1PERLGIT(1)             Perl Programmers Reference Guide             PERLGIT(1)
2
3
4

NAME

6       perlgit - Detailed information about git and the Perl repository
7

DESCRIPTION

9       This document provides details on using git to develop Perl. If you are
10       just interested in working on a quick patch, see perlhack first.  This
11       document is intended for people who are regular contributors to Perl,
12       including those with write access to the git repository.
13

CLONING THE REPOSITORY

15       All of Perl's source code is kept centrally in a Git repository at
16       perl5.git.perl.org.
17
18       You can make a read-only clone of the repository by running:
19
20         % git clone git://perl5.git.perl.org/perl.git perl
21
22       This uses the git protocol (port 9418).
23
24       If you cannot use the git protocol for firewall reasons, you can also
25       clone via http, though this is much slower:
26
27         % git clone http://perl5.git.perl.org/perl.git perl
28

WORKING WITH THE REPOSITORY

30       Once you have changed into the repository directory, you can inspect
31       it. After a clone the repository will contain a single local branch,
32       which will be the current branch as well, as indicated by the asterisk.
33
34         % git branch
35         * blead
36
37       Using the -a switch to "branch" will also show the remote tracking
38       branches in the repository:
39
40         % git branch -a
41         * blead
42           origin/HEAD
43           origin/blead
44         ...
45
46       The branches that begin with "origin" correspond to the "git remote"
47       that you cloned from (which is named "origin"). Each branch on the
48       remote will be exactly tracked by these branches. You should NEVER do
49       work on these remote tracking branches. You only ever do work in a
50       local branch. Local branches can be configured to automerge (on pull)
51       from a designated remote tracking branch. This is the case with the
52       default branch "blead" which will be configured to merge from the
53       remote tracking branch "origin/blead".
54
55       You can see recent commits:
56
57         % git log
58
59       And pull new changes from the repository, and update your local
60       repository (must be clean first)
61
62         % git pull
63
64       Assuming we are on the branch "blead" immediately after a pull, this
65       command would be more or less equivalent to:
66
67         % git fetch
68         % git merge origin/blead
69
70       In fact if you want to update your local repository without touching
71       your working directory you do:
72
73         % git fetch
74
75       And if you want to update your remote-tracking branches for all defined
76       remotes simultaneously you can do
77
78         % git remote update
79
80       Neither of these last two commands will update your working directory,
81       however both will update the remote-tracking branches in your
82       repository.
83
84       To make a local branch of a remote branch:
85
86         % git checkout -b maint-5.10 origin/maint-5.10
87
88       To switch back to blead:
89
90         % git checkout blead
91
92   Finding out your status
93       The most common git command you will use will probably be
94
95         % git status
96
97       This command will produce as output a description of the current state
98       of the repository, including modified files and unignored untracked
99       files, and in addition it will show things like what files have been
100       staged for the next commit, and usually some useful information about
101       how to change things. For instance the following:
102
103        % git status
104        On branch blead
105        Your branch is ahead of 'origin/blead' by 1 commit.
106
107        Changes to be committed:
108          (use "git reset HEAD <file>..." to unstage)
109
110              modified:   pod/perlgit.pod
111
112        Changes not staged for commit:
113          (use "git add <file>..." to update what will be committed)
114          (use "git checkout -- <file>..." to discard changes in working
115                                                                     directory)
116
117              modified:   pod/perlgit.pod
118
119        Untracked files:
120          (use "git add <file>..." to include in what will be committed)
121
122              deliberate.untracked
123
124       This shows that there were changes to this document staged for commit,
125       and that there were further changes in the working directory not yet
126       staged. It also shows that there was an untracked file in the working
127       directory, and as you can see shows how to change all of this. It also
128       shows that there is one commit on the working branch "blead" which has
129       not been pushed to the "origin" remote yet. NOTE: This output is also
130       what you see as a template if you do not provide a message to "git
131       commit".
132
133   Patch workflow
134       First, please read perlhack for details on hacking the Perl core.  That
135       document covers many details on how to create a good patch.
