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{$LILYPOND_WEB_MEDIA_GIT}
545 environment variable to point to that repository.
548 @uref{https://github.com/gperciva/lilypond-extra}
551 To configure an environment variable in bash (the default for most
552 Linux distributions),
555 export LILYPOND_WEB_MEDIA_GIT=$HOME/dir/of/lilypond-extra/
558 @node Grand Unified Builder (GUB)
559 @unnumberedsubsubsec Grand Unified Builder (GUB)
561 Another item of interest might be the Grand Unified Builder, our
562 cross-platform building tool. Since it is used by projects as
563 well, it is not stored in our gub repository. For more info, see
564 @uref{http://lilypond.org/gub}.
566 There are two locations for this repository, which will hopefully
567 be kept up-to-date with each other:
570 @uref{http://github.com/janneke/gub}
571 @uref{http://github.com/gperciva/gub}
576 @unnumberedsubsubsec lilypad
578 Our binary releases on MacOS X and Windows contain a lightweight
579 text editor. This code is here:
582 https://github.com/gperciva/lilypad
586 @node yet more repositories
587 @unnumberedsubsubsec yet more repositories
589 There are a few other repositories floating around, which will
590 hopefully be documented in the near future.
593 @node Downloading remote branches
594 @subsection Downloading remote branches
596 @warning{contains obsolete + misleading info}
599 * Organization of remote branches::
600 * LilyPond repository sources::
601 * Downloading individual branches::
602 * Downloading all remote branches::
607 @node Organization of remote branches
608 @unnumberedsubsubsec Organization of remote branches
611 The main LilyPond repository is organized into @emph{branches} to
612 facilitate development. These are often called @emph{remote}
613 branches to distinguish them from @emph{local} branches you might
614 create yourself (see @ref{Using local branches}).
616 The @code{master} branch contains all the source files used to
617 build LilyPond, which includes the program itself (both stable and
618 development releases), the documentation (and its translations),
619 and the website. Generally, the @code{master} branch is expected
620 to compile successfully.
622 The @code{translation} branch is a side branch that
623 allows translators to work without needing to worry about
624 compilation problems. Periodically, the Translation Meister
625 (after verifying that it doesn't break compilation), will
626 @emph{merge} this branch into @code{staging} to incorporate
627 recent translations. Similarly, the @code{master} branch is
628 usually merged into the @code{translation} branch after
629 significant changes to the English documentation. See
630 @ref{Translating the documentation} for details.
633 @node LilyPond repository sources
634 @unnumberedsubsubsec LilyPond repository sources
637 The recommended source for downloading a copy of the main
641 git://git.sv.gnu.org/lilypond.git
644 However, if your internet router filters out connections using the
645 GIT protocol, or if you experience difficulty connecting via GIT,
646 you can try these other sources:
649 ssh://git.sv.gnu.org/srv/git/lilypond.git
650 http://git.sv.gnu.org/r/lilypond.git
653 The SSH protocol can only be used if your system is properly set
654 up to use it. Also, the HTTP protocol is slowest, so it should
655 only be used as a last resort.
658 @node Downloading individual branches
659 @unnumberedsubsubsec Downloading individual branches
661 @warning{obsolete, should be deleted!}
664 Once you have initialized an empty Git repository on your system
665 (see @ref{Initializing a repository}), you can download a remote
666 branch into it. Make sure you know which branch you want to start
669 To download the @code{master} branch, enter the following:
672 git remote add -ft master -m master \
673 origin git://git.sv.gnu.org/lilypond.git/
676 To download the @code{translation} branch, enter:
679 git remote add -ft translation -m \
680 translation origin git://git.sv.gnu.org/lilypond.git/
683 The @command{git@tie{}remote@tie{}add} process could take up to
684 ten minutes, depending on the speed of your connection. The
685 output will be something like this:
689 remote: Counting objects: 235967, done.
690 remote: Compressing objects: 100% (42721/42721), done.
691 remote: Total 235967 (delta 195098), reused 233311 (delta 192772)
692 Receiving objects: 100% (235967/235967), 68.37 MiB | 479 KiB/s, done.
693 Resolving deltas: 100% (195098/195098), done.
694 From git://git.sv.gnu.org/lilypond
695 * [new branch] master -> origin/master
696 From git://git.sv.gnu.org/lilypond
697 * [new tag] flower/1.0.1 -> flower/1.0.1
698 * [new tag] flower/1.0.10 -> flower/1.0.10
700 * [new tag] release/2.9.6 -> release/2.9.6
701 * [new tag] release/2.9.7 -> release/2.9.7
704 When @command{git@tie{}remote@tie{}add} is finished, the remote
705 branch should be downloaded into your repository---though not yet
706 in a form that you can use. In order to browse the source code
707 files, you need to @emph{create} and @emph{checkout} your own
708 local branch. In this case, however, it is easier to have Git
709 create the branch automatically by using the @command{checkout}
710 command on a non-existent branch. Enter the following:
713 git checkout -b @var{branch} origin/@var{branch}
717 where @code{@var{branch}} is the name of your tracking branch,
718 either @code{master} or @code{translation}.
720 Git will issue some warnings; this is normal:
723 warning: You appear to be on a branch yet to be born.
724 warning: Forcing checkout of origin/master.
725 Branch master set up to track remote branch master from origin.
729 By now the source files should be accessible---you should be able
730 to edit any files in the @file{lilypond-git/} directory using a
731 text editor of your choice. But don't start just yet! Before
732 editing any source files, learn how to keep your changes organized
733 and prevent problems later---read @ref{Basic Git procedures}.
735 @subsubheading Technical Details
737 The @command{git@tie{}remote@tie{}add} command should add some
738 lines to your local repository's @file{.git/config} file:
742 url = git://git.sv.gnu.org/lilypond.git/
743 fetch = +refs/heads/master:refs/remotes/origin/master
747 @node Downloading all remote branches
748 @unnumberedsubsubsec Downloading all remote branches
751 To download all remote branches at once, you can @command{clone}
752 the entire repository:
755 git clone git://git.sv.gnu.org/lilypond.git
760 @unnumberedsubsubsec Other branches
762 Most contributors will never need to touch the other branches. If
763 you wish to do so, you will need more familiarity with Git; please
764 see @ref{Other Git documentation}.
767 @item @code{dev/XYZ}:
768 These branches are for individual developers. They store code
769 which is not yet stable enough to be added to the @code{master}
772 @item @code{stable/XYZ}:
773 The branches are kept for archival reasons.
775 @item @code{archive/XYZ}:
776 The branches are kept for archival reasons.
781 @node Basic Git procedures
782 @section Basic Git procedures
786 * The Git contributor's cycle::
787 * Pulling and rebasing::
788 * Using local branches::
789 * Commits and patches::
793 @node The Git contributor's cycle
794 @subsection The Git contributor's cycle
797 Here is a simplified view of the contribution process on Git:
801 Update your local repository by @emph{pulling} the most recent
802 updates from the remote repository.
