1 @c -*- coding: utf-8; mode: texinfo; -*-
4 @node Working with source code
5 @chapter Working with source code
7 @warning{New contributors should read @ref{Quick start}, and in
8 particular @ref{lily-git}, instead of this chapter.}
10 Advanced contributors will find this material quite useful,
11 particularly if they are working on major new features.
14 * Manually installing lily-git.tcl::
16 * Basic Git procedures::
17 * Advanced Git procedures::
19 * Repository directory structure::
20 * Other Git documentation::
24 @node Manually installing lily-git.tcl
25 @section Manually installing lily-git.tcl
27 We have created an easy-to-use GUI to simplify git for new
28 contributors. If you are comfortable with the command-line, then
29 skip ahead to @ref{Starting with Git}.
31 @warning{These instructions are only for people who are @emph{not}
34 @c there's some duplication in this section with stuff covered in
35 @c Quick Start, but moving it into a macro inside included/ would
36 @c be getting a bit icky. -gp
40 If you haven't already, download and install Git.
44 @item Windows users: download the @code{.exe} file labeled
45 @qq{Full installer for official Git} from:
48 @uref{http://code.google.com/p/msysgit/downloads/list}
51 @item Other operating systems: either install @command{git} with
52 your package manager, or download it from the @qq{Binaries}
56 @uref{http://git-scm.com/download}
63 Download the @command{lily-git.tcl} script from:
65 @c don't change the cgit link below to gitweb; gitweb uses
66 @c long filenames like "scripts_auxiliar_lily-git.tcl"
69 @uref{http://git.sv.gnu.org/cgit/lilypond.git/plain/scripts/auxiliar/lily-git.tcl}
73 To run the program from the command line, navigate to the
74 directory containing @command{lily-git.tcl} and enter:
81 Click on the @qq{Get source} button.
83 This will create a directory called @file{lilypond-git/} within
84 your home directory, and will download the source code into that
85 directory (around 150@tie{}Mb). When the process is finished, the
86 @qq{Command output} window will display @qq{Done}, and the button
87 label will change to say @qq{Update source}.
90 Navigate to the @file{lilypond-git/} directory to view the source
95 @warning{Throughout the rest of this manual, most command-line
96 input should be entered from @file{~/lilypond-git/}. This is
97 referred to as the @emph{top source directory}.}
99 Further instructions are in @ref{How to use lily-git}.
102 @node Starting with Git
103 @section Starting with Git
105 Using the Git program directly (as opposed to using the
106 @command{lily-git.tcl} GUI) allows you to have much greater control
107 over the contributing process. You should consider using Git if
108 you want to work on complex projects, or if you want to work on
109 multiple projects concurrently.
114 * Git for the impatient::
115 * Other repositories::
116 * Downloading remote branches::
121 @subsection Setting up
123 @warning{These instructions assume that you are using the
124 command-line version of Git 1.5 or higher. Windows users should
125 skip to @ref{Git on Windows}.}
129 * Initializing a repository::
135 @unnumberedsubsubsec Installing Git
137 If you are using a Unix-based machine, the easiest way to download
138 and install Git is through a package manager such as @command{rpm}
139 or @command{apt-get} -- the installation is generally automatic.
140 The only required package is (usually) called @command{git-core},
141 although some of the auxiliary @command{git@var{*}} packages are
142 also useful (such as @command{gitk}).
144 Alternatively, you can visit the Git website
145 (@uref{http://git-scm.com/}) for downloadable binaries and
149 @node Initializing a repository
150 @unnumberedsubsubsec Initializing a repository
152 Once Git is installed, get a copy of the source code:
155 git clone git://git.sv.gnu.org/lilypond.git ~/lilypond-git
158 The above command will put the it in @file{~/lilypond-git}, where
159 @code{~} represents your home directory.
161 @subsubheading Technical details
163 This creates (within the @file{~/lilypond-git/} directory) a
164 subdirectory called @file{.git/}, which Git uses to keep track of
165 changes to the repository, among other things. Normally you don't
166 need to access it, but it's good to know it's there.
169 @node Configuring Git
170 @unnumberedsubsubsec Configuring Git
172 @warning{Throughout the rest of this manual, all command-line
173 input should be entered from the top directory of the Git
174 repository being discussed (eg. @file{~/lilypond-git/}). This is
175 referred to as the @emph{top source directory}.}
177 Before working with the copy of the main LilyPond repository, you
178 should configure some basic settings with the
179 @command{git@tie{}config} command. Git allows you to set both
180 global and repository-specific options.
182 To configure settings that affect all repositories, use the
183 @option{--global} command line option. For example, the first
184 two options that you should always set are your @var{name} and
185 @var{email}, since Git needs these to keep track of commit
189 git config --global user.name "@var{John Smith}"
190 git config --global user.email @var{john@@example.com}
193 To configure Git to use colored output where possible, use:
196 git config --global color.ui auto
199 The text editor that opens when using @command{git@tie{}commit}
200 can also be changed. If none of your editor-related environment
201 variables are set ($GIT_EDITOR, $VISUAL, or $EDITOR), the default
202 editor is usually @command{vi} or @command{vim}. If you're not
203 familiar with either of these, you should probably change the
204 default to an editor that you know how to use. For example, to
205 change the default editor to @command{nano}, enter:
208 git config --global core.editor @var{nano}
211 Finally, and in some ways most importantly, let's make sure that
212 we know what branch we're on. If you're not using LilyDev, add
213 this to your @file{~/.bashrc}:
216 export PS1="\u@\h \w\$(__git_ps1)$ "
219 If you are not using LilyDev, you may need to install the
220 additional @code{git-completion} package, but it is definitely
224 @subsubheading Technical details
226 Git stores the information entered with
227 @command{git@tie{}config@tie{}--global} in the file
228 @file{.gitconfig}, located in your home directory. This file can
229 also be modified directly, without using
230 @command{git@tie{}config}. The @file{.gitconfig} file generated
231 by the above commands would look like this:
236 email = john@@example.com
243 Using the @command{git@tie{}config} command @emph{without} the
244 @option{--global} option configures repository-specific settings,
245 which are stored in the file @file{.git/config}. This file is
246 created when a repository is initialized (using
247 @command{git@tie{}init}), and by default contains these lines:
251 repositoryformatversion = 0
254 logallrefupdates = true
257 However, since different repository-specific options are
258 recommended for different development tasks, it is best to avoid
259 setting any now. Specific recommendations will be mentioned later
263 @node Git for the impatient
264 @subsection Git for the impatient
266 @advanced{The intent of this subsection is to get you working on lilypond as
267 soon as possible. If you want to learn about git, go read
268 @ref{Other Git documentation}.
270 Also, these instructions are designed to eliminate the most common
271 problems we have found in using git. If you already know git and
272 have a different way of working, great! Feel free to ignore the
273 advice in this subsection.}
276 Ok, so you've been using @command{lily-git.tcl} for a while, but
277 it's time to take the next step. Since our review process delays
278 patches by 60-120 hours, and you want to be able to work on other
279 stuff while your previous work is getting reviewed, you're going
280 to use @strong{branches}.
282 You can think of a branch as being a separate copy of the source
283 code. But don't worry about it.
285 @subsubheading Start work: make a new branch
287 Let's pretend you want to add a section to the Contributor's Guide
288 about using branches.
290 Start by updating the repository, then making a new branch. Call
291 the branch anything you want as long as the name starts with
292 @code{dev/}. Branch names that don't begin with @code{dev/} are
293 reserved for special things in lilypond.
297 git pull -r origin master
301 @subsubheading Switch to that branch
303 Nothing has happened to the files yet. Let's change into the new
304 branch. You can think of this as @qq{loading a file}, although in
305 this case it's really @qq{loading a directory and subdirectories
312 Your prompt now shows you that you're on the other branch:
315 gperciva@@LilyDev:~/lilypond-git (dev/cg)$
318 To be able to manage multiple lilypond issues at once, you'll need to switch
319 branches. You should have each lilypond issue on a separate branch.
320 Switching branches is easy:
324 git checkout origin/staging
325 git checkout origin/release/unstable
329 Branches that begin with @code{origin/} are part of the remote repository,
330 rather than your local repository, so when you check them out you get a
331 temporary local branch. You should never make changes directly on a
332 branch beginning with @code{origin/}. You get changes into the remote
333 repository by making them in local branches, and then pushing them to
334 @code{origin/staging} as described below.
336 @subsubheading Make your changes
338 Edit files, then commit them.
345 Remember how I said that switching to a branch was like
346 @qq{loading a directory}? Well, you've just @qq{saved a
347 directory}, so that you can @qq{load} it later.