136
137       If you already have a Perl repository, you should ensure that you're on
138       the blead branch, and your repository is up to date:
139
140         % git checkout blead
141         % git pull
142
143       It's preferable to patch against the latest blead version, since this
144       is where new development occurs for all changes other than critical bug
145       fixes. Critical bug fix patches should be made against the relevant
146       maint branches, or should be submitted with a note indicating all the
147       branches where the fix should be applied.
148
149       Now that we have everything up to date, we need to create a temporary
150       new branch for these changes and switch into it:
151
152         % git checkout -b orange
153
154       which is the short form of
155
156         % git branch orange
157         % git checkout orange
158
159       Creating a topic branch makes it easier for the maintainers to rebase
160       or merge back into the master blead for a more linear history. If you
161       don't work on a topic branch the maintainer has to manually cherry pick
162       your changes onto blead before they can be applied.
163
164       That'll get you scolded on perl5-porters, so don't do that. Be Awesome.
165
166       Then make your changes. For example, if Leon Brocard changes his name
167       to Orange Brocard, we should change his name in the AUTHORS file:
168
169         % perl -pi -e 's{Leon Brocard}{Orange Brocard}' AUTHORS
170
171       You can see what files are changed:
172
173         % git status
174         On branch orange
175         Changes to be committed:
176           (use "git reset HEAD <file>..." to unstage)
177
178            modified:   AUTHORS
179
180       And you can see the changes:
181
182        % git diff
183        diff --git a/AUTHORS b/AUTHORS
184        index 293dd70..722c93e 100644
185        --- a/AUTHORS
186        +++ b/AUTHORS
187        @@ -541,7 +541,7 @@    Lars Hecking              <lhecking@nmrc.ucc.ie>
188         Laszlo Molnar                  <laszlo.molnar@eth.ericsson.se>
189         Leif Huhn                      <leif@hale.dkstat.com>
190         Len Johnson                    <lenjay@ibm.net>
191        -Leon Brocard                   <acme@astray.com>
192        +Orange Brocard                 <acme@astray.com>
193         Les Peters                     <lpeters@aol.net>
194         Lesley Binks                   <lesley.binks@gmail.com>
195         Lincoln D. Stein               <lstein@cshl.org>
196
197       Now commit your change locally:
198
199        % git commit -a -m 'Rename Leon Brocard to Orange Brocard'
200        Created commit 6196c1d: Rename Leon Brocard to Orange Brocard
201         1 files changed, 1 insertions(+), 1 deletions(-)
202
203       The "-a" option is used to include all files that git tracks that you
204       have changed. If at this time, you only want to commit some of the
205       files you have worked on, you can omit the "-a" and use the command
206       "git add FILE ..." before doing the commit. "git add --interactive"
207       allows you to even just commit portions of files instead of all the
208       changes in them.
209
210       The "-m" option is used to specify the commit message. If you omit it,
211       git will open a text editor for you to compose the message
212       interactively. This is useful when the changes are more complex than
213       the sample given here, and, depending on the editor, to know that the
214       first line of the commit message doesn't exceed the 50 character legal
215       maximum.
216
217       Once you've finished writing your commit message and exited your
218       editor, git will write your change to disk and tell you something like
219       this:
220
221        Created commit daf8e63: explain git status and stuff about remotes
222         1 files changed, 83 insertions(+), 3 deletions(-)
223
224       If you re-run "git status", you should see something like this:
225
226        % git status
227        On branch orange
228        Untracked files:
229          (use "git add <file>..." to include in what will be committed)
230
231              deliberate.untracked
232
233        nothing added to commit but untracked files present (use "git add" to
234                                                                         track)
235
236       When in doubt, before you do anything else, check your status and read
237       it carefully, many questions are answered directly by the git status
238       output.
239
240       You can examine your last commit with:
241
242         % git show HEAD
243
244       and if you are not happy with either the description or the patch
245       itself you can fix it up by editing the files once more and then issue:
246
247         % git commit -a --amend
248
249       Now you should create a patch file for all your local changes:
250
251         % git format-patch -M blead..
