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{Using 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{Daily use of lily-git.tcl}.
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 chages 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{lilypond/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 back into @code{master} to incorporate
627 recent translations. Similarly, the @code{master} branch is
628 usually merged into the @code{lilypond/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{lilypond/translation} branch, enter:
679 git remote add -ft lilypond/translation -m \
680 lilypond/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{lilypond/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.
778 @node Basic Git procedures
779 @section Basic Git procedures
783 * The Git contributor's cycle::
784 * Pulling and rebasing::
785 * Using local branches::
786 * Commits and patches::
790 @node The Git contributor's cycle
791 @subsection The Git contributor's cycle
794 Here is a simplified view of the contribution process on Git:
798 Update your local repository by @emph{pulling} the most recent
799 updates from the remote repository.
802 Edit source files within your local repository's @emph{working
806 @emph{Commit} the changes you've made to a local @emph{branch}.
809 Generate a @emph{patch} to share your changes with the developers.
813 @node Pulling and rebasing
814 @subsection Pulling and rebasing
817 When developers push new patches to the @code{git.sv.gnu.org}
818 repository, your local repository is @strong{not} automatically
819 updated. It is important to keep your repository up-to-date by
820 periodically @emph{pulling} the most recent @emph{commits} from
821 the remote branch. Developers expect patches to be as current as
822 possible, since outdated patches require extra work before they
825 Occasionally you may need to rework some of your own modifications
826 to match changes made to the remote branch (see @ref{Resolving
827 conflicts}), and it's considerably easier to rework things
828 incrementally. If you don't update your repository along the way,
829 you may have to spend a lot of time resolving branch conflicts and
830 reconfiguring much of the work you've already done.
832 Fortunately, Git is able to resolve certain types of branch
833 conflicts automatically with a process called @emph{rebasing}.
834 When rebasing, Git tries to modify your old commits so they appear
835 as new commits (based on the latest updates). For a more involved
836 explanation, see the @command{git-rebase} man page.
838 To pull without rebasing (recommended for translators), use the
842 git pull # recommended for translators
845 If you're tracking the remote @code{master} branch, you should add
846 the @option{-r} option (short for @option{--rebase}) to keep commits
847 on your local branch current:
850 git pull -r # use with caution when translating
853 If you don't edit translated documentation and don't want to type
854 @option{-r} every time, configure the master branch to rebase by
855 default with this command:
858 git config branch.master.rebase true
861 If pull fails because of a message like
864 error: Your local changes to 'Documentation/learning/tutorial.itely'
865 would be overwritten by merge. Aborting.
872 Documentation/learning/tutorial.itely: needs update
873 refusing to pull with rebase: your working tree is not up-to-date
877 it means that you have modified some files in you working tree
878 without committing changes (see @ref{Commits and patches}); you
879 can use the @command{git@tie{}stash} command to work around this:
882 git stash # save uncommitted changes
883 git pull -r # pull using rebase (translators omit "-r")
884 git stash pop # reapply previously saved changes
887 Note that @command{git@tie{}stash@tie{}pop} will try to apply a
888 patch, and this may create a conflict. If this happens, see
889 @ref{Resolving conflicts}.
891 TODO: I think the next paragraph is confusing. Perhaps prepare
892 the reader for new terms `committish' and `head'? -mp
894 @warning{translators and documentation editors, if you have
895 changed committishes in the head of translated files using commits
896 you have not yet pushed to @code{git.sv.gnu.org}, please do not
897 rebase. If you want to avoid wondering whether you should rebase
898 each time you pull, please always use committishes from master
899 and/or lilypond/translation branch on @code{git.sv.gnu.org}, which
900 in particular implies that you must push your changes to
901 documentation except committishes updates (possibly after having
902 rebased), then update the committishes and push them.}
904 TODO: when committishes automatic conditional update have been
905 tested and documented, append the following to the warning above:
906 Note that using update-committishes make target generally touches
909 @subsubheading Technical details
911 The @command{git@tie{}config} command mentioned above adds the
912 line @code{rebase = true} to the master branch in your local
913 repository's @file{.git/config} file:
918 merge = refs/heads/master
923 @node Using local branches
924 @subsection Using local branches
928 * Creating and removing branches::
929 * Listing branches and remotes::
930 * Checking out branches::
935 @node Creating and removing branches
936 @unnumberedsubsubsec Creating and removing branches
939 Local branches are useful when you're working on several different
940 projects concurrently. To create a new branch, enter:
943 git branch @var{name}
946 To delete a branch, enter:
949 git branch -d @var{name}
952 Git will ask you for confirmation if it sees that data would be
953 lost by deleting the branch. Use @option{-D} instead of @option{-d}
954 to bypass this. Note that you cannot delete a branch if it is
955 currently checked out.
958 @node Listing branches and remotes
959 @unnumberedsubsubsec Listing branches and remotes
961 You can get the exact path or URL of all remote branches by
968 To list Git branches on your local repositories, run
971 git branch # list local branches only
972 git branch -r # list remote branches
973 git branch -a # list all branches
977 @node Checking out branches
978 @unnumberedsubsubsec Checking out branches
980 To know the currently checked out branch, i.e. the branch whose
981 source files are present in your working tree, read the first line
989 The currently checked out branch is also marked with an asterisk
990 in the output of @command{git branch}.
992 You can check out another branch @code{@var{other_branch}}, i.e.
993 check out @code{@var{other_branch}} to the working tree, by
997 git checkout @var{other_branch}
1000 Note that it is possible to check out another branch while having
1001 uncommitted changes, but it is not recommended unless you know
1002 what you are doing; it is recommended to run @command{git status}
1003 to check this kind of issue before checking out another branch.
1005 @node Merging branches
1006 @unnumberedsubsubsec Merging branches
1008 To merge branch @code{@var{foo}} into branch @code{@var{bar}},
1009 i.e. to @qq{add} all changes made in branch @code{@var{foo}} to
1010 branch @code{@var{bar}}, run
1013 git checkout @var{bar}
1017 If any conflict happens, see @ref{Resolving conflicts}.
1019 There are common usage cases for merging: as a translator, you
1020 will often want to merge @code{master} into
1021 @code{lilypond/translation}; on the other hand, the Translations
1022 meister wants to merge @code{lilypond/translation} into
1023 @code{master} whenever he has checked that
1024 @code{lilypond/translation} builds successfully.