349 @advanced{If you have used @command{cvs} or @command{svn}, you may
350 be very confused: those programs use @qq{commit} to mean
351 @qq{upload my changes to the shared source repository}.
352 Unfortunately, just to be different, @w{@command{git commit}}
353 means @qq{save my changes to the files}.}
355 When you create a new file, you need to add it to git, then commit it:
358 git add input/regression/avoid-crash-on-condition.ly
363 Edit more files. Commit them again. Edit yet more files, commit
364 them again. Go eat dinner. Switch to @code{master} so you can
365 play with the latest changes from other developers. Switch back
366 to your branch and edit some more. Commit those changes.
368 At this stage, don't worry about how many commits you have.
371 @subsubheading Save commits to external files
373 Branches are nerve-wracking until you get used to them. You can
374 save your hard work as individual @file{.patch} files. Be sure to
375 commit your changes first.
379 git format-patch master
382 I personally have between 4 and 20 of those files saved in a
383 special folder at any point in time. Git experts might laugh as
384 that behavior, but I feel a @emph{lot} better knowing that I've
388 @subsubheading Prepare your branch for review
390 After committing, you can update your branch with the latest master:
395 git pull -r origin master
401 Due to the speed of lilypond development, sometimes
402 @code{master} has changed so much that your branch can no
403 longer be applied to it. In that happens, you will have a merge
404 conflict. Stop for a moment to either cry or have a stiff drink,
405 then proceed to @ref{Merge conflicts}.
408 @subsubheading Upload your branch
410 Finally, you're finished your changes. Time to upload for review.
411 Make sure that you're on your branch, then upload:
419 @subsubheading Wait for reviews
421 While you're waiting for a countdown and reviews, go back to
422 master, make a @code{dev/doc-beams} branch, and start adding doc
423 suggestions from issue 12345 from the tracker. Or make a
424 @code{dev/page-breaks} and fix bug in page breaking. Or whatever.
425 Don't worry, your @code{dev/cg} is safe.
428 @subsubheading Combining commits (optional unless you have broken commits)
430 Does the history of your branch look good?
436 If you have a lot of commits on your branch, you might want to
437 combine some of them. Alternately, you may like your commits, but
438 want to edit the commit messages.
444 Follow instructions on the screen.
446 @warning{This step gives you the power to completely lose your
447 work. Make a backup of your commits by saving them to
448 @file{.patch} files before playing with this. If you do lose
449 your work, don't despair. You can get it back by using @code{git reflog}.
450 The use of @code{git reflog} is not covered here.}
452 @warning{If any of the commits on your branch represent partial work that will
453 not pass @var{make && make doc}, you @strong{must} squash these
454 commits into a working commit. Otherwise, your push will break staging
455 and will not be able to be merged to master. In general, you will
456 be safer to have one commit per push.}
459 @subsubheading Push to staging
461 When you've got the coveted @code{Patch-push} status, time to
466 git rebase origin/staging dev/cg~0
470 @warning{Do not skip the @command{gitk} step; a quick 5-second
471 check of the visual history can save a great deal of frustration
472 later on. You should see a set of your commits that are ahead of
473 @code{origin/staging}, with no label for the top commit -- only a
476 @warning{If @code{origin/staging} and @code{origin/master} are the
477 same commit, your branch (@code{dev/cg} in the example) will also
478 be at the top of the @code{gitk} tree. This is normal.}
480 If everything looks good, push it:
483 git push origin HEAD:staging
486 Then change back to your working branch:
492 @warning{It is a best practice to avoid rebasing any of your branches
493 to @code{origin/staging}. If @code{origin/staging} is broken, it
494 will be deleted and rebuilt. If you have rebased one of your branches
495 to @code{origin/staging}, the broken commits can end up in your branch.
496 The commands given above do the rebase on a temporary branch, and avoid
497 changing your working branch.}
500 @subsubheading Delete your branch (safe)
502 After a few hours, if there's nothing wrong with your branch, it
503 should be automatically moved to @code{origin/master}. Update,
504 then try removing your branch:
508 git pull -r origin master
512 The last command will fail if the contents of @code{dev/cg} are
513 not present in @code{origin/master}.
516 @subsubheading Delete your branch (UNSAFE)
518 @c don't give explicit commands here -- this is too dangerous to copy and paste
519 Sometimes everything goes wrong. If you want to remove a branch even though
520 it will cause your work to be lost (that is, if the contents of @code{dev/cg}
521 are @strong{not} present in master), follow the instructions in @qq{Delete
522 your branch (safe)}, but replace the @code{-d} on the final line with
526 @node Other repositories
527 @subsection Other repositories
529 We have a few other code repositories.
533 * Grand Unified Builder (GUB)::
535 * yet more repositories::
539 @unnumberedsubsubsec lilypond-extra
541 There is a separate repository for general administrative scripts,
542 as well as pictures and media files for the website. People
543 interested in working on the website should download this
544 repository, and set their @code{$LILYPOND_WEB_MEDIA_GIT}
545 environment variable to point to that repository.
548 @uref{https://github.com/gperciva/lilypond-extra}
551 To configure an environment variable in bash (the default for most
552 GNU/Linux distributions),
555 export LILYPOND_WEB_MEDIA_GIT=$HOME/dir/of/lilypond-extra/
558 @node Grand Unified Builder (GUB)
559 @unnumberedsubsubsec Grand Unified Builder (GUB)
561 Another item of interest might be the Grand Unified Builder, our
562 cross-platform building tool. Since it is used by other projects as
563 well, it is not stored in our gub repository. For more info, see
564 @uref{http://lilypond.org/gub}.
566 There are two locations for this repository: the version being used to
567 build lilypond, which is at
570 @uref{http://github.com/gperciva/gub}
573 and the original version by Jan Nieuwenhuizen, kept at
576 @uref{http://github.com/janneke/gub}
581 @unnumberedsubsubsec lilypad
583 Our binary releases on MacOS X and Windows contain a lightweight
584 text editor. This code is here:
587 https://github.com/gperciva/lilypad
591 @node yet more repositories
592 @unnumberedsubsubsec yet more repositories
594 There are a few other repositories floating around, which will
595 hopefully be documented in the near future.
598 @node Downloading remote branches
599 @subsection Downloading remote branches
601 @warning{contains obsolete + misleading info}
604 * Organization of remote branches::
605 * LilyPond repository sources::
606 * Downloading individual branches::
607 * Downloading all remote branches::
612 @node Organization of remote branches
613 @unnumberedsubsubsec Organization of remote branches
616 The main LilyPond repository is organized into @emph{branches} to
617 facilitate development. These are often called @emph{remote}
618 branches to distinguish them from @emph{local} branches you might
619 create yourself (see @ref{Using local branches}).
621 The @code{master} branch contains all the source files used to
622 build LilyPond, which includes the program itself (both stable and
623 development releases), the documentation (and its translations),
624 and the website. Generally, the @code{master} branch is expected
625 to compile successfully.
627 The @code{translation} branch is a side branch that
628 allows translators to work without needing to worry about
629 compilation problems. Periodically, the Translation Meister
630 (after verifying that it doesn't break compilation), will
631 @emph{merge} this branch into @code{staging} to incorporate
632 recent translations. Similarly, the @code{master} branch is
633 usually merged into the @code{translation} branch after
634 significant changes to the English documentation. See
635 @ref{Translating the documentation} for details.
638 @node LilyPond repository sources
639 @unnumberedsubsubsec LilyPond repository sources
642 The recommended source for downloading a copy of the main
646 git://git.sv.gnu.org/lilypond.git
649 However, if your internet router filters out connections using the
650 GIT protocol, or if you experience difficulty connecting via GIT,
651 you can try these other sources:
654 ssh://git.sv.gnu.org/srv/git/lilypond.git
655 http://git.sv.gnu.org/r/lilypond.git
658 The SSH protocol can only be used if your system is properly set
659 up to use it. Also, the HTTP protocol is slowest, so it should
660 only be used as a last resort.
663 @node Downloading individual branches
664 @unnumberedsubsubsec Downloading individual branches
666 @warning{obsolete, should be deleted!}
669 Once you have initialized an empty Git repository on your system
670 (see @ref{Initializing a repository}), you can download a remote
671 branch into it. Make sure you know which branch you want to start
674 To download the @code{master} branch, enter the following:
677 git remote add -ft master -m master \
678 origin git://git.sv.gnu.org/lilypond.git/
681 To download the @code{translation} branch, enter:
684 git remote add -ft translation -m \
685 translation origin git://git.sv.gnu.org/lilypond.git/
688 The @command{git@tie{}remote@tie{}add} process could take up to
689 ten minutes, depending on the speed of your connection. The
690 output will be something like this:
694 remote: Counting objects: 235967, done.