252         0001-Rename-Leon-Brocard-to-Orange-Brocard.patch
253
254       Or for a lot of changes, e.g. from a topic branch:
255
256         % git format-patch --stdout -M blead.. > topic-branch-changes.patch
257
258       You should now send an email to perlbug@perl.org
259       <mailto:perlbug@perl.org> with a description of your changes, and
260       include this patch file as an attachment. In addition to being tracked
261       by RT, mail to perlbug will automatically be forwarded to perl5-porters
262       (with manual moderation, so please be patient). You should only send
263       patches to perl5-porters@perl.org <mailto:perl5-porters@perl.org>
264       directly if the patch is not ready to be applied, but intended for
265       discussion.
266
267       Please do not use git-send-email(1) to send your patch. See Sending
268       patch emails for more information.
269
270       If you want to delete your temporary branch, you may do so with:
271
272        % git checkout blead
273        % git branch -d orange
274        error: The branch 'orange' is not an ancestor of your current HEAD.
275        If you are sure you want to delete it, run 'git branch -D orange'.
276        % git branch -D orange
277        Deleted branch orange.
278
279   Committing your changes
280       Assuming that you'd like to commit all the changes you've made as a
281       single atomic unit, run this command:
282
283         % git commit -a
284
285       (That "-a" tells git to add every file you've changed to this commit.
286       New files aren't automatically added to your commit when you use
287       "commit -a" If you want to add files or to commit some, but not all of
288       your changes, have a look at the documentation for "git add".)
289
290       Git will start up your favorite text editor, so that you can craft a
291       commit message for your change. See "Commit message" in perlhack for
292       more information about what makes a good commit message.
293
294       Once you've finished writing your commit message and exited your
295       editor, git will write your change to disk and tell you something like
296       this:
297
298        Created commit daf8e63: explain git status and stuff about remotes
299         1 files changed, 83 insertions(+), 3 deletions(-)
300
301       If you re-run "git status", you should see something like this:
302
303        % git status
304        On branch blead
305        Your branch is ahead of 'origin/blead' by 2 commits.
306          (use "git push" to publish your local commits)
307        Untracked files:
308          (use "git add <file>..." to include in what will be committed)
309
310              deliberate.untracked
311
312        nothing added to commit but untracked files present (use "git add" to
313                                                                         track)
314
315       When in doubt, before you do anything else, check your status and read
316       it carefully, many questions are answered directly by the git status
317       output.
318
319   Sending patch emails
320       After you've generated your patch you should send it to
321       perlbug@perl.org <mailto:perlbug@perl.org> (as discussed in the
322       previous section) with a normal mail client as an attachment, along
323       with a description of the patch.
324
325       You must not use git-send-email(1) to send patches generated with
326       git-format-patch(1). The RT ticketing system living behind
327       perlbug@perl.org <mailto:perlbug@perl.org> does not respect the inline
328       contents of E-Mails, sending an inline patch to RT guarantees that your
329       patch will be destroyed.
330
331       Someone may download your patch from RT, which will result in the
332       subject (the first line of the commit message) being omitted.  See RT
333       #74192 <https://rt.perl.org/Ticket/Display.html?id=74192> and commit
334       a4583001 <http://perl5.git.perl.org/perl.git/commitdiff/a4583001> for
335       an example. Alternatively someone may apply your patch from RT after it
336       arrived in their mailbox, by which time RT will have modified the
337       inline content of the message.  See RT #74532
338       <https://rt.perl.org/Ticket/Display.html?id=74532> and commit f9bcfeac
339       <http://perl5.git.perl.org/perl.git/commitdiff/f9bcfeac> for a bad
340       example of this failure mode.
341
342   A note on derived files
343       Be aware that many files in the distribution are derivative--avoid
344       patching them, because git won't see the changes to them, and the build
345       process will overwrite them. Patch the originals instead. Most
346       utilities (like perldoc) are in this category, i.e. patch
347       utils/perldoc.PL rather than utils/perldoc. Similarly, don't create
348       patches for files under $src_root/ext from their copies found in
349       $install_root/lib. If you are unsure about the proper location of a
350       file that may have gotten copied while building the source
351       distribution, consult the MANIFEST.
