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 There is a separate repository for general administrative scripts,
530 as well as pictures and media files for the website. People
531 interested in working on the website should download this
532 repository, and set their @code{$LILYPOND_WEB_MEDIA_GIT}
533 environment variable to point to that repository.
536 @uref{https://github.com/gperciva/lilypond-extra}
539 To configure an environment variable in bash (the default for most
540 Linux distributions),
543 export LILYPOND_WEB_MEDIA_GIT=$HOME/dir/of/lilypond-extra/
547 There are a few other repositories floating around, which will
548 hopefully be documented in the near future.
551 @node Downloading remote branches
552 @subsection Downloading remote branches
554 @warning{contains obsolete + misleading info}
557 * Organization of remote branches::
558 * LilyPond repository sources::
559 * Downloading individual branches::
560 * Downloading all remote branches::
565 @node Organization of remote branches
566 @unnumberedsubsubsec Organization of remote branches
569 The main LilyPond repository is organized into @emph{branches} to
570 facilitate development. These are often called @emph{remote}
571 branches to distinguish them from @emph{local} branches you might
572 create yourself (see @ref{Using local branches}).
574 The @code{master} branch contains all the source files used to
575 build LilyPond, which includes the program itself (both stable and
576 development releases), the documentation (and its translations),
577 and the website. Generally, the @code{master} branch is expected
578 to compile successfully.
580 The @code{lilypond/translation} branch is a side branch that
581 allows translators to work without needing to worry about
582 compilation problems. Periodically, the Translation Meister
583 (after verifying that it doesn't break compilation), will
584 @emph{merge} this branch back into @code{master} to incorporate
585 recent translations. Similarly, the @code{master} branch is
586 usually merged into the @code{lilypond/translation} branch after
587 significant changes to the English documentation. See
588 @ref{Translating the documentation} for details.
591 @node LilyPond repository sources
592 @unnumberedsubsubsec LilyPond repository sources
595 The recommended source for downloading a copy of the main
599 git://git.sv.gnu.org/lilypond.git
602 However, if your internet router filters out connections using the
603 GIT protocol, or if you experience difficulty connecting via GIT,
604 you can try these other sources:
607 ssh://git.sv.gnu.org/srv/git/lilypond.git
608 http://git.sv.gnu.org/r/lilypond.git
611 The SSH protocol can only be used if your system is properly set
612 up to use it. Also, the HTTP protocol is slowest, so it should
613 only be used as a last resort.
616 @node Downloading individual branches
617 @unnumberedsubsubsec Downloading individual branches
619 @warning{obsolete, should be deleted!}
622 Once you have initialized an empty Git repository on your system
623 (see @ref{Initializing a repository}), you can download a remote
624 branch into it. Make sure you know which branch you want to start
627 To download the @code{master} branch, enter the following:
630 git remote add -ft master -m master \
631 origin git://git.sv.gnu.org/lilypond.git/
634 To download the @code{lilypond/translation} branch, enter:
637 git remote add -ft lilypond/translation -m \
638 lilypond/translation origin git://git.sv.gnu.org/lilypond.git/
641 The @command{git@tie{}remote@tie{}add} process could take up to
642 ten minutes, depending on the speed of your connection. The
643 output will be something like this:
647 remote: Counting objects: 235967, done.
648 remote: Compressing objects: 100% (42721/42721), done.
649 remote: Total 235967 (delta 195098), reused 233311 (delta 192772)
650 Receiving objects: 100% (235967/235967), 68.37 MiB | 479 KiB/s, done.
651 Resolving deltas: 100% (195098/195098), done.
652 From git://git.sv.gnu.org/lilypond
653 * [new branch] master -> origin/master
654 From git://git.sv.gnu.org/lilypond
655 * [new tag] flower/1.0.1 -> flower/1.0.1
656 * [new tag] flower/1.0.10 -> flower/1.0.10
658 * [new tag] release/2.9.6 -> release/2.9.6
659 * [new tag] release/2.9.7 -> release/2.9.7
662 When @command{git@tie{}remote@tie{}add} is finished, the remote
663 branch should be downloaded into your repository---though not yet
664 in a form that you can use. In order to browse the source code
665 files, you need to @emph{create} and @emph{checkout} your own
666 local branch. In this case, however, it is easier to have Git
667 create the branch automatically by using the @command{checkout}
668 command on a non-existent branch. Enter the following:
671 git checkout -b @var{branch} origin/@var{branch}
675 where @code{@var{branch}} is the name of your tracking branch,
676 either @code{master} or @code{lilypond/translation}.
678 Git will issue some warnings; this is normal:
681 warning: You appear to be on a branch yet to be born.
682 warning: Forcing checkout of origin/master.