695 remote: Compressing objects: 100% (42721/42721), done.
696 remote: Total 235967 (delta 195098), reused 233311 (delta 192772)
697 Receiving objects: 100% (235967/235967), 68.37 MiB | 479 KiB/s, done.
698 Resolving deltas: 100% (195098/195098), done.
699 From git://git.sv.gnu.org/lilypond
700 * [new branch] master -> origin/master
701 From git://git.sv.gnu.org/lilypond
702 * [new tag] flower/1.0.1 -> flower/1.0.1
703 * [new tag] flower/1.0.10 -> flower/1.0.10
705 * [new tag] release/2.9.6 -> release/2.9.6
706 * [new tag] release/2.9.7 -> release/2.9.7
709 When @command{git@tie{}remote@tie{}add} is finished, the remote
710 branch should be downloaded into your repository---though not yet
711 in a form that you can use. In order to browse the source code
712 files, you need to @emph{create} and @emph{checkout} your own
713 local branch. In this case, however, it is easier to have Git
714 create the branch automatically by using the @command{checkout}
715 command on a non-existent branch. Enter the following:
718 git checkout -b @var{branch} origin/@var{branch}
722 where @code{@var{branch}} is the name of your tracking branch,
723 either @code{master} or @code{translation}.
725 Git will issue some warnings; this is normal:
728 warning: You appear to be on a branch yet to be born.
729 warning: Forcing checkout of origin/master.
730 Branch master set up to track remote branch master from origin.
734 By now the source files should be accessible---you should be able
735 to edit any files in the @file{lilypond-git/} directory using a
736 text editor of your choice. But don't start just yet! Before
737 editing any source files, learn how to keep your changes organized
738 and prevent problems later---read @ref{Basic Git procedures}.
740 @subsubheading Technical Details
742 The @command{git@tie{}remote@tie{}add} command should add some
743 lines to your local repository's @file{.git/config} file:
747 url = git://git.sv.gnu.org/lilypond.git/
748 fetch = +refs/heads/master:refs/remotes/origin/master
752 @node Downloading all remote branches
753 @unnumberedsubsubsec Downloading all remote branches
756 To download all remote branches at once, you can @command{clone}
757 the entire repository:
760 git clone git://git.sv.gnu.org/lilypond.git
765 @unnumberedsubsubsec Other branches
767 Most contributors will never need to touch the other branches. If
768 you wish to do so, you will need more familiarity with Git; please
769 see @ref{Other Git documentation}.
772 @item @code{dev/XYZ}:
773 These branches are for individual developers. They store code
774 which is not yet stable enough to be added to the @code{master}
777 @item @code{stable/XYZ}:
778 The branches are kept for archival reasons.
780 @item @code{archive/XYZ}:
781 The branches are kept for archival reasons.
786 @node Basic Git procedures
787 @section Basic Git procedures
791 * The Git contributor's cycle::
792 * Pulling and rebasing::
793 * Using local branches::
794 * Commits and patches::
798 @node The Git contributor's cycle
799 @subsection The Git contributor's cycle
802 Here is a simplified view of the contribution process on Git:
806 Update your local repository by @emph{pulling} the most recent
807 updates from the remote repository.
810 Edit source files within your local repository's @emph{working
814 @emph{Commit} the changes you've made to a local @emph{branch}.
817 Generate a @emph{patch} to share your changes with the developers.
821 @node Pulling and rebasing
822 @subsection Pulling and rebasing
825 When developers push new patches to the @code{git.sv.gnu.org}
826 repository, your local repository is @strong{not} automatically
827 updated. It is important to keep your repository up-to-date by
828 periodically @emph{pulling} the most recent @emph{commits} from
829 the remote branch. Developers expect patches to be as current as
830 possible, since outdated patches require extra work before they
833 Occasionally you may need to rework some of your own modifications
834 to match changes made to the remote branch (see @ref{Resolving
835 conflicts}), and it's considerably easier to rework things
836 incrementally. If you don't update your repository along the way,
837 you may have to spend a lot of time resolving branch conflicts and
838 reconfiguring much of the work you've already done.
840 Fortunately, Git is able to resolve certain types of branch
841 conflicts automatically with a process called @emph{rebasing}.
842 When rebasing, Git tries to modify your old commits so they appear
843 as new commits (based on the latest updates). For a more involved
844 explanation, see the @command{git-rebase} man page.
846 To pull without rebasing (recommended for translators), use the
850 git pull # recommended for translators
853 If you're tracking the remote @code{master} branch, you should add
854 the @option{-r} option (short for @option{--rebase}) to keep commits
855 on your local branch current:
858 git pull -r # use with caution when translating
861 If you don't edit translated documentation and don't want to type
862 @option{-r} every time, configure the master branch to rebase by
863 default with this command:
866 git config branch.master.rebase true
869 If pull fails because of a message like
872 error: Your local changes to 'Documentation/learning/tutorial.itely'
873 would be overwritten by merge. Aborting.
880 Documentation/learning/tutorial.itely: needs update
881 refusing to pull with rebase: your working tree is not up-to-date
885 it means that you have modified some files in you working tree
886 without committing changes (see @ref{Commits and patches}); you
887 can use the @command{git@tie{}stash} command to work around this:
890 git stash # save uncommitted changes
891 git pull -r # pull using rebase (translators omit "-r")
892 git stash pop # reapply previously saved changes
895 Note that @command{git@tie{}stash@tie{}pop} will try to apply a
896 patch, and this may create a conflict. If this happens, see
897 @ref{Resolving conflicts}.
899 TODO: I think the next paragraph is confusing. Perhaps prepare
900 the reader for new terms `committish' and `head'? -mp
902 @warning{translators and documentation editors, if you have
903 changed committishes in the head of translated files using commits
904 you have not yet pushed to @code{git.sv.gnu.org}, please do not
905 rebase. If you want to avoid wondering whether you should rebase
906 each time you pull, please always use committishes from master
907 and/or translation branch on @code{git.sv.gnu.org}, which
908 in particular implies that you must push your changes to
909 documentation except committishes updates (possibly after having
910 rebased), then update the committishes and push them.}
912 TODO: when committishes automatic conditional update have been
913 tested and documented, append the following to the warning above:
914 Note that using update-committishes make target generally touches
917 @subsubheading Technical details
919 The @command{git@tie{}config} command mentioned above adds the
920 line @code{rebase = true} to the master branch in your local
921 repository's @file{.git/config} file:
926 merge = refs/heads/master
931 @node Using local branches
932 @subsection Using local branches
936 * Creating and removing branches::
937 * Listing branches and remotes::
938 * Checking out branches::
943 @node Creating and removing branches
944 @unnumberedsubsubsec Creating and removing branches
947 Local branches are useful when you're working on several different
948 projects concurrently. To create a new branch, enter:
951 git branch @var{name}
954 To delete a branch, enter:
957 git branch -d @var{name}
960 Git will ask you for confirmation if it sees that data would be
961 lost by deleting the branch. Use @option{-D} instead of @option{-d}
962 to bypass this. Note that you cannot delete a branch if it is
963 currently checked out.
966 @node Listing branches and remotes
967 @unnumberedsubsubsec Listing branches and remotes
969 You can get the exact path or URL of all remote branches by
976 To list Git branches on your local repositories, run
979 git branch # list local branches only
980 git branch -r # list remote branches
981 git branch -a # list all branches
985 @node Checking out branches
986 @unnumberedsubsubsec Checking out branches
988 To know the currently checked out branch, i.e. the branch whose
989 source files are present in your working tree, read the first line
997 The currently checked out branch is also marked with an asterisk
998 in the output of @command{git branch}.
1000 You can check out another branch @code{@var{other_branch}}, i.e.
1001 check out @code{@var{other_branch}} to the working tree, by
1005 git checkout @var{other_branch}
1008 Note that it is possible to check out another branch while having
1009 uncommitted changes, but it is not recommended unless you know
1010 what you are doing; it is recommended to run @command{git status}
1011 to check this kind of issue before checking out another branch.
1013 @node Merging branches
1014 @unnumberedsubsubsec Merging branches
1016 To merge branch @code{@var{foo}} into branch @code{@var{bar}},
1017 i.e. to @qq{add} all changes made in branch @code{@var{foo}} to
1018 branch @code{@var{bar}}, run
1021 git checkout @var{bar}
1025 If any conflict happens, see @ref{Resolving conflicts}.
1027 There are common usage cases for merging: as a translator, you will
1028 often want the Translations meister to merge @code{master} into
1029 @code{translation}; on the other hand, the Translations meister wants
1030 to merge @code{translation} into @code{staging} whenever he has
1031 checked that @code{translation} builds successfully.