1027 @node Commits and patches
1028 @subsection Commits and patches
1032 * Understanding commits::
1036 * Uploading a patch for review::
1040 @node Understanding commits
1041 @unnumberedsubsubsec Understanding commits
1043 Technically, a @emph{commit} is a single point in the history of a
1044 branch, but most developers use the term to mean a @emph{commit
1045 object}, which stores information about a particular revision. A
1046 single commit can record changes to multiple source files, and
1047 typically represents one logical set of related changes (such as a
1048 bug-fix). You can list the ten most recent commits in your
1049 current branch with this command:
1052 git log -10 --oneline
1055 If you're using an older version of Git and get an @q{unrecognized
1056 argument} error, use this instead:
1059 git log -10 --pretty=oneline --abbrev-commit
1062 More interactive lists of the commits on the remote @code{master}
1063 branch are available at
1064 @uref{http://git.sv.gnu.org/gitweb/?p=lilypond.git;a=shortlog} and
1065 @uref{http://git.sv.gnu.org/cgit/lilypond.git/log/}.
1068 @node Making commits
1069 @unnumberedsubsubsec Making commits
1072 Once you have modified some source files in your working
1073 directory, you can make a commit with the following procedure:
1077 Make sure you've configured Git properly (see @ref{Configuring
1078 Git}). Check that your changes meet the requirements described in
1079 @ref{Code style} and/or @ref{Documentation policy}. For advanced
1080 edits, you may also want to verify that the changes don't break
1081 the compilation process.
1084 Run the following command:
1091 to make sure you're on the right branch, and to see which files
1092 have been modified, added or removed, etc. You may need to tell
1093 Git about any files you've added by running one of these:
1096 git add @var{file} # add untracked @var{file} individually
1097 git add . # add all untracked files in current directory
1101 After @command{git@tie{}add}, run @command{git@tie{}status} again
1102 to make sure you got everything. You may also need to modify
1106 Preview the changes about to be committed (to make sure everything
1114 The @code{HEAD} argument refers to the most recent commit on the
1115 currently checked-out branch.
1118 Generate the commit with:
1125 The @option{-a} is short for @option{--all} which includes modified
1126 and deleted files, but only those newly created files that have
1127 previously been added.
1132 @node Commit messages
1133 @unnumberedsubsubsec Commit messages
1136 When you run the @command{git@tie{}commit@tie{}-a} command, Git
1137 automatically opens the default text editor so you can enter a
1138 @emph{commit message}. If you find yourself in a foreign editing
1139 environment, you're probably in @command{vi} or @command{vim}. If
1140 you want to switch to an editor you're more familiar with, quit by
1141 typing @code{:q!} and pressing @code{<Enter>}. See
1142 @ref{Configuring Git} for instructions on changing the default
1145 In any case, Git will open a text file for your commit message
1146 that looks like this:
1150 # Please enter the commit message for your changes. Lines starting
1151 # with '#' will be ignored, and an empty message aborts the commit.
1153 # Changes to be committed:
1154 # (use "git reset HEAD <file>..." to unstage)
1156 # modified: working.itexi
1160 Your commit message should begin with a one-line summary
1161 describing the change (no more than 50 characters long), and if
1162 necessary a blank line followed by several lines giving the
1165 @c $ git log -1 --pretty=medium 4d6f1e5
1167 Doc: add Baerenreiter and Henle solo cello suites
1169 Added comparison of solo cello suite engravings to new essay with
1170 high-res images, fixed cropping on Finale example.
1173 Commit messages often start with a short prefix describing the
1174 general location of the changes. If a commit affects the
1175 documentation in English (or in several languages simultaneously)
1176 the commit message should be prefixed with @qq{Doc:@tie{}}. If
1177 the commit affects only one of the translations, the commit
1178 message should be prefixed with @qq{Doc-@var{**}:@tie{}}, where
1179 @var{**} is the two-letter language code. Commits that affect the
1180 website should use @qq{Web:@tie{}} for English, and
1181 @qq{Web-@var{**}:@tie{}} for the other languages. Also, changes
1182 to a single file are often prefixed with the name of the file
1183 involved. Visit the links listed in @ref{Understanding commits}
1187 @node Making patches
1188 @unnumberedsubsubsec Making patches
1190 If you want to share your changes with other contributors and
1191 developers, you need to generate @emph{patches} from your commits.
1192 We prefer it if you follow the instructions in
1193 @ref{Uploading a patch for review}. However, we present an
1194 alternate method here.
1196 You should always run @command{git@tie{}pull@tie{}-r} (translators
1197 should leave off the @option{-r}) before doing this to ensure that
1198 your patches are as current as possible.
1200 Once you have made one or more commits in your local repository,
1201 and pulled the most recent commits from the remote branch, you can
1202 generate patches from your local commits with the command:
1205 git format-patch origin
1208 The @code{origin} argument refers to the remote tracking branch at
1209 @code{git.sv.gnu.org}. This command generates a separate patch
1210 for each commit that's in the current branch but not in the remote
1211 branch. Patches are placed in the current working directory and
1212 will have names that look something like this:
1215 0001-Doc-Fix-typos.patch
1216 0002-Web-Remove-dead-links.patch
1220 Send an email (must be less than 64 KB) to
1221 @email{lilypond-devel@@gnu.org} briefly explaining your work, with
1222 the patch files attached. Translators should send patches to
1223 @email{translations@@lilynet.net}. After your patches are
1224 reviewed, the developers may push one or more of them to the main
1225 repository or discuss them with you.