805 Edit source files within your local repository's @emph{working
809 @emph{Commit} the changes you've made to a local @emph{branch}.
812 Generate a @emph{patch} to share your changes with the developers.
816 @node Pulling and rebasing
817 @subsection Pulling and rebasing
820 When developers push new patches to the @code{git.sv.gnu.org}
821 repository, your local repository is @strong{not} automatically
822 updated. It is important to keep your repository up-to-date by
823 periodically @emph{pulling} the most recent @emph{commits} from
824 the remote branch. Developers expect patches to be as current as
825 possible, since outdated patches require extra work before they
828 Occasionally you may need to rework some of your own modifications
829 to match changes made to the remote branch (see @ref{Resolving
830 conflicts}), and it's considerably easier to rework things
831 incrementally. If you don't update your repository along the way,
832 you may have to spend a lot of time resolving branch conflicts and
833 reconfiguring much of the work you've already done.
835 Fortunately, Git is able to resolve certain types of branch
836 conflicts automatically with a process called @emph{rebasing}.
837 When rebasing, Git tries to modify your old commits so they appear
838 as new commits (based on the latest updates). For a more involved
839 explanation, see the @command{git-rebase} man page.
841 To pull without rebasing (recommended for translators), use the
845 git pull # recommended for translators
848 If you're tracking the remote @code{master} branch, you should add
849 the @option{-r} option (short for @option{--rebase}) to keep commits
850 on your local branch current:
853 git pull -r # use with caution when translating
856 If you don't edit translated documentation and don't want to type
857 @option{-r} every time, configure the master branch to rebase by
858 default with this command:
861 git config branch.master.rebase true
864 If pull fails because of a message like
867 error: Your local changes to 'Documentation/learning/tutorial.itely'
868 would be overwritten by merge. Aborting.
875 Documentation/learning/tutorial.itely: needs update
876 refusing to pull with rebase: your working tree is not up-to-date
880 it means that you have modified some files in you working tree
881 without committing changes (see @ref{Commits and patches}); you
882 can use the @command{git@tie{}stash} command to work around this:
885 git stash # save uncommitted changes
886 git pull -r # pull using rebase (translators omit "-r")
887 git stash pop # reapply previously saved changes
890 Note that @command{git@tie{}stash@tie{}pop} will try to apply a
891 patch, and this may create a conflict. If this happens, see
892 @ref{Resolving conflicts}.
894 TODO: I think the next paragraph is confusing. Perhaps prepare
895 the reader for new terms `committish' and `head'? -mp
897 @warning{translators and documentation editors, if you have
898 changed committishes in the head of translated files using commits
899 you have not yet pushed to @code{git.sv.gnu.org}, please do not
900 rebase. If you want to avoid wondering whether you should rebase
901 each time you pull, please always use committishes from master
902 and/or translation branch on @code{git.sv.gnu.org}, which
903 in particular implies that you must push your changes to
904 documentation except committishes updates (possibly after having
905 rebased), then update the committishes and push them.}
907 TODO: when committishes automatic conditional update have been
908 tested and documented, append the following to the warning above:
909 Note that using update-committishes make target generally touches
912 @subsubheading Technical details
914 The @command{git@tie{}config} command mentioned above adds the
915 line @code{rebase = true} to the master branch in your local
916 repository's @file{.git/config} file:
921 merge = refs/heads/master
926 @node Using local branches
927 @subsection Using local branches
931 * Creating and removing branches::
932 * Listing branches and remotes::
933 * Checking out branches::
938 @node Creating and removing branches
939 @unnumberedsubsubsec Creating and removing branches
942 Local branches are useful when you're working on several different
943 projects concurrently. To create a new branch, enter:
946 git branch @var{name}
949 To delete a branch, enter:
952 git branch -d @var{name}
955 Git will ask you for confirmation if it sees that data would be
956 lost by deleting the branch. Use @option{-D} instead of @option{-d}
957 to bypass this. Note that you cannot delete a branch if it is
958 currently checked out.
961 @node Listing branches and remotes
962 @unnumberedsubsubsec Listing branches and remotes
964 You can get the exact path or URL of all remote branches by
971 To list Git branches on your local repositories, run
974 git branch # list local branches only
975 git branch -r # list remote branches
976 git branch -a # list all branches
980 @node Checking out branches
981 @unnumberedsubsubsec Checking out branches
983 To know the currently checked out branch, i.e. the branch whose
984 source files are present in your working tree, read the first line
992 The currently checked out branch is also marked with an asterisk
993 in the output of @command{git branch}.
995 You can check out another branch @code{@var{other_branch}}, i.e.
996 check out @code{@var{other_branch}} to the working tree, by
1000 git checkout @var{other_branch}
1003 Note that it is possible to check out another branch while having
1004 uncommitted changes, but it is not recommended unless you know
1005 what you are doing; it is recommended to run @command{git status}
1006 to check this kind of issue before checking out another branch.
1008 @node Merging branches
1009 @unnumberedsubsubsec Merging branches
1011 To merge branch @code{@var{foo}} into branch @code{@var{bar}},
1012 i.e. to @qq{add} all changes made in branch @code{@var{foo}} to
1013 branch @code{@var{bar}}, run
1016 git checkout @var{bar}
1020 If any conflict happens, see @ref{Resolving conflicts}.
1022 There are common usage cases for merging: as a translator, you
1023 will often want the Translations meister to merge @code{master} into
1024 @code{translation}; on the other hand, the Translations
1025 meister wants to merge @code{translation} into
1026 @code{staging} whenever he has checked that
1027 @code{translation} builds successfully.
1030 @node Commits and patches
1031 @subsection Commits and patches
1035 * Understanding commits::
1039 * Uploading a patch for review::
1043 @node Understanding commits
1044 @unnumberedsubsubsec Understanding commits
1046 Technically, a @emph{commit} is a single point in the history of a
1047 branch, but most developers use the term to mean a @emph{commit
1048 object}, which stores information about a particular revision. A
1049 single commit can record changes to multiple source files, and
1050 typically represents one logical set of related changes (such as a
1051 bug-fix). You can list the ten most recent commits in your
1052 current branch with this command:
1055 git log -10 --oneline
1058 If you're using an older version of Git and get an @q{unrecognized
1059 argument} error, use this instead:
1062 git log -10 --pretty=oneline --abbrev-commit
1065 More interactive lists of the commits on the remote @code{master}
1066 branch are available at
1067 @uref{http://git.sv.gnu.org/gitweb/?p=lilypond.git;a=shortlog} and
1068 @uref{http://git.sv.gnu.org/cgit/lilypond.git/log/}.