1034 @node Commits and patches
1035 @subsection Commits and patches
1039 * Understanding commits::
1043 * Uploading a patch for review::
1047 @node Understanding commits
1048 @unnumberedsubsubsec Understanding commits
1050 Technically, a @emph{commit} is a single point in the history of a
1051 branch, but most developers use the term to mean a @emph{commit
1052 object}, which stores information about a particular revision. A
1053 single commit can record changes to multiple source files, and
1054 typically represents one logical set of related changes (such as a
1055 bug-fix). You can list the ten most recent commits in your
1056 current branch with this command:
1059 git log -10 --oneline
1062 If you're using an older version of Git and get an @q{unrecognized
1063 argument} error, use this instead:
1066 git log -10 --pretty=oneline --abbrev-commit
1069 More interactive lists of the commits on the remote @code{master}
1070 branch are available at
1071 @uref{http://git.sv.gnu.org/gitweb/?p=lilypond.git;a=shortlog} and
1072 @uref{http://git.sv.gnu.org/cgit/lilypond.git/log/}.
1075 @node Making commits
1076 @unnumberedsubsubsec Making commits
1079 Once you have modified some source files in your working
1080 directory, you can make a commit with the following procedure:
1084 Make sure you've configured Git properly (see @ref{Configuring
1085 Git}). Check that your changes meet the requirements described in
1086 @ref{Code style} and/or @ref{Documentation policy}. For advanced
1087 edits, you may also want to verify that the changes don't break
1088 the compilation process.
1091 Run the following command:
1098 to make sure you're on the right branch, and to see which files
1099 have been modified, added or removed, etc. You may need to tell
1100 Git about any files you've added by running one of these:
1103 git add @var{file} # add untracked @var{file} individually
1104 git add . # add all untracked files in current directory
1108 After @command{git@tie{}add}, run @command{git@tie{}status} again
1109 to make sure you got everything. You may also need to modify
1113 Preview the changes about to be committed (to make sure everything
1121 The @code{HEAD} argument refers to the most recent commit on the
1122 currently checked-out branch.
1125 Generate the commit with:
1132 The @option{-a} is short for @option{--all} which includes modified
1133 and deleted files, but only those newly created files that have
1134 previously been added.
1139 @node Commit messages
1140 @unnumberedsubsubsec Commit messages
1143 When you run the @command{git@tie{}commit@tie{}-a} command, Git
1144 automatically opens the default text editor so you can enter a
1145 @emph{commit message}. If you find yourself in a foreign editing
1146 environment, you're probably in @command{vi} or @command{vim}. If
1147 you want to switch to an editor you're more familiar with, quit by
1148 typing @code{:q!} and pressing @code{<Enter>}. See
1149 @ref{Configuring Git} for instructions on changing the default
1152 In any case, Git will open a text file for your commit message
1153 that looks like this:
1157 # Please enter the commit message for your changes. Lines starting
1158 # with '#' will be ignored, and an empty message aborts the commit.
1160 # Changes to be committed:
1161 # (use "git reset HEAD <file>..." to unstage)
1163 # modified: working.itexi
1167 Your commit message should begin with a one-line summary
1168 describing the change (no more than 50 characters long), and if
1169 necessary a blank line followed by several lines giving the
1172 @c $ git log -1 --pretty=medium 4d6f1e5
1174 Doc: add Baerenreiter and Henle solo cello suites
1176 Added comparison of solo cello suite engravings to new essay with
1177 high-res images, fixed cropping on Finale example.
1180 Commit messages often start with a short prefix describing the
1181 general location of the changes. If a commit affects the
1182 documentation in English (or in several languages simultaneously)
1183 the commit message should be prefixed with @qq{Doc:@tie{}}. If
1184 the commit affects only one of the translations, the commit
1185 message should be prefixed with @qq{Doc-@var{**}:@tie{}}, where
1186 @var{**} is the two-letter language code. Commits that affect the
1187 website should use @qq{Web:@tie{}} for English, and
1188 @qq{Web-@var{**}:@tie{}} for the other languages. Also, changes
1189 to a single file are often prefixed with the name of the file
1190 involved. Visit the links listed in @ref{Understanding commits}
1194 @node Making patches
1195 @unnumberedsubsubsec Making patches
1197 If you want to share your changes with other contributors and
1198 developers, you need to generate @emph{patches} from your commits.
1199 We prefer it if you follow the instructions in
1200 @ref{Uploading a patch for review}. However, we present an
1201 alternate method here.
1203 You should always run @command{git@tie{}pull@tie{}-r} (translators
1204 should leave off the @option{-r}) before doing this to ensure that
1205 your patches are as current as possible.
1207 Once you have made one or more commits in your local repository,
1208 and pulled the most recent commits from the remote branch, you can
1209 generate patches from your local commits with the command:
1212 git format-patch origin
1215 The @code{origin} argument refers to the remote tracking branch at
1216 @code{git.sv.gnu.org}. This command generates a separate patch
1217 for each commit that's in the current branch but not in the remote
1218 branch. Patches are placed in the current working directory and
1219 will have names that look something like this:
1222 0001-Doc-Fix-typos.patch
1223 0002-Web-Remove-dead-links.patch
1227 Send an email (must be less than 64 KB) to
1228 @email{lilypond-devel@@gnu.org} briefly explaining your work, with
1229 the patch files attached. Translators should send patches to
1230 @email{translations@@lilynet.net}. After your patches are
1231 reviewed, the developers may push one or more of them to the main
1232 repository or discuss them with you.
1235 @node Uploading a patch for review
1236 @unnumberedsubsubsec Uploading a patch for review
1238 Any non-trivial change should be uploaded to our @qq{Rietveld}
1239 code review website:
1242 @uref{http://codereview.appspot.com/}
1245 @subsubheading @command{git-cl} install
1247 LilyDev users should skip over these @q{install} instructions.
1252 Install @command{git-cl} by entering:
1255 git clone https://github.com/gperciva/git-cl.git
1258 If that command fails for some reason, try this instead:
1261 git clone git://github.com/gperciva/git-cl.git
1265 Add the @file{git-cl/} directory to your PATH,
1266 or create a symbolic link to the @command{git-cl}
1267 and @command{upload.py} scripts in one of your PATH
1268 directories (such as @file{$HOME/bin}).
1270 In Ubuntu (and LilyDev), you can add directories to PATH
1271 by adding this line to a hidden file @file{.bashrc},
1272 located in your home directory:
1275 PATH=~/type-here-directory-containing-git-cl:"$@{PATH@}"
1280 @subsubheading @command{git-cl} configuration
1282 LilyDev users should perform these @q{configuration} instructions.
1286 You must have a google account; please create one if you do not
1289 Note that a google account does not need to be a gmail account; you can
1290 use any email address for your google account when you sign up.
1293 Move into the top source directory and then configure @command{git
1294 cl} with the following commands. If you do not understand any
1295 question, just answer with a newline (CR).
1298 cd $HOME/lilypond-git/
1302 The @qq{CC list} question should be answered with:
1305 lilypond-devel@@gnu.org
1310 @subsubheading Uploading patch set
1312 @warning{Unless you are familiar with branches, only work on one
1313 set of changes at once.}
1315 There are two methods, depending on your git setup.
1319 @strong{Master branch}: (easy option, and used in @command{lily-git.tcl})
1321 If you added your patch to @code{master}, then:
1325 git cl upload origin/master
1328 @c Mention staging here?
1329 If you have git push ability, make sure that you @emph{remove}
1330 your patch (with @command{git rebase} or @command{git reset})
1331 before pushing other stuff.
1333 @c don't make this one an @example; we don't want to make it easy
1334 @c for people to use this accidently
1335 Notifications of patches are automatically added to our issue
1336 tracker to reduce the chance of patches getting lost. To suppress
1337 this (not recommended), add the @code{-n / --no-code-issue}
1341 @strong{Separate branch}: (complicated option)
1343 Ensure your changes are committed in a separate branch, which
1344 should differ from the reference branch to be used by just the
1345 changes to be uploaded. If the reference branch is to be
1346 origin/master, ensure this is up-to-date. If necessary, use git
1347 rebase to rebase the branch containing the changes to the head of
1348 origin/master. Finally, check out branch with the changes and
1352 git cl upload <reference SHA1 ID>
1356 where <reference SHA1 ID> is the SHA1 ID of the commit to be used
1357 as a reference source for the patch. Generally, this will be the
1358 SHA1 ID of origin/master, and in that case the command:
1361 git cl upload origin/master
1369 After prompting for your Google email address and password, the
1370 patch set will be posted to Rietveld, and you will be given a URL
1373 @warning{Some installations of git-cl fail when uploading a patch
1374 with certain filename extensions. If this happens, it can
1375 generally be fixed by editing the list of exceptions at top of
1378 @subsubheading Announcing your patch set
1380 You should then announce the patch by logging into the code review
1381 issue webpage and using @qq{Publish + Mail Comments} to add a
1382 (mostly bogus) comment to your issue. The text of your comment
1383 will be sent to our developer mailing list.