683 Branch master set up to track remote branch master from origin.
687 By now the source files should be accessible---you should be able
688 to edit any files in the @file{lilypond-git/} directory using a
689 text editor of your choice. But don't start just yet! Before
690 editing any source files, learn how to keep your changes organized
691 and prevent problems later---read @ref{Basic Git procedures}.
693 @subsubheading Technical Details
695 The @command{git@tie{}remote@tie{}add} command should add some
696 lines to your local repository's @file{.git/config} file:
700 url = git://git.sv.gnu.org/lilypond.git/
701 fetch = +refs/heads/master:refs/remotes/origin/master
705 @node Downloading all remote branches
706 @unnumberedsubsubsec Downloading all remote branches
709 To download all remote branches at once, you can @command{clone}
710 the entire repository:
713 git clone git://git.sv.gnu.org/lilypond.git
718 @unnumberedsubsubsec Other branches
720 Most contributors will never need to touch the other branches. If
721 you wish to do so, you will need more familiarity with Git; please
722 see @ref{Other Git documentation}.
725 @item @code{dev/XYZ}:
726 These branches are for individual developers. They store code
727 which is not yet stable enough to be added to the @code{master}
730 @item @code{stable/XYZ}:
731 The branches are kept for archival reasons.
735 Another item of interest might be the Grand Unified Builder, our
736 cross-platform building tool. Since it is used by projects as
737 well, it is not stored in our gub repository. For more info, see
738 @uref{http://lilypond.org/gub}. The git location is
739 @uref{http://github.com/janneke/gub}.
742 @node Basic Git procedures
743 @section Basic Git procedures
747 * The Git contributor's cycle::
748 * Pulling and rebasing::
749 * Using local branches::
750 * Commits and patches::
754 @node The Git contributor's cycle
755 @subsection The Git contributor's cycle
758 Here is a simplified view of the contribution process on Git:
762 Update your local repository by @emph{pulling} the most recent
763 updates from the remote repository.
766 Edit source files within your local repository's @emph{working
770 @emph{Commit} the changes you've made to a local @emph{branch}.
773 Generate a @emph{patch} to share your changes with the developers.
777 @node Pulling and rebasing
778 @subsection Pulling and rebasing
781 When developers push new patches to the @code{git.sv.gnu.org}
782 repository, your local repository is @strong{not} automatically
783 updated. It is important to keep your repository up-to-date by
784 periodically @emph{pulling} the most recent @emph{commits} from
785 the remote branch. Developers expect patches to be as current as
786 possible, since outdated patches require extra work before they
789 Occasionally you may need to rework some of your own modifications
790 to match changes made to the remote branch (see @ref{Resolving
791 conflicts}), and it's considerably easier to rework things
792 incrementally. If you don't update your repository along the way,
793 you may have to spend a lot of time resolving branch conflicts and
794 reconfiguring much of the work you've already done.
796 Fortunately, Git is able to resolve certain types of branch
797 conflicts automatically with a process called @emph{rebasing}.
798 When rebasing, Git tries to modify your old commits so they appear
799 as new commits (based on the latest updates). For a more involved
800 explanation, see the @command{git-rebase} man page.
802 To pull without rebasing (recommended for translators), use the
806 git pull # recommended for translators
809 If you're tracking the remote @code{master} branch, you should add
810 the @option{-r} option (short for @option{--rebase}) to keep commits
811 on your local branch current:
814 git pull -r # use with caution when translating
817 If you don't edit translated documentation and don't want to type
818 @option{-r} every time, configure the master branch to rebase by
819 default with this command:
822 git config branch.master.rebase true
825 If pull fails because of a message like
828 error: Your local changes to 'Documentation/learning/tutorial.itely'
829 would be overwritten by merge. Aborting.
836 Documentation/learning/tutorial.itely: needs update
837 refusing to pull with rebase: your working tree is not up-to-date
841 it means that you have modified some files in you working tree
842 without committing changes (see @ref{Commits and patches}); you
843 can use the @command{git@tie{}stash} command to work around this:
846 git stash # save uncommitted changes
847 git pull -r # pull using rebase (translators omit "-r")
848 git stash pop # reapply previously saved changes
851 Note that @command{git@tie{}stash@tie{}pop} will try to apply a
852 patch, and this may create a conflict. If this happens, see
853 @ref{Resolving conflicts}.
