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 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
594 text editor. This code is here:
597 https://github.com/gperciva/lilypad
601 @node yet more repositories
602 @unnumberedsubsubsec yet more repositories
604 There are a few other repositories floating around, which will
605 hopefully be documented in the near future.
608 @node Downloading remote branches
609 @subsection Downloading remote branches
611 @warning{contains obsolete + misleading info}
614 * Organization of remote branches::
615 * LilyPond repository sources::
616 * Downloading individual branches::
617 * Downloading all remote branches::
622 @node Organization of remote branches
623 @unnumberedsubsubsec Organization of remote branches
626 The main LilyPond repository is organized into @emph{branches} to
627 facilitate development. These are often called @emph{remote}
628 branches to distinguish them from @emph{local} branches you might
629 create yourself (see @ref{Using local branches}).
631 The @code{master} branch contains all the source files used to
632 build LilyPond, which includes the program itself (both stable and
633 development releases), the documentation (and its translations),
634 and the website. Generally, the @code{master} branch is expected
635 to compile successfully.
637 The @code{translation} branch is a side branch that
638 allows translators to work without needing to worry about
639 compilation problems. Periodically, the Translation Meister
640 (after verifying that it doesn't break compilation), will
641 @emph{merge} this branch into @code{staging} to incorporate
642 recent translations. Similarly, the @code{master} branch is
643 usually merged into the @code{translation} branch after
644 significant changes to the English documentation. See
645 @ref{Translating the documentation} for details.
648 @node LilyPond repository sources
649 @unnumberedsubsubsec LilyPond repository sources
652 The recommended source for downloading a copy of the main
656 git://git.sv.gnu.org/lilypond.git
659 However, if your internet router filters out connections using the
660 GIT protocol, or if you experience difficulty connecting via GIT,
661 you can try these other sources:
664 ssh://git.sv.gnu.org/srv/git/lilypond.git
665 http://git.sv.gnu.org/r/lilypond.git
668 The SSH protocol can only be used if your system is properly set
669 up to use it. Also, the HTTP protocol is slowest, so it should
670 only be used as a last resort.
673 @node Downloading individual branches
674 @unnumberedsubsubsec Downloading individual branches
676 @warning{obsolete, should be deleted!}
679 Once you have initialized an empty Git repository on your system
680 (see @ref{Initializing a repository}), you can download a remote
681 branch into it. Make sure you know which branch you want to start
684 To download the @code{master} branch, enter the following:
687 git remote add -ft master -m master \
688 origin git://git.sv.gnu.org/lilypond.git/
691 To download the @code{translation} branch, enter:
694 git remote add -ft translation -m \
695 translation origin git://git.sv.gnu.org/lilypond.git/
698 The @command{git@tie{}remote@tie{}add} process could take up to
699 ten minutes, depending on the speed of your connection. The
700 output will be something like this:
704 remote: Counting objects: 235967, done.
705 remote: Compressing objects: 100% (42721/42721), done.
706 remote: Total 235967 (delta 195098), reused 233311 (delta 192772)
707 Receiving objects: 100% (235967/235967), 68.37 MiB | 479 KiB/s, done.
708 Resolving deltas: 100% (195098/195098), done.
709 From git://git.sv.gnu.org/lilypond
710 * [new branch] master -> origin/master
711 From git://git.sv.gnu.org/lilypond
712 * [new tag] flower/1.0.1 -> flower/1.0.1
713 * [new tag] flower/1.0.10 -> flower/1.0.10
715 * [new tag] release/2.9.6 -> release/2.9.6
716 * [new tag] release/2.9.7 -> release/2.9.7
719 When @command{git@tie{}remote@tie{}add} is finished, the remote
720 branch should be downloaded into your repository---though not yet
721 in a form that you can use. In order to browse the source code
722 files, you need to @emph{create} and @emph{checkout} your own
723 local branch. In this case, however, it is easier to have Git
724 create the branch automatically by using the @command{checkout}
725 command on a non-existent branch. Enter the following:
728 git checkout -b @var{branch} origin/@var{branch}
732 where @code{@var{branch}} is the name of your tracking branch,
733 either @code{master} or @code{translation}.
735 Git will issue some warnings; this is normal:
738 warning: You appear to be on a branch yet to be born.
739 warning: Forcing checkout of origin/master.
740 Branch master set up to track remote branch master from origin.
744 By now the source files should be accessible---you should be able
745 to edit any files in the @file{$LILYPOND_GIT} directory using a
746 text editor of your choice. But don't start just yet! Before
747 editing any source files, learn how to keep your changes organized
748 and prevent problems later---read @ref{Basic Git procedures}.
750 @subsubheading Technical Details
752 The @command{git@tie{}remote@tie{}add} command should add some
753 lines to your local repository's @file{.git/config} file:
757 url = git://git.sv.gnu.org/lilypond.git/
758 fetch = +refs/heads/master:refs/remotes/origin/master
762 @node Downloading all remote branches
763 @unnumberedsubsubsec Downloading all remote branches
766 To download all remote branches at once, you can @command{clone}
767 the entire repository:
770 git clone git://git.sv.gnu.org/lilypond.git
775 @unnumberedsubsubsec Other branches
777 Most contributors will never need to touch the other branches. If
778 you wish to do so, you will need more familiarity with Git; please
779 see @ref{Other Git documentation}.
782 @item @code{dev/XYZ}:
783 These branches are for individual developers. They store code
784 which is not yet stable enough to be added to the @code{master}
787 @item @code{stable/XYZ}:
788 The branches are kept for archival reasons.
790 @item @code{archive/XYZ}:
791 The branches are kept for archival reasons.
796 @node Basic Git procedures
797 @section Basic Git procedures
801 * The Git contributor's cycle::
802 * Pulling and rebasing::
803 * Using local branches::
804 * Commits and patches::
808 @node The Git contributor's cycle
809 @subsection The Git contributor's cycle
812 Here is a simplified view of the contribution process on Git:
816 Update your local repository by @emph{pulling} the most recent
817 updates from the remote repository.
820 Edit source files within your local repository's @emph{working
824 @emph{Commit} the changes you've made to a local @emph{branch}.
827 Generate a @emph{patch} to share your changes with the developers.
831 @node Pulling and rebasing
832 @subsection Pulling and rebasing
835 When developers push new patches to the @code{git.sv.gnu.org}
836 repository, your local repository is @strong{not} automatically
837 updated. It is important to keep your repository up-to-date by
838 periodically @emph{pulling} the most recent @emph{commits} from
839 the remote branch. Developers expect patches to be as current as
840 possible, since outdated patches require extra work before they
843 Occasionally you may need to rework some of your own modifications
844 to match changes made to the remote branch (see @ref{Resolving
845 conflicts}), and it's considerably easier to rework things
846 incrementally. If you don't update your repository along the way,
847 you may have to spend a lot of time resolving branch conflicts and
848 reconfiguring much of the work you've already done.