1228 @node Uploading a patch for review
1229 @unnumberedsubsubsec Uploading a patch for review
1231 Any non-trivial change should be uploaded to our @qq{Rietveld}
1232 code review website:
1235 @uref{http://codereview.appspot.com/}
1238 @subsubheading @command{git-cl} install
1240 LilyDev users should skip over these @q{install} instructions.
1245 Install @command{git-cl} by entering:
1248 git clone https://github.com/gperciva/git-cl.git
1251 If that command fails for some reason, try this instead:
1254 git clone git://github.com/gperciva/git-cl.git
1258 Add the @file{git-cl/} directory to your PATH,
1259 or create a symbolic link to the @command{git-cl}
1260 and @command{upload.py} scripts in one of your PATH
1261 directories (such as @file{$HOME/bin}).
1263 In Ubuntu (and Lilydev), you can add directories to PATH
1264 by adding this line to a hidden file @file{.bashrc},
1265 located in your home directory:
1268 PATH=~/type-here-directory-containing-git-cl:"$@{PATH@}"
1273 @subsubheading @command{git-cl} configuration
1275 LilyDev users should perform these @q{configuration} instructions.
1279 You must have a google account; please create one if you do not
1282 Note that a google account does not need to be a gmail account; you can
1283 use any email address for your google account when you sign up.
1286 Move into the top source directory and then configure @command{git
1287 cl} with the following commands. If you do not understand any
1288 question, just answer with a newline (CR).
1291 cd $HOME/lilypond-git/
1295 The @qq{CC list} question should be answered with:
1298 lilypond-devel@@gnu.org
1303 @subsubheading Uploading patch set
1305 @warning{Unless you are familiar with branches, only work on one
1306 set of changes at once.}
1308 There are two methods, depending on your git setup.
1312 @strong{Master branch}: (easy option, and used in @command{lily-git.tcl})
1314 If you added your patch to @code{master}, then:
1318 git cl upload origin/master
1321 If you have git push ability, make sure that you @emph{remove}
1322 your patch (with @command{git rebase} or @command{git reset})
1323 before pushing other stuff.
1325 @c don't make this one an @example; we don't want to make it easy
1326 @c for people to use this accidently
1327 Notifications of patches are automatically added to our issue
1328 tracker to reduce the chance of patches getting lost. To suppress
1329 this (not recommended), add the @code{-n / --no-code-issue}
1333 @strong{Separate branch}: (complicated option)
1335 Ensure your changes are committed in a separate branch, which
1336 should differ from the reference branch to be used by just the
1337 changes to be uploaded. If the reference branch is to be
1338 origin/master, ensure this is up-to-date. If necessary, use git
1339 rebase to rebase the branch containing the changes to the head of
1340 origin/master. Finally, check out branch with the changes and
1344 git cl upload <reference SHA1 ID>
1348 where <reference SHA1 ID> is the SHA1 ID of the commit to be used
1349 as a reference source for the patch. Generally, this will be the
1350 SHA1 ID of origin/master, and in that case the command:
1353 git cl upload origin/master
1361 After prompting for your Google email address and password, the
1362 patch set will be posted to Rietveld, and you will be given a URL
1365 @warning{Some installations of git-cl fail when uploading a patch
1366 with certain filename extensions. If this happens, it can
1367 generally be fixed by editing the list of exceptions at top of
1370 @subsubheading Announcing your patch set
1372 You should then announce the patch by logging into the code review
1373 issue webpage and using @qq{Publish + Mail Comments} to add a
1374 (mostly bogus) comment to your issue. The text of your comment
1375 will be sent to our developer mailing list.
1377 @warning{There is no automatic notification of a new patch; you
1378 must add a comment yourself.}
1380 @subsubheading Revisions
1382 As revisions are made in response to comments, successive patch sets
1383 for the same issue can be uploaded by reissuing the git-cl command
1384 with the modified branch checked out.
1386 Sometimes in response to comments on revisions, the best way to
1387 work may require creation of a new branch in git. In order to
1388 associate the new branch with an existing Rietveld issue,
1389 the following command can be used:
1392 git cl issue issue-number
1396 where @code{issue-number} is the number of the existing Rietveld
1399 @subsubheading Resetting git cl
1401 If @command{git cl} becomes confused, you can @qq{reset} it by
1408 @subsubheading Wait for a countdown
1410 Your patch will be available for reviews for the next few hours or
1411 days. Three times a week, patches with no known problems are
1412 gathered into a @qq{patch countdown} and their status changed to
1413 @code{patch-countdown}. The countdown is a 48-hour waiting period
1414 in which any final reviews or complaints should be made.
1416 During the countdown, your patch may be set to
1417 @code{patch-needs_work}, indicating that you should fix something
1418 (or at least discuss why the patch needs no modification). If no
1419 problems are found, the patch will be set to @code{patch-push}.
1421 Once a patch has @code{patch-push}, it should be sent to your
1422 mentor for uploading. If you have git push ability, look at
1423 @ref{Pushing to staging}.
1426 @node Advanced Git procedures
1427 @section Advanced Git procedures
1430 @warning{This section is not necessary for normal contributors;
1431 these commands are presented for information for people interested
1432 in learning more about git.}
1434 It is possible to work with several branches on the same local Git
1435 repository; this is especially useful for translators who may have
1436 to deal with both @code{lilypond/translation} and a stable branch,
1437 e.g. @code{stable/2.12}.
1439 Some Git commands are introduced first, then a workflow with
1440 several Git branches of LilyPond source code is presented.
1445 * Advanced Git concepts::
1446 * Resolving conflicts::
1447 * Reverting all local changes::
1448 * Working with remote branches::
1450 * Applying remote patches::
1451 * Sending and receiving patches via email::
1452 * Cleaning up multiple patches::
1454 * Pushing to staging::
1458 @node Merge conflicts
1459 @subsection Merge conflicts
1461 To be filled in later, and/or moved to a different section. I
1462 just wanted to make sure that I had a stub ready somewhere.
1465 @node Advanced Git concepts
1466 @subsection Advanced Git concepts
1469 A bit of Git vocabulary will be explained below. The following is
1470 only introductory; for a better understanding of Git concepts, you
1471 may wish to read @ref{Other Git documentation}.