855 TODO: I think the next paragraph is confusing. Perhaps prepare
856 the reader for new terms `committish' and `head'? -mp
858 @warning{translators and documentation editors, if you have
859 changed committishes in the head of translated files using commits
860 you have not yet pushed to @code{git.sv.gnu.org}, please do not
861 rebase. If you want to avoid wondering whether you should rebase
862 each time you pull, please always use committishes from master
863 and/or lilypond/translation branch on @code{git.sv.gnu.org}, which
864 in particular implies that you must push your changes to
865 documentation except committishes updates (possibly after having
866 rebased), then update the committishes and push them.}
868 TODO: when committishes automatic conditional update have been
869 tested and documented, append the following to the warning above:
870 Note that using update-committishes make target generally touches
873 @subsubheading Technical details
875 The @command{git@tie{}config} command mentioned above adds the
876 line @code{rebase = true} to the master branch in your local
877 repository's @file{.git/config} file:
882 merge = refs/heads/master
887 @node Using local branches
888 @subsection Using local branches
892 * Creating and removing branches::
893 * Listing branches and remotes::
894 * Checking out branches::
899 @node Creating and removing branches
900 @unnumberedsubsubsec Creating and removing branches
903 Local branches are useful when you're working on several different
904 projects concurrently. To create a new branch, enter:
907 git branch @var{name}
910 To delete a branch, enter:
913 git branch -d @var{name}
916 Git will ask you for confirmation if it sees that data would be
917 lost by deleting the branch. Use @option{-D} instead of @option{-d}
918 to bypass this. Note that you cannot delete a branch if it is
919 currently checked out.
922 @node Listing branches and remotes
923 @unnumberedsubsubsec Listing branches and remotes
925 You can get the exact path or URL of all remote branches by
932 To list Git branches on your local repositories, run
935 git branch # list local branches only
936 git branch -r # list remote branches
937 git branch -a # list all branches
941 @node Checking out branches
942 @unnumberedsubsubsec Checking out branches
944 To know the currently checked out branch, i.e. the branch whose
945 source files are present in your working tree, read the first line
953 The currently checked out branch is also marked with an asterisk
954 in the output of @command{git branch}.
956 You can check out another branch @code{@var{other_branch}}, i.e.
957 check out @code{@var{other_branch}} to the working tree, by
961 git checkout @var{other_branch}
964 Note that it is possible to check out another branch while having
965 uncommitted changes, but it is not recommended unless you know
966 what you are doing; it is recommended to run @command{git status}
967 to check this kind of issue before checking out another branch.
969 @node Merging branches
970 @unnumberedsubsubsec Merging branches
972 To merge branch @code{@var{foo}} into branch @code{@var{bar}},
973 i.e. to @qq{add} all changes made in branch @code{@var{foo}} to
974 branch @code{@var{bar}}, run
977 git checkout @var{bar}
981 If any conflict happens, see @ref{Resolving conflicts}.
983 There are common usage cases for merging: as a translator, you
984 will often want to merge @code{master} into
985 @code{lilypond/translation}; on the other hand, the Translations
986 meister wants to merge @code{lilypond/translation} into
987 @code{master} whenever he has checked that
988 @code{lilypond/translation} builds successfully.
991 @node Commits and patches
992 @subsection Commits and patches
996 * Understanding commits::
1000 * Uploading a patch for review::
1004 @node Understanding commits
1005 @unnumberedsubsubsec Understanding commits
1007 Technically, a @emph{commit} is a single point in the history of a
1008 branch, but most developers use the term to mean a @emph{commit
1009 object}, which stores information about a particular revision. A
1010 single commit can record changes to multiple source files, and
1011 typically represents one logical set of related changes (such as a
1012 bug-fix). You can list the ten most recent commits in your
1013 current branch with this command:
1016 git log -10 --oneline
1019 If you're using an older version of Git and get an @q{unrecognized
1020 argument} error, use this instead:
1023 git log -10 --pretty=oneline --abbrev-commit
1026 More interactive lists of the commits on the remote @code{master}
1027 branch are available at
1028 @uref{http://git.sv.gnu.org/gitweb/?p=lilypond.git;a=shortlog} and
1029 @uref{http://git.sv.gnu.org/cgit/lilypond.git/log/}.
1032 @node Making commits
1033 @unnumberedsubsubsec Making commits
1036 Once you have modified some source files in your working
1037 directory, you can make a commit with the following procedure:
1041 Make sure you've configured Git properly (see @ref{Configuring
1042 Git}). Check that your changes meet the requirements described in
1043 @ref{Code style} and/or @ref{Documentation policy}. For advanced
1044 edits, you may also want to verify that the changes don't break
1045 the compilation process.
1048 Run the following command:
1055 to make sure you're on the right branch, and to see which files
1056 have been modified, added or removed, etc. You may need to tell
1057 Git about any files you've added by running one of these:
1060 git add @var{file} # add untracked @var{file} individually
1061 git add . # add all untracked files in current directory
1065 After @command{git@tie{}add}, run @command{git@tie{}status} again
1066 to make sure you got everything. You may also need to modify
1070 Preview the changes about to be committed (to make sure everything
1078 The @code{HEAD} argument refers to the most recent commit on the
1079 currently checked-out branch.