850 Fortunately, Git is able to resolve certain types of branch
851 conflicts automatically with a process called @emph{rebasing}.
852 When rebasing, Git tries to modify your old commits so they appear
853 as new commits (based on the latest updates). For a more involved
854 explanation, see the @command{git-rebase} man page.
856 To pull without rebasing (recommended for translators), use the
860 git pull # recommended for translators
863 If you're tracking the remote @code{master} branch, you should add
864 the @option{-r} option (short for @option{--rebase}) to keep commits
865 on your local branch current:
868 git pull -r # use with caution when translating
871 If you don't edit translated documentation and don't want to type
872 @option{-r} every time, configure the master branch to rebase by
873 default with this command:
876 git config branch.master.rebase true
879 If pull fails because of a message like
882 error: Your local changes to 'Documentation/learning/tutorial.itely'
883 would be overwritten by merge. Aborting.
890 Documentation/learning/tutorial.itely: needs update
891 refusing to pull with rebase: your working tree is not up-to-date
895 it means that you have modified some files in you working tree
896 without committing changes (see @ref{Commits and patches}); you
897 can use the @command{git@tie{}stash} command to work around this:
900 git stash # save uncommitted changes
901 git pull -r # pull using rebase (translators omit "-r")
902 git stash pop # reapply previously saved changes
905 Note that @command{git@tie{}stash@tie{}pop} will try to apply a
906 patch, and this may create a conflict. If this happens, see
907 @ref{Resolving conflicts}.
909 TODO: I think the next paragraph is confusing. Perhaps prepare
910 the reader for new terms `committish' and `head'? -mp
912 @warning{translators and documentation editors, if you have
913 changed committishes in the head of translated files using commits
914 you have not yet pushed to @code{git.sv.gnu.org}, please do not
915 rebase. If you want to avoid wondering whether you should rebase
916 each time you pull, please always use committishes from master
917 and/or translation branch on @code{git.sv.gnu.org}, which
918 in particular implies that you must push your changes to
919 documentation except committishes updates (possibly after having
920 rebased), then update the committishes and push them.}
922 TODO: when committishes automatic conditional update have been
923 tested and documented, append the following to the warning above:
924 Note that using update-committishes make target generally touches
927 @subsubheading Technical details
929 The @command{git@tie{}config} command mentioned above adds the
930 line @code{rebase = true} to the master branch in your local
931 repository's @file{.git/config} file:
936 merge = refs/heads/master
941 @node Using local branches
942 @subsection Using local branches
946 * Creating and removing branches::
947 * Listing branches and remotes::
948 * Checking out branches::
953 @node Creating and removing branches
954 @unnumberedsubsubsec Creating and removing branches
957 Local branches are useful when you're working on several different
958 projects concurrently. To create a new branch, enter:
961 git branch @var{name}
964 To delete a branch, enter:
967 git branch -d @var{name}
970 Git will ask you for confirmation if it sees that data would be
971 lost by deleting the branch. Use @option{-D} instead of @option{-d}
972 to bypass this. Note that you cannot delete a branch if it is
973 currently checked out.
976 @node Listing branches and remotes
977 @unnumberedsubsubsec Listing branches and remotes
979 You can get the exact path or URL of all remote branches by
986 To list Git branches on your local repositories, run
989 git branch # list local branches only
990 git branch -r # list remote branches
991 git branch -a # list all branches
995 @node Checking out branches
996 @unnumberedsubsubsec Checking out branches
998 To know the currently checked out branch, i.e. the branch whose
999 source files are present in your working tree, read the first line
1007 The currently checked out branch is also marked with an asterisk
1008 in the output of @command{git branch}.
1010 You can check out another branch @code{@var{other_branch}}, i.e.
1011 check out @code{@var{other_branch}} to the working tree, by
1015 git checkout @var{other_branch}
1018 Note that it is possible to check out another branch while having
1019 uncommitted changes, but it is not recommended unless you know
1020 what you are doing; it is recommended to run @command{git status}
1021 to check this kind of issue before checking out another branch.
1023 @node Merging branches
1024 @unnumberedsubsubsec Merging branches
1026 To merge branch @code{@var{foo}} into branch @code{@var{bar}},
1027 i.e. to @qq{add} all changes made in branch @code{@var{foo}} to
1028 branch @code{@var{bar}}, run
1031 git checkout @var{bar}
1035 If any conflict happens, see @ref{Resolving conflicts}.
1037 There are common usage cases for merging: as a translator, you will
1038 often want the Translations meister to merge @code{master} into
1039 @code{translation}; on the other hand, the Translations meister wants
1040 to merge @code{translation} into @code{staging} whenever he has
1041 checked that @code{translation} builds successfully.
1044 @node Commits and patches
1045 @subsection Commits and patches
1049 * Understanding commits::
1053 * Uploading a patch for review::
1057 @node Understanding commits
1058 @unnumberedsubsubsec Understanding commits
1060 Technically, a @emph{commit} is a single point in the history of a
1061 branch, but most developers use the term to mean a @emph{commit
1062 object}, which stores information about a particular revision. A
1063 single commit can record changes to multiple source files, and
1064 typically represents one logical set of related changes (such as a
1065 bug-fix). You can list the ten most recent commits in your
1066 current branch with this command:
1069 git log -10 --oneline
1072 If you're using an older version of Git and get an @q{unrecognized
1073 argument} error, use this instead:
1076 git log -10 --pretty=oneline --abbrev-commit
1079 More interactive lists of the commits on the remote @code{master}
1080 branch are available at
1081 @uref{http://git.sv.gnu.org/gitweb/?p=lilypond.git;a=shortlog} and
1082 @uref{http://git.sv.gnu.org/cgit/lilypond.git/log/}.
1085 @node Making commits
1086 @unnumberedsubsubsec Making commits
1089 Once you have modified some source files in your working
1090 directory, you can make a commit with the following procedure:
1094 Make sure you've configured Git properly (see @ref{Configuring
1095 Git}). Check that your changes meet the requirements described in
1096 @ref{Code style} and/or @ref{Documentation policy}. For advanced
1097 edits, you may also want to verify that the changes don't break
1098 the compilation process.
1101 Run the following command:
1108 to make sure you're on the right branch, and to see which files
1109 have been modified, added or removed, etc. You may need to tell
1110 Git about any files you've added by running one of these:
1113 git add @var{file} # add untracked @var{file} individually
1114 git add . # add all untracked files in current directory
1118 After @command{git@tie{}add}, run @command{git@tie{}status} again
1119 to make sure you got everything. You may also need to modify
1123 Preview the changes about to be committed (to make sure everything
1131 The @code{HEAD} argument refers to the most recent commit on the
1132 currently checked-out branch.
1135 Generate the commit with:
1142 The @option{-a} is short for @option{--all} which includes modified
1143 and deleted files, but only those newly created files that have
1144 previously been added.