1385 @warning{There is no automatic notification of a new patch; you
1386 must add a comment yourself.}
1388 @subsubheading Revisions
1390 As revisions are made in response to comments, successive patch sets
1391 for the same issue can be uploaded by reissuing the git-cl command
1392 with the modified branch checked out.
1394 Sometimes in response to comments on revisions, the best way to
1395 work may require creation of a new branch in git. In order to
1396 associate the new branch with an existing Rietveld issue,
1397 the following command can be used:
1400 git cl issue issue-number
1404 where @code{issue-number} is the number of the existing Rietveld
1407 @subsubheading Resetting git cl
1409 If @command{git cl} becomes confused, you can @qq{reset} it by
1416 @subsubheading Wait for a countdown
1418 Your patch will be available for reviews for the next few hours or
1419 days. Three times a week, patches with no known problems are
1420 gathered into a @qq{patch countdown} and their status changed to
1421 @code{patch-countdown}. The countdown is a 48-hour waiting period
1422 in which any final reviews or complaints should be made.
1424 During the countdown, your patch may be set to
1425 @code{patch-needs_work}, indicating that you should fix something
1426 (or at least discuss why the patch needs no modification). If no
1427 problems are found, the patch will be set to @code{patch-push}.
1429 Once a patch has @code{patch-push}, it should be sent to your
1430 mentor for uploading. If you have git push ability, look at
1431 @ref{Pushing to staging}.
1434 @node Advanced Git procedures
1435 @section Advanced Git procedures
1438 @warning{This section is not necessary for normal contributors;
1439 these commands are presented for information for people interested
1440 in learning more about git.}
1442 It is possible to work with several branches on the same local Git
1443 repository; this is especially useful for translators who may have
1444 to deal with both @code{translation} and a stable branch,
1445 e.g. @code{stable/2.12}.
1447 Some Git commands are introduced first, then a workflow with
1448 several Git branches of LilyPond source code is presented.
1453 * Advanced Git concepts::
1454 * Resolving conflicts::
1455 * Reverting all local changes::
1456 * Working with remote branches::
1458 * Applying remote patches::
1459 * Sending and receiving patches via email::
1460 * Cleaning up multiple patches::
1462 * Pushing to staging::
1466 @node Merge conflicts
1467 @subsection Merge conflicts
1469 To be filled in later, and/or moved to a different section. I
1470 just wanted to make sure that I had a stub ready somewhere.
1473 @node Advanced Git concepts
1474 @subsection Advanced Git concepts
1477 A bit of Git vocabulary will be explained below. The following is
1478 only introductory; for a better understanding of Git concepts, you
1479 may wish to read @ref{Other Git documentation}.
1481 The @code{git@tie{}pull@tie{}origin} command above is just a
1482 shortcut for this command:
1485 git pull git://git.sv.gnu.org/lilypond.git/ @var{branch}:origin/@var{branch}
1489 where @code{@var{branch}} is typically @code{master} or
1490 @code{translation}; if you do not know or remember, see
1491 @ref{Downloading remote branches} to remember which commands you
1492 issued or which source code you wanted to get.
1494 A @emph{commit} is a set of changes made to the sources; it also
1495 includes the committish of the parent commit, the name and e-mail
1496 of the @emph{author} (the person who wrote the changes), the name
1497 and e-mail of the @emph{committer} (the person who brings these
1498 changes into the Git repository), and a commit message.
1500 A @emph{committish} is the SHA1 checksum of a commit, a number
1501 made of 40 hexadecimal digits, which acts as the internal unique
1502 identifier for this commit. To refer to a particular revision,
1503 don't use vague references like the (approximative) date, simply
1504 copy and paste the committish.
1506 A @emph{branch} is nothing more than a pointer to a particular
1507 commit, which is called the @emph{head} of the branch; when
1508 referring to a branch, one often actually thinks about its head
1509 and the ancestor commits of the head.
1511 Now we will explain the two last commands you used to get the
1512 source code from Git---see @ref{Downloading individual branches}.
1515 git remote add -ft @var{branch} -m @var{branch} \
1516 origin git://git.sv.gnu.org/lilypond.git/
1518 git checkout -b @var{branch} origin/@var{branch}
1521 The @command{git@tie{}remote} has created a branch called
1522 @code{origin/@var{branch}} in your local Git repository. As this
1523 branch is a copy of the remote branch web from git.sv.gnu.org
1524 LilyPond repository, it is called a @emph{remote branch}, and is
1525 meant to track the changes on the branch from git.sv.gnu.org: it
1526 will be updated every time you run
1527 @command{git@tie{}pull@tie{}origin} or
1528 @command{git@tie{}fetch@tie{}origin}.
1530 The @command{git@tie{}checkout} command has created a branch named
1531 @code{@var{branch}}. At the beginning, this branch is identical
1532 to @code{origin/@var{branch}}, but it will differ as soon as you
1533 make changes, e.g. adding newly translated pages or editing some
1534 documentation or code source file. Whenever you pull, you merge
1535 the changes from @code{origin/@var{branch}} and
1536 @code{@var{branch}} since the last pulling. If you do not have
1537 push (i.e. @qq{write}) access on git.sv.gnu.org, your
1538 @code{@var{branch}} will always differ from
1539 @code{origin/@var{branch}}. In this case, remember that other
1540 people working like you with the remote branch @code{@var{branch}}
1541 of git://git.sv.gnu.org/lilypond.git/ (called
1542 @code{origin/@var{branch}} on your local repository) know nothing
1543 about your own @code{@var{branch}}: this means that whenever you
1544 use a committish or make a patch, others expect you to take the
1545 latest commit of @code{origin/@var{branch}} as a reference.
1547 Finally, please remember to read the man page of every Git command
1548 you will find in this manual in case you want to discover
1549 alternate methods or just understand how it works.
1552 @node Resolving conflicts
1553 @subsection Resolving conflicts
1556 Occasionally an update may result in conflicts -- this happens
1557 when you and somebody else have modified the same part of the same
1558 file and git cannot figure out how to merge the two versions
1559 together. When this happens, you must manually merge the two
1562 If you need some documentation to understand and resolve
1563 conflicts, see paragraphs @emph{How conflicts are presented} and
1564 @emph{How to resolve conflicts} in @command{git merge} man page.
1566 If all else fails, you can follow the instructions in
1567 @ref{Reverting all local changes}. Be aware that this eliminates
1568 any changes you have made!
1571 @node Reverting all local changes
1572 @subsection Reverting all local changes
1574 Sometimes git will become hopelessly confused, and you just want
1575 to get back to a known, stable state. This command destroys any
1576 local changes you have made in the currently checked-out branch,
1577 but at least you get back to the current online version:
1580 git reset --hard origin/master
1584 @node Working with remote branches
1585 @subsection Working with remote branches
1588 @subsubheading Fetching new branches from git.sv.gnu.org
1590 To fetch and check out a new branch named @code{@var{branch}} on
1591 git.sv.gnu.org, run from top of the Git repository
1594 git config --add remote.origin.fetch \
1595 +refs/heads/@var{branch}:refs/remotes/origin/@var{branch}
1597 git checkout --track -b @var{branch} origin/@var{branch}
1600 After this, you can pull @code{@var{branch}} from git.sv.gnu.org
1607 Note that this command generally fetches all branches you added
1608 with @command{git@tie{}remote@tie{}add} (when you initialized the
1609 repository) or @command{git@tie{}config@tie{}--add}, i.e. it
1610 updates all remote branches from remote @code{origin}, then it
1611 merges the remote branch tracked by the current branch into the
1612 current branch. For example, if your current branch is
1613 @code{master}, @code{origin/master} will be merged into
1617 @subsubheading Local clones, or having several working trees
1619 If you play with several Git branches, e.g. @code{master},
1620 @code{translation}, @code{stable/2.12}), you may want to
1621 have one source and build tree for each branch; this is possible
1622 with subdirectories of your local Git repository, used as local
1623 cloned subrepositories. To create a local clone for the branch
1624 named @code{@var{branch}}, run
1627 git checkout @var{branch}
1628 git clone -lsn . @var{subdir}
1633 Note that @code{@var{subdir}} must be a directory name which does
1634 not already exist. In @code{@var{subdir}}, you can use all Git
1635 commands to browse revisions history, commit and uncommit changes;
1636 to update the cloned subrepository with changes made on the main
1637 repository, cd into @code{@var{subdir}} and run
1638 @command{git@tie{}pull}; to send changes made on the subrepository
1639 back to the main repository, run @command{git@tie{}push} from
1640 @code{@var{subdir}}. Note that only one branch (the currently
1641 checked out branch) is created in the subrepository by default; it
1642 is possible to have several branches in a subrepository and do
1643 usual operations (checkout, merge, create, delete...) on these
1644 branches, but this possibility is not detailed here.