1082 Generate the commit with:
1089 The @option{-a} is short for @option{--all} which includes modified
1090 and deleted files, but only those newly created files that have
1091 previously been added.
1096 @node Commit messages
1097 @unnumberedsubsubsec Commit messages
1100 When you run the @command{git@tie{}commit@tie{}-a} command, Git
1101 automatically opens the default text editor so you can enter a
1102 @emph{commit message}. If you find yourself in a foreign editing
1103 environment, you're probably in @command{vi} or @command{vim}. If
1104 you want to switch to an editor you're more familiar with, quit by
1105 typing @code{:q!} and pressing @code{<Enter>}. See
1106 @ref{Configuring Git} for instructions on changing the default
1109 In any case, Git will open a text file for your commit message
1110 that looks like this:
1114 # Please enter the commit message for your changes. Lines starting
1115 # with '#' will be ignored, and an empty message aborts the commit.
1117 # Changes to be committed:
1118 # (use "git reset HEAD <file>..." to unstage)
1120 # modified: working.itexi
1124 Your commit message should begin with a one-line summary
1125 describing the change (no more than 50 characters long), and if
1126 necessary a blank line followed by several lines giving the
1129 @c $ git log -1 --pretty=medium 4d6f1e5
1131 Doc: add Baerenreiter and Henle solo cello suites
1133 Added comparison of solo cello suite engravings to new essay with
1134 high-res images, fixed cropping on Finale example.
1137 Commit messages often start with a short prefix describing the
1138 general location of the changes. If a commit affects the
1139 documentation in English (or in several languages simultaneously)
1140 the commit message should be prefixed with @qq{Doc:@tie{}}. If
1141 the commit affects only one of the translations, the commit
1142 message should be prefixed with @qq{Doc-@var{**}:@tie{}}, where
1143 @var{**} is the two-letter language code. Commits that affect the
1144 website should use @qq{Web:@tie{}} for English, and
1145 @qq{Web-@var{**}:@tie{}} for the other languages. Also, changes
1146 to a single file are often prefixed with the name of the file
1147 involved. Visit the links listed in @ref{Understanding commits}
1151 @node Making patches
1152 @unnumberedsubsubsec Making patches
1154 If you want to share your changes with other contributors and
1155 developers, you need to generate @emph{patches} from your commits.
1156 We prefer it if you follow the instructions in
1157 @ref{Uploading a patch for review}. However, we present an
1158 alternate method here.
1160 You should always run @command{git@tie{}pull@tie{}-r} (translators
1161 should leave off the @option{-r}) before doing this to ensure that
1162 your patches are as current as possible.
1164 Once you have made one or more commits in your local repository,
1165 and pulled the most recent commits from the remote branch, you can
1166 generate patches from your local commits with the command:
1169 git format-patch origin
1172 The @code{origin} argument refers to the remote tracking branch at
1173 @code{git.sv.gnu.org}. This command generates a separate patch
1174 for each commit that's in the current branch but not in the remote
1175 branch. Patches are placed in the current working directory and
1176 will have names that look something like this:
1179 0001-Doc-Fix-typos.patch
1180 0002-Web-Remove-dead-links.patch
1184 Send an email (must be less than 64 KB) to
1185 @email{lilypond-devel@@gnu.org} briefly explaining your work, with
1186 the patch files attached. Translators should send patches to
1187 @email{translations@@lilynet.net}. After your patches are
1188 reviewed, the developers may push one or more of them to the main
1189 repository or discuss them with you.
1192 @node Uploading a patch for review
1193 @unnumberedsubsubsec Uploading a patch for review
1195 Any non-trivial change should be uploaded to our @qq{Rietveld}
1196 code review website:
1199 @uref{http://codereview.appspot.com/}
1202 @subsubheading @command{git-cl} install
1204 LilyDev users should skip over these @q{install} instructions.
1209 Install @command{git-cl} by entering:
1212 git clone https://github.com/gperciva/git-cl.git
1215 If that command fails for some reason, try this instead:
1218 git clone git://github.com/gperciva/git-cl.git
1222 Add the @file{git-cl/} directory to your PATH,
1223 or create a symbolic link to the @command{git-cl}
1224 and @command{upload.py} scripts in one of your PATH
1225 directories (such as @file{$HOME/bin}).