1149 @node Commit messages
1150 @unnumberedsubsubsec Commit messages
1153 When you run the @command{git@tie{}commit@tie{}-a} command, Git
1154 automatically opens the default text editor so you can enter a
1155 @emph{commit message}. If you find yourself in a foreign editing
1156 environment, you're probably in @command{vi} or @command{vim}. If
1157 you want to switch to an editor you're more familiar with, quit by
1158 typing @code{:q!} and pressing @code{<Enter>}. See
1159 @ref{Configuring Git} for instructions on changing the default
1162 In any case, Git will open a text file for your commit message
1163 that looks like this:
1167 # Please enter the commit message for your changes. Lines starting
1168 # with '#' will be ignored, and an empty message aborts the commit.
1170 # Changes to be committed:
1171 # (use "git reset HEAD <file>..." to unstage)
1173 # modified: working.itexi
1177 Your commit message should begin with a one-line summary
1178 describing the change (no more than 50 characters long), and if
1179 necessary a blank line followed by several lines giving the
1182 @c $ git log -1 --pretty=medium 4d6f1e5
1184 Doc: add Baerenreiter and Henle solo cello suites
1186 Added comparison of solo cello suite engravings to new essay with
1187 high-res images, fixed cropping on Finale example.
1190 Commit messages often start with a short prefix describing the
1191 general location of the changes. If a commit affects the
1192 documentation in English (or in several languages simultaneously)
1193 the commit message should be prefixed with @qq{Doc:@tie{}}. If
1194 the commit affects only one of the translations, the commit
1195 message should be prefixed with @qq{Doc-@var{**}:@tie{}}, where
1196 @var{**} is the two-letter language code. Commits that affect the
1197 website should use @qq{Web:@tie{}} for English, and
1198 @qq{Web-@var{**}:@tie{}} for the other languages. Also, changes
1199 to a single file are often prefixed with the name of the file
1200 involved. Visit the links listed in @ref{Understanding commits}
1204 @node Making patches
1205 @unnumberedsubsubsec Making patches
1207 If you want to share your changes with other contributors and
1208 developers, you need to generate @emph{patches} from your commits.
1209 We prefer it if you follow the instructions in
1210 @ref{Uploading a patch for review}. However, we present an
1211 alternate method here.
1213 You should always run @command{git@tie{}pull@tie{}-r} (translators
1214 should leave off the @option{-r}) before doing this to ensure that
1215 your patches are as current as possible.
1217 Once you have made one or more commits in your local repository,
1218 and pulled the most recent commits from the remote branch, you can
1219 generate patches from your local commits with the command:
1222 git format-patch origin
1225 The @code{origin} argument refers to the remote tracking branch at
1226 @code{git.sv.gnu.org}. This command generates a separate patch
1227 for each commit that's in the current branch but not in the remote
1228 branch. Patches are placed in the current working directory and
1229 will have names that look something like this:
1232 0001-Doc-Fix-typos.patch
1233 0002-Web-Remove-dead-links.patch
1237 Send an email (must be less than 64 KB) to
1238 @email{lilypond-devel@@gnu.org} briefly explaining your work, with
1239 the patch files attached. Translators should send patches to
1240 @email{translations@@lilynet.net}. After your patches are
1241 reviewed, the developers may push one or more of them to the main
1242 repository or discuss them with you.
1245 @node Uploading a patch for review
1246 @unnumberedsubsubsec Uploading a patch for review
1248 Any non-trivial change should be uploaded to our @qq{Rietveld}
1249 code review website:
1252 @uref{http://codereview.appspot.com/}
1255 @subsubheading @command{git-cl} install
1257 LilyDev users should skip over these @q{install} instructions.
1262 Install @command{git-cl} by entering:
1265 git clone https://github.com/gperciva/git-cl.git
1268 If that command fails for some reason, try this instead:
1271 git clone git://github.com/gperciva/git-cl.git
1275 Add the @file{git-cl/} directory to your PATH,
1276 or create a symbolic link to the @command{git-cl}
1277 and @command{upload.py} scripts in one of your PATH
1278 directories (such as @file{$HOME/bin}).
1280 In Ubuntu (and LilyDev), you can add directories to PATH
1281 by adding this line to a hidden file @file{.bashrc},
1282 located in your home directory:
1285 PATH=~/type-here-directory-containing-git-cl:"$@{PATH@}"
1290 @subsubheading @command{git-cl} configuration
1292 LilyDev users should perform these @q{configuration} instructions.
1296 You must have a google account; please create one if you do not
1299 Note that a google account does not need to be a gmail account; you can
1300 use any email address for your google account when you sign up.
1303 Move into the top source directory and then configure @command{git
1304 cl} with the following commands:
1311 For the @qq{Rietveld server} question, the default value
1312 (@qq{codereview.appspot.com}) should be accepted by
1313 answering with a newline (CR).
1315 The @qq{CC list} question should be answered with:
1318 lilypond-devel@@gnu.org
1321 The @qq{Tree status URL} value should be left blank. So should
1322 the @qq{ViewVC URL} value, since it is used by @command{git cl
1323 dcommit} which is only for repositories which use @command{git
1324 svn} (LilyPond doesn't).
1328 @subsubheading Uploading patch set
1330 @warning{Unless you are familiar with branches, only work on one
1331 set of changes at once.}
1333 There are two methods, depending on your git setup.
1337 @strong{Master branch}: (easy option, and used in @command{lily-git.tcl})
1339 If you added your patch to @code{master}, then:
1343 git cl upload origin/master
1346 @c Mention staging here?
1347 If you have git push ability, make sure that you @emph{remove}
1348 your patch (with @command{git rebase} or @command{git reset})
1349 before pushing other stuff.
1351 @c don't make this one an @example; we don't want to make it easy
1352 @c for people to use this accidently
1353 Notifications of patches are automatically added to our issue
1354 tracker to reduce the chance of patches getting lost. To suppress
1355 this (not recommended), add the @code{-n / --no-code-issue}
1359 @strong{Separate branch}: (complicated option)
1361 Ensure your changes are committed in a separate branch, which
1362 should differ from the reference branch to be used by just the
1363 changes to be uploaded. If the reference branch is to be
1364 origin/master, ensure this is up-to-date. If necessary, use git
1365 rebase to rebase the branch containing the changes to the head of
1366 origin/master. Finally, check out branch with the changes and
1370 git cl upload <reference SHA1 ID>
1374 where <reference SHA1 ID> is the SHA1 ID of the commit to be used
1375 as a reference source for the patch. Generally, this will be the
1376 SHA1 ID of origin/master, and in that case the command:
1379 git cl upload origin/master
1387 First you will see a terminal editor where you can edit the
1388 message that will accompany your patch. @command{git-cl} will
1389 respect the @env{EDITOR} environment variable if defined,
1390 otherwise it will use @command{vi} as the default editor.
