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{https://git-for-windows.github.io/}
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 You may need to install the additional @code{bash-completion}
220 package, but it is definitely worth it. After installation
221 you must log out, and then log back in again to enable it.
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 Be aware that @code{lilypond-extra} is the definitive source for some binary
559 files - in particular PDF versions of papers concerning LilyPond. To add
560 further PDFs of this sort, all that is necessary is to add the PDF to
561 @code{lilypond-extra} and then add a reference to it in the documentation. The
562 file will then be copied to the website when @code{make website} is run.
564 However, pictures that are also used in the documentation build are mastered in
565 the main git repository. If any of these is changed, it should be updated in
566 git, and then the updates copied to @code{lilypond-extra}.
568 @node Grand Unified Builder (GUB)
569 @unnumberedsubsubsec Grand Unified Builder (GUB)
571 Another item of interest might be the Grand Unified Builder, our
572 cross-platform building tool. Since it is used by other projects as
573 well, it is not stored in our gub repository. For more info, see
574 @uref{http://lilypond.org/gub}.
576 There are two locations for this repository: the version being used to
577 build lilypond, which is at
580 @uref{http://github.com/gperciva/gub}
583 and the original version by Jan Nieuwenhuizen, kept at
586 @uref{http://github.com/janneke/gub}
591 @unnumberedsubsubsec LilyPad
593 Our binary releases on MacOS X and Windows contain a lightweight
596 To make any modifications the Windows editor, you will need to do the
601 Clone the git repository from @code{https://github.com/gperciva/lilypad}
604 Make changes to the source, and check it compiles. In a Windows environment
605 @code{MinGW} provides both a @code{Git} installation and a @code{gcc}
606 compiler. This can be obtained from @code{http://www.mingw.org/}
609 Update the version which is contained in the @file{rsrc.rc}. Check
613 Commit the changes with an informative commit message.
616 Push the changes to github. You will need to use syntax similiar to this:
619 git push https://UserName@@github.com/gperciva/lilypad.git
622 You will need to have push access to the git repository for this to be
626 Make a tarball of the source code to be used by GUB by pulling the updated
627 repository from GitHub. Ensure that the tarball has the correct Version
631 Copy the tarball to @code{http://lilypond.org/download/gub-sources/lilypad/}.
632 You will need to have SSH access to @code{lilypond.org}. If you do not, contact
633 the Release Manager via the lilypond-devel mailing list.
636 Update GUB to make it use the new tarball by editing
637 @file{gub/specs/lilypad.py} and changing the @code{source =} line to point to
641 Push this updated @file{lilypad.py} version to the GUB repository on GitHub.
644 Test the changes with a new GUB compile.
648 @node yet more repositories
649 @unnumberedsubsubsec yet more repositories
651 There are a few other repositories floating around, which will
652 hopefully be documented in the near future.
655 @node Downloading remote branches
656 @subsection Downloading remote branches
658 @warning{contains obsolete + misleading info}
661 * Organization of remote branches::
662 * LilyPond repository sources::
663 * Downloading individual branches::
664 * Downloading all remote branches::
669 @node Organization of remote branches
670 @unnumberedsubsubsec Organization of remote branches
673 The main LilyPond repository is organized into @emph{branches} to
674 facilitate development. These are often called @emph{remote}
675 branches to distinguish them from @emph{local} branches you might
676 create yourself (see @ref{Using local branches}).
678 The @code{master} branch contains all the source files used to
679 build LilyPond, which includes the program itself (both stable and
680 development releases), the documentation (and its translations),
681 and the website. Generally, the @code{master} branch is expected
682 to compile successfully.
684 The @code{translation} branch is a side branch that
685 allows translators to work without needing to worry about
686 compilation problems. Periodically, the Translation Meister
687 (after verifying that it doesn't break compilation), will
688 @emph{merge} this branch into @code{staging} to incorporate
689 recent translations. Similarly, the @code{master} branch is
690 usually merged into the @code{translation} branch after
691 significant changes to the English documentation. See
692 @ref{Translating the documentation} for details.
695 @node LilyPond repository sources
696 @unnumberedsubsubsec LilyPond repository sources
699 The recommended source for downloading a copy of the main
703 git://git.sv.gnu.org/lilypond.git
706 However, if your internet router filters out connections using the
707 GIT protocol, or if you experience difficulty connecting via GIT,
708 you can try these other sources:
711 ssh://git.sv.gnu.org/srv/git/lilypond.git
712 http://git.sv.gnu.org/r/lilypond.git
715 The SSH protocol can only be used if your system is properly set
716 up to use it. Also, the HTTP protocol is slowest, so it should
717 only be used as a last resort.
720 @node Downloading individual branches
721 @unnumberedsubsubsec Downloading individual branches
723 @warning{obsolete, should be deleted!}
726 Once you have initialized an empty Git repository on your system
727 (see @ref{Initializing a repository}), you can download a remote
728 branch into it. Make sure you know which branch you want to start
731 To download the @code{master} branch, enter the following:
734 git remote add -ft master -m master \
735 origin git://git.sv.gnu.org/lilypond.git/
738 To download the @code{translation} branch, enter:
741 git remote add -ft translation -m \
742 translation origin git://git.sv.gnu.org/lilypond.git/
745 The @command{git@tie{}remote@tie{}add} process could take up to
746 ten minutes, depending on the speed of your connection. The
747 output will be something like this:
751 remote: Counting objects: 235967, done.
752 remote: Compressing objects: 100% (42721/42721), done.
753 remote: Total 235967 (delta 195098), reused 233311 (delta 192772)
754 Receiving objects: 100% (235967/235967), 68.37 MiB | 479 KiB/s, done.
755 Resolving deltas: 100% (195098/195098), done.
756 From git://git.sv.gnu.org/lilypond
757 * [new branch] master -> origin/master
758 From git://git.sv.gnu.org/lilypond
759 * [new tag] flower/1.0.1 -> flower/1.0.1
760 * [new tag] flower/1.0.10 -> flower/1.0.10
762 * [new tag] release/2.9.6 -> release/2.9.6
763 * [new tag] release/2.9.7 -> release/2.9.7
766 When @command{git@tie{}remote@tie{}add} is finished, the remote
767 branch should be downloaded into your repository---though not yet
768 in a form that you can use. In order to browse the source code
769 files, you need to @emph{create} and @emph{checkout} your own
770 local branch. In this case, however, it is easier to have Git
771 create the branch automatically by using the @command{checkout}
772 command on a non-existent branch. Enter the following:
775 git checkout -b @var{branch} origin/@var{branch}
779 where @code{@var{branch}} is the name of your tracking branch,
780 either @code{master} or @code{translation}.
782 Git will issue some warnings; this is normal:
785 warning: You appear to be on a branch yet to be born.
786 warning: Forcing checkout of origin/master.
787 Branch master set up to track remote branch master from origin.
791 By now the source files should be accessible---you should be able
792 to edit any files in the @file{$LILYPOND_GIT} directory using a
793 text editor of your choice. But don't start just yet! Before
794 editing any source files, learn how to keep your changes organized
795 and prevent problems later---read @ref{Basic Git procedures}.
797 @subsubheading Technical Details
799 The @command{git@tie{}remote@tie{}add} command should add some
800 lines to your local repository's @file{.git/config} file:
804 url = git://git.sv.gnu.org/lilypond.git/
805 fetch = +refs/heads/master:refs/remotes/origin/master
809 @node Downloading all remote branches
810 @unnumberedsubsubsec Downloading all remote branches
813 To download all remote branches at once, you can @command{clone}
814 the entire repository:
817 git clone git://git.sv.gnu.org/lilypond.git
822 @unnumberedsubsubsec Other branches
824 Most contributors will never need to touch the other branches. If
825 you wish to do so, you will need more familiarity with Git; please
826 see @ref{Other Git documentation}.