1227 In Ubuntu (and Lilydev), you can add directories to PATH
1228 by adding this line to a hidden file @file{.bashrc},
1229 located in your home directory:
1232 PATH=~/type-here-directory-containing-git-cl:"$@{PATH@}"
1237 @subsubheading @command{git-cl} configuration
1239 LilyDev users should perform these @q{configuration} instructions.
1243 You must have a google account; please create one if you do not
1246 Note that a google account does not need to be a gmail account; you can
1247 use any email address for your google account when you sign up.
1250 Move into the top source directory and then configure @command{git
1251 cl} with the following commands. If you do not understand any
1252 question, just answer with a newline (CR).
1255 cd $HOME/lilypond-git/
1259 The @qq{CC list} question should be answered with:
1262 lilypond-devel@@gnu.org
1267 @subsubheading Uploading patch set
1269 @warning{Unless you are familiar with branches, only work on one
1270 set of changes at once.}
1272 There are two methods, depending on your git setup.
1276 @strong{Master branch}: (easy option, and used in @command{lily-git.tcl})
1278 If you added your patch to @code{master}, then:
1282 git cl upload origin/master
1285 If you have git push ability, make sure that you @emph{remove}
1286 your patch (with @command{git rebase} or @command{git reset})
1287 before pushing other stuff.
1289 @c don't make this one an @example; we don't want to make it easy
1290 @c for people to use this accidently
1291 Notifications of patches are automatically added to our issue
1292 tracker to reduce the chance of patches getting lost. To suppress
1293 this (not recommended), add the @code{-n / --no-code-issue}
1297 @strong{Separate branch}: (complicated option)
1299 Ensure your changes are committed in a separate branch, which
1300 should differ from the reference branch to be used by just the
1301 changes to be uploaded. If the reference branch is to be
1302 origin/master, ensure this is up-to-date. If necessary, use git
1303 rebase to rebase the branch containing the changes to the head of
1304 origin/master. Finally, check out branch with the changes and
1308 git cl upload <reference SHA1 ID>
1312 where <reference SHA1 ID> is the SHA1 ID of the commit to be used
1313 as a reference source for the patch. Generally, this will be the
1314 SHA1 ID of origin/master, and in that case the command:
1317 git cl upload origin/master
1325 After prompting for your Google email address and password, the
1326 patch set will be posted to Rietveld, and you will be given a URL
1329 @warning{Some installations of git-cl fail when uploading a patch
1330 with certain filename extensions. If this happens, it can
1331 generally be fixed by editing the list of exceptions at top of
1334 @subsubheading Announcing your patch set
1336 You should then announce the patch by logging into the code review
1337 issue webpage and using @qq{Publish + Mail Comments} to add a
1338 (mostly bogus) comment to your issue. The text of your comment
1339 will be sent to our developer mailing list.
1341 @warning{There is no automatic notification of a new patch; you
1342 must add a comment yourself.}
1344 @subsubheading Revisions
1346 As revisions are made in response to comments, successive patch sets
1347 for the same issue can be uploaded by reissuing the git-cl command
1348 with the modified branch checked out.
1350 Sometimes in response to comments on revisions, the best way to
1351 work may require creation of a new branch in git. In order to
1352 associate the new branch with an existing Rietveld issue,
1353 the following command can be used:
1356 git cl issue issue-number
1360 where @code{issue-number} is the number of the existing Rietveld
1363 @subsubheading Resetting git cl
1365 If @command{git cl} becomes confused, you can @qq{reset} it by
1372 @subsubheading Wait for a countdown
1374 Your patch will be available for reviews for the next few hours or
1375 days. Three times a week, patches with no known problems are
1376 gathered into a @qq{patch countdown} and their status changed to
1377 @code{patch-countdown}. The countdown is a 48-hour waiting period
1378 in which any final reviews or complaints should be made.
1380 During the countdown, your patch may be set to
1381 @code{patch-needs_work}, indicating that you should fix something
1382 (or at least discuss why the patch needs no modification). If no
1383 problems are found, the patch will be set to @code{patch-push}.
1385 Once a patch has @code{patch-push}, it should be sent to your
1386 mentor for uploading. If you have git push ability, look at
1387 @ref{Pushing to staging}.
1390 @node Advanced Git procedures
1391 @section Advanced Git procedures
1394 @warning{This section is not necessary for normal contributors;
1395 these commands are presented for information for people interested
1396 in learning more about git.}
1398 It is possible to work with several branches on the same local Git
1399 repository; this is especially useful for translators who may have
1400 to deal with both @code{lilypond/translation} and a stable branch,
1401 e.g. @code{stable/2.12}.
1403 Some Git commands are introduced first, then a workflow with
1404 several Git branches of LilyPond source code is presented.