1392 After prompting for your Google email address and password, the
1393 patch set will be posted to Rietveld, and you will be given a URL
1396 @warning{Some installations of git-cl fail when uploading a patch
1397 with certain filename extensions. If this happens, it can
1398 generally be fixed by editing the list of exceptions at top of
1401 @subsubheading Announcing your patch set
1403 You should then announce the patch by logging into the code review
1404 issue webpage and using @qq{Publish + Mail Comments} to add a
1405 (mostly bogus) comment to your issue. The text of your comment
1406 will be sent to our developer mailing list.
1408 @warning{There is no automatic notification of a new patch; you
1409 must add a comment yourself.}
1411 @subsubheading Revisions
1413 As revisions are made in response to comments, successive patch sets
1414 for the same issue can be uploaded by reissuing the git-cl command
1415 with the modified branch checked out.
1417 Sometimes in response to comments on revisions, the best way to
1418 work may require creation of a new branch in git. In order to
1419 associate the new branch with an existing Rietveld issue,
1420 the following command can be used:
1423 git cl issue issue-number
1427 where @code{issue-number} is the number of the existing Rietveld
1430 @subsubheading Resetting git cl
1432 If @command{git cl} becomes confused, you can @qq{reset} it by
1439 @subsubheading Wait for a countdown
1441 Your patch will be available for reviews for the next few hours or
1442 days. Three times a week, patches with no known problems are
1443 gathered into a @qq{patch countdown} and their status changed to
1444 @code{patch-countdown}. The countdown is a 48-hour waiting period
1445 in which any final reviews or complaints should be made.
1447 During the countdown, your patch may be set to
1448 @code{patch-needs_work}, indicating that you should fix something
1449 (or at least discuss why the patch needs no modification). If no
1450 problems are found, the patch will be set to @code{patch-push}.
1452 Once a patch has @code{patch-push}, it should be sent to your
1453 mentor for uploading. If you have git push ability, look at
1454 @ref{Pushing to staging}.
1457 @node Advanced Git procedures
1458 @section Advanced Git procedures
1461 @warning{This section is not necessary for normal contributors;
1462 these commands are presented for information for people interested
1463 in learning more about git.}
1465 It is possible to work with several branches on the same local Git
1466 repository; this is especially useful for translators who may have
1467 to deal with both @code{translation} and a stable branch,
1468 e.g. @code{stable/2.12}.
1470 Some Git commands are introduced first, then a workflow with
1471 several Git branches of LilyPond source code is presented.
1476 * Advanced Git concepts::
1477 * Resolving conflicts::
1478 * Reverting all local changes::
1479 * Working with remote branches::
1481 * Applying remote patches::
1482 * Sending and receiving patches via email::
1483 * Cleaning up multiple patches::
1485 * Pushing to staging::
1489 @node Merge conflicts
1490 @subsection Merge conflicts
1492 To be filled in later, and/or moved to a different section. I
1493 just wanted to make sure that I had a stub ready somewhere.
1496 @node Advanced Git concepts
1497 @subsection Advanced Git concepts
1500 A bit of Git vocabulary will be explained below. The following is
1501 only introductory; for a better understanding of Git concepts, you
1502 may wish to read @ref{Other Git documentation}.
1504 The @code{git@tie{}pull@tie{}origin} command above is just a
1505 shortcut for this command:
1508 git pull git://git.sv.gnu.org/lilypond.git/ @var{branch}:origin/@var{branch}
1512 where @code{@var{branch}} is typically @code{master} or
1513 @code{translation}; if you do not know or remember, see
1514 @ref{Downloading remote branches} to remember which commands you
1515 issued or which source code you wanted to get.
1517 A @emph{commit} is a set of changes made to the sources; it also
1518 includes the committish of the parent commit, the name and e-mail
1519 of the @emph{author} (the person who wrote the changes), the name
1520 and e-mail of the @emph{committer} (the person who brings these
1521 changes into the Git repository), and a commit message.
1523 A @emph{committish} is the SHA1 checksum of a commit, a number
1524 made of 40 hexadecimal digits, which acts as the internal unique
1525 identifier for this commit. To refer to a particular revision,
1526 don't use vague references like the (approximative) date, simply
1527 copy and paste the committish.
1529 A @emph{branch} is nothing more than a pointer to a particular
1530 commit, which is called the @emph{head} of the branch; when
1531 referring to a branch, one often actually thinks about its head
1532 and the ancestor commits of the head.
1534 Now we will explain the two last commands you used to get the
1535 source code from Git---see @ref{Downloading individual branches}.
1538 git remote add -ft @var{branch} -m @var{branch} \
1539 origin git://git.sv.gnu.org/lilypond.git/
1541 git checkout -b @var{branch} origin/@var{branch}
1544 The @command{git@tie{}remote} has created a branch called
1545 @code{origin/@var{branch}} in your local Git repository. As this
1546 branch is a copy of the remote branch web from git.sv.gnu.org
1547 LilyPond repository, it is called a @emph{remote branch}, and is
1548 meant to track the changes on the branch from git.sv.gnu.org: it
1549 will be updated every time you run
1550 @command{git@tie{}pull@tie{}origin} or
1551 @command{git@tie{}fetch@tie{}origin}.
1553 The @command{git@tie{}checkout} command has created a branch named
1554 @code{@var{branch}}. At the beginning, this branch is identical
1555 to @code{origin/@var{branch}}, but it will differ as soon as you
1556 make changes, e.g. adding newly translated pages or editing some
1557 documentation or code source file. Whenever you pull, you merge
1558 the changes from @code{origin/@var{branch}} and
1559 @code{@var{branch}} since the last pulling. If you do not have
1560 push (i.e. @qq{write}) access on git.sv.gnu.org, your
1561 @code{@var{branch}} will always differ from
1562 @code{origin/@var{branch}}. In this case, remember that other
1563 people working like you with the remote branch @code{@var{branch}}
1564 of git://git.sv.gnu.org/lilypond.git/ (called
1565 @code{origin/@var{branch}} on your local repository) know nothing
1566 about your own @code{@var{branch}}: this means that whenever you
1567 use a committish or make a patch, others expect you to take the
1568 latest commit of @code{origin/@var{branch}} as a reference.
1570 Finally, please remember to read the man page of every Git command
1571 you will find in this manual in case you want to discover
1572 alternate methods or just understand how it works.
1575 @node Resolving conflicts
1576 @subsection Resolving conflicts
1579 Occasionally an update may result in conflicts -- this happens
1580 when you and somebody else have modified the same part of the same
1581 file and git cannot figure out how to merge the two versions
1582 together. When this happens, you must manually merge the two
1585 If you need some documentation to understand and resolve
1586 conflicts, see paragraphs @emph{How conflicts are presented} and
1587 @emph{How to resolve conflicts} in @command{git merge} man page.
1589 If all else fails, you can follow the instructions in
1590 @ref{Reverting all local changes}. Be aware that this eliminates
1591 any changes you have made!