829 @item @code{dev/XYZ}:
830 These branches are for individual developers. They store code
831 which is not yet stable enough to be added to the @code{master}
834 @item @code{stable/XYZ}:
835 The branches are kept for archival reasons.
837 @item @code{archive/XYZ}:
838 The branches are kept for archival reasons.
843 @node Basic Git procedures
844 @section Basic Git procedures
848 * The Git contributor's cycle::
849 * Pulling and rebasing::
850 * Using local branches::
853 * Uploading a patch for review::
854 * The patch review cycle::
858 @node The Git contributor's cycle
859 @subsection The Git contributor's cycle
862 Here is a simplified view of the contribution process on Git:
866 Update your local repository by @emph{pulling} the most recent
867 updates from the remote repository.
870 Edit source files within your local repository's @emph{working
874 @emph{Commit} the changes you've made to a local @emph{branch}.
877 Generate a @emph{patch} to share your changes with the developers.
881 @node Pulling and rebasing
882 @subsection Pulling and rebasing
885 When developers push new patches to the @code{git.sv.gnu.org}
886 repository, your local repository is @strong{not} automatically
887 updated. It is important to keep your repository up-to-date by
888 periodically @emph{pulling} the most recent @emph{commits} from
889 the remote branch. Developers expect patches to be as current as
890 possible, since outdated patches require extra work before they
893 Occasionally you may need to rework some of your own modifications
894 to match changes made to the remote branch (see @ref{Resolving
895 conflicts}), and it's considerably easier to rework things
896 incrementally. If you don't update your repository along the way,
897 you may have to spend a lot of time resolving branch conflicts and
898 reconfiguring much of the work you've already done.
900 Fortunately, Git is able to resolve certain types of branch
901 conflicts automatically with a process called @emph{rebasing}.
902 When rebasing, Git tries to modify your old commits so they appear
903 as new commits (based on the latest updates). For a more involved
904 explanation, see the @command{git-rebase} man page.
906 To pull without rebasing (recommended for translators), use the
910 git pull # recommended for translators
913 If you're tracking the remote @code{master} branch, you should add
914 the @option{-r} option (short for @option{--rebase}) to keep commits
915 on your local branch current:
918 git pull -r # use with caution when translating
921 If you don't edit translated documentation and don't want to type
922 @option{-r} every time, configure the master branch to rebase by
923 default with this command:
926 git config branch.master.rebase true
929 If pull fails because of a message like
932 error: Your local changes to 'Documentation/learning/tutorial.itely'
933 would be overwritten by merge. Aborting.
940 Documentation/learning/tutorial.itely: needs update
941 refusing to pull with rebase: your working tree is not up-to-date
945 it means that you have modified some files in you working tree
946 without committing changes (see @ref{Commits}); you
947 can use the @command{git@tie{}stash} command to work around this:
950 git stash # save uncommitted changes
951 git pull -r # pull using rebase (translators omit "-r")
952 git stash pop # reapply previously saved changes
955 Note that @command{git@tie{}stash@tie{}pop} will try to apply a
956 patch, and this may create a conflict. If this happens, see
957 @ref{Resolving conflicts}.
959 TODO: I think the next paragraph is confusing. Perhaps prepare
960 the reader for new terms `committish' and `head'? -mp
962 @warning{translators and documentation editors, if you have
963 changed committishes in the head of translated files using commits
964 you have not yet pushed to @code{git.sv.gnu.org}, please do not
965 rebase. If you want to avoid wondering whether you should rebase
966 each time you pull, please always use committishes from master
967 and/or translation branch on @code{git.sv.gnu.org}, which
968 in particular implies that you must push your changes to
969 documentation except committishes updates (possibly after having
970 rebased), then update the committishes and push them.}
972 TODO: when committishes automatic conditional update have been
973 tested and documented, append the following to the warning above:
974 Note that using update-committishes make target generally touches
977 @subsubheading Technical details
979 The @command{git@tie{}config} command mentioned above adds the
980 line @code{rebase = true} to the master branch in your local
981 repository's @file{.git/config} file:
986 merge = refs/heads/master
991 @node Using local branches
992 @subsection Using local branches
996 * Creating and removing branches::
997 * Listing branches and remotes::
998 * Checking out branches::
1003 @node Creating and removing branches
1004 @unnumberedsubsubsec Creating and removing branches
1007 Local branches are useful when you're working on several different
1008 projects concurrently. To create a new branch, enter:
1011 git branch @var{name}
1014 To delete a branch, enter:
1017 git branch -d @var{name}
1020 Git will ask you for confirmation if it sees that data would be
1021 lost by deleting the branch. Use @option{-D} instead of @option{-d}
1022 to bypass this. Note that you cannot delete a branch if it is
1023 currently checked out.
1026 @node Listing branches and remotes
1027 @unnumberedsubsubsec Listing branches and remotes
1029 You can get the exact path or URL of all remote branches by
1036 To list Git branches on your local repositories, run
1039 git branch # list local branches only
1040 git branch -r # list remote branches
1041 git branch -a # list all branches
1045 @node Checking out branches
1046 @unnumberedsubsubsec Checking out branches
1048 To know the currently checked out branch, i.e. the branch whose
1049 source files are present in your working tree, read the first line
1057 The currently checked out branch is also marked with an asterisk
1058 in the output of @command{git branch}.
1060 You can check out another branch @code{@var{other_branch}}, i.e.
1061 check out @code{@var{other_branch}} to the working tree, by
1065 git checkout @var{other_branch}
1068 Note that it is possible to check out another branch while having
1069 uncommitted changes, but it is not recommended unless you know
1070 what you are doing; it is recommended to run @command{git status}
1071 to check this kind of issue before checking out another branch.
1073 @node Merging branches
1074 @unnumberedsubsubsec Merging branches
1076 To merge branch @code{@var{foo}} into branch @code{@var{bar}},
1077 i.e. to @qq{add} all changes made in branch @code{@var{foo}} to
1078 branch @code{@var{bar}}, run
1081 git checkout @var{bar}
1085 If any conflict happens, see @ref{Resolving conflicts}.
1087 There are common usage cases for merging: as a translator, you will
1088 often want the Translations meister to merge @code{master} into
1089 @code{translation}; on the other hand, the Translations meister wants
1090 to merge @code{translation} into @code{staging} whenever he has
1091 checked that @code{translation} builds successfully.
1098 * Understanding commits::
1099 * How to make a commit::
1104 @node Understanding commits
1105 @unnumberedsubsubsec Understanding commits
1107 Technically, a @emph{commit} is a single point in the history of a
1108 branch, but most developers use the term to mean a @emph{commit
1109 object}, which stores information about a particular revision. A
1110 single commit can record changes to multiple source files, and
1111 typically represents one logical set of related changes (such as a
1112 bug-fix). You can list the ten most recent commits in your
1113 current branch with this command:
1116 git log -10 --oneline
1119 If you're using an older version of Git and get an @q{unrecognized
1120 argument} error, use this instead:
1123 git log -10 --pretty=oneline --abbrev-commit
1126 More interactive lists of the commits on the remote @code{master}
1127 branch are available at
1128 @uref{http://git.sv.gnu.org/gitweb/?p=lilypond.git;a=shortlog} and
1129 @uref{http://git.sv.gnu.org/cgit/lilypond.git/log/}.
1132 @node How to make a commit
1133 @unnumberedsubsubsec How to make a commit
1136 Once you have modified some source files in your working
1137 directory, you can make a commit with the following procedure:
1141 Make sure you've configured Git properly (see @ref{Configuring
1142 Git}). Check that your changes meet the requirements described in
1143 @ref{Code style} and/or @ref{Documentation policy}. For advanced
1144 edits, you may also want to verify that the changes don't break
1145 the compilation process.