1409 * Advanced Git concepts::
1410 * Resolving conflicts::
1411 * Reverting all local changes::
1412 * Working with remote branches::
1414 * Applying remote patches::
1415 * Sending and receiving patches via email::
1416 * Cleaning up multiple patches::
1418 * Pushing to staging::
1422 @node Merge conflicts
1423 @subsection Merge conflicts
1425 To be filled in later, and/or moved to a different section. I
1426 just wanted to make sure that I had a stub ready somewhere.
1429 @node Advanced Git concepts
1430 @subsection Advanced Git concepts
1433 A bit of Git vocabulary will be explained below. The following is
1434 only introductory; for a better understanding of Git concepts, you
1435 may wish to read @ref{Other Git documentation}.
1437 The @code{git@tie{}pull@tie{}origin} command above is just a
1438 shortcut for this command:
1441 git pull git://git.sv.gnu.org/lilypond.git/ @var{branch}:origin/@var{branch}
1445 where @code{@var{branch}} is typically @code{master} or
1446 @code{lilypond/translation}; if you do not know or remember, see
1447 @ref{Downloading remote branches} to remember which commands you
1448 issued or which source code you wanted to get.
1450 A @emph{commit} is a set of changes made to the sources; it also
1451 includes the committish of the parent commit, the name and e-mail
1452 of the @emph{author} (the person who wrote the changes), the name
1453 and e-mail of the @emph{committer} (the person who brings these
1454 changes into the Git repository), and a commit message.
1456 A @emph{committish} is the SHA1 checksum of a commit, a number
1457 made of 40 hexadecimal digits, which acts as the internal unique
1458 identifier for this commit. To refer to a particular revision,
1459 don't use vague references like the (approximative) date, simply
1460 copy and paste the committish.
1462 A @emph{branch} is nothing more than a pointer to a particular
1463 commit, which is called the @emph{head} of the branch; when
1464 referring to a branch, one often actually thinks about its head
1465 and the ancestor commits of the head.
1467 Now we will explain the two last commands you used to get the
1468 source code from Git---see @ref{Downloading individual branches}.
1471 git remote add -ft @var{branch} -m @var{branch} \
1472 origin git://git.sv.gnu.org/lilypond.git/
1474 git checkout -b @var{branch} origin/@var{branch}
1477 The @command{git@tie{}remote} has created a branch called
1478 @code{origin/@var{branch}} in your local Git repository. As this
1479 branch is a copy of the remote branch web from git.sv.gnu.org
1480 LilyPond repository, it is called a @emph{remote branch}, and is
1481 meant to track the changes on the branch from git.sv.gnu.org: it
1482 will be updated every time you run
1483 @command{git@tie{}pull@tie{}origin} or
1484 @command{git@tie{}fetch@tie{}origin}.
1486 The @command{git@tie{}checkout} command has created a branch named
1487 @code{@var{branch}}. At the beginning, this branch is identical
1488 to @code{origin/@var{branch}}, but it will differ as soon as you
1489 make changes, e.g. adding newly translated pages or editing some
1490 documentation or code source file. Whenever you pull, you merge
1491 the changes from @code{origin/@var{branch}} and
1492 @code{@var{branch}} since the last pulling. If you do not have
1493 push (i.e. @qq{write}) access on git.sv.gnu.org, your
1494 @code{@var{branch}} will always differ from
1495 @code{origin/@var{branch}}. In this case, remember that other
1496 people working like you with the remote branch @code{@var{branch}}
1497 of git://git.sv.gnu.org/lilypond.git/ (called
1498 @code{origin/@var{branch}} on your local repository) know nothing
1499 about your own @code{@var{branch}}: this means that whenever you
1500 use a committish or make a patch, others expect you to take the
1501 latest commit of @code{origin/@var{branch}} as a reference.
1503 Finally, please remember to read the man page of every Git command
1504 you will find in this manual in case you want to discover
1505 alternate methods or just understand how it works.
1508 @node Resolving conflicts
1509 @subsection Resolving conflicts
1512 Occasionally an update may result in conflicts -- this happens
1513 when you and somebody else have modified the same part of the same
1514 file and git cannot figure out how to merge the two versions
1515 together. When this happens, you must manually merge the two
1518 If you need some documentation to understand and resolve
1519 conflicts, see paragraphs @emph{How conflicts are presented} and
1520 @emph{How to resolve conflicts} in @command{git merge} man page.
1522 If all else fails, you can follow the instructions in
1523 @ref{Reverting all local changes}. Be aware that this eliminates
1524 any changes you have made!