1473 The @code{git@tie{}pull@tie{}origin} command above is just a
1474 shortcut for this command:
1477 git pull git://git.sv.gnu.org/lilypond.git/ @var{branch}:origin/@var{branch}
1481 where @code{@var{branch}} is typically @code{master} or
1482 @code{lilypond/translation}; if you do not know or remember, see
1483 @ref{Downloading remote branches} to remember which commands you
1484 issued or which source code you wanted to get.
1486 A @emph{commit} is a set of changes made to the sources; it also
1487 includes the committish of the parent commit, the name and e-mail
1488 of the @emph{author} (the person who wrote the changes), the name
1489 and e-mail of the @emph{committer} (the person who brings these
1490 changes into the Git repository), and a commit message.
1492 A @emph{committish} is the SHA1 checksum of a commit, a number
1493 made of 40 hexadecimal digits, which acts as the internal unique
1494 identifier for this commit. To refer to a particular revision,
1495 don't use vague references like the (approximative) date, simply
1496 copy and paste the committish.
1498 A @emph{branch} is nothing more than a pointer to a particular
1499 commit, which is called the @emph{head} of the branch; when
1500 referring to a branch, one often actually thinks about its head
1501 and the ancestor commits of the head.
1503 Now we will explain the two last commands you used to get the
1504 source code from Git---see @ref{Downloading individual branches}.
1507 git remote add -ft @var{branch} -m @var{branch} \
1508 origin git://git.sv.gnu.org/lilypond.git/
1510 git checkout -b @var{branch} origin/@var{branch}
1513 The @command{git@tie{}remote} has created a branch called
1514 @code{origin/@var{branch}} in your local Git repository. As this
1515 branch is a copy of the remote branch web from git.sv.gnu.org
1516 LilyPond repository, it is called a @emph{remote branch}, and is
1517 meant to track the changes on the branch from git.sv.gnu.org: it
1518 will be updated every time you run
1519 @command{git@tie{}pull@tie{}origin} or
1520 @command{git@tie{}fetch@tie{}origin}.
1522 The @command{git@tie{}checkout} command has created a branch named
1523 @code{@var{branch}}. At the beginning, this branch is identical
1524 to @code{origin/@var{branch}}, but it will differ as soon as you
1525 make changes, e.g. adding newly translated pages or editing some
1526 documentation or code source file. Whenever you pull, you merge
1527 the changes from @code{origin/@var{branch}} and
1528 @code{@var{branch}} since the last pulling. If you do not have
1529 push (i.e. @qq{write}) access on git.sv.gnu.org, your
1530 @code{@var{branch}} will always differ from
1531 @code{origin/@var{branch}}. In this case, remember that other
1532 people working like you with the remote branch @code{@var{branch}}
1533 of git://git.sv.gnu.org/lilypond.git/ (called
1534 @code{origin/@var{branch}} on your local repository) know nothing
1535 about your own @code{@var{branch}}: this means that whenever you
1536 use a committish or make a patch, others expect you to take the
1537 latest commit of @code{origin/@var{branch}} as a reference.
1539 Finally, please remember to read the man page of every Git command
1540 you will find in this manual in case you want to discover
1541 alternate methods or just understand how it works.
1544 @node Resolving conflicts
1545 @subsection Resolving conflicts
1548 Occasionally an update may result in conflicts -- this happens
1549 when you and somebody else have modified the same part of the same
1550 file and git cannot figure out how to merge the two versions
1551 together. When this happens, you must manually merge the two
1554 If you need some documentation to understand and resolve
1555 conflicts, see paragraphs @emph{How conflicts are presented} and
1556 @emph{How to resolve conflicts} in @command{git merge} man page.
1558 If all else fails, you can follow the instructions in
1559 @ref{Reverting all local changes}. Be aware that this eliminates
1560 any changes you have made!
1563 @node Reverting all local changes
1564 @subsection Reverting all local changes
1566 Sometimes git will become hopelessly confused, and you just want
1567 to get back to a known, stable state. This command destroys any
1568 local changes you have made in the currently checked-out branch,
1569 but at least you get back to the current online version:
1572 git reset --hard origin/master
1576 @node Working with remote branches
1577 @subsection Working with remote branches
1580 @subsubheading Fetching new branches from git.sv.gnu.org
1582 To fetch and check out a new branch named @code{@var{branch}} on
1583 git.sv.gnu.org, run from top of the Git repository
1586 git config --add remote.origin.fetch \
1587 +refs/heads/@var{branch}:refs/remotes/origin/@var{branch}
1589 git checkout --track -b @var{branch} origin/@var{branch}
1592 After this, you can pull @code{@var{branch}} from git.sv.gnu.org
1599 Note that this command generally fetches all branches you added
1600 with @command{git@tie{}remote@tie{}add} (when you initialized the
1601 repository) or @command{git@tie{}config@tie{}--add}, i.e. it
1602 updates all remote branches from remote @code{origin}, then it
1603 merges the remote branch tracked by the current branch into the
1604 current branch. For example, if your current branch is
1605 @code{master}, @code{origin/master} will be merged into
1609 @subsubheading Local clones, or having several working trees
1611 If you play with several Git branches, e.g. @code{master},
1612 @code{lilypond/translation}, @code{stable/2.12}), you may want to
1613 have one source and build tree for each branch; this is possible
1614 with subdirectories of your local Git repository, used as local
1615 cloned subrepositories. To create a local clone for the branch
1616 named @code{@var{branch}}, run
1619 git checkout @var{branch}
1620 git clone -lsn . @var{subdir}
1625 Note that @code{@var{subdir}} must be a directory name which does
1626 not already exist. In @code{@var{subdir}}, you can use all Git
1627 commands to browse revisions history, commit and uncommit changes;
1628 to update the cloned subrepository with changes made on the main
1629 repository, cd into @code{@var{subdir}} and run
1630 @command{git@tie{}pull}; to send changes made on the subrepository
1631 back to the main repository, run @command{git@tie{}push} from
1632 @code{@var{subdir}}. Note that only one branch (the currently
1633 checked out branch) is created in the subrepository by default; it
1634 is possible to have several branches in a subrepository and do
1635 usual operations (checkout, merge, create, delete...) on these
1636 branches, but this possibility is not detailed here.