1071 @node Making commits
1072 @unnumberedsubsubsec Making commits
1075 Once you have modified some source files in your working
1076 directory, you can make a commit with the following procedure:
1080 Make sure you've configured Git properly (see @ref{Configuring
1081 Git}). Check that your changes meet the requirements described in
1082 @ref{Code style} and/or @ref{Documentation policy}. For advanced
1083 edits, you may also want to verify that the changes don't break
1084 the compilation process.
1087 Run the following command:
1094 to make sure you're on the right branch, and to see which files
1095 have been modified, added or removed, etc. You may need to tell
1096 Git about any files you've added by running one of these:
1099 git add @var{file} # add untracked @var{file} individually
1100 git add . # add all untracked files in current directory
1104 After @command{git@tie{}add}, run @command{git@tie{}status} again
1105 to make sure you got everything. You may also need to modify
1109 Preview the changes about to be committed (to make sure everything
1117 The @code{HEAD} argument refers to the most recent commit on the
1118 currently checked-out branch.
1121 Generate the commit with:
1128 The @option{-a} is short for @option{--all} which includes modified
1129 and deleted files, but only those newly created files that have
1130 previously been added.
1135 @node Commit messages
1136 @unnumberedsubsubsec Commit messages
1139 When you run the @command{git@tie{}commit@tie{}-a} command, Git
1140 automatically opens the default text editor so you can enter a
1141 @emph{commit message}. If you find yourself in a foreign editing
1142 environment, you're probably in @command{vi} or @command{vim}. If
1143 you want to switch to an editor you're more familiar with, quit by
1144 typing @code{:q!} and pressing @code{<Enter>}. See
1145 @ref{Configuring Git} for instructions on changing the default
1148 In any case, Git will open a text file for your commit message
1149 that looks like this:
1153 # Please enter the commit message for your changes. Lines starting
1154 # with '#' will be ignored, and an empty message aborts the commit.
1156 # Changes to be committed:
1157 # (use "git reset HEAD <file>..." to unstage)
1159 # modified: working.itexi
1163 Your commit message should begin with a one-line summary
1164 describing the change (no more than 50 characters long), and if
1165 necessary a blank line followed by several lines giving the
1168 @c $ git log -1 --pretty=medium 4d6f1e5
1170 Doc: add Baerenreiter and Henle solo cello suites
1172 Added comparison of solo cello suite engravings to new essay with
1173 high-res images, fixed cropping on Finale example.
1176 Commit messages often start with a short prefix describing the
1177 general location of the changes. If a commit affects the
1178 documentation in English (or in several languages simultaneously)
1179 the commit message should be prefixed with @qq{Doc:@tie{}}. If
1180 the commit affects only one of the translations, the commit
1181 message should be prefixed with @qq{Doc-@var{**}:@tie{}}, where
1182 @var{**} is the two-letter language code. Commits that affect the
1183 website should use @qq{Web:@tie{}} for English, and
1184 @qq{Web-@var{**}:@tie{}} for the other languages. Also, changes
1185 to a single file are often prefixed with the name of the file
1186 involved. Visit the links listed in @ref{Understanding commits}
1190 @node Making patches
1191 @unnumberedsubsubsec Making patches
1193 If you want to share your changes with other contributors and
1194 developers, you need to generate @emph{patches} from your commits.
1195 We prefer it if you follow the instructions in
1196 @ref{Uploading a patch for review}. However, we present an
1197 alternate method here.
1199 You should always run @command{git@tie{}pull@tie{}-r} (translators
1200 should leave off the @option{-r}) before doing this to ensure that
1201 your patches are as current as possible.
1203 Once you have made one or more commits in your local repository,
1204 and pulled the most recent commits from the remote branch, you can
1205 generate patches from your local commits with the command:
1208 git format-patch origin
1211 The @code{origin} argument refers to the remote tracking branch at
1212 @code{git.sv.gnu.org}. This command generates a separate patch
1213 for each commit that's in the current branch but not in the remote
1214 branch. Patches are placed in the current working directory and
1215 will have names that look something like this:
1218 0001-Doc-Fix-typos.patch
1219 0002-Web-Remove-dead-links.patch
1223 Send an email (must be less than 64 KB) to
1224 @email{lilypond-devel@@gnu.org} briefly explaining your work, with
1225 the patch files attached. Translators should send patches to
1226 @email{translations@@lilynet.net}. After your patches are
1227 reviewed, the developers may push one or more of them to the main
1228 repository or discuss them with you.
1231 @node Uploading a patch for review
1232 @unnumberedsubsubsec Uploading a patch for review
1234 Any non-trivial change should be uploaded to our @qq{Rietveld}
1235 code review website:
1238 @uref{http://codereview.appspot.com/}
1241 @subsubheading @command{git-cl} install
1243 LilyDev users should skip over these @q{install} instructions.
1248 Install @command{git-cl} by entering:
1251 git clone https://github.com/gperciva/git-cl.git
1254 If that command fails for some reason, try this instead:
1257 git clone git://github.com/gperciva/git-cl.git
1261 Add the @file{git-cl/} directory to your PATH,
1262 or create a symbolic link to the @command{git-cl}
1263 and @command{upload.py} scripts in one of your PATH
1264 directories (such as @file{$HOME/bin}).
1266 In Ubuntu (and LilyDev), you can add directories to PATH
1267 by adding this line to a hidden file @file{.bashrc},
1268 located in your home directory:
1271 PATH=~/type-here-directory-containing-git-cl:"$@{PATH@}"
1276 @subsubheading @command{git-cl} configuration
1278 LilyDev users should perform these @q{configuration} instructions.
1282 You must have a google account; please create one if you do not
1285 Note that a google account does not need to be a gmail account; you can
1286 use any email address for your google account when you sign up.
1289 Move into the top source directory and then configure @command{git
1290 cl} with the following commands. If you do not understand any
1291 question, just answer with a newline (CR).
1294 cd $HOME/lilypond-git/
1298 The @qq{CC list} question should be answered with:
1301 lilypond-devel@@gnu.org
1306 @subsubheading Uploading patch set
1308 @warning{Unless you are familiar with branches, only work on one
1309 set of changes at once.}
1311 There are two methods, depending on your git setup.
1315 @strong{Master branch}: (easy option, and used in @command{lily-git.tcl})
1317 If you added your patch to @code{master}, then:
1321 git cl upload origin/master
1324 @c Mention staging here?
1325 If you have git push ability, make sure that you @emph{remove}
1326 your patch (with @command{git rebase} or @command{git reset})
1327 before pushing other stuff.