1527 @node Reverting all local changes
1528 @subsection Reverting all local changes
1530 Sometimes git will become hopelessly confused, and you just want
1531 to get back to a known, stable state. This command destroys any
1532 local changes you have made in the currently checked-out branch,
1533 but at least you get back to the current online version:
1536 git reset --hard origin/master
1540 @node Working with remote branches
1541 @subsection Working with remote branches
1544 @subsubheading Fetching new branches from git.sv.gnu.org
1546 To fetch and check out a new branch named @code{@var{branch}} on
1547 git.sv.gnu.org, run from top of the Git repository
1550 git config --add remote.origin.fetch \
1551 +refs/heads/@var{branch}:refs/remotes/origin/@var{branch}
1553 git checkout --track -b @var{branch} origin/@var{branch}
1556 After this, you can pull @code{@var{branch}} from git.sv.gnu.org
1563 Note that this command generally fetches all branches you added
1564 with @command{git@tie{}remote@tie{}add} (when you initialized the
1565 repository) or @command{git@tie{}config@tie{}--add}, i.e. it
1566 updates all remote branches from remote @code{origin}, then it
1567 merges the remote branch tracked by the current branch into the
1568 current branch. For example, if your current branch is
1569 @code{master}, @code{origin/master} will be merged into
1573 @subsubheading Local clones, or having several working trees
1575 If you play with several Git branches, e.g. @code{master},
1576 @code{lilypond/translation}, @code{stable/2.12}), you may want to
1577 have one source and build tree for each branch; this is possible
1578 with subdirectories of your local Git repository, used as local
1579 cloned subrepositories. To create a local clone for the branch
1580 named @code{@var{branch}}, run
1583 git checkout @var{branch}
1584 git clone -lsn . @var{subdir}
1589 Note that @code{@var{subdir}} must be a directory name which does
1590 not already exist. In @code{@var{subdir}}, you can use all Git
1591 commands to browse revisions history, commit and uncommit changes;
1592 to update the cloned subrepository with changes made on the main
1593 repository, cd into @code{@var{subdir}} and run
1594 @command{git@tie{}pull}; to send changes made on the subrepository
1595 back to the main repository, run @command{git@tie{}push} from
1596 @code{@var{subdir}}. Note that only one branch (the currently
1597 checked out branch) is created in the subrepository by default; it
1598 is possible to have several branches in a subrepository and do
1599 usual operations (checkout, merge, create, delete...) on these
1600 branches, but this possibility is not detailed here.
1602 When you push @code{@var{branch}} from @code{@var{subdir}} to the
1603 main repository, and @code{@var{branch}} is checked out in the
1604 main repository, you must save uncommitted changes (see
1605 @command{git@tie{}stash}) and do
1606 @command{git@tie{}reset@tie{}--hard} in the main repository in
1607 order to apply pushed changes in the working tree of the main
1615 The commands above don't only bring you the latest version of the
1616 sources, but also the full history of revisions (revisions, also
1617 called commits, are changes made to the sources), stored in the
1618 @file{.git} directory. You can browse this history with
1621 git log # only shows the logs (author, committish and commit message)
1622 git log -p # also shows diffs
1623 gitk # shows history graphically
1626 @warning{The @code{gitk} command may require a separate
1627 @code{gitk} package, available in the appropriate distribution's
1631 @node Applying remote patches
1632 @subsection Applying remote patches
1635 TODO: Explain how to determine if a patch was created with
1636 @code{git@tie{}format-patch}.
1638 Well-formed git patches created with @code{git@tie{}format-patch}
1639 should be committed with the following command:
1645 Patches created without @code{git@tie{}format-patch} can be
1646 applied in two steps. The first step is to apply the patch to the
1650 git apply @var{patch}
1654 The second step is to commit the changes and give credit to the
1655 author of the patch. This can be done with the following command:
1658 git commit -a --author="@var{John Smith} <@var{john@@example.com}>"
1662 @node Sending and receiving patches via email
1663 @subsection Sending and receiving patches via email
1666 The default @code{x-diff} MIME type associated with patch files
1667 (i.e., files whose name ends in @code{.patch}) means that the
1668 encoding of line endings may be changed from UNIX to DOS format
1669 when they are sent as attachments. Attempting to apply such an
1670 inadvertently altered patch will cause git to fail with a message
1671 about @q{whitespace errors}.
1673 The solution to such problems is surprisingly simple---just change
1674 the default file extension of patches generated by git to end in
1675 @code{.txt}, for example:
1678 git config format.suffix '.patch.txt'
1681 This should cause email programs to apply the correct base64
1682 encoding to attached patches.
1684 If you receive a patch with DOS instead of UNIX line-endings, it
1685 can be converted back using the @code{dos2unix} utility.
1687 Lots of useful information on email complications with patches is
1688 provided on the Wine wiki at
1689 @uref{http://wiki.winehq.org/GitWine}.