352
353   Cleaning a working directory
354       The command "git clean" can with varying arguments be used as a
355       replacement for "make clean".
356
357       To reset your working directory to a pristine condition you can do:
358
359         % git clean -dxf
360
361       However, be aware this will delete ALL untracked content. You can use
362
363         % git clean -Xf
364
365       to remove all ignored untracked files, such as build and test
366       byproduct, but leave any manually created files alone.
367
368       If you only want to cancel some uncommitted edits, you can use "git
369       checkout" and give it a list of files to be reverted, or "git checkout
370       -f" to revert them all.
371
372       If you want to cancel one or several commits, you can use "git reset".
373
374   Bisecting
375       "git" provides a built-in way to determine which commit should be
376       blamed for introducing a given bug. "git bisect" performs a binary
377       search of history to locate the first failing commit. It is fast,
378       powerful and flexible, but requires some setup and to automate the
379       process an auxiliary shell script is needed.
380
381       The core provides a wrapper program, Porting/bisect.pl, which attempts
382       to simplify as much as possible, making bisecting as simple as running
383       a Perl one-liner. For example, if you want to know when this became an
384       error:
385
386           perl -e 'my $a := 2'
387
388       you simply run this:
389
390           .../Porting/bisect.pl -e 'my $a := 2;'
391
392       Using Porting/bisect.pl, with one command (and no other files) it's
393       easy to find out
394
395       ·   Which commit caused this example code to break?
396
397       ·   Which commit caused this example code to start working?
398
399       ·   Which commit added the first file to match this regex?
400
401       ·   Which commit removed the last file to match this regex?
402
403       usually without needing to know which versions of perl to use as start
404       and end revisions, as Porting/bisect.pl automatically searches to find
405       the earliest stable version for which the test case passes. Run
406       "Porting/bisect.pl --help" for the full documentation, including how to
407       set the "Configure" and build time options.
408
409       If you require more flexibility than Porting/bisect.pl has to offer,
410       you'll need to run "git bisect" yourself. It's most useful to use "git
411       bisect run" to automate the building and testing of perl revisions. For
412       this you'll need a shell script for "git" to call to test a particular
413       revision. An example script is Porting/bisect-example.sh, which you
414       should copy outside of the repository, as the bisect process will reset
415       the state to a clean checkout as it runs. The instructions below assume
416       that you copied it as ~/run and then edited it as appropriate.
417
418       You first enter in bisect mode with:
419
420         % git bisect start
421
422       For example, if the bug is present on "HEAD" but wasn't in 5.10.0,
423       "git" will learn about this when you enter:
424
425         % git bisect bad
426         % git bisect good perl-5.10.0
427         Bisecting: 853 revisions left to test after this
428
429       This results in checking out the median commit between "HEAD" and
430       "perl-5.10.0". You can then run the bisecting process with:
431
432         % git bisect run ~/run
433
434       When the first bad commit is isolated, "git bisect" will tell you so:
435
436         ca4cfd28534303b82a216cfe83a1c80cbc3b9dc5 is first bad commit
437         commit ca4cfd28534303b82a216cfe83a1c80cbc3b9dc5
438         Author: Dave Mitchell <davem@fdisolutions.com>
439         Date:   Sat Feb 9 14:56:23 2008 +0000
440
441             [perl #49472] Attributes + Unknown Error
442             ...
443
444         bisect run success
445
446       You can peek into the bisecting process with "git bisect log" and "git
447       bisect visualize". "git bisect reset" will get you out of bisect mode.
448
449       Please note that the first "good" state must be an ancestor of the
450       first "bad" state. If you want to search for the commit that solved
451       some bug, you have to negate your test case (i.e. exit with 1 if OK and
452       0 if not) and still mark the lower bound as "good" and the upper as
453       "bad". The "first bad commit" has then to be understood as the "first
454       commit where the bug is solved".
455
456       "git help bisect" has much more information on how you can tweak your
457       binary searches.