1329 @c don't make this one an @example; we don't want to make it easy
1330 @c for people to use this accidently
1331 Notifications of patches are automatically added to our issue
1332 tracker to reduce the chance of patches getting lost. To suppress
1333 this (not recommended), add the @code{-n / --no-code-issue}
1337 @strong{Separate branch}: (complicated option)
1339 Ensure your changes are committed in a separate branch, which
1340 should differ from the reference branch to be used by just the
1341 changes to be uploaded. If the reference branch is to be
1342 origin/master, ensure this is up-to-date. If necessary, use git
1343 rebase to rebase the branch containing the changes to the head of
1344 origin/master. Finally, check out branch with the changes and
1348 git cl upload <reference SHA1 ID>
1352 where <reference SHA1 ID> is the SHA1 ID of the commit to be used
1353 as a reference source for the patch. Generally, this will be the
1354 SHA1 ID of origin/master, and in that case the command:
1357 git cl upload origin/master
1365 After prompting for your Google email address and password, the
1366 patch set will be posted to Rietveld, and you will be given a URL
1369 @warning{Some installations of git-cl fail when uploading a patch
1370 with certain filename extensions. If this happens, it can
1371 generally be fixed by editing the list of exceptions at top of
1374 @subsubheading Announcing your patch set
1376 You should then announce the patch by logging into the code review
1377 issue webpage and using @qq{Publish + Mail Comments} to add a
1378 (mostly bogus) comment to your issue. The text of your comment
1379 will be sent to our developer mailing list.
1381 @warning{There is no automatic notification of a new patch; you
1382 must add a comment yourself.}
1384 @subsubheading Revisions
1386 As revisions are made in response to comments, successive patch sets
1387 for the same issue can be uploaded by reissuing the git-cl command
1388 with the modified branch checked out.
1390 Sometimes in response to comments on revisions, the best way to
1391 work may require creation of a new branch in git. In order to
1392 associate the new branch with an existing Rietveld issue,
1393 the following command can be used:
1396 git cl issue issue-number
1400 where @code{issue-number} is the number of the existing Rietveld
1403 @subsubheading Resetting git cl
1405 If @command{git cl} becomes confused, you can @qq{reset} it by
1412 @subsubheading Wait for a countdown
1414 Your patch will be available for reviews for the next few hours or
1415 days. Three times a week, patches with no known problems are
1416 gathered into a @qq{patch countdown} and their status changed to
1417 @code{patch-countdown}. The countdown is a 48-hour waiting period
1418 in which any final reviews or complaints should be made.
1420 During the countdown, your patch may be set to
1421 @code{patch-needs_work}, indicating that you should fix something
1422 (or at least discuss why the patch needs no modification). If no
1423 problems are found, the patch will be set to @code{patch-push}.
1425 Once a patch has @code{patch-push}, it should be sent to your
1426 mentor for uploading. If you have git push ability, look at
1427 @ref{Pushing to staging}.
1430 @node Advanced Git procedures
1431 @section Advanced Git procedures
1434 @warning{This section is not necessary for normal contributors;
1435 these commands are presented for information for people interested
1436 in learning more about git.}
1438 It is possible to work with several branches on the same local Git
1439 repository; this is especially useful for translators who may have
1440 to deal with both @code{translation} and a stable branch,
1441 e.g. @code{stable/2.12}.
1443 Some Git commands are introduced first, then a workflow with
1444 several Git branches of LilyPond source code is presented.
1449 * Advanced Git concepts::
1450 * Resolving conflicts::
1451 * Reverting all local changes::
1452 * Working with remote branches::
1454 * Applying remote patches::
1455 * Sending and receiving patches via email::
1456 * Cleaning up multiple patches::
1458 * Pushing to staging::
1462 @node Merge conflicts
1463 @subsection Merge conflicts
1465 To be filled in later, and/or moved to a different section. I
1466 just wanted to make sure that I had a stub ready somewhere.
1469 @node Advanced Git concepts
1470 @subsection Advanced Git concepts
1473 A bit of Git vocabulary will be explained below. The following is
1474 only introductory; for a better understanding of Git concepts, you
1475 may wish to read @ref{Other Git documentation}.
1477 The @code{git@tie{}pull@tie{}origin} command above is just a
1478 shortcut for this command:
1481 git pull git://git.sv.gnu.org/lilypond.git/ @var{branch}:origin/@var{branch}
1485 where @code{@var{branch}} is typically @code{master} or
1486 @code{translation}; if you do not know or remember, see
1487 @ref{Downloading remote branches} to remember which commands you
1488 issued or which source code you wanted to get.
1490 A @emph{commit} is a set of changes made to the sources; it also
1491 includes the committish of the parent commit, the name and e-mail
1492 of the @emph{author} (the person who wrote the changes), the name
1493 and e-mail of the @emph{committer} (the person who brings these
1494 changes into the Git repository), and a commit message.
1496 A @emph{committish} is the SHA1 checksum of a commit, a number
1497 made of 40 hexadecimal digits, which acts as the internal unique
1498 identifier for this commit. To refer to a particular revision,
1499 don't use vague references like the (approximative) date, simply
1500 copy and paste the committish.
1502 A @emph{branch} is nothing more than a pointer to a particular
1503 commit, which is called the @emph{head} of the branch; when
1504 referring to a branch, one often actually thinks about its head
1505 and the ancestor commits of the head.
1507 Now we will explain the two last commands you used to get the
1508 source code from Git---see @ref{Downloading individual branches}.
1511 git remote add -ft @var{branch} -m @var{branch} \
1512 origin git://git.sv.gnu.org/lilypond.git/
1514 git checkout -b @var{branch} origin/@var{branch}
1517 The @command{git@tie{}remote} has created a branch called
1518 @code{origin/@var{branch}} in your local Git repository. As this
1519 branch is a copy of the remote branch web from git.sv.gnu.org
1520 LilyPond repository, it is called a @emph{remote branch}, and is
1521 meant to track the changes on the branch from git.sv.gnu.org: it
1522 will be updated every time you run
1523 @command{git@tie{}pull@tie{}origin} or
1524 @command{git@tie{}fetch@tie{}origin}.
1526 The @command{git@tie{}checkout} command has created a branch named
1527 @code{@var{branch}}. At the beginning, this branch is identical
1528 to @code{origin/@var{branch}}, but it will differ as soon as you
1529 make changes, e.g. adding newly translated pages or editing some
1530 documentation or code source file. Whenever you pull, you merge
1531 the changes from @code{origin/@var{branch}} and
1532 @code{@var{branch}} since the last pulling. If you do not have
1533 push (i.e. @qq{write}) access on git.sv.gnu.org, your
1534 @code{@var{branch}} will always differ from
1535 @code{origin/@var{branch}}. In this case, remember that other
1536 people working like you with the remote branch @code{@var{branch}}
1537 of git://git.sv.gnu.org/lilypond.git/ (called
1538 @code{origin/@var{branch}} on your local repository) know nothing
1539 about your own @code{@var{branch}}: this means that whenever you
1540 use a committish or make a patch, others expect you to take the
1541 latest commit of @code{origin/@var{branch}} as a reference.
1543 Finally, please remember to read the man page of every Git command
1544 you will find in this manual in case you want to discover
1545 alternate methods or just understand how it works.