1594 @node Reverting all local changes
1595 @subsection Reverting all local changes
1597 Sometimes git will become hopelessly confused, and you just want
1598 to get back to a known, stable state. This command destroys any
1599 local changes you have made in the currently checked-out branch,
1600 but at least you get back to the current online version:
1603 git reset --hard origin/master
1607 @node Working with remote branches
1608 @subsection Working with remote branches
1611 @subsubheading Fetching new branches from git.sv.gnu.org
1613 To fetch and check out a new branch named @code{@var{branch}} on
1614 git.sv.gnu.org, run from top of the Git repository
1617 git config --add remote.origin.fetch \
1618 +refs/heads/@var{branch}:refs/remotes/origin/@var{branch}
1620 git checkout --track -b @var{branch} origin/@var{branch}
1623 After this, you can pull @code{@var{branch}} from git.sv.gnu.org
1630 Note that this command generally fetches all branches you added
1631 with @command{git@tie{}remote@tie{}add} (when you initialized the
1632 repository) or @command{git@tie{}config@tie{}--add}, i.e. it
1633 updates all remote branches from remote @code{origin}, then it
1634 merges the remote branch tracked by the current branch into the
1635 current branch. For example, if your current branch is
1636 @code{master}, @code{origin/master} will be merged into
1640 @subsubheading Local clones, or having several working trees
1642 If you play with several Git branches, e.g. @code{master},
1643 @code{translation}, @code{stable/2.12}), you may want to
1644 have one source and build tree for each branch; this is possible
1645 with subdirectories of your local Git repository, used as local
1646 cloned subrepositories. To create a local clone for the branch
1647 named @code{@var{branch}}, run
1650 git checkout @var{branch}
1651 git clone -lsn . @var{subdir}
1656 Note that @code{@var{subdir}} must be a directory name which does
1657 not already exist. In @code{@var{subdir}}, you can use all Git
1658 commands to browse revisions history, commit and uncommit changes;
1659 to update the cloned subrepository with changes made on the main
1660 repository, cd into @code{@var{subdir}} and run
1661 @command{git@tie{}pull}; to send changes made on the subrepository
1662 back to the main repository, run @command{git@tie{}push} from
1663 @code{@var{subdir}}. Note that only one branch (the currently
1664 checked out branch) is created in the subrepository by default; it
1665 is possible to have several branches in a subrepository and do
1666 usual operations (checkout, merge, create, delete...) on these
1667 branches, but this possibility is not detailed here.
1669 When you push @code{@var{branch}} from @code{@var{subdir}} to the
1670 main repository, and @code{@var{branch}} is checked out in the
1671 main repository, you must save uncommitted changes (see
1672 @command{git@tie{}stash}) and do
1673 @command{git@tie{}reset@tie{}--hard} in the main repository in
1674 order to apply pushed changes in the working tree of the main
1682 The commands above don't only bring you the latest version of the
1683 sources, but also the full history of revisions (revisions, also
1684 called commits, are changes made to the sources), stored in the
1685 @file{.git} directory. You can browse this history with
1688 git log # only shows the logs (author, committish and commit message)
1689 git log -p # also shows diffs
1690 gitk # shows history graphically
1693 @warning{The @code{gitk} command may require a separate
1694 @code{gitk} package, available in the appropriate distribution's
1698 @node Applying remote patches
1699 @subsection Applying remote patches
1702 TODO: Explain how to determine if a patch was created with
1703 @code{git@tie{}format-patch}.
1705 Well-formed git patches created with @code{git@tie{}format-patch}
1706 should be committed with the following command:
1712 Patches created without @code{git@tie{}format-patch} can be
1713 applied in two steps. The first step is to apply the patch to the
1714 working tree and the index:
1717 git apply --index @var{patch}
1721 The second step is to commit the changes and give credit to the
1722 author of the patch. This can be done with the following command:
1725 git commit --author="@var{John Smith} <@var{john@@example.com}>"
1728 Please note that using the @code{--index} option for patching is quite
1729 important here and @emph{cannot} reliably be replaced by using the
1730 @code{-a} option when committing: that would only commit files from the
1731 working tree that are already registered with git, so every file that
1732 the patch actually @emph{adds}, like a regtest for a fixed bug, would
1733 get lost. For the same reason, you should not use the git-independent
1734 @samp{patch} program for applying patches.
1736 @node Sending and receiving patches via email
1737 @subsection Sending and receiving patches via email
1740 The default @code{x-diff} MIME type associated with patch files
1741 (i.e., files whose name ends in @code{.patch}) means that the
1742 encoding of line endings may be changed from UNIX to DOS format
1743 when they are sent as attachments. Attempting to apply such an
1744 inadvertently altered patch will cause git to fail with a message
1745 about @q{whitespace errors}.
1747 The solution to such problems is surprisingly simple---just change
1748 the default file extension of patches generated by git to end in
1749 @code{.txt}, for example:
1752 git config format.suffix '.patch.txt'
1755 This should cause email programs to apply the correct base64
1756 encoding to attached patches.
1758 If you receive a patch with DOS instead of UNIX line-endings, it
1759 can be converted back using the @code{dos2unix} utility.
1761 Lots of useful information on email complications with patches is
1762 provided on the Wine wiki at
1763 @uref{http://wiki.winehq.org/GitWine}.
1766 @node Cleaning up multiple patches
1767 @subsection Cleaning up multiple patches
1769 If you have been developing on your own branch for a while, you
1770 may have more commmits than is really sensible. To revise your
1771 work and condense commits, use:
1774 git rebase origin/master
1775 git rebase -i origin/master
1778 @warning{Be a bit cautious -- if you completely remove commits
1779 during the interactive session, you will... err... completely
1780 remove those commits.}
1784 @subsection Commit access
1786 Most contributors are not able to commit patches directly to the
1787 main repository---only members of the LilyPond development team
1788 have @emph{commit access}. If you are a contributor and are
1789 interested in joining the development team, contact the Project
1790 Manager through the mailing list
1791 (@email{lilypond-devel@@gnu.org}). Generally, only contributors
1792 who have already provided a number of patches which have been
1793 pushed to the main repository will be considered for membership.
1795 If you have been approved by the Project Manager, use the
1796 following procedure to obtain commit access:
1800 If you don't already have one, set up a Savannah user account at
1801 @uref{https://savannah.gnu.org/account/register.php}. If your web
1802 browser responds with an @qq{untrusted connection} message when
1803 you visit the link, follow the steps for including the CAcert root
1804 certificate in your browser, given at
1805 @uref{http://savannah.gnu.org/tls/tutorial/}.
1807 @warning{Savannah will silently put your username in lower-case --
1808 do not try to use capital letters.}
1812 After registering, if you are not logged in automatically, login
1813 at @uref{https://savannah.gnu.org/account/login.php}---this should
1814 take you to your @qq{my} page
1815 (@uref{https://savannah.gnu.org/my/}).