1638 When you push @code{@var{branch}} from @code{@var{subdir}} to the
1639 main repository, and @code{@var{branch}} is checked out in the
1640 main repository, you must save uncommitted changes (see
1641 @command{git@tie{}stash}) and do
1642 @command{git@tie{}reset@tie{}--hard} in the main repository in
1643 order to apply pushed changes in the working tree of the main
1651 The commands above don't only bring you the latest version of the
1652 sources, but also the full history of revisions (revisions, also
1653 called commits, are changes made to the sources), stored in the
1654 @file{.git} directory. You can browse this history with
1657 git log # only shows the logs (author, committish and commit message)
1658 git log -p # also shows diffs
1659 gitk # shows history graphically
1662 @warning{The @code{gitk} command may require a separate
1663 @code{gitk} package, available in the appropriate distribution's
1667 @node Applying remote patches
1668 @subsection Applying remote patches
1671 TODO: Explain how to determine if a patch was created with
1672 @code{git@tie{}format-patch}.
1674 Well-formed git patches created with @code{git@tie{}format-patch}
1675 should be committed with the following command:
1681 Patches created without @code{git@tie{}format-patch} can be
1682 applied in two steps. The first step is to apply the patch to the
1686 git apply @var{patch}
1690 The second step is to commit the changes and give credit to the
1691 author of the patch. This can be done with the following command:
1694 git commit -a --author="@var{John Smith} <@var{john@@example.com}>"
1698 @node Sending and receiving patches via email
1699 @subsection Sending and receiving patches via email
1702 The default @code{x-diff} MIME type associated with patch files
1703 (i.e., files whose name ends in @code{.patch}) means that the
1704 encoding of line endings may be changed from UNIX to DOS format
1705 when they are sent as attachments. Attempting to apply such an
1706 inadvertently altered patch will cause git to fail with a message
1707 about @q{whitespace errors}.
1709 The solution to such problems is surprisingly simple---just change
1710 the default file extension of patches generated by git to end in
1711 @code{.txt}, for example:
1714 git config format.suffix '.patch.txt'
1717 This should cause email programs to apply the correct base64
1718 encoding to attached patches.
1720 If you receive a patch with DOS instead of UNIX line-endings, it
1721 can be converted back using the @code{dos2unix} utility.
1723 Lots of useful information on email complications with patches is
1724 provided on the Wine wiki at
1725 @uref{http://wiki.winehq.org/GitWine}.
1728 @node Cleaning up multiple patches
1729 @subsection Cleaning up multiple patches
1731 If you have been developing on your own branch for a while, you
1732 may have more commmits than is really sensible. To revise your
1733 work and condense commits, use:
1736 git rebase origin/master
1737 git rebase -i origin/master
1740 @warning{Be a bit cautious -- if you completely remove commits
1741 during the interactive session, you will... err... completely
1742 remove those commits.}
1746 @subsection Commit access
1748 Most contributors are not able to commit patches directly to the
1749 main repository---only members of the LilyPond development team
1750 have @emph{commit access}. If you are a contributor and are
1751 interested in joining the development team, contact the Project
1752 Manager through the mailing list
1753 (@email{lilypond-devel@@gnu.org}). Generally, only contributors
1754 who have already provided a number of patches which have been
1755 pushed to the main repository will be considered for membership.
1757 If you have been approved by the Project Manager, use the
1758 following procedure to obtain commit access:
1762 If you don't already have one, set up a Savannah user account at
1763 @uref{https://savannah.gnu.org/account/register.php}. If your web
1764 browser responds with an @qq{untrusted connection} message when
1765 you visit the link, follow the steps for including the CAcert root
1766 certificate in your browser, given at
1767 @uref{http://savannah.gnu.org/tls/tutorial/}.
1769 @warning{Savannah will silently put your username in lower-case --
1770 do not try to use capital letters.}
1774 After registering, if you are not logged in automatically, login
1775 at @uref{https://savannah.gnu.org/account/login.php}---this should
1776 take you to your @qq{my} page
1777 (@uref{https://savannah.gnu.org/my/}).
1781 Click on the @qq{My Groups} link to access the @qq{My Group
1782 Membership} page. From there, find the @qq{Request for Inclusion}
1783 box and search for @qq{LilyPond}. Among the search results, check
1784 the box labeled @qq{GNU LilyPond Music Typesetter} and write a
1785 brief (required) message for the Project Manager (@qq{Hey it's
1786 me!} should be fine).
1788 Note that you will not have commit access until the Project
1789 Manager activates your membership. Once your membership is
1790 activated, LilyPond should appear under the heading @qq{Groups I'm
1791 Contributor of} on your @qq{My Group Membership} page.
1795 Generate an SSH @q{rsa} key pair. Enter the following at the
1802 When prompted for a location to save the key, press <ENTER> to
1803 accept the default location (@file{~/.ssh/id_rsa}).
1805 Next you are asked to enter an optional passphrase. On most
1806 systems, if you use a passphrase, you will likely be prompted for
1807 it every time you use @command{git@tie{}push} or
1808 @command{git@tie{}pull}. You may prefer this since it can protect
1809 you from your own mistakes (like pushing when you mean to pull),
1810 though you may find it tedious to keep re-entering it.
1812 You can change/enable/disable your passphrase at any time with:
1815 ssh-keygen -f ~/.ssh/id_rsa -p
1818 Note that the GNOME desktop has a feature which stores your
1819 passphrase for you for an entire GNOME session. If you use a
1820 passphrase to @qq{protect you from yourself}, you will want to
1821 disable this feature, since you'll only be prompted once. Run the
1822 following command, then logout of GNOME and log back in:
1825 gconftool-2 --set -t bool \
1826 /apps/gnome-keyring/daemon-components/ssh false
1829 After setting up your passphrase, your private key is saved as
1830 @file{~/.ssh/id_rsa} and your public key is saved as
1831 @file{~/.ssh/id_rsa.pub}.