1548 @node Resolving conflicts
1549 @subsection Resolving conflicts
1552 Occasionally an update may result in conflicts -- this happens
1553 when you and somebody else have modified the same part of the same
1554 file and git cannot figure out how to merge the two versions
1555 together. When this happens, you must manually merge the two
1558 If you need some documentation to understand and resolve
1559 conflicts, see paragraphs @emph{How conflicts are presented} and
1560 @emph{How to resolve conflicts} in @command{git merge} man page.
1562 If all else fails, you can follow the instructions in
1563 @ref{Reverting all local changes}. Be aware that this eliminates
1564 any changes you have made!
1567 @node Reverting all local changes
1568 @subsection Reverting all local changes
1570 Sometimes git will become hopelessly confused, and you just want
1571 to get back to a known, stable state. This command destroys any
1572 local changes you have made in the currently checked-out branch,
1573 but at least you get back to the current online version:
1576 git reset --hard origin/master
1580 @node Working with remote branches
1581 @subsection Working with remote branches
1584 @subsubheading Fetching new branches from git.sv.gnu.org
1586 To fetch and check out a new branch named @code{@var{branch}} on
1587 git.sv.gnu.org, run from top of the Git repository
1590 git config --add remote.origin.fetch \
1591 +refs/heads/@var{branch}:refs/remotes/origin/@var{branch}
1593 git checkout --track -b @var{branch} origin/@var{branch}
1596 After this, you can pull @code{@var{branch}} from git.sv.gnu.org
1603 Note that this command generally fetches all branches you added
1604 with @command{git@tie{}remote@tie{}add} (when you initialized the
1605 repository) or @command{git@tie{}config@tie{}--add}, i.e. it
1606 updates all remote branches from remote @code{origin}, then it
1607 merges the remote branch tracked by the current branch into the
1608 current branch. For example, if your current branch is
1609 @code{master}, @code{origin/master} will be merged into
1613 @subsubheading Local clones, or having several working trees
1615 If you play with several Git branches, e.g. @code{master},
1616 @code{translation}, @code{stable/2.12}), you may want to
1617 have one source and build tree for each branch; this is possible
1618 with subdirectories of your local Git repository, used as local
1619 cloned subrepositories. To create a local clone for the branch
1620 named @code{@var{branch}}, run
1623 git checkout @var{branch}
1624 git clone -lsn . @var{subdir}
1629 Note that @code{@var{subdir}} must be a directory name which does
1630 not already exist. In @code{@var{subdir}}, you can use all Git
1631 commands to browse revisions history, commit and uncommit changes;
1632 to update the cloned subrepository with changes made on the main
1633 repository, cd into @code{@var{subdir}} and run
1634 @command{git@tie{}pull}; to send changes made on the subrepository
1635 back to the main repository, run @command{git@tie{}push} from
1636 @code{@var{subdir}}. Note that only one branch (the currently
1637 checked out branch) is created in the subrepository by default; it
1638 is possible to have several branches in a subrepository and do
1639 usual operations (checkout, merge, create, delete...) on these
1640 branches, but this possibility is not detailed here.
1642 When you push @code{@var{branch}} from @code{@var{subdir}} to the
1643 main repository, and @code{@var{branch}} is checked out in the
1644 main repository, you must save uncommitted changes (see
1645 @command{git@tie{}stash}) and do
1646 @command{git@tie{}reset@tie{}--hard} in the main repository in
1647 order to apply pushed changes in the working tree of the main
1655 The commands above don't only bring you the latest version of the
1656 sources, but also the full history of revisions (revisions, also
1657 called commits, are changes made to the sources), stored in the
1658 @file{.git} directory. You can browse this history with
1661 git log # only shows the logs (author, committish and commit message)
1662 git log -p # also shows diffs
1663 gitk # shows history graphically
1666 @warning{The @code{gitk} command may require a separate
1667 @code{gitk} package, available in the appropriate distribution's
1671 @node Applying remote patches
1672 @subsection Applying remote patches
1675 TODO: Explain how to determine if a patch was created with
1676 @code{git@tie{}format-patch}.
1678 Well-formed git patches created with @code{git@tie{}format-patch}
1679 should be committed with the following command:
1685 Patches created without @code{git@tie{}format-patch} can be
1686 applied in two steps. The first step is to apply the patch to the
1687 working tree and the index:
1690 git apply --index @var{patch}
1694 The second step is to commit the changes and give credit to the
1695 author of the patch. This can be done with the following command:
1698 git commit --author="@var{John Smith} <@var{john@@example.com}>"
1701 Please note that using the @code{--index} option for patching is quite
1702 important here and @emph{cannot} reliably be replaced by using the
1703 @code{-a} option when committing: that would only commit files from the
1704 working tree that are already registered with git, so every file that
1705 the patch actually @emph{adds}, like a regtest for a fixed bug, would
1706 get lost. For the same reason, you should not use the git-independent
1707 @samp{patch} program for applying patches.
1709 @node Sending and receiving patches via email
1710 @subsection Sending and receiving patches via email
1713 The default @code{x-diff} MIME type associated with patch files
1714 (i.e., files whose name ends in @code{.patch}) means that the
1715 encoding of line endings may be changed from UNIX to DOS format
1716 when they are sent as attachments. Attempting to apply such an
1717 inadvertently altered patch will cause git to fail with a message
1718 about @q{whitespace errors}.
1720 The solution to such problems is surprisingly simple---just change
1721 the default file extension of patches generated by git to end in
1722 @code{.txt}, for example:
1725 git config format.suffix '.patch.txt'
1728 This should cause email programs to apply the correct base64
1729 encoding to attached patches.
1731 If you receive a patch with DOS instead of UNIX line-endings, it
1732 can be converted back using the @code{dos2unix} utility.
1734 Lots of useful information on email complications with patches is
1735 provided on the Wine wiki at
1736 @uref{http://wiki.winehq.org/GitWine}.
1739 @node Cleaning up multiple patches
1740 @subsection Cleaning up multiple patches
1742 If you have been developing on your own branch for a while, you
1743 may have more commmits than is really sensible. To revise your
1744 work and condense commits, use:
1747 git rebase origin/master
1748 git rebase -i origin/master
1751 @warning{Be a bit cautious -- if you completely remove commits
1752 during the interactive session, you will... err... completely
1753 remove those commits.}
1757 @subsection Commit access
1759 Most contributors are not able to commit patches directly to the
1760 main repository---only members of the LilyPond development team
1761 have @emph{commit access}. If you are a contributor and are
1762 interested in joining the development team, contact the Project
1763 Manager through the mailing list
1764 (@email{lilypond-devel@@gnu.org}). Generally, only contributors
1765 who have already provided a number of patches which have been
1766 pushed to the main repository will be considered for membership.
1768 If you have been approved by the Project Manager, use the
1769 following procedure to obtain commit access:
1773 If you don't already have one, set up a Savannah user account at
1774 @uref{https://savannah.gnu.org/account/register.php}. If your web
1775 browser responds with an @qq{untrusted connection} message when
1776 you visit the link, follow the steps for including the CAcert root
1777 certificate in your browser, given at
1778 @uref{http://savannah.gnu.org/tls/tutorial/}.