1646 When you push @code{@var{branch}} from @code{@var{subdir}} to the
1647 main repository, and @code{@var{branch}} is checked out in the
1648 main repository, you must save uncommitted changes (see
1649 @command{git@tie{}stash}) and do
1650 @command{git@tie{}reset@tie{}--hard} in the main repository in
1651 order to apply pushed changes in the working tree of the main
1659 The commands above don't only bring you the latest version of the
1660 sources, but also the full history of revisions (revisions, also
1661 called commits, are changes made to the sources), stored in the
1662 @file{.git} directory. You can browse this history with
1665 git log # only shows the logs (author, committish and commit message)
1666 git log -p # also shows diffs
1667 gitk # shows history graphically
1670 @warning{The @code{gitk} command may require a separate
1671 @code{gitk} package, available in the appropriate distribution's
1675 @node Applying remote patches
1676 @subsection Applying remote patches
1679 TODO: Explain how to determine if a patch was created with
1680 @code{git@tie{}format-patch}.
1682 Well-formed git patches created with @code{git@tie{}format-patch}
1683 should be committed with the following command:
1689 Patches created without @code{git@tie{}format-patch} can be
1690 applied in two steps. The first step is to apply the patch to the
1691 working tree and the index:
1694 git apply --index @var{patch}
1698 The second step is to commit the changes and give credit to the
1699 author of the patch. This can be done with the following command:
1702 git commit --author="@var{John Smith} <@var{john@@example.com}>"
1705 Please note that using the @code{--index} option for patching is quite
1706 important here and @emph{cannot} reliably be replaced by using the
1707 @code{-a} option when committing: that would only commit files from the
1708 working tree that are already registered with git, so every file that
1709 the patch actually @emph{adds}, like a regtest for a fixed bug, would
1710 get lost. For the same reason, you should not use the git-independent
1711 @samp{patch} program for applying patches.
1713 @node Sending and receiving patches via email
1714 @subsection Sending and receiving patches via email
1717 The default @code{x-diff} MIME type associated with patch files
1718 (i.e., files whose name ends in @code{.patch}) means that the
1719 encoding of line endings may be changed from UNIX to DOS format
1720 when they are sent as attachments. Attempting to apply such an
1721 inadvertently altered patch will cause git to fail with a message
1722 about @q{whitespace errors}.
1724 The solution to such problems is surprisingly simple---just change
1725 the default file extension of patches generated by git to end in
1726 @code{.txt}, for example:
1729 git config format.suffix '.patch.txt'
1732 This should cause email programs to apply the correct base64
1733 encoding to attached patches.
1735 If you receive a patch with DOS instead of UNIX line-endings, it
1736 can be converted back using the @code{dos2unix} utility.
1738 Lots of useful information on email complications with patches is
1739 provided on the Wine wiki at
1740 @uref{http://wiki.winehq.org/GitWine}.
1743 @node Cleaning up multiple patches
1744 @subsection Cleaning up multiple patches
1746 If you have been developing on your own branch for a while, you
1747 may have more commmits than is really sensible. To revise your
1748 work and condense commits, use:
1751 git rebase origin/master
1752 git rebase -i origin/master
1755 @warning{Be a bit cautious -- if you completely remove commits
1756 during the interactive session, you will... err... completely
1757 remove those commits.}
1761 @subsection Commit access
1763 Most contributors are not able to commit patches directly to the
1764 main repository---only members of the LilyPond development team
1765 have @emph{commit access}. If you are a contributor and are
1766 interested in joining the development team, contact the Project
1767 Manager through the mailing list
1768 (@email{lilypond-devel@@gnu.org}). Generally, only contributors
1769 who have already provided a number of patches which have been
1770 pushed to the main repository will be considered for membership.
1772 If you have been approved by the Project Manager, use the
1773 following procedure to obtain commit access:
1777 If you don't already have one, set up a Savannah user account at
1778 @uref{https://savannah.gnu.org/account/register.php}. If your web
1779 browser responds with an @qq{untrusted connection} message when
1780 you visit the link, follow the steps for including the CAcert root
1781 certificate in your browser, given at
1782 @uref{http://savannah.gnu.org/tls/tutorial/}.
1784 @warning{Savannah will silently put your username in lower-case --
1785 do not try to use capital letters.}
1789 After registering, if you are not logged in automatically, login
1790 at @uref{https://savannah.gnu.org/account/login.php}---this should
1791 take you to your @qq{my} page
1792 (@uref{https://savannah.gnu.org/my/}).
1796 Click on the @qq{My Groups} link to access the @qq{My Group
1797 Membership} page. From there, find the @qq{Request for Inclusion}
1798 box and search for @qq{LilyPond}. Among the search results, check
1799 the box labeled @qq{GNU LilyPond Music Typesetter} and write a
1800 brief (required) message for the Project Manager (@qq{Hey it's
1801 me!} should be fine).
1803 Note that you will not have commit access until the Project
1804 Manager activates your membership. Once your membership is
1805 activated, LilyPond should appear under the heading @qq{Groups I'm
1806 Contributor of} on your @qq{My Group Membership} page.
1810 Generate an SSH @q{rsa} key pair. Enter the following at the
1817 When prompted for a location to save the key, press <ENTER> to
1818 accept the default location (@file{~/.ssh/id_rsa}).
1820 Next you are asked to enter an optional passphrase. On most
1821 systems, if you use a passphrase, you will likely be prompted for
1822 it every time you use @command{git@tie{}push} or
1823 @command{git@tie{}pull}. You may prefer this since it can protect
1824 you from your own mistakes (like pushing when you mean to pull),
1825 though you may find it tedious to keep re-entering it.
1827 You can change/enable/disable your passphrase at any time with:
1830 ssh-keygen -f ~/.ssh/id_rsa -p
1833 Note that the GNOME desktop has a feature which stores your
1834 passphrase for you for an entire GNOME session. If you use a
1835 passphrase to @qq{protect you from yourself}, you will want to
1836 disable this feature, since you'll only be prompted once. Run the
1837 following command, then logout of GNOME and log back in:
1840 gconftool-2 --set -t bool \
1841 /apps/gnome-keyring/daemon-components/ssh false
1844 After setting up your passphrase, your private key is saved as
1845 @file{~/.ssh/id_rsa} and your public key is saved as
1846 @file{~/.ssh/id_rsa.pub}.
1850 Register your public SSH @q{rsa} key with Savannah. From the
1851 @qq{My Account Configuration} page, click on @qq{Edit SSH Keys},
1852 then paste the contents of your @file{~/.ssh/id_rsa.pub} file into
1853 one of the @qq{Authorized keys} text fields, and click
1856 Savannah should respond with something like:
1859 Success: Key #1 seen Keys registered
1864 Configure Git to use the SSH protocol (instead of the GIT
1865 protocol). From your local Git repository, enter:
1868 git config remote.origin.url \
1869 ssh://@var{user}@@git.sv.gnu.org/srv/git/lilypond.git
1873 replacing @var{user} with your Savannah username.
1877 After your membership has been activated and you've configured Git
1878 to use SSH, test the connection with:
1884 SSH should issue the following warning:
1887 The authenticity of host 'git.sv.gnu.org (140.186.70.72)' can't
1889 RSA key fingerprint is
1890 80:5a:b0:0c:ec:93:66:29:49:7e:04:2b:fd:ba:2c:d5.
1891 Are you sure you want to continue connecting (yes/no)?
1894 Make sure the RSA key fingerprint displayed matches the one above.
1895 If it doesn't, respond @qq{no} and check that you configured Git
1896 properly in the previous step. If it does match, respond
1897 @qq{yes}. SSH should then issue another warning:
1900 Warning: Permanently added 'git.sv.gnu.org,140.186.70.72' (RSA) to
1901 the list of known hosts.