1148 Run the following command:
1155 to make sure you're on the right branch, and to see which files
1156 have been modified, added or removed, etc. You may need to tell
1157 Git about any files you've added by running one of these:
1160 git add @var{file} # add untracked @var{file} individually
1161 git add . # add all untracked files in current directory
1165 After @command{git@tie{}add}, run @command{git@tie{}status} again
1166 to make sure you got everything. You may also need to modify
1170 Preview the changes about to be committed (to make sure everything
1178 The @code{HEAD} argument refers to the most recent commit on the
1179 currently checked-out branch.
1182 Generate the commit with:
1189 The @option{-a} is short for @option{--all} which includes modified
1190 and deleted files, but only those newly created files that have
1191 previously been added.
1196 @node Commit messages
1197 @unnumberedsubsubsec Commit messages
1200 When you run the @command{git@tie{}commit@tie{}-a} command, Git
1201 automatically opens the default text editor so you can enter a
1202 @emph{commit message}. If you find yourself in a foreign editing
1203 environment, you're probably in @command{vi} or @command{vim}. If
1204 you want to switch to an editor you're more familiar with, quit by
1205 typing @code{:q!} and pressing @code{<Enter>}. See
1206 @ref{Configuring Git} for instructions on changing the default
1209 In any case, Git will open a text file for your commit message
1210 that looks like this:
1214 # Please enter the commit message for your changes. Lines starting
1215 # with '#' will be ignored, and an empty message aborts the commit.
1217 # Changes to be committed:
1218 # (use "git reset HEAD <file>..." to unstage)
1220 # modified: working.itexi
1224 Your commit message should begin with a one-line summary
1225 describing the change (no more than 50 characters long), and if
1226 necessary a blank line followed by several lines giving the
1229 @c $ git log -1 --pretty=medium 4d6f1e5
1231 Doc: add Baerenreiter and Henle solo cello suites
1233 Added comparison of solo cello suite engravings to new essay with
1234 high-res images, fixed cropping on Finale example.
1237 Commit messages often start with a short prefix describing the
1238 general location of the changes. If a commit affects the
1239 documentation in English (or in several languages simultaneously)
1240 the commit message should be prefixed with @qq{Doc:@tie{}}. If
1241 the commit affects only one of the translations, the commit
1242 message should be prefixed with @qq{Doc-@var{**}:@tie{}}, where
1243 @var{**} is the two-letter language code. Commits that affect the
1244 website should use @qq{Web:@tie{}} for English, and
1245 @qq{Web-@var{**}:@tie{}} for the other languages. Also, changes
1246 to a single file are often prefixed with the name of the file
1247 involved. Visit the links listed in @ref{Understanding commits}
1255 * How to make a patch::
1256 * Emailing patches::
1259 @node How to make a patch
1260 @unnumberedsubsubsec How to make a patch
1262 If you want to share your changes with other contributors and
1263 developers, you need to generate @emph{patches} from your commits.
1264 We prefer it if you follow the instructions in
1265 @ref{Uploading a patch for review}. However, we present an
1266 alternate method here.
1268 You should always run @command{git@tie{}pull@tie{}-r} (translators
1269 should leave off the @option{-r}) before doing this to ensure that
1270 your patches are as current as possible.
1272 Once you have made one or more commits in your local repository,
1273 and pulled the most recent commits from the remote branch, you can
1274 generate patches from your local commits with the command:
1277 git format-patch origin
1280 The @code{origin} argument refers to the remote tracking branch at
1281 @code{git.sv.gnu.org}. This command generates a separate patch
1282 for each commit that's in the current branch but not in the remote
1283 branch. Patches are placed in the current working directory and
1284 will have names that look something like this:
1287 0001-Doc-Fix-typos.patch
1288 0002-Web-Remove-dead-links.patch
1292 Send an email (must be less than 64 KB) to
1293 @email{lilypond-devel@@gnu.org} briefly explaining your work, with
1294 the patch files attached. Translators should send patches to
1295 @email{translations@@lilynet.net}. After your patches are
1296 reviewed, the developers may push one or more of them to the main
1297 repository or discuss them with you.
1300 @node Emailing patches
1301 @unnumberedsubsubsec Emailing patches
1303 The default @code{x-diff} MIME type associated with patch files
1304 (i.e., files whose name ends in @code{.patch}) means that the
1305 encoding of line endings may be changed from UNIX to DOS format
1306 when they are sent as attachments. Attempting to apply such an
1307 inadvertently altered patch will cause git to fail with a message
1308 about @q{whitespace errors}.
1310 The solution to such problems is surprisingly simple---just change
1311 the default file extension of patches generated by git to end in
1312 @code{.txt}, for example:
1315 git config format.suffix '.patch.txt'
1318 This should cause email programs to apply the correct base64
1319 encoding to attached patches.
1321 If you receive a patch with DOS instead of UNIX line-endings, it
1322 can be converted back using the @code{dos2unix} utility.
1324 Lots of useful information on email complications with patches is
1325 provided on the Wine wiki at
1326 @uref{http://wiki.winehq.org/GitWine}.
1329 @node Uploading a patch for review
1330 @subsection Uploading a patch for review
1332 Any non-trivial change should be uploaded to our @qq{Rietveld}
1333 code review website:
1336 @uref{http://codereview.appspot.com/}
1339 You can upload a patch for review by using our custom @code{git-cl}
1340 @q{helper-script}. This section assumes you have already installed,
1341 updated, and configured @code{git-cl}. See @ref{git-cl}.
1343 @warning{Unless you are familiar with branches, only work on one
1344 set of changes at once.}
1346 There are two methods, depending on your git setup.
1350 @strong{Master branch}: (easy option)
1352 If you added your patch to @code{master}, then:
1356 git-cl upload origin/master
1359 @c Mention staging here?
1360 If you have git push ability, make sure that you @emph{remove}
1361 your patch (with @command{git rebase} or @command{git reset})
1362 before pushing other stuff.
1364 @c don't make this one an @example; we don't want to make it easy
1365 @c for people to use this accidently
1366 Notifications of patches are automatically added to our issue
1367 tracker to reduce the chance of patches getting lost. To suppress
1368 this (not recommended), add the @code{-n / --no-code-issue}
1372 @strong{Separate branch}: (complicated option)
1374 Ensure your changes are committed in a separate branch, which should
1375 differ from the reference branch to be used (usually
1376 @code{origin/master}) by just the changes to be uploaded. Checkout the
1377 branch with the changes:
1380 git checkout some-branch-with-changes
1383 If the reference branch is to be @code{origin/master}, ensure that the
1384 branch containing the changes is up-to-date with it. Use
1385 @command{git rebase} or @command{git pull -r} to rebase the branch to
1386 the head of @code{origin/master}. For example:
1389 git pull -r origin master
1392 Finally, start the upload by entering:
1395 git-cl upload <reference SHA1 ID>
1399 where <reference SHA1 ID> is the SHA1 ID of the commit to be used
1400 as a reference source for the patch. Generally, this will be the
1401 SHA1 ID of origin/master, and in that case you can just use the command:
1404 git-cl upload origin/master
1409 First you will see a terminal editor where you can edit the
1410 message that will accompany your patch. @command{git-cl} will
1411 respect the @env{EDITOR} environment variable if defined,
1412 otherwise it will use @command{vi} as the default editor.
1414 After prompting for your Google email address and password, the
1415 patch set will be posted to Rietveld, and you will be given a URL
1418 @warning{Some installations of git-cl fail when uploading a patch
1419 with certain filename extensions. If this happens, it can
1420 generally be fixed by editing the list of exceptions at top of
1423 @subsubheading Announcing your patch set
1425 You should then announce the patch by logging into the code review
1426 issue webpage and using @qq{Publish + Mail Comments} to add a
1427 (mostly bogus) comment to your issue. The text of your comment
1428 will be sent to our developer mailing list.