1780 @warning{Savannah will silently put your username in lower-case --
1781 do not try to use capital letters.}
1785 After registering, if you are not logged in automatically, login
1786 at @uref{https://savannah.gnu.org/account/login.php}---this should
1787 take you to your @qq{my} page
1788 (@uref{https://savannah.gnu.org/my/}).
1792 Click on the @qq{My Groups} link to access the @qq{My Group
1793 Membership} page. From there, find the @qq{Request for Inclusion}
1794 box and search for @qq{LilyPond}. Among the search results, check
1795 the box labeled @qq{GNU LilyPond Music Typesetter} and write a
1796 brief (required) message for the Project Manager (@qq{Hey it's
1797 me!} should be fine).
1799 Note that you will not have commit access until the Project
1800 Manager activates your membership. Once your membership is
1801 activated, LilyPond should appear under the heading @qq{Groups I'm
1802 Contributor of} on your @qq{My Group Membership} page.
1806 Generate an SSH @q{rsa} key pair. Enter the following at the
1813 When prompted for a location to save the key, press <ENTER> to
1814 accept the default location (@file{~/.ssh/id_rsa}).
1816 Next you are asked to enter an optional passphrase. On most
1817 systems, if you use a passphrase, you will likely be prompted for
1818 it every time you use @command{git@tie{}push} or
1819 @command{git@tie{}pull}. You may prefer this since it can protect
1820 you from your own mistakes (like pushing when you mean to pull),
1821 though you may find it tedious to keep re-entering it.
1823 You can change/enable/disable your passphrase at any time with:
1826 ssh-keygen -f ~/.ssh/id_rsa -p
1829 Note that the GNOME desktop has a feature which stores your
1830 passphrase for you for an entire GNOME session. If you use a
1831 passphrase to @qq{protect you from yourself}, you will want to
1832 disable this feature, since you'll only be prompted once. Run the
1833 following command, then logout of GNOME and log back in:
1836 gconftool-2 --set -t bool \
1837 /apps/gnome-keyring/daemon-components/ssh false
1840 After setting up your passphrase, your private key is saved as
1841 @file{~/.ssh/id_rsa} and your public key is saved as
1842 @file{~/.ssh/id_rsa.pub}.
1846 Register your public SSH @q{rsa} key with Savannah. From the
1847 @qq{My Account Configuration} page, click on @qq{Edit SSH Keys},
1848 then paste the contents of your @file{~/.ssh/id_rsa.pub} file into
1849 one of the @qq{Authorized keys} text fields, and click
1852 Savannah should respond with something like:
1855 Success: Key #1 seen Keys registered
1860 Configure Git to use the SSH protocol (instead of the GIT
1861 protocol). From your local Git repository, enter:
1864 git config remote.origin.url \
1865 ssh://@var{user}@@git.sv.gnu.org/srv/git/lilypond.git
1869 replacing @var{user} with your Savannah username.
1873 After your membership has been activated and you've configured Git
1874 to use SSH, test the connection with:
1880 SSH should issue the following warning:
1883 The authenticity of host 'git.sv.gnu.org (140.186.70.72)' can't
1885 RSA key fingerprint is
1886 80:5a:b0:0c:ec:93:66:29:49:7e:04:2b:fd:ba:2c:d5.
1887 Are you sure you want to continue connecting (yes/no)?
1890 Make sure the RSA key fingerprint displayed matches the one above.
1891 If it doesn't, respond @qq{no} and check that you configured Git
1892 properly in the previous step. If it does match, respond
1893 @qq{yes}. SSH should then issue another warning:
1896 Warning: Permanently added 'git.sv.gnu.org,140.186.70.72' (RSA) to
1897 the list of known hosts.
1900 The list of known hosts is stored in the file
1901 @file{~/.ssh/known_hosts}.
1903 At this point, you are prompted for your passphrase if you have
1904 one, then Git will attempt a pull.
1906 If @command{git@tie{}pull@tie{}--verbose} fails, you should see
1907 error messages like these:
1910 Permission denied (publickey).
1911 fatal: The remote end hung up unexpectedly
1914 If you get the above error, you may have made a mistake when
1915 registering your SSH key at Savannah. If the key is properly
1916 registered, you probably just need to wait for the Savannah server
1917 to activate it. It usually takes a few minutes for the key to be
1918 active after registering it, but if it still doesn't work after an
1919 hour, ask for help on the mailing list.
1921 If @command{git@tie{}pull@tie{}--verbose} succeeds, the output
1922 will include a @q{From} line that shows @q{ssh} as the protocol:
1925 From ssh://git.sv.gnu.org/srv/git/lilypond
1928 If the protocol shown is not @q{ssh}, check that you configured
1929 Git properly in the previous step.
1933 Test your commit access with a dry run:
1935 @warning{Do not push directly to master; instead, push to staging.
1936 See @ref{Pushing to staging}.}
1939 git push --dry-run --verbose
1942 Note that recent versions of Git (Git 1.6.3 or later) will issue a
1943 big warning if the above command is used. The simplest solution
1944 is to tell Git to push all matching branches by default:
1947 git config push.default matching
1951 Then @code{git@tie{}push} should work as before. For more
1952 details, consult the @code{git@tie{}push} man page.
1956 Repeat the steps from generating an RSA key through to testing
1957 your commit access, for each machine from which you will be
1958 making commits, or you may simply copy the files from your
1959 local @file{~/.ssh} folder to the same folder on the other
1964 @subsubheading Technical details
1968 On Firefox, to view or remove the CAcert root certificate, go to:
1969 Edit > Preferences > Advanced > Encryption > View Certificates >
1970 Authorities > Certificate Name > Root CA > CA Cert Signing
1974 The @command{git@tie{}config} commands above should modify your
1975 local repository's @file{.git/config} file. These lines:
1979 url = git://git.sv.gnu.org/lilypond.git/
1983 should now be changed to:
1987 url = ssh://@var{user}@@git.sv.gnu.org/srv/git/lilypond.git
1991 where @var{user} is your login name on Savannah.
1995 @command{git@tie{}config@tie{}push.default@tie{}matching} command
1996 should add these lines to @file{.git/config}:
2005 Encryption protocols, including ssh, generally do not permit packet
2006 fragmentation to avoid introducing a point of insecurity. This
2007 means that the maximum packet size must not exceed the smallest
2008 MTU (Maximum Transmission Unit) set in the routers along the path.
2009 This smallest MTU is determined by a procedure during call set-up
2010 which relies on the transmission over the path of ICMP packets.