1819 Click on the @qq{My Groups} link to access the @qq{My Group
1820 Membership} page. From there, find the @qq{Request for Inclusion}
1821 box and search for @qq{LilyPond}. Among the search results, check
1822 the box labeled @qq{GNU LilyPond Music Typesetter} and write a
1823 brief (required) message for the Project Manager (@qq{Hey it's
1824 me!} should be fine).
1826 Note that you will not have commit access until the Project
1827 Manager activates your membership. Once your membership is
1828 activated, LilyPond should appear under the heading @qq{Groups I'm
1829 Contributor of} on your @qq{My Group Membership} page.
1833 Generate an SSH @q{rsa} key pair. Enter the following at the
1840 When prompted for a location to save the key, press <ENTER> to
1841 accept the default location (@file{~/.ssh/id_rsa}).
1843 Next you are asked to enter an optional passphrase. On most
1844 systems, if you use a passphrase, you will likely be prompted for
1845 it every time you use @command{git@tie{}push} or
1846 @command{git@tie{}pull}. You may prefer this since it can protect
1847 you from your own mistakes (like pushing when you mean to pull),
1848 though you may find it tedious to keep re-entering it.
1850 You can change/enable/disable your passphrase at any time with:
1853 ssh-keygen -f ~/.ssh/id_rsa -p
1856 Note that the GNOME desktop has a feature which stores your
1857 passphrase for you for an entire GNOME session. If you use a
1858 passphrase to @qq{protect you from yourself}, you will want to
1859 disable this feature, since you'll only be prompted once. Run the
1860 following command, then logout of GNOME and log back in:
1863 gconftool-2 --set -t bool \
1864 /apps/gnome-keyring/daemon-components/ssh false
1867 After setting up your passphrase, your private key is saved as
1868 @file{~/.ssh/id_rsa} and your public key is saved as
1869 @file{~/.ssh/id_rsa.pub}.
1873 Register your public SSH @q{rsa} key with Savannah. From the
1874 @qq{My Account Configuration} page, click on @qq{Edit SSH Keys},
1875 then paste the contents of your @file{~/.ssh/id_rsa.pub} file into
1876 one of the @qq{Authorized keys} text fields, and click
1879 Savannah should respond with something like:
1882 Success: Key #1 seen Keys registered
1887 Configure Git to use the SSH protocol (instead of the GIT
1888 protocol). From your local Git repository, enter:
1891 git config remote.origin.url \
1892 ssh://@var{user}@@git.sv.gnu.org/srv/git/lilypond.git
1896 replacing @var{user} with your Savannah username.
1900 After your membership has been activated and you've configured Git
1901 to use SSH, test the connection with:
1907 SSH should issue the following warning:
1910 The authenticity of host 'git.sv.gnu.org (140.186.70.72)' can't
1912 RSA key fingerprint is
1913 80:5a:b0:0c:ec:93:66:29:49:7e:04:2b:fd:ba:2c:d5.
1914 Are you sure you want to continue connecting (yes/no)?
1917 Make sure the RSA key fingerprint displayed matches the one above.
1918 If it doesn't, respond @qq{no} and check that you configured Git
1919 properly in the previous step. If it does match, respond
1920 @qq{yes}. SSH should then issue another warning:
1923 Warning: Permanently added 'git.sv.gnu.org,140.186.70.72' (RSA) to
1924 the list of known hosts.
1927 The list of known hosts is stored in the file
1928 @file{~/.ssh/known_hosts}.
1930 At this point, you are prompted for your passphrase if you have
1931 one, then Git will attempt a pull.
1933 If @command{git@tie{}pull@tie{}--verbose} fails, you should see
1934 error messages like these:
1937 Permission denied (publickey).
1938 fatal: The remote end hung up unexpectedly
1941 If you get the above error, you may have made a mistake when
1942 registering your SSH key at Savannah. If the key is properly
1943 registered, you probably just need to wait for the Savannah server
1944 to activate it. It usually takes a few minutes for the key to be
1945 active after registering it, but if it still doesn't work after an
1946 hour, ask for help on the mailing list.
1948 If @command{git@tie{}pull@tie{}--verbose} succeeds, the output
1949 will include a @q{From} line that shows @q{ssh} as the protocol:
1952 From ssh://git.sv.gnu.org/srv/git/lilypond
1955 If the protocol shown is not @q{ssh}, check that you configured
1956 Git properly in the previous step.
1960 Test your commit access with a dry run:
1962 @warning{Do not push directly to master; instead, push to staging.
1963 See @ref{Pushing to staging}.}
1966 git push --dry-run --verbose
1969 Note that recent versions of Git (Git 1.6.3 or later) will issue a
1970 big warning if the above command is used. The simplest solution
1971 is to tell Git to push all matching branches by default:
1974 git config push.default matching
1978 Then @code{git@tie{}push} should work as before. For more
1979 details, consult the @code{git@tie{}push} man page.
1983 Repeat the steps from generating an RSA key through to testing
1984 your commit access, for each machine from which you will be
1985 making commits, or you may simply copy the files from your
1986 local @file{~/.ssh} folder to the same folder on the other
1991 @subsubheading Technical details
1995 On Firefox, to view or remove the CAcert root certificate, go to:
1996 Edit > Preferences > Advanced > Encryption > View Certificates >
1997 Authorities > Certificate Name > Root CA > CA Cert Signing
2001 The @command{git@tie{}config} commands above should modify your
2002 local repository's @file{.git/config} file. These lines:
2006 url = git://git.sv.gnu.org/lilypond.git/
2010 should now be changed to:
2014 url = ssh://@var{user}@@git.sv.gnu.org/srv/git/lilypond.git
2018 where @var{user} is your login name on Savannah.
2022 @command{git@tie{}config@tie{}push.default@tie{}matching} command
2023 should add these lines to @file{.git/config}:
2032 Encryption protocols, including ssh, generally do not permit packet
2033 fragmentation to avoid introducing a point of insecurity. This
2034 means that the maximum packet size must not exceed the smallest
2035 MTU (Maximum Transmission Unit) set in the routers along the path.
2036 This smallest MTU is determined by a procedure during call set-up
2037 which relies on the transmission over the path of ICMP packets.
2038 If any of the routers in the path block ICMP packets this mechanism
2039 fails, resulting in the possibility of packets being transmitted
2040 which exceed the MTU of one of the routers. If this happens the
2041 packet is discarded, causing the ssh session to hang, timeout or
2042 terminate with the error message
2045 ssh: connect to host <host ip addr> port 22: Bad file number
2046 fatal: The remote end hung up unexpectedly
2049 depending on precisely when in the proceedings the first large
2050 packet is transmitted. Most routers on the internet have MTU
2051 set to 1500, but routers installed in homes to connect via
2052 broadband may use a slightly smaller MTU for efficient transmission
2053 over ATM. If this problem is encountered a possible work-around is
2054 to set the MTU in the local router to 1500.