1430 @warning{There is no automatic notification of a new patch; you
1431 must add a comment yourself.}
1433 @subsubheading Revisions
1435 As revisions are made in response to comments, successive patch sets
1436 for the same issue can be uploaded by reissuing the git-cl command
1437 with the modified branch checked out.
1439 Sometimes in response to comments on revisions, the best way to
1440 work may require creation of a new branch in git. In order to
1441 associate the new branch with an existing Rietveld issue,
1442 the following command can be used:
1445 git-cl issue issue-number
1449 where @code{issue-number} is the number of the existing Rietveld
1452 @subsubheading Resetting git-cl
1454 If @command{git-cl} becomes confused, you can @qq{reset} it by
1462 @node The patch review cycle
1463 @subsection The patch review cycle
1465 Your patch will be available for reviews for the next few hours or
1466 days. Three times a week, patches with no known problems are
1467 gathered into a @qq{patch countdown} and their status changed to
1468 @code{patch-countdown}. The countdown is a 48-hour waiting period
1469 in which any final reviews or complaints should be made.
1471 During the countdown, your patch may be set to
1472 @code{patch-needs_work}, indicating that you should fix something
1473 (or at least discuss why the patch needs no modification). If no
1474 problems are found, the patch will be set to @code{patch-push}.
1476 Once a patch has @code{patch-push}, it should be sent to your
1477 mentor for uploading. If you have git push ability, look at
1478 @ref{Pushing to staging}.
1483 Patches get added to the tracker and to Rietveld by the @qq{git-cl} tool, with
1484 a status of @qq{patch-new}.
1487 The automated tester, Patchy, verifies that the patch can be applied
1488 to current master. By default, it checks that the patch allows @code{make}
1489 and @code{make test} to complete successfully. It can also be configured to
1490 check that @code{make doc} is successful. If it passes, Patchy changes the
1491 status to @qq{patch-review} and emails the developer list. If the patch
1492 fails, Patchy sets it to @qq{patch-needs_work} and notifies the developer list.
1495 The Patch Meister reviews the tracker periodically, to list patches
1496 which have been on review for at least 24 hours. The list is found at
1499 @uref{http://code.google.com/p/lilypond/issues/list?can=2&q=label:patch%20patch=review&sort=modified+patch&colspec=ID%20Type%20Status%20Priority%20Owner%20Patch%20Summary%20Modified}
1503 For each patch, the Handler reviews any discussion on the tracker
1504 and on Rietveld, to determine whether the patch can go forward. If
1505 there is any indication that a developer thinks the patch is not
1506 ready, the Handler marks it @qq{patch-needs_work} and makes a comment
1507 regarding the reason, referring to the Rietveld item if needed.
1510 Patches with explicit approval, or at least no negative comment, can
1511 be updated to @qq{patch-countdown}. When saving the tracker item,
1512 clear the @qq{send email} box to prevent sending notification for
1516 The Patch Meister sends an email to the developer list, with a fixed
1517 subject line, to enable filtering by email clients:
1520 PATCH: Countdown to 20130113
1523 The text of the email sets the deadline for this countdown batch. At
1524 present, batches are done on Tuesday, Thursday and Sunday evenings.
1526 To create the countdown announcement, use the
1527 @code{make-countdown-announcement.sh} script, which takes the
1528 deadline date, and optionally your name. Follow the instructions
1533 scripts/auxiliar/make-countdown-announcement.sh "Jan 1, 2001" James
1536 The script produces an announcement that is easily readable in all
1537 email clients. Also, whenever a new contributor submits a patch,
1538 you will be prompted to add the new username and author name to
1539 the script itself, and then commit those changes to the main git
1544 On the scheduled countdown day, the Patch Meister reviews the
1545 previous list of patches on countdown, with the same procedure and
1546 criteria as before. Patches with no controversy can be set to
1547 @qq{patch-push} with a courtesy message added to the comment block.
1550 Roughly at six month intervals, the Patch Meister can list the
1551 patches which have been set to @qq{patch-needs-work} and send the
1552 results to the developer list for review. In most cases, these
1553 patches should be marked @qq{patch-abandoned} but this should come
1554 from the developer if possible.
1557 As in most organisations of unpaid volunteers, fixed procedures are
1558 useful in as much as they get the job done. In our community, there
1559 is room for senior developers to bypass normal patch handling flows,
1560 particularly now that the testing of patches is largely automated.
1561 Similarly, the minimum age of 24 hours can reasonably be waived if
1562 the patch is minor and from an experienced developer.
1568 There is a single Patch Meister, and a number of Patch Helpers
1569 (rename this?). The list of known patches awaiting review is:
1572 @uref{http://code.google.com/p/lilypond/issues/list?can=2&q=label:patch&sort=patch}
1576 @subheading Helpers: adding patches
1578 The primary duty is to add patches to the google tracker; we have
1579 a bad track record of losing patches in email. Patches generally
1580 come to the @code{lilypond-devel} mailing list, but are sometimes
1581 sent to @code{bug-lilypond}, @code{lilypond-users}, or
1582 @code{frogs} mailing list instead.
1586 Unless a patch is clearly in response to an existing issue, add a
1587 new issue with the @code{Patch-new} label and a link to the patch
1588 (either on the mailing list archives or the codereview url).
1590 Issue numbers are cheap; losing developers because they got fed up
1591 with us losing their hard work is expensive.
1594 @c if we enter patches immediately, I don't think this is relevant.
1597 Before adding a patch-reminder issue, do a quick check to see if
1598 it was pushed without sending any email. This can be checked for
1599 searching for relevant terms (from the patch subject or commit
1600 message) on the webgit page:
1603 @uref{http://git.savannah.gnu.org/gitweb/?p=lilypond.git}
1608 If the patch is clearly in response to an existing issue, then
1609 update that issue with the @code{Patch-new} label and a link to
1610 the patch (either on the mailing list archives or the codereview
1614 After adding the issue, please send a response email to the same
1615 group(s) that the initial patch was sent to.
1617 If the initial email was sent to multiple mailing lists (such as
1618 both @code{bugs} and @code{devel}), then reply to all those
1619 mailing lists as well. The email should contain a link to the
1620 issue you just added.
1624 @subheading Helpers: @code{Patch-review} label
1626 The secondary duty is to do make sure that every issue in the
1627 tracker with a @code{Patch-review} label has passed these
1632 Applies automatically to git master.
1634 It's ok to have offsets, but not conflicts.
1637 Regtest comparison looks ok; no unexpected changes.
1640 Descriptive subject line.
1642 Avoid subjects like @qq{fixes 123}; instead write @qq{Doc: discuss
1643 stacking-dir for BassFigureAlignment (fix 123)}.
1646 Compiles docs from scratch. Only check this if you have reason to
1647 suspect it might not work.
1652 Check code indentation and style. This should be easier post-GOP
1653 when we have a better-defined code style.
1658 @subheading Patch Meister
1660 The Patch Meister will:
1665 send @qq{countdown} emails to
1666 @code{lilypond-devel} when patches appear to be ready.
1669 send general requests to review patches, or even nasty requests to
1673 downgrade patches from @code{Patch-review} to
1674 @code{Patch-needs_work} as appropriate.
1677 downgrade patches from @code{Patch-needs_work} to
1678 @code{Patch-abandoned} if no actions have been taken in four
1686 @node Advanced Git procedures
1687 @section Advanced Git procedures
1690 @warning{This section is not necessary for normal contributors;
1691 these commands are presented for information for people interested
1692 in learning more about git.}
1694 It is possible to work with several branches on the same local Git
1695 repository; this is especially useful for translators who may have
1696 to deal with both @code{translation} and a stable branch,
1697 e.g. @code{stable/2.12}.