1835 Register your public SSH @q{rsa} key with Savannah. From the
1836 @qq{My Account Configuration} page, click on @qq{Edit SSH Keys},
1837 then paste the contents of your @file{~/.ssh/id_rsa.pub} file into
1838 one of the @qq{Authorized keys} text fields, and click
1841 Savannah should respond with something like:
1844 Success: Key #1 seen Keys registered
1849 Configure Git to use the SSH protocol (instead of the GIT
1850 protocol). From your local Git repository, enter:
1853 git config remote.origin.url \
1854 ssh://@var{user}@@git.sv.gnu.org/srv/git/lilypond.git
1858 replacing @var{user} with your Savannah username.
1862 After your membership has been activated and you've configured Git
1863 to use SSH, test the connection with:
1869 SSH should issue the following warning:
1872 The authenticity of host 'git.sv.gnu.org (140.186.70.72)' can't
1874 RSA key fingerprint is
1875 80:5a:b0:0c:ec:93:66:29:49:7e:04:2b:fd:ba:2c:d5.
1876 Are you sure you want to continue connecting (yes/no)?
1879 Make sure the RSA key fingerprint displayed matches the one above.
1880 If it doesn't, respond @qq{no} and check that you configured Git
1881 properly in the previous step. If it does match, respond
1882 @qq{yes}. SSH should then issue another warning:
1885 Warning: Permanently added 'git.sv.gnu.org,140.186.70.72' (RSA) to
1886 the list of known hosts.
1889 The list of known hosts is stored in the file
1890 @file{~/.ssh/known_hosts}.
1892 At this point, you are prompted for your passphrase if you have
1893 one, then Git will attempt a pull.
1895 If @command{git@tie{}pull@tie{}--verbose} fails, you should see
1896 error messages like these:
1899 Permission denied (publickey).
1900 fatal: The remote end hung up unexpectedly
1903 If you get the above error, you may have made a mistake when
1904 registering your SSH key at Savannah. If the key is properly
1905 registered, you probably just need to wait for the Savannah server
1906 to activate it. It usually takes a few minutes for the key to be
1907 active after registering it, but if it still doesn't work after an
1908 hour, ask for help on the mailing list.
1910 If @command{git@tie{}pull@tie{}--verbose} succeeds, the output
1911 will include a @q{From} line that shows @q{ssh} as the protocol:
1914 From ssh://git.sv.gnu.org/srv/git/lilypond
1917 If the protocol shown is not @q{ssh}, check that you configured
1918 Git properly in the previous step.
1922 Test your commit access with a dry run:
1924 @warning{Do not push directly to master; instead, push to staging.
1925 See @ref{Pushing to staging}.}
1928 git push --dry-run --verbose
1931 Note that recent versions of Git (Git 1.6.3 or later) will issue a
1932 big warning if the above command is used. The simplest solution
1933 is to tell Git to push all matching branches by default:
1936 git config push.default matching
1940 Then @code{git@tie{}push} should work as before. For more
1941 details, consult the @code{git@tie{}push} man page.
1945 Repeat the steps from generating an RSA key through to testing
1946 your commit access, for each machine from which you will be
1947 making commits, or you may simply copy the files from your
1948 local @file{~/.ssh} folder to the same folder on the other
1953 @subsubheading Technical details
1957 On Firefox, to view or remove the CAcert root certificate, go to:
1958 Edit > Preferences > Advanced > Encryption > View Certificates >
1959 Authorities > Certificate Name > Root CA > CA Cert Signing
1963 The @command{git@tie{}config} commands above should modify your
1964 local repository's @file{.git/config} file. These lines:
1968 url = git://git.sv.gnu.org/lilypond.git/
1972 should now be changed to:
1976 url = ssh://@var{user}@@git.sv.gnu.org/srv/git/lilypond.git
1980 where @var{user} is your login name on Savannah.
1984 @command{git@tie{}config@tie{}push.default@tie{}matching} command
1985 should add these lines to @file{.git/config}:
1994 Encryption protocols, including ssh, generally do not permit packet
1995 fragmentation to avoid introducing a point of insecurity. This
1996 means that the maximum packet size must not exceed the smallest
1997 MTU (Maximum Transmission Unit) set in the routers along the path.
1998 This smallest MTU is determined by a procedure during call set-up
1999 which relies on the transmission over the path of ICMP packets.
2000 If any of the routers in the path block ICMP packets this mechanism
2001 fails, resulting in the possibility of packets being transmitted
2002 which exceed the MTU of one of the routers. If this happens the
2003 packet is discarded, causing the ssh session to hang, timeout or
2004 terminate with the error message
2007 ssh: connect to host <host ip addr> port 22: Bad file number
2008 fatal: The remote end hung up unexpectedly
2011 depending on precisely when in the proceedings the first large
2012 packet is transmitted. Most routers on the internet have MTU
2013 set to 1500, but routers installed in homes to connect via
2014 broadband may use a slightly smaller MTU for efficient transmission
2015 over ATM. If this problem is encountered a possible work-around is
2016 to set the MTU in the local router to 1500.
2019 @node Pushing to staging
2020 @subsection Pushing to staging
2022 Do not push directly to the git @code{master} branch. Instead,
2023 push to @code{staging}.