458
459   Topic branches and rewriting history
460       Individual committers should create topic branches under
461       yourname/some_descriptive_name:
462
463         % branch="$yourname/$some_descriptive_name"
464         % git checkout -b $branch
465         ... do local edits, commits etc ...
466         % git push origin -u $branch
467
468       Should you be stuck with an ancient version of git (prior to 1.7), then
469       "git push" will not have the "-u" switch, and you have to replace the
470       last step with the following sequence:
471
472         % git push origin $branch:refs/heads/$branch
473         % git config branch.$branch.remote origin
474         % git config branch.$branch.merge refs/heads/$branch
475
476       If you want to make changes to someone else's topic branch, you should
477       check with its creator before making any change to it.
478
479       You might sometimes find that the original author has edited the
480       branch's history. There are lots of good reasons for this. Sometimes,
481       an author might simply be rebasing the branch onto a newer source
482       point.  Sometimes, an author might have found an error in an early
483       commit which they wanted to fix before merging the branch to blead.
484
485       Currently the master repository is configured to forbid non-fast-
486       forward merges. This means that the branches within can not be rebased
487       and pushed as a single step.
488
489       The only way you will ever be allowed to rebase or modify the history
490       of a pushed branch is to delete it and push it as a new branch under
491       the same name. Please think carefully about doing this. It may be
492       better to sequentially rename your branches so that it is easier for
493       others working with you to cherry-pick their local changes onto the new
494       version. (XXX: needs explanation).
495
496       If you want to rebase a personal topic branch, you will have to delete
497       your existing topic branch and push as a new version of it. You can do
498       this via the following formula (see the explanation about "refspec"'s
499       in the git push documentation for details) after you have rebased your
500       branch:
501
502         # first rebase
503         % git checkout $user/$topic
504         % git fetch
505         % git rebase origin/blead
506
507         # then "delete-and-push"
508         % git push origin :$user/$topic
509         % git push origin $user/$topic
510
511       NOTE: it is forbidden at the repository level to delete any of the
512       "primary" branches. That is any branch matching
513       "m!^(blead|maint|perl)!". Any attempt to do so will result in git
514       producing an error like this:
515
516         % git push origin :blead
517         *** It is forbidden to delete blead/maint branches in this repository
518         error: hooks/update exited with error code 1
519         error: hook declined to update refs/heads/blead
520         To ssh://perl5.git.perl.org/perl
521          ! [remote rejected] blead (hook declined)
522          error: failed to push some refs to 'ssh://perl5.git.perl.org/perl'
523
524       As a matter of policy we do not edit the history of the blead and
525       maint-* branches. If a typo (or worse) sneaks into a commit to blead or
526       maint-*, we'll fix it in another commit. The only types of updates
527       allowed on these branches are "fast-forwards", where all history is
528       preserved.
529
530       Annotated tags in the canonical perl.git repository will never be
531       deleted or modified. Think long and hard about whether you want to push
532       a local tag to perl.git before doing so. (Pushing simple tags is not
533       allowed.)
534
535   Grafts
536       The perl history contains one mistake which was not caught in the
537       conversion: a merge was recorded in the history between blead and
538       maint-5.10 where no merge actually occurred. Due to the nature of git,
539       this is now impossible to fix in the public repository. You can remove
540       this mis-merge locally by adding the following line to your
541       ".git/info/grafts" file:
542
543        296f12bbbbaa06de9be9d09d3dcf8f4528898a49 434946e0cb7a32589ed92d18008aaa1d88515930
544
545       It is particularly important to have this graft line if any bisecting
546       is done in the area of the "merge" in question.