1699 Some Git commands are introduced first, then a workflow with
1700 several Git branches of LilyPond source code is presented.
1705 * Advanced Git concepts::
1706 * Resolving conflicts::
1707 * Reverting all local changes::
1708 * Working with remote branches::
1710 * Applying remote patches::
1711 * Cleaning up multiple patches::
1713 * Pushing to staging::
1717 @node Merge conflicts
1718 @subsection Merge conflicts
1720 To be filled in later, and/or moved to a different section. I
1721 just wanted to make sure that I had a stub ready somewhere.
1724 @node Advanced Git concepts
1725 @subsection Advanced Git concepts
1728 A bit of Git vocabulary will be explained below. The following is
1729 only introductory; for a better understanding of Git concepts, you
1730 may wish to read @ref{Other Git documentation}.
1732 The @code{git@tie{}pull@tie{}origin} command above is just a
1733 shortcut for this command:
1736 git pull git://git.sv.gnu.org/lilypond.git/ @var{branch}:origin/@var{branch}
1740 where @code{@var{branch}} is typically @code{master} or
1741 @code{translation}; if you do not know or remember, see
1742 @ref{Downloading remote branches} to remember which commands you
1743 issued or which source code you wanted to get.
1745 A @emph{commit} is a set of changes made to the sources; it also
1746 includes the committish of the parent commit, the name and e-mail
1747 of the @emph{author} (the person who wrote the changes), the name
1748 and e-mail of the @emph{committer} (the person who brings these
1749 changes into the Git repository), and a commit message.
1751 A @emph{committish} is the SHA1 checksum of a commit, a number
1752 made of 40 hexadecimal digits, which acts as the internal unique
1753 identifier for this commit. To refer to a particular revision,
1754 don't use vague references like the (approximative) date, simply
1755 copy and paste the committish.
1757 A @emph{branch} is nothing more than a pointer to a particular
1758 commit, which is called the @emph{head} of the branch; when
1759 referring to a branch, one often actually thinks about its head
1760 and the ancestor commits of the head.
1762 Now we will explain the two last commands you used to get the
1763 source code from Git---see @ref{Downloading individual branches}.
1766 git remote add -ft @var{branch} -m @var{branch} \
1767 origin git://git.sv.gnu.org/lilypond.git/
1769 git checkout -b @var{branch} origin/@var{branch}
1772 The @command{git@tie{}remote} has created a branch called
1773 @code{origin/@var{branch}} in your local Git repository. As this
1774 branch is a copy of the remote branch web from git.sv.gnu.org
1775 LilyPond repository, it is called a @emph{remote branch}, and is
1776 meant to track the changes on the branch from git.sv.gnu.org: it
1777 will be updated every time you run
1778 @command{git@tie{}pull@tie{}origin} or
1779 @command{git@tie{}fetch@tie{}origin}.
1781 The @command{git@tie{}checkout} command has created a branch named
1782 @code{@var{branch}}. At the beginning, this branch is identical
1783 to @code{origin/@var{branch}}, but it will differ as soon as you
1784 make changes, e.g. adding newly translated pages or editing some
1785 documentation or code source file. Whenever you pull, you merge
1786 the changes from @code{origin/@var{branch}} and
1787 @code{@var{branch}} since the last pulling. If you do not have
1788 push (i.e. @qq{write}) access on git.sv.gnu.org, your
1789 @code{@var{branch}} will always differ from
1790 @code{origin/@var{branch}}. In this case, remember that other
1791 people working like you with the remote branch @code{@var{branch}}
1792 of git://git.sv.gnu.org/lilypond.git/ (called
1793 @code{origin/@var{branch}} on your local repository) know nothing
1794 about your own @code{@var{branch}}: this means that whenever you
1795 use a committish or make a patch, others expect you to take the
1796 latest commit of @code{origin/@var{branch}} as a reference.
1798 Finally, please remember to read the man page of every Git command
1799 you will find in this manual in case you want to discover
1800 alternate methods or just understand how it works.
1803 @node Resolving conflicts
1804 @subsection Resolving conflicts
1807 Occasionally an update may result in conflicts -- this happens
1808 when you and somebody else have modified the same part of the same
1809 file and git cannot figure out how to merge the two versions
1810 together. When this happens, you must manually merge the two
1813 If you need some documentation to understand and resolve
1814 conflicts, see paragraphs @emph{How conflicts are presented} and
1815 @emph{How to resolve conflicts} in @command{git merge} man page.
1817 If all else fails, you can follow the instructions in
1818 @ref{Reverting all local changes}. Be aware that this eliminates
1819 any changes you have made!
1822 @node Reverting all local changes
1823 @subsection Reverting all local changes
1825 Sometimes git will become hopelessly confused, and you just want
1826 to get back to a known, stable state. This command destroys any
1827 local changes you have made in the currently checked-out branch,
1828 but at least you get back to the current online version:
1831 git reset --hard origin/master
1835 @node Working with remote branches
1836 @subsection Working with remote branches
1839 @subsubheading Fetching new branches from git.sv.gnu.org
1841 To fetch and check out a new branch named @code{@var{branch}} on
1842 git.sv.gnu.org, run from top of the Git repository
1845 git config --add remote.origin.fetch \
1846 +refs/heads/@var{branch}:refs/remotes/origin/@var{branch}
1848 git checkout --track -b @var{branch} origin/@var{branch}
1851 After this, you can pull @code{@var{branch}} from git.sv.gnu.org
1858 Note that this command generally fetches all branches you added
1859 with @command{git@tie{}remote@tie{}add} (when you initialized the
1860 repository) or @command{git@tie{}config@tie{}--add}, i.e. it
1861 updates all remote branches from remote @code{origin}, then it
1862 merges the remote branch tracked by the current branch into the
1863 current branch. For example, if your current branch is
1864 @code{master}, @code{origin/master} will be merged into
1868 @subsubheading Local clones, or having several working trees
1870 If you play with several Git branches, e.g. @code{master},
1871 @code{translation}, @code{stable/2.12}), you may want to
1872 have one source and build tree for each branch; this is possible
1873 with subdirectories of your local Git repository, used as local
1874 cloned subrepositories. To create a local clone for the branch
1875 named @code{@var{branch}}, run
1878 git checkout @var{branch}
1879 git clone -lsn . @var{subdir}
1884 Note that @code{@var{subdir}} must be a directory name which does
1885 not already exist. In @code{@var{subdir}}, you can use all Git
1886 commands to browse revisions history, commit and uncommit changes;
1887 to update the cloned subrepository with changes made on the main
1888 repository, cd into @code{@var{subdir}} and run
1889 @command{git@tie{}pull}; to send changes made on the subrepository
1890 back to the main repository, run @command{git@tie{}push} from
1891 @code{@var{subdir}}. Note that only one branch (the currently
1892 checked out branch) is created in the subrepository by default; it
1893 is possible to have several branches in a subrepository and do
1894 usual operations (checkout, merge, create, delete...) on these
1895 branches, but this possibility is not detailed here.
1897 When you push @code{@var{branch}} from @code{@var{subdir}} to the
1898 main repository, and @code{@var{branch}} is checked out in the
1899 main repository, you must save uncommitted changes (see
1900 @command{git@tie{}stash}) and do
1901 @command{git@tie{}reset@tie{}--hard} in the main repository in
1902 order to apply pushed changes in the working tree of the main
1910 The commands above don't only bring you the latest version of the
1911 sources, but also the full history of revisions (revisions, also
1912 called commits, are changes made to the sources), stored in the
1913 @file{.git} directory. You can browse this history with
1916 git log # only shows the logs (author, committish and commit message)
1917 git log -p # also shows diffs
1918 gitk # shows history graphically
1921 @warning{The @code{gitk} command may require a separate
1922 @code{gitk} package, available in the appropriate distribution's
1926 @node Applying remote patches
1927 @subsection Applying remote patches
1930 TODO: Explain how to determine if a patch was created with
1931 @code{git@tie{}format-patch}.