1904 The list of known hosts is stored in the file
1905 @file{~/.ssh/known_hosts}.
1907 At this point, you are prompted for your passphrase if you have
1908 one, then Git will attempt a pull.
1910 If @command{git@tie{}pull@tie{}--verbose} fails, you should see
1911 error messages like these:
1914 Permission denied (publickey).
1915 fatal: The remote end hung up unexpectedly
1918 If you get the above error, you may have made a mistake when
1919 registering your SSH key at Savannah. If the key is properly
1920 registered, you probably just need to wait for the Savannah server
1921 to activate it. It usually takes a few minutes for the key to be
1922 active after registering it, but if it still doesn't work after an
1923 hour, ask for help on the mailing list.
1925 If @command{git@tie{}pull@tie{}--verbose} succeeds, the output
1926 will include a @q{From} line that shows @q{ssh} as the protocol:
1929 From ssh://git.sv.gnu.org/srv/git/lilypond
1932 If the protocol shown is not @q{ssh}, check that you configured
1933 Git properly in the previous step.
1937 Test your commit access with a dry run:
1939 @warning{Do not push directly to master; instead, push to staging.
1940 See @ref{Pushing to staging}.}
1943 git push --dry-run --verbose
1946 Note that recent versions of Git (Git 1.6.3 or later) will issue a
1947 big warning if the above command is used. The simplest solution
1948 is to tell Git to push all matching branches by default:
1951 git config push.default matching
1955 Then @code{git@tie{}push} should work as before. For more
1956 details, consult the @code{git@tie{}push} man page.
1960 Repeat the steps from generating an RSA key through to testing
1961 your commit access, for each machine from which you will be
1962 making commits, or you may simply copy the files from your
1963 local @file{~/.ssh} folder to the same folder on the other
1968 @subsubheading Technical details
1972 On Firefox, to view or remove the CAcert root certificate, go to:
1973 Edit > Preferences > Advanced > Encryption > View Certificates >
1974 Authorities > Certificate Name > Root CA > CA Cert Signing
1978 The @command{git@tie{}config} commands above should modify your
1979 local repository's @file{.git/config} file. These lines:
1983 url = git://git.sv.gnu.org/lilypond.git/
1987 should now be changed to:
1991 url = ssh://@var{user}@@git.sv.gnu.org/srv/git/lilypond.git
1995 where @var{user} is your login name on Savannah.
1999 @command{git@tie{}config@tie{}push.default@tie{}matching} command
2000 should add these lines to @file{.git/config}:
2009 Encryption protocols, including ssh, generally do not permit packet
2010 fragmentation to avoid introducing a point of insecurity. This
2011 means that the maximum packet size must not exceed the smallest
2012 MTU (Maximum Transmission Unit) set in the routers along the path.
2013 This smallest MTU is determined by a procedure during call set-up
2014 which relies on the transmission over the path of ICMP packets.
2015 If any of the routers in the path block ICMP packets this mechanism
2016 fails, resulting in the possibility of packets being transmitted
2017 which exceed the MTU of one of the routers. If this happens the
2018 packet is discarded, causing the ssh session to hang, timeout or
2019 terminate with the error message
2022 ssh: connect to host <host ip addr> port 22: Bad file number
2023 fatal: The remote end hung up unexpectedly
2026 depending on precisely when in the proceedings the first large
2027 packet is transmitted. Most routers on the internet have MTU
2028 set to 1500, but routers installed in homes to connect via
2029 broadband may use a slightly smaller MTU for efficient transmission
2030 over ATM. If this problem is encountered a possible work-around is
2031 to set the MTU in the local router to 1500.
2034 @node Pushing to staging
2035 @subsection Pushing to staging
2037 Do not push directly to the git @code{master} branch. Instead,
2038 push to @code{staging}.
2040 You will not see your patch on @code{origin/master} until some
2041 automatic tests have been run. These tests are run every couple
2042 of hours; please wait at least 12 hours before wondering if your
2043 patch has been lost. Note that you can check the commits on
2044 @code{origin/staging} by looking at the git web interface on
2047 It may happen occasionally that the staging branch breaks automated
2048 testing. In this case the automatic move of staging material to
2049 master gets halted in order to avoid broken material entering master.
2050 This is a safety net. Please do not try breaking out from it by
2051 adding fixes on top of staging: in that case the whole sequence will
2052 end up in master after all, defeating the purpose of the system. The
2053 proper fix usually involves rewriting the staging branch and is best
2054 left to core developers after discussion on the developer list.
2056 @subsubheading If your work is in a patch file
2058 Assuming that your patch is in a file called
2059 @file{0001-my-patch.patch}, and you are currently on git master,
2063 git checkout staging
2065 git am 0001-my-patch.patch
2067 git push origin staging
2071 @warning{Do not skip the @command{gitk} step; a quick 5-second
2072 check of the visual history can save a great deal of frustration
2073 later on. You should only see that @command{staging} is only 1
2074 commit ahead of @code{origin/staging}.}
2076 @subsubheading If your work is in a branch
2078 If you are working on branches and your work in is
2079 @code{my_branch_name}, then do:
2082 git checkout staging
2084 git merge my_branch_name
2086 git push origin staging
2089 @warning{Do not skip the @command{gitk} step; a quick 5-second
2090 check of the visual history can save a great deal of frustration
2091 later on. You should see that @code{staging} is only ahead of
2092 @code{origin/staging} by the commits from your branch.}
2096 @node Git on Windows
2097 @section Git on Windows
2099 @warning{We heavily recommend that development be done with our
2100 virtual machine @ref{LilyDev}.}
2102 @c Some of this may duplicate stuff in other sections
2103 @c But it is probably best for windows users to have it all together
2104 @c If necessary, clear this up later -td
2106 TODO: Decide what to do with this... Pare it down? Move
2107 paragraphs next to analogous Unix instructions? -mp
2109 @subsection Background to nomenclature
2111 Git is a system for tracking the changes made to source files by a
2112 distributed set of editors. It is designed to work without a
2113 master repository, but we have chosen to have a master repository
2114 for LilyPond files. Editors hold a local copy of the master
2115 repository together with any changes they have made locally.
2116 Local changes are held in a local @q{branch}, of which there may
2117 be several, but these instructions assume you are using just one.
2118 The files visible in the local repository always correspond to
2119 those on the currently @q{checked out} local branch.
2121 Files are edited on a local branch, and in that state the changes
2122 are said to be @q{unstaged}. When editing is complete, the
2123 changes are moved to being @q{staged for commit}, and finally the
2124 changes are @q{committed} to the local branch. Once committed,
2125 the changes (called a @q{commit}) are given a unique 40-digit
2126 hexadecimal reference number called the @q{Committish} or @q{SHA1
2127 ID} which identifies the commit to Git. Such committed changes
2128 can be sent to the master repository by @q{pushing} them (if you
2129 have write permission) or by sending them by email to someone who
2130 has, either as a complete file or as a @q{diff} or @q{patch}
2131 (which send just the differences from the master repository).
2133 @subsection Installing git
2136 @uref{http://code.google.com/p/msysgit/downloads/list} (note, not
2137 msysGit, which is for Git developers and not PortableGit, which is
2138 not a full git installation) and install it.
2140 Note that most users will not need to install SSH. That is not
2141 required until you have been granted direct push permissions to
2142 the master git repository.
2144 Start Git by clicking on the desktop icon. This will bring up a
2145 command line bash shell. This may be unfamiliar to Windows users.
2146 If so, follow these instructions carefully. Commands are entered
2147 at a $ prompt and are terminated by keying a newline.
2149 @subsection Initialising Git
2151 Decide where you wish to place your local Git repository, creating
2152 the folders in Windows as necessary. Here we call the folder to
2153 contain the repository @code{[path]/Git}, but if you intend using
2154 Git for other projects a directory name like @code{lilypond-git}
2155 might be better. You will need to have space for around
2158 Start the Git bash shell by clicking on the desk-top icon
2159 installed with Git and type
2165 to position the shell at your new Git repository.
2167 Note: if [path] contains folders with names containing spaces use
2179 to initialize your Git repository.
2181 Then type (all on one line; the shell will wrap automatically)
2184 git remote add -ft master origin git://git.sv.gnu.org/lilypond.git
2187 to download the lilypond master files.
2189 @warning{Be patient! Even on a broadband connection this can take
2190 10 minutes or more. Wait for lots of [new tag] messages and the $
2193 We now need to generate a local copy of the downloaded files in a
2194 new local branch. Your local branch needs to have a name. It is
2195 usual to call it @q{master} and we shall do that here.