547

WRITE ACCESS TO THE GIT REPOSITORY

549       Once you have write access, you will need to modify the URL for the
550       origin remote to enable pushing. Edit .git/config with the
551       git-config(1) command:
552
553         % git config remote.origin.url ssh://perl5.git.perl.org/perl.git
554
555       You can also set up your user name and e-mail address. Most people do
556       this once globally in their ~/.gitconfig by doing something like:
557
558         % git config --global user.name "AEvar Arnfjoerd` Bjarmason"
559         % git config --global user.email avarab@gmail.com
560
561       However, if you'd like to override that just for perl, execute
562       something like the following in perl:
563
564         % git config user.email avar@cpan.org
565
566       It is also possible to keep "origin" as a git remote, and add a new
567       remote for ssh access:
568
569         % git remote add camel perl5.git.perl.org:/perl.git
570
571       This allows you to update your local repository by pulling from
572       "origin", which is faster and doesn't require you to authenticate, and
573       to push your changes back with the "camel" remote:
574
575         % git fetch camel
576         % git push camel
577
578       The "fetch" command just updates the "camel" refs, as the objects
579       themselves should have been fetched when pulling from "origin".
580
581   Accepting a patch
582       If you have received a patch file generated using the above section,
583       you should try out the patch.
584
585       First we need to create a temporary new branch for these changes and
586       switch into it:
587
588        % git checkout -b experimental
589
590       Patches that were formatted by "git format-patch" are applied with "git
591       am":
592
593        % git am 0001-Rename-Leon-Brocard-to-Orange-Brocard.patch
594        Applying Rename Leon Brocard to Orange Brocard
595
596       Note that some UNIX mail systems can mess with text attachments
597       containing 'From '. This will fix them up:
598
599        % perl -pi -e's/^>From /From /' \
600                               0001-Rename-Leon-Brocard-to-Orange-Brocard.patch
601
602       If just a raw diff is provided, it is also possible use this two-step
603       process:
604
605        % git apply bugfix.diff
606        % git commit -a -m "Some fixing" \
607                                   --author="That Guy <that.guy@internets.com>"
608
609       Now we can inspect the change:
610
611        % git show HEAD
612        commit b1b3dab48344cff6de4087efca3dbd63548ab5e2
613        Author: Leon Brocard <acme@astray.com>
614        Date:   Fri Dec 19 17:02:59 2008 +0000
615
616          Rename Leon Brocard to Orange Brocard
617
618        diff --git a/AUTHORS b/AUTHORS
619        index 293dd70..722c93e 100644
620        --- a/AUTHORS
621        +++ b/AUTHORS
622        @@ -541,7 +541,7 @@ Lars Hecking                 <lhecking@nmrc.ucc.ie>
623         Laszlo Molnar                  <laszlo.molnar@eth.ericsson.se>
624         Leif Huhn                      <leif@hale.dkstat.com>
625         Len Johnson                    <lenjay@ibm.net>
626        -Leon Brocard                   <acme@astray.com>
627        +Orange Brocard                 <acme@astray.com>
628         Les Peters                     <lpeters@aol.net>
629         Lesley Binks                   <lesley.binks@gmail.com>
630         Lincoln D. Stein               <lstein@cshl.org>
631
632       If you are a committer to Perl and you think the patch is good, you can
633       then merge it into blead then push it out to the main repository:
634
635         % git checkout blead
636         % git merge experimental
637         % git push origin blead
638
639       If you want to delete your temporary branch, you may do so with:
640
641        % git checkout blead
642        % git branch -d experimental
643        error: The branch 'experimental' is not an ancestor of your current
644        HEAD.  If you are sure you want to delete it, run 'git branch -D
645        experimental'.
646        % git branch -D experimental
647        Deleted branch experimental.
648
649   Committing to blead
650       The 'blead' branch will become the next production release of Perl.
651
652       Before pushing any local change to blead, it's incredibly important
653       that you do a few things, lest other committers come after you with
654       pitchforks and torches:
655
656       ·   Make sure you have a good commit message. See "Commit message" in
657           perlhack for details.
658
659       ·   Run the test suite. You might not think that one typo fix would
660           break a test file. You'd be wrong. Here's an example of where not
661           running the suite caused problems. A patch was submitted that added
662           a couple of tests to an existing .t. It couldn't possibly affect
663           anything else, so no need to test beyond the single affected .t,
664           right?  But, the submitter's email address had changed since the
665           last of their submissions, and this caused other tests to fail.
666           Running the test target given in the next item would have caught
667           this problem.
668
669       ·   If you don't run the full test suite, at least "make test_porting".
670           This will run basic sanity checks. To see which sanity checks, have
671           a look in t/porting.