1933 Well-formed git patches created with @code{git@tie{}format-patch}
1934 should be committed with the following command:
1940 Patches created without @code{git@tie{}format-patch} can be
1941 applied in two steps. The first step is to apply the patch to the
1942 working tree and the index:
1945 git apply --index @var{patch}
1949 The second step is to commit the changes and give credit to the
1950 author of the patch. This can be done with the following command:
1953 git commit --author="@var{John Smith} <@var{john@@example.com}>"
1956 Please note that using the @code{--index} option for patching is quite
1957 important here and @emph{cannot} reliably be replaced by using the
1958 @code{-a} option when committing: that would only commit files from the
1959 working tree that are already registered with git, so every file that
1960 the patch actually @emph{adds}, like a regtest for a fixed bug, would
1961 get lost. For the same reason, you should not use the git-independent
1962 @samp{patch} program for applying patches.
1966 @node Cleaning up multiple patches
1967 @subsection Cleaning up multiple patches
1969 If you have been developing on your own branch for a while, you
1970 may have more commmits than is really sensible. To revise your
1971 work and condense commits, use:
1974 git rebase origin/master
1975 git rebase -i origin/master
1978 @warning{Be a bit cautious -- if you completely remove commits
1979 during the interactive session, you will... err... completely
1980 remove those commits.}
1984 @subsection Commit access
1986 Most contributors are not able to commit patches directly to the
1987 main repository---only members of the LilyPond development team
1988 have @emph{commit access}. If you are a contributor and are
1989 interested in joining the development team, contact the Project
1990 Manager through the mailing list
1991 (@email{lilypond-devel@@gnu.org}). Generally, only contributors
1992 who have already provided a number of patches which have been
1993 pushed to the main repository will be considered for membership.
1995 If you have been approved by the Project Manager, use the
1996 following procedure to obtain commit access:
2000 If you don't already have one, set up a Savannah user account at
2001 @uref{https://savannah.gnu.org/account/register.php}. If your web
2002 browser responds with an @qq{untrusted connection} message when
2003 you visit the link, follow the steps for including the CAcert root
2004 certificate in your browser, given at
2005 @uref{http://savannah.gnu.org/tls/tutorial/}.
2007 @warning{Savannah will silently put your username in lower-case --
2008 do not try to use capital letters.}
2012 After registering, if you are not logged in automatically, login
2013 at @uref{https://savannah.gnu.org/account/login.php}---this should
2014 take you to your @qq{my} page
2015 (@uref{https://savannah.gnu.org/my/}).
2019 Click on the @qq{My Groups} link to access the @qq{My Group
2020 Membership} page. From there, find the @qq{Request for Inclusion}
2021 box and search for @qq{LilyPond}. Among the search results, check
2022 the box labeled @qq{GNU LilyPond Music Typesetter} and write a
2023 brief (required) message for the Project Manager (@qq{Hey it's
2024 me!} should be fine).
2026 Note that you will not have commit access until the Project
2027 Manager activates your membership. Once your membership is
2028 activated, LilyPond should appear under the heading @qq{Groups I'm
2029 Contributor of} on your @qq{My Group Membership} page.
2033 Generate an SSH @q{rsa} key pair. Enter the following at the
2040 When prompted for a location to save the key, press <ENTER> to
2041 accept the default location (@file{~/.ssh/id_rsa}).
2043 Next you are asked to enter an optional passphrase. On most
2044 systems, if you use a passphrase, you will likely be prompted for
2045 it every time you use @command{git@tie{}push} or
2046 @command{git@tie{}pull}. You may prefer this since it can protect
2047 you from your own mistakes (like pushing when you mean to pull),
2048 though you may find it tedious to keep re-entering it.
2050 You can change/enable/disable your passphrase at any time with:
2053 ssh-keygen -f ~/.ssh/id_rsa -p
2056 Note that the GNOME desktop has a feature which stores your
2057 passphrase for you for an entire GNOME session. If you use a
2058 passphrase to @qq{protect you from yourself}, you will want to
2059 disable this feature, since you'll only be prompted once. Run the
2060 following command, then logout of GNOME and log back in:
2063 gconftool-2 --set -t bool \
2064 /apps/gnome-keyring/daemon-components/ssh false
2067 After setting up your passphrase, your private key is saved as
2068 @file{~/.ssh/id_rsa} and your public key is saved as
2069 @file{~/.ssh/id_rsa.pub}.
2073 Register your public SSH @q{rsa} key with Savannah. From the
2074 @qq{My Account Configuration} page, click on @qq{Edit SSH Keys},
2075 then paste the contents of your @file{~/.ssh/id_rsa.pub} file into
2076 one of the @qq{Authorized keys} text fields, and click
2079 Savannah should respond with something like:
2082 Success: Key #1 seen Keys registered
2087 Configure Git to use the SSH protocol (instead of the GIT
2088 protocol). From your local Git repository, enter:
2091 git config remote.origin.url \
2092 ssh://@var{user}@@git.sv.gnu.org/srv/git/lilypond.git
2096 replacing @var{user} with your Savannah username.
2100 After your membership has been activated and you've configured Git
2101 to use SSH, test the connection with:
2107 SSH should issue the following warning:
2110 The authenticity of host 'git.sv.gnu.org (140.186.70.72)' can't
2112 RSA key fingerprint is
2113 80:5a:b0:0c:ec:93:66:29:49:7e:04:2b:fd:ba:2c:d5.
2114 Are you sure you want to continue connecting (yes/no)?
2117 Make sure the RSA key fingerprint displayed matches the one above.
2118 If it doesn't, respond @qq{no} and check that you configured Git
2119 properly in the previous step. If it does match, respond
2120 @qq{yes}. SSH should then issue another warning:
2123 Warning: Permanently added 'git.sv.gnu.org,140.186.70.72' (RSA) to
2124 the list of known hosts.
2127 The list of known hosts is stored in the file
2128 @file{~/.ssh/known_hosts}.
2130 At this point, you are prompted for your passphrase if you have
2131 one, then Git will attempt a pull.
2133 If @command{git@tie{}pull@tie{}--verbose} fails, you should see
2134 error messages like these:
2137 Permission denied (publickey).
2138 fatal: The remote end hung up unexpectedly
2141 If you get the above error, you may have made a mistake when
2142 registering your SSH key at Savannah. If the key is properly
2143 registered, you probably just need to wait for the Savannah server
2144 to activate it. It usually takes a few minutes for the key to be
2145 active after registering it, but if it still doesn't work after an
2146 hour, ask for help on the mailing list.
2148 If @command{git@tie{}pull@tie{}--verbose} succeeds, the output
2149 will include a @q{From} line that shows @q{ssh} as the protocol:
2152 From ssh://git.sv.gnu.org/srv/git/lilypond
2155 If the protocol shown is not @q{ssh}, check that you configured
2156 Git properly in the previous step.
2160 Test your commit access with a dry run:
2162 @warning{Do not push directly to master; instead, push to staging.
2163 See @ref{Pushing to staging}.}
2166 git push --dry-run --verbose
2169 Note that recent versions of Git (Git 1.6.3 or later) will issue a
2170 big warning if the above command is used. The simplest solution
2171 is to tell Git to push all matching branches by default:
2174 git config push.default matching
2178 Then @code{git@tie{}push} should work as before. For more
2179 details, consult the @code{git@tie{}push} man page.