2057 @node Pushing to staging
2058 @subsection Pushing to staging
2060 Do not push directly to the git @code{master} branch. Instead,
2061 push to @code{staging}.
2063 You will not see your patch on @code{origin/master} until some
2064 automatic tests have been run. These tests are run every couple
2065 of hours; please wait at least 12 hours before wondering if your
2066 patch has been lost. Note that you can check the commits on
2067 @code{origin/staging} by looking at the git web interface on
2070 It may happen occasionally that the staging branch breaks automated
2071 testing. In this case the automatic move of staging material to
2072 master gets halted in order to avoid broken material entering master.
2073 This is a safety net. Please do not try breaking out from it by
2074 adding fixes on top of staging: in that case the whole sequence will
2075 end up in master after all, defeating the purpose of the system. The
2076 proper fix usually involves rewriting the staging branch and is best
2077 left to core developers after discussion on the developer list.
2079 @subsubheading If your work is in a patch file
2081 Assuming that your patch is in a file called
2082 @file{0001-my-patch.patch}, and you are currently on git master,
2086 git checkout staging
2088 git am 0001-my-patch.patch
2090 git push origin staging
2094 @warning{Do not skip the @command{gitk} step; a quick 5-second
2095 check of the visual history can save a great deal of frustration
2096 later on. You should only see that @command{staging} is only 1
2097 commit ahead of @code{origin/staging}.}
2099 @subsubheading If your work is in a branch
2101 If you are working on branches and your work in is
2102 @code{my_branch_name}, then do:
2105 git checkout staging
2107 git merge my_branch_name
2109 git push origin staging
2112 @warning{Do not skip the @command{gitk} step; a quick 5-second
2113 check of the visual history can save a great deal of frustration
2114 later on. You should see that @code{staging} is only ahead of
2115 @code{origin/staging} by the commits from your branch.}
2119 @node Git on Windows
2120 @section Git on Windows
2122 @warning{We heavily recommend that development be done with our
2123 virtual machine @ref{LilyDev}.}
2125 @c Some of this may duplicate stuff in other sections
2126 @c But it is probably best for windows users to have it all together
2127 @c If necessary, clear this up later -td
2129 TODO: Decide what to do with this... Pare it down? Move
2130 paragraphs next to analogous Unix instructions? -mp
2132 @subsection Background to nomenclature
2134 Git is a system for tracking the changes made to source files by a
2135 distributed set of editors. It is designed to work without a
2136 master repository, but we have chosen to have a master repository
2137 for LilyPond files. Editors hold a local copy of the master
2138 repository together with any changes they have made locally.
2139 Local changes are held in a local @q{branch}, of which there may
2140 be several, but these instructions assume you are using just one.
2141 The files visible in the local repository always correspond to
2142 those on the currently @q{checked out} local branch.
2144 Files are edited on a local branch, and in that state the changes
2145 are said to be @q{unstaged}. When editing is complete, the
2146 changes are moved to being @q{staged for commit}, and finally the
2147 changes are @q{committed} to the local branch. Once committed,
2148 the changes (called a @q{commit}) are given a unique 40-digit
2149 hexadecimal reference number called the @q{Committish} or @q{SHA1
2150 ID} which identifies the commit to Git. Such committed changes
2151 can be sent to the master repository by @q{pushing} them (if you
2152 have write permission) or by sending them by email to someone who
2153 has, either as a complete file or as a @q{diff} or @q{patch}
2154 (which send just the differences from the master repository).
2156 @subsection Installing git
2159 @uref{http://code.google.com/p/msysgit/downloads/list} (note, not
2160 msysGit, which is for Git developers and not PortableGit, which is
2161 not a full git installation) and install it.
2163 Note that most users will not need to install SSH. That is not
2164 required until you have been granted direct push permissions to
2165 the master git repository.
2167 Start Git by clicking on the desktop icon. This will bring up a
2168 command line bash shell. This may be unfamiliar to Windows users.
2169 If so, follow these instructions carefully. Commands are entered
2170 at a $ prompt and are terminated by keying a newline.
2172 @subsection Initialising Git
2174 Decide where you wish to place your local Git repository, creating
2175 the folders in Windows as necessary. Here we call the folder to
2176 contain the repository @code{[path]/Git}, but if you intend using
2177 Git for other projects a directory name like @code{lilypond-git}
2178 might be better. You will need to have space for around
2181 Start the Git bash shell by clicking on the desk-top icon
2182 installed with Git and type
2188 to position the shell at your new Git repository.
2190 Note: if [path] contains folders with names containing spaces use
2202 to initialize your Git repository.
2204 Then type (all on one line; the shell will wrap automatically)
2207 git remote add -ft master origin git://git.sv.gnu.org/lilypond.git
2210 to download the lilypond master files.
2212 @warning{Be patient! Even on a broadband connection this can take
2213 10 minutes or more. Wait for lots of [new tag] messages and the $
2216 We now need to generate a local copy of the downloaded files in a
2217 new local branch. Your local branch needs to have a name. It is
2218 usual to call it @q{master} and we shall do that here.
2223 git checkout -b master origin/master
2226 This creates a second branch called @q{master}. You will see two
2227 warnings (ignore these), and a message advising you that your
2228 local branch @q{master} has been set up to track the remote
2229 branch. You now have two branches, a local branch called
2230 @q{master}, and a tracking branch called @q{origin/master}, which
2231 is a shortened form of @q{remotes/origin/master}.
2233 Return to Windows Explorer and look in your Git repository. You
2234 should see lots of folders. For example, the LilyPond
2235 documentation can be found in [path]/Git/Documentation/.
2237 The Git bash shell is terminated by typing @code{exit} or by
2238 clicking on the usual Windows close-window widget.
2242 Almost all subsequent work will use the Git Graphical User
2243 Interface, which avoids having to type command line commands. To
2244 start Git GUI first start the Git bash shell by clicking on the
2245 desktop icon, and type
2252 The Git GUI will open in a new window. It contains four panels
2253 and 7 pull-down menus. At this stage do not use any of the
2254 commands under Branch, Commit, Merge or Remote. These will be
2257 The top panel on the left contains the names of files which you
2258 are in the process of editing (Unstaged Changes), and the lower
2259 panel on the left contains the names of files you have finished
2260 editing and have staged ready for committing (Staged Changes). At
2261 present, these panels will be empty as you have not yet made any
2262 changes to any file. After a file has been edited and saved the
2263 top panel on the right will display the differences between the
2264 edited file selected in one of the panels on the left and the last
2265 version committed on the current branch.
2267 The panel at bottom right is used to enter a descriptive message
2268 about the change before committing it.