2025 You will not see your patch on @code{origin/master} until some
2026 automatic tests have been run. These tests are run every couple
2027 of hours; please wait at least 12 hours before wondering if your
2028 patch has been lost. Note that you can check the commits on
2029 @code{origin/staging} by looking at the git web interface on
2032 @subsubheading If your work is in a patch file
2034 Assuming that your patch is in a file called
2035 @file{0001-my-patch.patch}, and you are currently on git master,
2039 git checkout staging
2041 git am 0001-my-patch.patch
2043 git push origin staging
2047 @warning{Do not skip the @command{gitk} step; a quick 5-second
2048 check of the visual history can save a great deal of frustration
2049 later on. You should only see that @command{staging} is only 1
2050 commit ahead of @code{origin/staging}.}
2052 @subsubheading If your work is in a branch
2054 If you are working on branches and your work in is
2055 @code{my_branch_name}, then do:
2058 git checkout staging
2060 git merge my_branch_name
2062 git push origin staging
2065 @warning{Do not skip the @command{gitk} step; a quick 5-second
2066 check of the visual history can save a great deal of frustration
2067 later on. You should see that @code{staging} is only ahead of
2068 @code{origin/staging} by the commits from your branch.}
2072 @node Git on Windows
2073 @section Git on Windows
2075 @warning{We heavily recommend that development be done with our
2076 virtual machine @ref{Lilydev}.}
2078 @c Some of this may duplicate stuff in other sections
2079 @c But it is probably best for windows users to have it all together
2080 @c If necessary, clear this up later -td
2082 TODO: Decide what to do with this... Pare it down? Move
2083 paragraphs next to analogous Unix instructions? -mp
2085 @subsection Background to nomenclature
2087 Git is a system for tracking the changes made to source files by a
2088 distributed set of editors. It is designed to work without a
2089 master repository, but we have chosen to have a master repository
2090 for LilyPond files. Editors hold a local copy of the master
2091 repository together with any changes they have made locally.
2092 Local changes are held in a local @q{branch}, of which there may
2093 be several, but these instructions assume you are using just one.
2094 The files visible in the local repository always correspond to
2095 those on the currently @q{checked out} local branch.
2097 Files are edited on a local branch, and in that state the changes
2098 are said to be @q{unstaged}. When editing is complete, the
2099 changes are moved to being @q{staged for commit}, and finally the
2100 changes are @q{committed} to the local branch. Once committed,
2101 the changes (called a @q{commit}) are given a unique 40-digit
2102 hexadecimal reference number called the @q{Committish} or @q{SHA1
2103 ID} which identifies the commit to Git. Such committed changes
2104 can be sent to the master repository by @q{pushing} them (if you
2105 have write permission) or by sending them by email to someone who
2106 has, either as a complete file or as a @q{diff} or @q{patch}
2107 (which send just the differences from the master repository).
2109 @subsection Installing git
2112 @uref{http://code.google.com/p/msysgit/downloads/list} (note, not
2113 msysGit, which is for Git developers and not PortableGit, which is
2114 not a full git installation) and install it.
2116 Note that most users will not need to install SSH. That is not
2117 required until you have been granted direct push permissions to
2118 the master git repository.
2120 Start Git by clicking on the desktop icon. This will bring up a
2121 command line bash shell. This may be unfamiliar to Windows users.
2122 If so, follow these instructions carefully. Commands are entered
2123 at a $ prompt and are terminated by keying a newline.
2125 @subsection Initialising Git
2127 Decide where you wish to place your local Git repository, creating
2128 the folders in Windows as necessary. Here we call the folder to
2129 contain the repository @code{[path]/Git}, but if you intend using
2130 Git for other projects a directory name like @code{lilypond-git}
2131 might be better. You will need to have space for around
2134 Start the Git bash shell by clicking on the desk-top icon
2135 installed with Git and type
2141 to position the shell at your new Git repository.
2143 Note: if [path] contains folders with names containing spaces use
2155 to initialize your Git repository.
2157 Then type (all on one line; the shell will wrap automatically)
2160 git remote add -ft master origin git://git.sv.gnu.org/lilypond.git
2163 to download the lilypond master files.
2165 @warning{Be patient! Even on a broadband connection this can take
2166 10 minutes or more. Wait for lots of [new tag] messages and the $
2169 We now need to generate a local copy of the downloaded files in a
2170 new local branch. Your local branch needs to have a name. It is
2171 usual to call it @q{master} and we shall do that here.
2176 git checkout -b master origin/master
2179 This creates a second branch called @q{master}. You will see two
2180 warnings (ignore these), and a message advising you that your
2181 local branch @q{master} has been set up to track the remote
2182 branch. You now have two branches, a local branch called
2183 @q{master}, and a tracking branch called @q{origin/master}, which
2184 is a shortened form of @q{remotes/origin/master}.
2186 Return to Windows Explorer and look in your Git repository. You
2187 should see lots of folders. For example, the LilyPond
2188 documentation can be found in [path]/Git/Documentation/.
2190 The Git bash shell is terminated by typing @code{exit} or by
2191 clicking on the usual Windows close-window widget.
2195 Almost all subsequent work will use the Git Graphical User
2196 Interface, which avoids having to type command line commands. To
2197 start Git GUI first start the Git bash shell by clicking on the
2198 desktop icon, and type
2205 The Git GUI will open in a new window. It contains four panels
2206 and 7 pull-down menus. At this stage do not use any of the
2207 commands under Branch, Commit, Merge or Remote. These will be
2210 The top panel on the left contains the names of files which you
2211 are in the process of editing (Unstaged Changes), and the lower
2212 panel on the left contains the names of files you have finished
2213 editing and have staged ready for committing (Staged Changes). At
2214 present, these panels will be empty as you have not yet made any
2215 changes to any file. After a file has been edited and saved the
2216 top panel on the right will display the differences between the
2217 edited file selected in one of the panels on the left and the last
2218 version committed on the current branch.
2220 The panel at bottom right is used to enter a descriptive message
2221 about the change before committing it.
2223 The Git GUI is terminated by entering CNTL-Q while it is the
2224 active window or by clicking on the usual Windows close-window
2227 @subsection Personalising your local git repository
2229 Open the Git GUI, click on
2235 and enter your name and email address in the left-hand (Git
2236 Repository) panel. Leave everything else unchanged and save it.
2238 Note that Windows users must leave the default setting for line
2239 endings unchanged. All files in a git repository must have lines
2240 terminated by just a LF, as this is required for Merge to work,
2241 but Windows files are terminated by CRLF by default. The git
2242 default setting causes the line endings of files in a Windows git
2243 repository to be flipped automatically between LF and CRLF as
2244 required. This enables files to be edited by any Windows editor
2245 without causing problems in the git repository.
2247 @subsection Checking out a branch
2249 At this stage you have two branches in your local repository,
2250 both identical. To see them click on
2256 You should have one local branch called @q{master} and one
2257 tracking branch called @q{origin/master}. The latter is your
2258 local copy of the @q{remotes/origin/master} branch in the master
2259 LilyPond repository. The local @q{master} branch is where you
2260 will make your local changes.