2183 Repeat the steps from generating an RSA key through to testing
2184 your commit access, for each machine from which you will be
2185 making commits, or you may simply copy the files from your
2186 local @file{~/.ssh} folder to the same folder on the other
2191 @subsubheading Technical details
2195 On Firefox, to view or remove the CAcert root certificate, go to:
2196 Edit > Preferences > Advanced > Encryption > View Certificates >
2197 Authorities > Certificate Name > Root CA > CA Cert Signing
2201 The @command{git@tie{}config} commands above should modify your
2202 local repository's @file{.git/config} file. These lines:
2206 url = git://git.sv.gnu.org/lilypond.git/
2210 should now be changed to:
2214 url = ssh://@var{user}@@git.sv.gnu.org/srv/git/lilypond.git
2218 where @var{user} is your login name on Savannah.
2222 @command{git@tie{}config@tie{}push.default@tie{}matching} command
2223 should add these lines to @file{.git/config}:
2232 Encryption protocols, including ssh, generally do not permit packet
2233 fragmentation to avoid introducing a point of insecurity. This
2234 means that the maximum packet size must not exceed the smallest
2235 MTU (Maximum Transmission Unit) set in the routers along the path.
2236 This smallest MTU is determined by a procedure during call set-up
2237 which relies on the transmission over the path of ICMP packets.
2238 If any of the routers in the path block ICMP packets this mechanism
2239 fails, resulting in the possibility of packets being transmitted
2240 which exceed the MTU of one of the routers. If this happens the
2241 packet is discarded, causing the ssh session to hang, timeout or
2242 terminate with the error message
2245 ssh: connect to host <host ip addr> port 22: Bad file number
2246 fatal: The remote end hung up unexpectedly
2249 depending on precisely when in the proceedings the first large
2250 packet is transmitted. Most routers on the internet have MTU
2251 set to 1500, but routers installed in homes to connect via
2252 broadband may use a slightly smaller MTU for efficient transmission
2253 over ATM. If this problem is encountered a possible work-around is
2254 to set the MTU in the local router to 1500.
2257 @node Pushing to staging
2258 @subsection Pushing to staging
2260 Do not push directly to the git @code{master} branch. Instead,
2261 push to @code{staging}.
2263 You will not see your patch on @code{origin/master} until some
2264 automatic tests have been run. These tests are run every couple
2265 of hours; please wait at least 12 hours before wondering if your
2266 patch has been lost. Note that you can check the commits on
2267 @code{origin/staging} by looking at the git web interface on
2270 It may happen occasionally that the staging branch breaks automated
2271 testing. In this case the automatic move of staging material to
2272 master gets halted in order to avoid broken material entering master.
2273 This is a safety net. Please do not try breaking out from it by
2274 adding fixes on top of staging: in that case the whole sequence will
2275 end up in master after all, defeating the purpose of the system. The
2276 proper fix usually involves rewriting the staging branch and is best
2277 left to core developers after discussion on the developer list.
2279 @subsubheading If your work is in a patch file
2281 Assuming that your patch is in a file called
2282 @file{0001-my-patch.patch}, and you are currently on git master,
2286 git checkout staging
2288 git am 0001-my-patch.patch
2290 git push origin staging
2294 @warning{Do not skip the @command{gitk} step; a quick 5-second
2295 check of the visual history can save a great deal of frustration
2296 later on. You should only see that @command{staging} is only 1
2297 commit ahead of @code{origin/staging}.}
2299 @subsubheading If your work is in a branch
2301 If you are working on branches and your work in is
2302 @code{my_branch_name}, then do:
2305 git checkout staging
2307 git merge my_branch_name
2309 git push origin staging
2312 @warning{Do not skip the @command{gitk} step; a quick 5-second
2313 check of the visual history can save a great deal of frustration
2314 later on. You should see that @code{staging} is only ahead of
2315 @code{origin/staging} by the commits from your branch.}
2319 @node Git on Windows
2320 @section Git on Windows
2322 @warning{We heavily recommend that development be done with our
2323 virtual machine @ref{LilyDev}.}
2325 @c Some of this may duplicate stuff in other sections
2326 @c But it is probably best for windows users to have it all together
2327 @c If necessary, clear this up later -td
2329 TODO: Decide what to do with this... Pare it down? Move
2330 paragraphs next to analogous Unix instructions? -mp
2332 @subsection Background to nomenclature
2334 Git is a system for tracking the changes made to source files by a
2335 distributed set of editors. It is designed to work without a
2336 master repository, but we have chosen to have a master repository
2337 for LilyPond files. Editors hold a local copy of the master
2338 repository together with any changes they have made locally.
2339 Local changes are held in a local @q{branch}, of which there may
2340 be several, but these instructions assume you are using just one.
2341 The files visible in the local repository always correspond to
2342 those on the currently @q{checked out} local branch.
2344 Files are edited on a local branch, and in that state the changes
2345 are said to be @q{unstaged}. When editing is complete, the
2346 changes are moved to being @q{staged for commit}, and finally the
2347 changes are @q{committed} to the local branch. Once committed,
2348 the changes (called a @q{commit}) are given a unique 40-digit
2349 hexadecimal reference number called the @q{Committish} or @q{SHA1
2350 ID} which identifies the commit to Git. Such committed changes
2351 can be sent to the master repository by @q{pushing} them (if you
2352 have write permission) or by sending them by email to someone who
2353 has, either as a complete file or as a @q{diff} or @q{patch}
2354 (which send just the differences from the master repository).
2356 @subsection Installing git
2359 @uref{https://git-for-windows.github.io/}.
2361 Note that most users will not need to install SSH. That is not
2362 required until you have been granted direct push permissions to
2363 the master git repository.
2365 Start Git by clicking on the desktop icon. This will bring up a
2366 command line bash shell. This may be unfamiliar to Windows users.
2367 If so, follow these instructions carefully. Commands are entered
2368 at a $ prompt and are terminated by keying a newline.
2370 @subsection Initialising Git
2372 Decide where you wish to place your local Git repository, creating
2373 the folders in Windows as necessary. Here we call the folder to
2374 contain the repository @code{[path]/Git}, but if you intend using
2375 Git for other projects a directory name like @code{lilypond-git}
2376 might be better. You will need to have space for around
2379 Start the Git bash shell by clicking on the desk-top icon
2380 installed with Git and type
2386 to position the shell at your new Git repository.
2388 Note: if [path] contains folders with names containing spaces use
2400 to initialize your Git repository.
2402 Then type (all on one line; the shell will wrap automatically)
2405 git remote add -ft master origin git://git.sv.gnu.org/lilypond.git
2408 to download the lilypond master files.
2410 @warning{Be patient! Even on a broadband connection this can take
2411 10 minutes or more. Wait for lots of [new tag] messages and the $
2414 We now need to generate a local copy of the downloaded files in a
2415 new local branch. Your local branch needs to have a name. It is
2416 usual to call it @q{master} and we shall do that here.
2421 git checkout -b master origin/master
2424 This creates a second branch called @q{master}. You will see two
2425 warnings (ignore these), and a message advising you that your
2426 local branch @q{master} has been set up to track the remote
2427 branch. You now have two branches, a local branch called
2428 @q{master}, and a tracking branch called @q{origin/master}, which
2429 is a shortened form of @q{remotes/origin/master}.
2431 Return to Windows Explorer and look in your Git repository. You
2432 should see lots of folders. For example, the LilyPond
2433 documentation can be found in [path]/Git/Documentation/.
2435 The Git bash shell is terminated by typing @code{exit} or by
2436 clicking on the usual Windows close-window widget.