2011 If any of the routers in the path block ICMP packets this mechanism
2012 fails, resulting in the possibility of packets being transmitted
2013 which exceed the MTU of one of the routers. If this happens the
2014 packet is discarded, causing the ssh session to hang, timeout or
2015 terminate with the error message
2018 ssh: connect to host <host ip addr> port 22: Bad file number
2019 fatal: The remote end hung up unexpectedly
2022 depending on precisely when in the proceedings the first large
2023 packet is transmitted. Most routers on the internet have MTU
2024 set to 1500, but routers installed in homes to connect via
2025 broadband may use a slightly smaller MTU for efficient transmission
2026 over ATM. If this problem is encountered a possible work-around is
2027 to set the MTU in the local router to 1500.
2030 @node Pushing to staging
2031 @subsection Pushing to staging
2033 Do not push directly to the git @code{master} branch. Instead,
2034 push to @code{staging}.
2036 You will not see your patch on @code{origin/master} until some
2037 automatic tests have been run. These tests are run every couple
2038 of hours; please wait at least 12 hours before wondering if your
2039 patch has been lost. Note that you can check the commits on
2040 @code{origin/staging} by looking at the git web interface on
2043 @subsubheading If your work is in a patch file
2045 Assuming that your patch is in a file called
2046 @file{0001-my-patch.patch}, and you are currently on git master,
2050 git checkout staging
2052 git am 0001-my-patch.patch
2054 git push origin staging
2058 @warning{Do not skip the @command{gitk} step; a quick 5-second
2059 check of the visual history can save a great deal of frustration
2060 later on. You should only see that @command{staging} is only 1
2061 commit ahead of @code{origin/staging}.}
2063 @subsubheading If your work is in a branch
2065 If you are working on branches and your work in is
2066 @code{my_branch_name}, then do:
2069 git checkout staging
2071 git merge my_branch_name
2073 git push origin staging
2076 @warning{Do not skip the @command{gitk} step; a quick 5-second
2077 check of the visual history can save a great deal of frustration
2078 later on. You should see that @code{staging} is only ahead of
2079 @code{origin/staging} by the commits from your branch.}
2083 @node Git on Windows
2084 @section Git on Windows
2086 @warning{We heavily recommend that development be done with our
2087 virtual machine @ref{LilyDev}.}
2089 @c Some of this may duplicate stuff in other sections
2090 @c But it is probably best for windows users to have it all together
2091 @c If necessary, clear this up later -td
2093 TODO: Decide what to do with this... Pare it down? Move
2094 paragraphs next to analogous Unix instructions? -mp
2096 @subsection Background to nomenclature
2098 Git is a system for tracking the changes made to source files by a
2099 distributed set of editors. It is designed to work without a
2100 master repository, but we have chosen to have a master repository
2101 for LilyPond files. Editors hold a local copy of the master
2102 repository together with any changes they have made locally.
2103 Local changes are held in a local @q{branch}, of which there may
2104 be several, but these instructions assume you are using just one.
2105 The files visible in the local repository always correspond to
2106 those on the currently @q{checked out} local branch.
2108 Files are edited on a local branch, and in that state the changes
2109 are said to be @q{unstaged}. When editing is complete, the
2110 changes are moved to being @q{staged for commit}, and finally the
2111 changes are @q{committed} to the local branch. Once committed,
2112 the changes (called a @q{commit}) are given a unique 40-digit
2113 hexadecimal reference number called the @q{Committish} or @q{SHA1
2114 ID} which identifies the commit to Git. Such committed changes
2115 can be sent to the master repository by @q{pushing} them (if you
2116 have write permission) or by sending them by email to someone who
2117 has, either as a complete file or as a @q{diff} or @q{patch}
2118 (which send just the differences from the master repository).
2120 @subsection Installing git
2123 @uref{http://code.google.com/p/msysgit/downloads/list} (note, not
2124 msysGit, which is for Git developers and not PortableGit, which is
2125 not a full git installation) and install it.
2127 Note that most users will not need to install SSH. That is not
2128 required until you have been granted direct push permissions to
2129 the master git repository.
2131 Start Git by clicking on the desktop icon. This will bring up a
2132 command line bash shell. This may be unfamiliar to Windows users.
2133 If so, follow these instructions carefully. Commands are entered
2134 at a $ prompt and are terminated by keying a newline.
2136 @subsection Initialising Git
2138 Decide where you wish to place your local Git repository, creating
2139 the folders in Windows as necessary. Here we call the folder to
2140 contain the repository @code{[path]/Git}, but if you intend using
2141 Git for other projects a directory name like @code{lilypond-git}
2142 might be better. You will need to have space for around
2145 Start the Git bash shell by clicking on the desk-top icon
2146 installed with Git and type
2152 to position the shell at your new Git repository.
2154 Note: if [path] contains folders with names containing spaces use
2166 to initialize your Git repository.
2168 Then type (all on one line; the shell will wrap automatically)
2171 git remote add -ft master origin git://git.sv.gnu.org/lilypond.git
2174 to download the lilypond master files.
2176 @warning{Be patient! Even on a broadband connection this can take
2177 10 minutes or more. Wait for lots of [new tag] messages and the $
2180 We now need to generate a local copy of the downloaded files in a
2181 new local branch. Your local branch needs to have a name. It is
2182 usual to call it @q{master} and we shall do that here.
2187 git checkout -b master origin/master
2190 This creates a second branch called @q{master}. You will see two
2191 warnings (ignore these), and a message advising you that your
2192 local branch @q{master} has been set up to track the remote
2193 branch. You now have two branches, a local branch called
2194 @q{master}, and a tracking branch called @q{origin/master}, which
2195 is a shortened form of @q{remotes/origin/master}.
2197 Return to Windows Explorer and look in your Git repository. You
2198 should see lots of folders. For example, the LilyPond
2199 documentation can be found in [path]/Git/Documentation/.
2201 The Git bash shell is terminated by typing @code{exit} or by
2202 clicking on the usual Windows close-window widget.
2206 Almost all subsequent work will use the Git Graphical User
2207 Interface, which avoids having to type command line commands. To
2208 start Git GUI first start the Git bash shell by clicking on the
2209 desktop icon, and type
2216 The Git GUI will open in a new window. It contains four panels
2217 and 7 pull-down menus. At this stage do not use any of the
2218 commands under Branch, Commit, Merge or Remote. These will be
2221 The top panel on the left contains the names of files which you
2222 are in the process of editing (Unstaged Changes), and the lower
2223 panel on the left contains the names of files you have finished
2224 editing and have staged ready for committing (Staged Changes). At
2225 present, these panels will be empty as you have not yet made any
2226 changes to any file. After a file has been edited and saved the
2227 top panel on the right will display the differences between the
2228 edited file selected in one of the panels on the left and the last
2229 version committed on the current branch.
2231 The panel at bottom right is used to enter a descriptive message
2232 about the change before committing it.