672
673       ·   If you make any changes that affect miniperl or core routines that
674           have different code paths for miniperl, be sure to run "make
675           minitest".  This will catch problems that even the full test suite
676           will not catch because it runs a subset of tests under miniperl
677           rather than perl.
678
679   On merging and rebasing
680       Simple, one-off commits pushed to the 'blead' branch should be simple
681       commits that apply cleanly.  In other words, you should make sure your
682       work is committed against the current position of blead, so that you
683       can push back to the master repository without merging.
684
685       Sometimes, blead will move while you're building or testing your
686       changes.  When this happens, your push will be rejected with a message
687       like this:
688
689        To ssh://perl5.git.perl.org/perl.git
690         ! [rejected]        blead -> blead (non-fast-forward)
691        error: failed to push some refs to 'ssh://perl5.git.perl.org/perl.git'
692        To prevent you from losing history, non-fast-forward updates were
693        rejected Merge the remote changes (e.g. 'git pull') before pushing
694        again.  See the 'Note about fast-forwards' section of 'git push --help'
695        for details.
696
697       When this happens, you can just rebase your work against the new
698       position of blead, like this (assuming your remote for the master
699       repository is "p5p"):
700
701         % git fetch p5p
702         % git rebase p5p/blead
703
704       You will see your commits being re-applied, and you will then be able
705       to push safely.  More information about rebasing can be found in the
706       documentation for the git-rebase(1) command.
707
708       For larger sets of commits that only make sense together, or that would
709       benefit from a summary of the set's purpose, you should use a merge
710       commit.  You should perform your work on a topic branch, which you
711       should regularly rebase against blead to ensure that your code is not
712       broken by blead moving.  When you have finished your work, please
713       perform a final rebase and test.  Linear history is something that gets
714       lost with every commit on blead, but a final rebase makes the history
715       linear again, making it easier for future maintainers to see what has
716       happened.  Rebase as follows (assuming your work was on the branch
717       "committer/somework"):
718
719         % git checkout committer/somework
720         % git rebase blead
721
722       Then you can merge it into master like this:
723
724         % git checkout blead
725         % git merge --no-ff --no-commit committer/somework
726         % git commit -a
727
728       The switches above deserve explanation.  "--no-ff" indicates that even
729       if all your work can be applied linearly against blead, a merge commit
730       should still be prepared.  This ensures that all your work will be
731       shown as a side branch, with all its commits merged into the mainstream
732       blead by the merge commit.
733
734       "--no-commit" means that the merge commit will be prepared but not
735       committed.  The commit is then actually performed when you run the next
736       command, which will bring up your editor to describe the commit.
737       Without "--no-commit", the commit would be made with nearly no useful
738       message, which would greatly diminish the value of the merge commit as
739       a placeholder for the work's description.
740
741       When describing the merge commit, explain the purpose of the branch,
742       and keep in mind that this description will probably be used by the
743       eventual release engineer when reviewing the next perldelta document.
744
745   Committing to maintenance versions
746       Maintenance versions should only be altered to add critical bug fixes,
747       see perlpolicy.
748
749       To commit to a maintenance version of perl, you need to create a local
750       tracking branch:
751
752         % git checkout --track -b maint-5.005 origin/maint-5.005
753
754       This creates a local branch named "maint-5.005", which tracks the
755       remote branch "origin/maint-5.005". Then you can pull, commit, merge
756       and push as before.
757
758       You can also cherry-pick commits from blead and another branch, by
759       using the "git cherry-pick" command. It is recommended to use the -x
760       option to "git cherry-pick" in order to record the SHA1 of the original
761       commit in the new commit message.
762
763       Before pushing any change to a maint version, make sure you've
764       satisfied the steps in "Committing to blead" above.
765
766   Merging from a branch via GitHub
767       While we don't encourage the submission of patches via GitHub, that
768       will still happen. Here is a guide to merging patches from a GitHub
769       repository.