2270 The Git GUI is terminated by entering CNTL-Q while it is the
2271 active window or by clicking on the usual Windows close-window
2274 @subsection Personalising your local git repository
2276 Open the Git GUI, click on
2282 and enter your name and email address in the left-hand (Git
2283 Repository) panel. Leave everything else unchanged and save it.
2285 Note that Windows users must leave the default setting for line
2286 endings unchanged. All files in a git repository must have lines
2287 terminated by just a LF, as this is required for Merge to work,
2288 but Windows files are terminated by CRLF by default. The git
2289 default setting causes the line endings of files in a Windows git
2290 repository to be flipped automatically between LF and CRLF as
2291 required. This enables files to be edited by any Windows editor
2292 without causing problems in the git repository.
2294 @subsection Checking out a branch
2296 At this stage you have two branches in your local repository,
2297 both identical. To see them click on
2303 You should have one local branch called @q{master} and one
2304 tracking branch called @q{origin/master}. The latter is your
2305 local copy of the @q{remotes/origin/master} branch in the master
2306 LilyPond repository. The local @q{master} branch is where you
2307 will make your local changes.
2309 When a particular branch is selected, i.e., checked out, the files
2310 visible in your repository are changed to reflect the state of the
2311 files on that branch.
2313 @subsection Updating files from @q{remote/origin/master}
2315 Before starting the editing of a file, ensure your local
2316 repository contains the latest version of the files in the remote
2317 repository by first clicking
2320 Remote -> Fetch from -> origin
2326 This will place the latest version of every file, including all
2327 the changes made by others, into the @q{origin/master} branch of
2328 the tracking branches in your git repository. You can see these
2329 files by checking out this branch, but you must @emph{never} edit
2330 any files while this branch is checked out. Check out your local
2331 @q{master} branch again.
2333 You then need to merge these fetched files into your local
2334 @q{master} branch by clicking on
2337 Merge -> Local Merge
2341 and if necessary select the local @q{master} branch.
2343 Note that a merge cannot be completed if you have made any local
2344 changes which have not yet been committed.
2346 This merge will update all the files in the @q{master} branch to
2347 reflect the current state of the @q{origin/master} branch. If any
2348 of the changes conflict with changes you have made yourself
2349 recently you will be notified of the conflict (see below).
2351 @subsection Editing files
2353 First ensure your @q{master} branch is checked out, then simply
2354 edit the files in your local Git repository with your favourite
2355 editor and save them back there. If any file contains non-ASCII
2356 characters ensure you save it in UTF-8 format. Git will detect
2357 any changes whenever you restart Git GUI and the file names will
2358 then be listed in the Unstaged Changes panel. Or you can click
2359 the Rescan button to refresh the panel contents at any time. You
2360 may break off and resume editing any time.
2362 The changes you have made may be displayed in diff form in the top
2363 right-hand panel of Git GUI by clicking on the file name shown in
2364 one of the left panels.
2366 When your editing is complete, move the files from being Unstaged
2367 to Staged by clicking the document symbol to the left of each
2368 name. If you change your mind it can be moved back by clicking on
2369 the ticked box to the left of the name.
2371 Finally the changes you have made may be committed to your
2372 @q{master} branch by entering a brief message in the Commit
2373 Message box and clicking the Commit button.
2375 If you wish to amend your changes after a commit has been made,
2376 the original version and the changes you made in that commit may
2377 be recovered by selecting
2380 Commit -> Amend Last Commit
2384 or by checking the Amend Last Commit radio button at bottom right.
2385 This will return the changes to the Staged state, so further
2386 editing made be carried out within that commit. This must only be
2387 done @emph{before} the changes have been Pushed or sent to your
2388 mentor for Pushing - after that it is too late and corrections
2389 have to be made as a separate commit.
2392 @subsection Sending changes to @q{remotes/origin/master}
2394 If you do not have write access to @q{remotes/origin/master} you
2395 will need to send your changes by email to someone who does.
2397 First you need to create a diff or patch file containing your
2398 changes. To create this, the file must first be committed. Then
2399 terminate the Git GUI. In the git bash shell first cd to your Git
2406 if necessary, then produce the patch with
2409 git format-patch origin
2412 This will create a patch file for all the locally committed files
2413 which differ from @q{origin/master}. The patch file can be found
2414 in [path]/Git and will have a name formed from the commit message.
2416 @subsection Resolving merge conflicts
2418 As soon as you have committed a changed file your local
2419 @code{master} branch has diverged from @code{origin/master}, and
2420 will remain diverged until your changes have been committed in
2421 @code{remotes/origin/master} and Fetched back into your
2422 @code{origin/master} branch. Similarly, if a new commit has been
2423 made to @code{remotes/origin/master} by someone else and Fetched,
2424 your local @code{master} branch is divergent. You can detect a
2425 divergent branch by clicking on
2428 Repository -> Visualise all branch history
2431 This opens up a very useful new window called @q{gitk}. Use this
2432 to browse all the commits made by yourself and others.
2434 If the diagram at top left of the resulting window does not show
2435 your @code{master} tag on the same node as the
2436 @code{remotes/origin/master} tag your branch has diverged from
2437 @code{origin/master}. This is quite normal if files you have
2438 modified yourself have not yet been Pushed to
2439 @code{remotes/origin/master} and Fetched, or if files modified and
2440 committed by others have been Fetched since you last Merged
2441 @code{origin/master} into your local @code{master} branch.
2443 If a file being merged from @code{origin/master} differs from one
2444 you have modified in a way that cannot be resolved automatically
2445 by git, Merge will report a Conflict which you must resolve by
2446 editing the file to create the version you wish to keep.
2448 This could happen if the person updating
2449 @code{remotes/origin/master} for you has added some changes of his
2450 own before committing your changes to
2451 @code{remotes/origin/master}, or if someone else has changed the
2452 same file since you last fetched the file from
2453 @code{remotes/origin/master}.
2455 Open the file in your editor and look for sections which are
2458 [to be completed when I next have a merge conflict to be sure I
2459 give the right instructions -td]
2462 @subsection Other actions
2464 The instructions above describe the simplest way of using git on
2465 Windows. Other git facilities which may usefully supplement these
2469 @item Using multiple local branches (Create, Rename, Delete)
2470 @item Resetting branches
2471 @item Cherry-picking commits
2472 @item Pushing commits to @w{remote/origin/master}
2473 @item Using gitk to review history
2476 Once familiarity with using git on Windows has been gained the
2477 standard git manuals can be used to learn about these.
2480 @node Repository directory structure
2481 @section Repository directory structure
2484 @c TODO: integrate the roadmap better
2485 @verbatiminclude ROADMAP
2488 @node Other Git documentation
2489 @section Other Git documentation
2493 Official git man pages:
2494 @uref{http://www.kernel.org/pub/software/scm/git/docs/}
2497 More in-depth tutorials: @uref{http://git-scm.com/documentation}
2500 Book about git: @uref{http://progit.org/,Pro Git}
2503 Github help: @uref{http://help.github.com/}
2504 (very highly recommended by Graham)