2234 The Git GUI is terminated by entering CNTL-Q while it is the
2235 active window or by clicking on the usual Windows close-window
2238 @subsection Personalising your local git repository
2240 Open the Git GUI, click on
2246 and enter your name and email address in the left-hand (Git
2247 Repository) panel. Leave everything else unchanged and save it.
2249 Note that Windows users must leave the default setting for line
2250 endings unchanged. All files in a git repository must have lines
2251 terminated by just a LF, as this is required for Merge to work,
2252 but Windows files are terminated by CRLF by default. The git
2253 default setting causes the line endings of files in a Windows git
2254 repository to be flipped automatically between LF and CRLF as
2255 required. This enables files to be edited by any Windows editor
2256 without causing problems in the git repository.
2258 @subsection Checking out a branch
2260 At this stage you have two branches in your local repository,
2261 both identical. To see them click on
2267 You should have one local branch called @q{master} and one
2268 tracking branch called @q{origin/master}. The latter is your
2269 local copy of the @q{remotes/origin/master} branch in the master
2270 LilyPond repository. The local @q{master} branch is where you
2271 will make your local changes.
2273 When a particular branch is selected, i.e., checked out, the files
2274 visible in your repository are changed to reflect the state of the
2275 files on that branch.
2277 @subsection Updating files from @q{remote/origin/master}
2279 Before starting the editing of a file, ensure your local
2280 repository contains the latest version of the files in the remote
2281 repository by first clicking
2284 Remote -> Fetch from -> origin
2290 This will place the latest version of every file, including all
2291 the changes made by others, into the @q{origin/master} branch of
2292 the tracking branches in your git repository. You can see these
2293 files by checking out this branch, but you must @emph{never} edit
2294 any files while this branch is checked out. Check out your local
2295 @q{master} branch again.
2297 You then need to merge these fetched files into your local
2298 @q{master} branch by clicking on
2301 Merge -> Local Merge
2305 and if necessary select the local @q{master} branch.
2307 Note that a merge cannot be completed if you have made any local
2308 changes which have not yet been committed.
2310 This merge will update all the files in the @q{master} branch to
2311 reflect the current state of the @q{origin/master} branch. If any
2312 of the changes conflict with changes you have made yourself
2313 recently you will be notified of the conflict (see below).
2315 @subsection Editing files
2317 First ensure your @q{master} branch is checked out, then simply
2318 edit the files in your local Git repository with your favourite
2319 editor and save them back there. If any file contains non-ASCII
2320 characters ensure you save it in UTF-8 format. Git will detect
2321 any changes whenever you restart Git GUI and the file names will
2322 then be listed in the Unstaged Changes panel. Or you can click
2323 the Rescan button to refresh the panel contents at any time. You
2324 may break off and resume editing any time.
2326 The changes you have made may be displayed in diff form in the top
2327 right-hand panel of Git GUI by clicking on the file name shown in
2328 one of the left panels.
2330 When your editing is complete, move the files from being Unstaged
2331 to Staged by clicking the document symbol to the left of each
2332 name. If you change your mind it can be moved back by clicking on
2333 the ticked box to the left of the name.
2335 Finally the changes you have made may be committed to your
2336 @q{master} branch by entering a brief message in the Commit
2337 Message box and clicking the Commit button.
2339 If you wish to amend your changes after a commit has been made,
2340 the original version and the changes you made in that commit may
2341 be recovered by selecting
2344 Commit -> Amend Last Commit
2348 or by checking the Amend Last Commit radio button at bottom right.
2349 This will return the changes to the Staged state, so further
2350 editing made be carried out within that commit. This must only be
2351 done @emph{before} the changes have been Pushed or sent to your
2352 mentor for Pushing - after that it is too late and corrections
2353 have to be made as a separate commit.
2356 @subsection Sending changes to @q{remotes/origin/master}
2358 If you do not have write access to @q{remotes/origin/master} you
2359 will need to send your changes by email to someone who does.
2361 First you need to create a diff or patch file containing your
2362 changes. To create this, the file must first be committed. Then
2363 terminate the Git GUI. In the git bash shell first cd to your Git
2370 if necessary, then produce the patch with
2373 git format-patch origin
2376 This will create a patch file for all the locally committed files
2377 which differ from @q{origin/master}. The patch file can be found
2378 in [path]/Git and will have a name formed from the commit message.
2380 @subsection Resolving merge conflicts
2382 As soon as you have committed a changed file your local
2383 @code{master} branch has diverged from @code{origin/master}, and
2384 will remain diverged until your changes have been committed in
2385 @code{remotes/origin/master} and Fetched back into your
2386 @code{origin/master} branch. Similarly, if a new commit has been
2387 made to @code{remotes/origin/master} by someone else and Fetched,
2388 your local @code{master} branch is divergent. You can detect a
2389 divergent branch by clicking on
2392 Repository -> Visualise all branch history
2395 This opens up a very useful new window called @q{gitk}. Use this
2396 to browse all the commits made by yourself and others.
2398 If the diagram at top left of the resulting window does not show
2399 your @code{master} tag on the same node as the
2400 @code{remotes/origin/master} tag your branch has diverged from
2401 @code{origin/master}. This is quite normal if files you have
2402 modified yourself have not yet been Pushed to
2403 @code{remotes/origin/master} and Fetched, or if files modified and
2404 committed by others have been Fetched since you last Merged
2405 @code{origin/master} into your local @code{master} branch.
2407 If a file being merged from @code{origin/master} differs from one
2408 you have modified in a way that cannot be resolved automatically
2409 by git, Merge will report a Conflict which you must resolve by
2410 editing the file to create the version you wish to keep.
2412 This could happen if the person updating
2413 @code{remotes/origin/master} for you has added some changes of his
2414 own before committing your changes to
2415 @code{remotes/origin/master}, or if someone else has changed the
2416 same file since you last fetched the file from
2417 @code{remotes/origin/master}.
2419 Open the file in your editor and look for sections which are
2422 [to be completed when I next have a merge conflict to be sure I
2423 give the right instructions -td]
2426 @subsection Other actions
2428 The instructions above describe the simplest way of using git on
2429 Windows. Other git facilities which may usefully supplement these
2433 @item Using multiple local branches (Create, Rename, Delete)
2434 @item Resetting branches
2435 @item Cherry-picking commits
2436 @item Pushing commits to @w{remote/origin/master}
2437 @item Using gitk to review history
2440 Once familiarity with using git on Windows has been gained the
2441 standard git manuals can be used to learn about these.
2444 @node Repository directory structure
2445 @section Repository directory structure
2448 @c TODO: integrate the roadmap better
2449 @verbatiminclude ROADMAP
2452 @node Other Git documentation
2453 @section Other Git documentation
2457 Official git man pages:
2458 @uref{http://www.kernel.org/pub/software/scm/git/docs/}
2461 More in-depth tutorials: @uref{http://git-scm.com/documentation}
2464 Book about git: @uref{http://progit.org/,Pro Git}
2467 Github help: @uref{http://help.github.com/}
2468 (very highly recommended by Graham)