770
771         % git remote add avar git://github.com/avar/perl.git
772         % git fetch avar
773
774       Now you can see the differences between the branch and blead:
775
776         % git diff avar/orange
777
778       And you can see the commits:
779
780         % git log avar/orange
781
782       If you approve of a specific commit, you can cherry pick it:
783
784         % git cherry-pick 0c24b290ae02b2ab3304f51d5e11e85eb3659eae
785
786       Or you could just merge the whole branch if you like it all:
787
788         % git merge avar/orange
789
790       And then push back to the repository:
791
792         % git push origin blead
793
794   Using a smoke-me branch to test changes
795       Sometimes a change affects code paths which you cannot test on the OSes
796       which are directly available to you and it would be wise to have users
797       on other OSes test the change before you commit it to blead.
798
799       Fortunately, there is a way to get your change smoke-tested on various
800       OSes: push it to a "smoke-me" branch and wait for certain automated
801       smoke-testers to report the results from their OSes.
802
803       The procedure for doing this is roughly as follows (using the example
804       of of tonyc's smoke-me branch called win32stat):
805
806       First, make a local branch and switch to it:
807
808         % git checkout -b win32stat
809
810       Make some changes, build perl and test your changes, then commit them
811       to your local branch. Then push your local branch to a remote smoke-me
812       branch:
813
814         % git push origin win32stat:smoke-me/tonyc/win32stat
815
816       Now you can switch back to blead locally:
817
818         % git checkout blead
819
820       and continue working on other things while you wait a day or two,
821       keeping an eye on the results reported for your smoke-me branch at
822       <http://perl.develop-help.com/?b=smoke-me/tonyc/win32state>.
823
824       If all is well then update your blead branch:
825
826         % git pull
827
828       then checkout your smoke-me branch once more and rebase it on blead:
829
830         % git rebase blead win32stat
831
832       Now switch back to blead and merge your smoke-me branch into it:
833
834         % git checkout blead
835         % git merge win32stat
836
837       As described earlier, if there are many changes on your smoke-me branch
838       then you should prepare a merge commit in which to give an overview of
839       those changes by using the following command instead of the last
840       command above:
841
842         % git merge win32stat --no-ff --no-commit
843
844       You should now build perl and test your (merged) changes one last time
845       (ideally run the whole test suite, but failing that at least run the
846       t/porting/*.t tests) before pushing your changes as usual:
847
848         % git push origin blead
849
850       Finally, you should then delete the remote smoke-me branch:
851
852         % git push origin :smoke-me/tonyc/win32stat
853
854       (which is likely to produce a warning like this, which can be ignored:
855
856        remote: fatal: ambiguous argument
857                                         'refs/heads/smoke-me/tonyc/win32stat':
858        unknown revision or path not in the working tree.
859        remote: Use '--' to separate paths from revisions
860
861       ) and then delete your local branch:
862
863         % git branch -d win32stat
864
865   A note on camel and dromedary
866       The committers have SSH access to the two servers that serve
867       "perl5.git.perl.org". One is "perl5.git.perl.org" itself (camel), which
868       is the 'master' repository. The second one is
869       "users.perl5.git.perl.org" (dromedary), which can be used for general
870       testing and development. Dromedary syncs the git tree from camel every
871       few minutes, you should not push there. Both machines also have a full
872       CPAN mirror in /srv/CPAN, please use this. To share files with the
873       general public, dromedary serves your ~/public_html/ as
874       "<http://users.perl5.git.perl.org/~yourlogin/>"
875
876       These hosts have fairly strict firewalls to the outside. Outgoing, only
877       rsync, ssh and git are allowed. For http and ftp, you can use
878       <http://webproxy:3128> as proxy. Incoming, the firewall tries to detect
879       attacks and blocks IP addresses with suspicious activity. This
880       sometimes (but very rarely) has false positives and you might get
881       blocked. The quickest way to get unblocked is to notify the admins.
882
883       These two boxes are owned, hosted, and operated by booking.com. You can
884       reach the sysadmins in #p5p on irc.perl.org or via mail to
885       perl5-porters@perl.org <mailto:perl5-porters@perl.org>.
886
887
888
889perl v5.26.3                      2018-03-23                        PERLGIT(1)
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