Committing to blead |
| 732 | |
| 733 | The 'blead' branch will become the next production release of Perl. |
| 734 | |
| 735 | Before pushing I<any> local change to blead, it's incredibly important |
| 736 | that you do a few things, lest other committers come after you with |
| 737 | pitchforks and torches: |
| 738 | |
| 739 | =over |
| 740 | |
| 741 | =item * |
| 742 | |
| 743 | Make sure you have a good commit message. See L<perlhack/Commit |
| 744 | message> for details. |
| 745 | |
| 746 | =item * |
| 747 | |
| 748 | Run the test suite. You might not think that one typo fix would break a |
| 749 | test file. You'd be wrong. Here's an example of where not running the |
| 750 | suite caused problems. A patch was submitted that added a couple of |
| 751 | tests to an existing .t. It couldn't possibly affect anything else, so |
| 752 | no need to test beyond the single affected .t, right? But, the |
| 753 | submitter's email address had changed since the last of their |
| 754 | submissions, and this caused other tests to fail. Running the test |
| 755 | target given in the next item would have caught this problem. |
| 756 | |
| 757 | =item * |
| 758 | |
| 759 | If you don't run the full test suite, at least C<make test_porting>. |
| 760 | This will run basic sanity checks. To see which sanity checks, have a |
| 761 | look in F<t/porting>. |
| 762 | |
| 763 | =back |
| 764 | |
| 765 | =head2 Committing to maintenance versions |
| 766 | |
| 767 | Maintenance versions should only be altered to add critical bug fixes, |
| 768 | see L<perlpolicy>. |
| 769 | |
| 770 | To commit to a maintenance version of perl, you need to create a local |
| 771 | tracking branch: |
| 772 | |
| 773 | % git checkout --track -b maint-5.005 origin/maint-5.005 |
| 774 | |
| 775 | This creates a local branch named C<maint-5.005>, which tracks the |
| 776 | remote branch C<origin/maint-5.005>. Then you can pull, commit, merge |
| 777 | and push as before. |
| 778 | |
| 779 | You can also cherry-pick commits from blead and another branch, by |
| 780 | using the C<git cherry-pick> command. It is recommended to use the |
| 781 | B<-x> option to C<git cherry-pick> in order to record the SHA1 of the |
| 782 | original commit in the new commit message. |
| 783 | |
| 784 | Before pushing any change to a maint version, make sure you've |
| 785 | satisfied the steps in L</Committing to blead> above. |
| 786 | |
| 787 | =head2 Grafts |
| 788 | |
| 789 | The perl history contains one mistake which was not caught in the |
| 790 | conversion: a merge was recorded in the history between blead and |
| 791 | maint-5.10 where no merge actually occurred. Due to the nature of git, |
| 792 | this is now impossible to fix in the public repository. You can remove |
| 793 | this mis-merge locally by adding the following line to your |
| 794 | C<.git/info/grafts> file: |
| 795 | |
| 796 | 296f12bbbbaa06de9be9d09d3dcf8f4528898a49 434946e0cb7a32589ed92d18008aaa1d88515930 |
| 797 | |
| 798 | It is particularly important to have this graft line if any bisecting |
| 799 | is done in the area of the "merge" in question. |
| 800 | |
| 801 | =head2 Merging from a branch via GitHub |
| 802 | |
| 803 | While we don't encourage the submission of patches via GitHub, that |
| 804 | will still happen. Here is a guide to merging patches from a GitHub |
| 805 | repository. |
| 806 | |
| 807 | % git remote add avar git://github.com/avar/perl.git |
| 808 | % git fetch avar |
| 809 | |
| 810 | Now you can see the differences between the branch and blead: |
| 811 | |
| 812 | % git diff avar/orange |
| 813 | |
| 814 | And you can see the commits: |
| 815 | |
| 816 | % git log avar/orange |
| 817 | |
| 818 | If you approve of a specific commit, you can cherry pick it: |
| 819 | |
| 820 | % git cherry-pick 0c24b290ae02b2ab3304f51d5e11e85eb3659eae |
| 821 | |
| 822 | Or you could just merge the whole branch if you like it all: |
| 823 | |
| 824 | % git merge avar/orange |
| 825 | |
| 826 | And then push back to the repository: |
| 827 | |
| 828 | % git push |
| 829 | |
| 830 | =head2 A note on camel and dromedary |
| 831 | |
| 832 | The committers have SSH access to the two servers that serve |
| 833 | C<perl5.git.perl.org>. One is C<perl5.git.perl.org> itself (I<camel>), |
| 834 | which is the 'master' repository. The second one is |
| 835 | C<users.perl5.git.perl.org> (I<dromedary>), which can be used for |
| 836 | general testing and development. Dromedary syncs the git tree from |
| 837 | camel every few minutes, you should not push there. Both machines also |
| 838 | have a full CPAN mirror in /srv/CPAN, please use this. To share files |
| 839 | with the general public, dromedary serves your ~/public_html/ as |
| 840 | C<http://users.perl5.git.perl.org/~yourlogin/> |
| 841 | |
| 842 | These hosts have fairly strict firewalls to the outside. Outgoing, only |
| 843 | rsync, ssh and git are allowed. For http and ftp, you can use |
| 844 | http://webproxy:3128 as proxy. Incoming, the firewall tries to detect |
| 845 | attacks and blocks IP addresses with suspicious activity. This |
| 846 | sometimes (but very rarely) has false positives and you might get |
| 847 | blocked. The quickest way to get unblocked is to notify the admins. |
| 848 | |
| 849 | These two boxes are owned, hosted, and operated by booking.com. You can |
| 850 | reach the sysadmins in #p5p on irc.perl.org or via mail to |
| 851 | C<perl5-porters@perl.org>. |