2440 Almost all subsequent work will use the Git Graphical User
2441 Interface, which avoids having to type command line commands. To
2442 start Git GUI first start the Git bash shell by clicking on the
2443 desktop icon, and type
2450 The Git GUI will open in a new window. It contains four panels
2451 and 7 pull-down menus. At this stage do not use any of the
2452 commands under Branch, Commit, Merge or Remote. These will be
2455 The top panel on the left contains the names of files which you
2456 are in the process of editing (Unstaged Changes), and the lower
2457 panel on the left contains the names of files you have finished
2458 editing and have staged ready for committing (Staged Changes). At
2459 present, these panels will be empty as you have not yet made any
2460 changes to any file. After a file has been edited and saved the
2461 top panel on the right will display the differences between the
2462 edited file selected in one of the panels on the left and the last
2463 version committed on the current branch.
2465 The panel at bottom right is used to enter a descriptive message
2466 about the change before committing it.
2468 The Git GUI is terminated by entering CNTL-Q while it is the
2469 active window or by clicking on the usual Windows close-window
2472 @subsection Personalising your local git repository
2474 Open the Git GUI, click on
2480 and enter your name and email address in the left-hand (Git
2481 Repository) panel. Leave everything else unchanged and save it.
2483 Note that Windows users must leave the default setting for line
2484 endings unchanged. All files in a git repository must have lines
2485 terminated by just a LF, as this is required for Merge to work,
2486 but Windows files are terminated by CRLF by default. The git
2487 default setting causes the line endings of files in a Windows git
2488 repository to be flipped automatically between LF and CRLF as
2489 required. This enables files to be edited by any Windows editor
2490 without causing problems in the git repository.
2492 @subsection Checking out a branch
2494 At this stage you have two branches in your local repository,
2495 both identical. To see them click on
2501 You should have one local branch called @q{master} and one
2502 tracking branch called @q{origin/master}. The latter is your
2503 local copy of the @q{remotes/origin/master} branch in the master
2504 LilyPond repository. The local @q{master} branch is where you
2505 will make your local changes.
2507 When a particular branch is selected, i.e., checked out, the files
2508 visible in your repository are changed to reflect the state of the
2509 files on that branch.
2511 @subsection Updating files from @q{remote/origin/master}
2513 Before starting the editing of a file, ensure your local
2514 repository contains the latest version of the files in the remote
2515 repository by first clicking
2518 Remote -> Fetch from -> origin
2524 This will place the latest version of every file, including all
2525 the changes made by others, into the @q{origin/master} branch of
2526 the tracking branches in your git repository. You can see these
2527 files by checking out this branch, but you must @emph{never} edit
2528 any files while this branch is checked out. Check out your local
2529 @q{master} branch again.
2531 You then need to merge these fetched files into your local
2532 @q{master} branch by clicking on
2535 Merge -> Local Merge
2539 and if necessary select the local @q{master} branch.
2541 Note that a merge cannot be completed if you have made any local
2542 changes which have not yet been committed.
2544 This merge will update all the files in the @q{master} branch to
2545 reflect the current state of the @q{origin/master} branch. If any
2546 of the changes conflict with changes you have made yourself
2547 recently you will be notified of the conflict (see below).
2549 @subsection Editing files
2551 First ensure your @q{master} branch is checked out, then simply
2552 edit the files in your local Git repository with your favourite
2553 editor and save them back there. If any file contains non-ASCII
2554 characters ensure you save it in UTF-8 format. Git will detect
2555 any changes whenever you restart Git GUI and the file names will
2556 then be listed in the Unstaged Changes panel. Or you can click
2557 the Rescan button to refresh the panel contents at any time. You
2558 may break off and resume editing any time.
2560 The changes you have made may be displayed in diff form in the top
2561 right-hand panel of Git GUI by clicking on the file name shown in
2562 one of the left panels.
2564 When your editing is complete, move the files from being Unstaged
2565 to Staged by clicking the document symbol to the left of each
2566 name. If you change your mind it can be moved back by clicking on
2567 the ticked box to the left of the name.
2569 Finally the changes you have made may be committed to your
2570 @q{master} branch by entering a brief message in the Commit
2571 Message box and clicking the Commit button.
2573 If you wish to amend your changes after a commit has been made,
2574 the original version and the changes you made in that commit may
2575 be recovered by selecting
2578 Commit -> Amend Last Commit
2582 or by checking the Amend Last Commit radio button at bottom right.
2583 This will return the changes to the Staged state, so further
2584 editing made be carried out within that commit. This must only be
2585 done @emph{before} the changes have been Pushed or sent to your
2586 mentor for Pushing - after that it is too late and corrections
2587 have to be made as a separate commit.
2590 @subsection Sending changes to @q{remotes/origin/master}
2592 If you do not have write access to @q{remotes/origin/master} you
2593 will need to send your changes by email to someone who does.
2595 First you need to create a diff or patch file containing your
2596 changes. To create this, the file must first be committed. Then
2597 terminate the Git GUI. In the git bash shell first cd to your Git
2604 if necessary, then produce the patch with
2607 git format-patch origin
2610 This will create a patch file for all the locally committed files
2611 which differ from @q{origin/master}. The patch file can be found
2612 in [path]/Git and will have a name formed from the commit message.
2614 @subsection Resolving merge conflicts
2616 As soon as you have committed a changed file your local
2617 @code{master} branch has diverged from @code{origin/master}, and
2618 will remain diverged until your changes have been committed in
2619 @code{remotes/origin/master} and Fetched back into your
2620 @code{origin/master} branch. Similarly, if a new commit has been
2621 made to @code{remotes/origin/master} by someone else and Fetched,
2622 your local @code{master} branch is divergent. You can detect a
2623 divergent branch by clicking on
2626 Repository -> Visualise all branch history
2629 This opens up a very useful new window called @q{gitk}. Use this
2630 to browse all the commits made by yourself and others.
2632 If the diagram at top left of the resulting window does not show
2633 your @code{master} tag on the same node as the
2634 @code{remotes/origin/master} tag your branch has diverged from
2635 @code{origin/master}. This is quite normal if files you have
2636 modified yourself have not yet been Pushed to
2637 @code{remotes/origin/master} and Fetched, or if files modified and
2638 committed by others have been Fetched since you last Merged
2639 @code{origin/master} into your local @code{master} branch.
2641 If a file being merged from @code{origin/master} differs from one
2642 you have modified in a way that cannot be resolved automatically
2643 by git, Merge will report a Conflict which you must resolve by
2644 editing the file to create the version you wish to keep.
2646 This could happen if the person updating
2647 @code{remotes/origin/master} for you has added some changes of his
2648 own before committing your changes to
2649 @code{remotes/origin/master}, or if someone else has changed the
2650 same file since you last fetched the file from
2651 @code{remotes/origin/master}.
2653 Open the file in your editor and look for sections which are
2656 [to be completed when I next have a merge conflict to be sure I
2657 give the right instructions -td]
2660 @subsection Other actions
2662 The instructions above describe the simplest way of using git on
2663 Windows. Other git facilities which may usefully supplement these
2667 @item Using multiple local branches (Create, Rename, Delete)
2668 @item Resetting branches
2669 @item Cherry-picking commits
2670 @item Pushing commits to @w{remote/origin/master}
2671 @item Using gitk to review history
2674 Once familiarity with using git on Windows has been gained the
2675 standard git manuals can be used to learn about these.
2678 @node Repository directory structure
2679 @section Repository directory structure
2682 @c TODO: integrate the roadmap better
2683 @verbatiminclude ROADMAP
2686 @node Other Git documentation
2687 @section Other Git documentation
2691 Official git man pages:
2692 @uref{http://www.kernel.org/pub/software/scm/git/docs/}
2695 More in-depth tutorials: @uref{http://git-scm.com/documentation}
2698 Book about git: @uref{http://progit.org/,Pro Git}
2701 Github help: @uref{http://help.github.com/}
2702 (very highly recommended by Graham)