2200 git checkout -b master origin/master
2203 This creates a second branch called @q{master}. You will see two
2204 warnings (ignore these), and a message advising you that your
2205 local branch @q{master} has been set up to track the remote
2206 branch. You now have two branches, a local branch called
2207 @q{master}, and a tracking branch called @q{origin/master}, which
2208 is a shortened form of @q{remotes/origin/master}.
2210 Return to Windows Explorer and look in your Git repository. You
2211 should see lots of folders. For example, the LilyPond
2212 documentation can be found in [path]/Git/Documentation/.
2214 The Git bash shell is terminated by typing @code{exit} or by
2215 clicking on the usual Windows close-window widget.
2219 Almost all subsequent work will use the Git Graphical User
2220 Interface, which avoids having to type command line commands. To
2221 start Git GUI first start the Git bash shell by clicking on the
2222 desktop icon, and type
2229 The Git GUI will open in a new window. It contains four panels
2230 and 7 pull-down menus. At this stage do not use any of the
2231 commands under Branch, Commit, Merge or Remote. These will be
2234 The top panel on the left contains the names of files which you
2235 are in the process of editing (Unstaged Changes), and the lower
2236 panel on the left contains the names of files you have finished
2237 editing and have staged ready for committing (Staged Changes). At
2238 present, these panels will be empty as you have not yet made any
2239 changes to any file. After a file has been edited and saved the
2240 top panel on the right will display the differences between the
2241 edited file selected in one of the panels on the left and the last
2242 version committed on the current branch.
2244 The panel at bottom right is used to enter a descriptive message
2245 about the change before committing it.
2247 The Git GUI is terminated by entering CNTL-Q while it is the
2248 active window or by clicking on the usual Windows close-window
2251 @subsection Personalising your local git repository
2253 Open the Git GUI, click on
2259 and enter your name and email address in the left-hand (Git
2260 Repository) panel. Leave everything else unchanged and save it.
2262 Note that Windows users must leave the default setting for line
2263 endings unchanged. All files in a git repository must have lines
2264 terminated by just a LF, as this is required for Merge to work,
2265 but Windows files are terminated by CRLF by default. The git
2266 default setting causes the line endings of files in a Windows git
2267 repository to be flipped automatically between LF and CRLF as
2268 required. This enables files to be edited by any Windows editor
2269 without causing problems in the git repository.
2271 @subsection Checking out a branch
2273 At this stage you have two branches in your local repository,
2274 both identical. To see them click on
2280 You should have one local branch called @q{master} and one
2281 tracking branch called @q{origin/master}. The latter is your
2282 local copy of the @q{remotes/origin/master} branch in the master
2283 LilyPond repository. The local @q{master} branch is where you
2284 will make your local changes.
2286 When a particular branch is selected, i.e., checked out, the files
2287 visible in your repository are changed to reflect the state of the
2288 files on that branch.
2290 @subsection Updating files from @q{remote/origin/master}
2292 Before starting the editing of a file, ensure your local
2293 repository contains the latest version of the files in the remote
2294 repository by first clicking
2297 Remote -> Fetch from -> origin
2303 This will place the latest version of every file, including all
2304 the changes made by others, into the @q{origin/master} branch of
2305 the tracking branches in your git repository. You can see these
2306 files by checking out this branch, but you must @emph{never} edit
2307 any files while this branch is checked out. Check out your local
2308 @q{master} branch again.
2310 You then need to merge these fetched files into your local
2311 @q{master} branch by clicking on
2314 Merge -> Local Merge
2318 and if necessary select the local @q{master} branch.
2320 Note that a merge cannot be completed if you have made any local
2321 changes which have not yet been committed.
2323 This merge will update all the files in the @q{master} branch to
2324 reflect the current state of the @q{origin/master} branch. If any
2325 of the changes conflict with changes you have made yourself
2326 recently you will be notified of the conflict (see below).
2328 @subsection Editing files
2330 First ensure your @q{master} branch is checked out, then simply
2331 edit the files in your local Git repository with your favourite
2332 editor and save them back there. If any file contains non-ASCII
2333 characters ensure you save it in UTF-8 format. Git will detect
2334 any changes whenever you restart Git GUI and the file names will
2335 then be listed in the Unstaged Changes panel. Or you can click
2336 the Rescan button to refresh the panel contents at any time. You
2337 may break off and resume editing any time.
2339 The changes you have made may be displayed in diff form in the top
2340 right-hand panel of Git GUI by clicking on the file name shown in
2341 one of the left panels.
2343 When your editing is complete, move the files from being Unstaged
2344 to Staged by clicking the document symbol to the left of each
2345 name. If you change your mind it can be moved back by clicking on
2346 the ticked box to the left of the name.
2348 Finally the changes you have made may be committed to your
2349 @q{master} branch by entering a brief message in the Commit
2350 Message box and clicking the Commit button.
2352 If you wish to amend your changes after a commit has been made,
2353 the original version and the changes you made in that commit may
2354 be recovered by selecting
2357 Commit -> Amend Last Commit
2361 or by checking the Amend Last Commit radio button at bottom right.
2362 This will return the changes to the Staged state, so further
2363 editing made be carried out within that commit. This must only be
2364 done @emph{before} the changes have been Pushed or sent to your
2365 mentor for Pushing - after that it is too late and corrections
2366 have to be made as a separate commit.
2369 @subsection Sending changes to @q{remotes/origin/master}
2371 If you do not have write access to @q{remotes/origin/master} you
2372 will need to send your changes by email to someone who does.
2374 First you need to create a diff or patch file containing your
2375 changes. To create this, the file must first be committed. Then
2376 terminate the Git GUI. In the git bash shell first cd to your Git
2383 if necessary, then produce the patch with
2386 git format-patch origin
2389 This will create a patch file for all the locally committed files
2390 which differ from @q{origin/master}. The patch file can be found
2391 in [path]/Git and will have a name formed from the commit message.
2393 @subsection Resolving merge conflicts
2395 As soon as you have committed a changed file your local
2396 @code{master} branch has diverged from @code{origin/master}, and
2397 will remain diverged until your changes have been committed in
2398 @code{remotes/origin/master} and Fetched back into your
2399 @code{origin/master} branch. Similarly, if a new commit has been
2400 made to @code{remotes/origin/master} by someone else and Fetched,
2401 your local @code{master} branch is divergent. You can detect a
2402 divergent branch by clicking on
2405 Repository -> Visualise all branch history
2408 This opens up a very useful new window called @q{gitk}. Use this
2409 to browse all the commits made by yourself and others.
2411 If the diagram at top left of the resulting window does not show
2412 your @code{master} tag on the same node as the
2413 @code{remotes/origin/master} tag your branch has diverged from
2414 @code{origin/master}. This is quite normal if files you have
2415 modified yourself have not yet been Pushed to
2416 @code{remotes/origin/master} and Fetched, or if files modified and
2417 committed by others have been Fetched since you last Merged
2418 @code{origin/master} into your local @code{master} branch.
2420 If a file being merged from @code{origin/master} differs from one
2421 you have modified in a way that cannot be resolved automatically
2422 by git, Merge will report a Conflict which you must resolve by
2423 editing the file to create the version you wish to keep.
2425 This could happen if the person updating
2426 @code{remotes/origin/master} for you has added some changes of his
2427 own before committing your changes to
2428 @code{remotes/origin/master}, or if someone else has changed the
2429 same file since you last fetched the file from
2430 @code{remotes/origin/master}.
2432 Open the file in your editor and look for sections which are
2435 [to be completed when I next have a merge conflict to be sure I
2436 give the right instructions -td]
2439 @subsection Other actions
2441 The instructions above describe the simplest way of using git on
2442 Windows. Other git facilities which may usefully supplement these
2446 @item Using multiple local branches (Create, Rename, Delete)
2447 @item Resetting branches
2448 @item Cherry-picking commits
2449 @item Pushing commits to @w{remote/origin/master}
2450 @item Using gitk to review history
2453 Once familiarity with using git on Windows has been gained the
2454 standard git manuals can be used to learn about these.
2457 @node Repository directory structure
2458 @section Repository directory structure
2461 @c TODO: integrate the roadmap better
2462 @verbatiminclude ROADMAP
2465 @node Other Git documentation
2466 @section Other Git documentation
2470 Official git man pages:
2471 @uref{http://www.kernel.org/pub/software/scm/git/docs/}
2474 More in-depth tutorials: @uref{http://git-scm.com/documentation}
2477 Book about git: @uref{http://progit.org/,Pro Git}
2480 Github help: @uref{http://help.github.com/}
2481 (very highly recommended by Graham)