2262 When a particular branch is selected, i.e., checked out, the files
2263 visible in your repository are changed to reflect the state of the
2264 files on that branch.
2266 @subsection Updating files from @q{remote/origin/master}
2268 Before starting the editing of a file, ensure your local
2269 repository contains the latest version of the files in the remote
2270 repository by first clicking
2273 Remote -> Fetch from -> origin
2279 This will place the latest version of every file, including all
2280 the changes made by others, into the @q{origin/master} branch of
2281 the tracking branches in your git repository. You can see these
2282 files by checking out this branch, but you must @emph{never} edit
2283 any files while this branch is checked out. Check out your local
2284 @q{master} branch again.
2286 You then need to merge these fetched files into your local
2287 @q{master} branch by clicking on
2290 Merge -> Local Merge
2294 and if necessary select the local @q{master} branch.
2296 Note that a merge cannot be completed if you have made any local
2297 changes which have not yet been committed.
2299 This merge will update all the files in the @q{master} branch to
2300 reflect the current state of the @q{origin/master} branch. If any
2301 of the changes conflict with changes you have made yourself
2302 recently you will be notified of the conflict (see below).
2304 @subsection Editing files
2306 First ensure your @q{master} branch is checked out, then simply
2307 edit the files in your local Git repository with your favourite
2308 editor and save them back there. If any file contains non-ASCII
2309 characters ensure you save it in UTF-8 format. Git will detect
2310 any changes whenever you restart Git GUI and the file names will
2311 then be listed in the Unstaged Changes panel. Or you can click
2312 the Rescan button to refresh the panel contents at any time. You
2313 may break off and resume editing any time.
2315 The changes you have made may be displayed in diff form in the top
2316 right-hand panel of Git GUI by clicking on the file name shown in
2317 one of the left panels.
2319 When your editing is complete, move the files from being Unstaged
2320 to Staged by clicking the document symbol to the left of each
2321 name. If you change your mind it can be moved back by clicking on
2322 the ticked box to the left of the name.
2324 Finally the changes you have made may be committed to your
2325 @q{master} branch by entering a brief message in the Commit
2326 Message box and clicking the Commit button.
2328 If you wish to amend your changes after a commit has been made,
2329 the original version and the changes you made in that commit may
2330 be recovered by selecting
2333 Commit -> Amend Last Commit
2337 or by checking the Amend Last Commit radio button at bottom right.
2338 This will return the changes to the Staged state, so further
2339 editing made be carried out within that commit. This must only be
2340 done @emph{before} the changes have been Pushed or sent to your
2341 mentor for Pushing - after that it is too late and corrections
2342 have to be made as a separate commit.
2345 @subsection Sending changes to @q{remotes/origin/master}
2347 If you do not have write access to @q{remotes/origin/master} you
2348 will need to send your changes by email to someone who does.
2350 First you need to create a diff or patch file containing your
2351 changes. To create this, the file must first be committed. Then
2352 terminate the Git GUI. In the git bash shell first cd to your Git
2359 if necessary, then produce the patch with
2362 git format-patch origin
2365 This will create a patch file for all the locally committed files
2366 which differ from @q{origin/master}. The patch file can be found
2367 in [path]/Git and will have a name formed from the commit message.
2369 @subsection Resolving merge conflicts
2371 As soon as you have committed a changed file your local
2372 @code{master} branch has diverged from @code{origin/master}, and
2373 will remain diverged until your changes have been committed in
2374 @code{remotes/origin/master} and Fetched back into your
2375 @code{origin/master} branch. Similarly, if a new commit has been
2376 made to @code{remotes/origin/master} by someone else and Fetched,
2377 your local @code{master} branch is divergent. You can detect a
2378 divergent branch by clicking on
2381 Repository -> Visualise all branch history
2384 This opens up a very useful new window called @q{gitk}. Use this
2385 to browse all the commits made by yourself and others.
2387 If the diagram at top left of the resulting window does not show
2388 your @code{master} tag on the same node as the
2389 @code{remotes/origin/master} tag your branch has diverged from
2390 @code{origin/master}. This is quite normal if files you have
2391 modified yourself have not yet been Pushed to
2392 @code{remotes/origin/master} and Fetched, or if files modified and
2393 committed by others have been Fetched since you last Merged
2394 @code{origin/master} into your local @code{master} branch.
2396 If a file being merged from @code{origin/master} differs from one
2397 you have modified in a way that cannot be resolved automatically
2398 by git, Merge will report a Conflict which you must resolve by
2399 editing the file to create the version you wish to keep.
2401 This could happen if the person updating
2402 @code{remotes/origin/master} for you has added some changes of his
2403 own before committing your changes to
2404 @code{remotes/origin/master}, or if someone else has changed the
2405 same file since you last fetched the file from
2406 @code{remotes/origin/master}.
2408 Open the file in your editor and look for sections which are
2411 [to be completed when I next have a merge conflict to be sure I
2412 give the right instructions -td]
2415 @subsection Other actions
2417 The instructions above describe the simplest way of using git on
2418 Windows. Other git facilities which may usefully supplement these
2422 @item Using multiple local branches (Create, Rename, Delete)
2423 @item Resetting branches
2424 @item Cherry-picking commits
2425 @item Pushing commits to @w{remote/origin/master}
2426 @item Using gitk to review history
2429 Once familiarity with using git on Windows has been gained the
2430 standard git manuals can be used to learn about these.
2433 @node Repository directory structure
2434 @section Repository directory structure
2437 @c TODO: integrate the roadmap better
2438 @verbatiminclude ROADMAP
2441 @node Other Git documentation
2442 @section Other Git documentation
2446 Official git man pages:
2447 @uref{http://www.kernel.org/pub/software/scm/git/docs/}
2450 More in-depth tutorials: @uref{http://git-scm.com/documentation}
2453 Book about git: @uref{http://progit.org/,Pro Git}
2456 Github help: @uref{http://help.github.com/}
2457 (very highly recommended by Graham)