1692 @node Cleaning up multiple patches
1693 @subsection Cleaning up multiple patches
1695 If you have been developing on your own branch for a while, you
1696 may have more commmits than is really sensible. To revise your
1697 work and condense commits, use:
1700 git rebase origin/master
1701 git rebase -i origin/master
1704 @warning{Be a bit cautious -- if you completely remove commits
1705 during the interactive session, you will... err... completely
1706 remove those commits.}
1710 @subsection Commit access
1712 Most contributors are not able to commit patches directly to the
1713 main repository---only members of the LilyPond development team
1714 have @emph{commit access}. If you are a contributor and are
1715 interested in joining the development team, contact the Project
1716 Manager through the mailing list
1717 (@email{lilypond-devel@@gnu.org}). Generally, only contributors
1718 who have already provided a number of patches which have been
1719 pushed to the main repository will be considered for membership.
1721 If you have been approved by the Project Manager, use the
1722 following procedure to obtain commit access:
1726 If you don't already have one, set up a Savannah user account at
1727 @uref{https://savannah.gnu.org/account/register.php}. If your web
1728 browser responds with an @qq{untrusted connection} message when
1729 you visit the link, follow the steps for including the CAcert root
1730 certificate in your browser, given at
1731 @uref{http://savannah.gnu.org/tls/tutorial/}.
1733 @warning{Savannah will silently put your username in lower-case --
1734 do not try to use capital letters.}
1738 After registering, if you are not logged in automatically, login
1739 at @uref{https://savannah.gnu.org/account/login.php}---this should
1740 take you to your @qq{my} page
1741 (@uref{https://savannah.gnu.org/my/}).
1745 Click on the @qq{My Groups} link to access the @qq{My Group
1746 Membership} page. From there, find the @qq{Request for Inclusion}
1747 box and search for @qq{LilyPond}. Among the search results, check
1748 the box labeled @qq{GNU LilyPond Music Typesetter} and write a
1749 brief (required) message for the Project Manager (@qq{Hey it's
1750 me!} should be fine).
1752 Note that you will not have commit access until the Project
1753 Manager activates your membership. Once your membership is
1754 activated, LilyPond should appear under the heading @qq{Groups I'm
1755 Contributor of} on your @qq{My Group Membership} page.
1759 Generate an SSH @q{rsa} key pair. Enter the following at the
1766 When prompted for a location to save the key, press <ENTER> to
1767 accept the default location (@file{~/.ssh/id_rsa}).
1769 Next you are asked to enter an optional passphrase. On most
1770 systems, if you use a passphrase, you will likely be prompted for
1771 it every time you use @command{git@tie{}push} or
1772 @command{git@tie{}pull}. You may prefer this since it can protect
1773 you from your own mistakes (like pushing when you mean to pull),
1774 though you may find it tedious to keep re-entering it.
1776 You can change/enable/disable your passphrase at any time with:
1779 ssh-keygen -f ~/.ssh/id_rsa -p
1782 Note that the GNOME desktop has a feature which stores your
1783 passphrase for you for an entire GNOME session. If you use a
1784 passphrase to @qq{protect you from yourself}, you will want to
1785 disable this feature, since you'll only be prompted once. Run the
1786 following command, then logout of GNOME and log back in:
1789 gconftool-2 --set -t bool \
1790 /apps/gnome-keyring/daemon-components/ssh false
1793 After setting up your passphrase, your private key is saved as
1794 @file{~/.ssh/id_rsa} and your public key is saved as
1795 @file{~/.ssh/id_rsa.pub}.
1799 Register your public SSH @q{rsa} key with Savannah. From the
1800 @qq{My Account Configuration} page, click on @qq{Edit SSH Keys},
1801 then paste the contents of your @file{~/.ssh/id_rsa.pub} file into
1802 one of the @qq{Authorized keys} text fields, and click
1805 Savannah should respond with something like:
1808 Success: Key #1 seen Keys registered
1813 Configure Git to use the SSH protocol (instead of the GIT
1814 protocol). From your local Git repository, enter:
1817 git config remote.origin.url \
1818 ssh://@var{user}@@git.sv.gnu.org/srv/git/lilypond.git
1822 replacing @var{user} with your Savannah username.
1826 After your membership has been activated and you've configured Git
1827 to use SSH, test the connection with:
1833 SSH should issue the following warning:
1836 The authenticity of host 'git.sv.gnu.org (140.186.70.72)' can't
1838 RSA key fingerprint is
1839 80:5a:b0:0c:ec:93:66:29:49:7e:04:2b:fd:ba:2c:d5.
1840 Are you sure you want to continue connecting (yes/no)?
1843 Make sure the RSA key fingerprint displayed matches the one above.
1844 If it doesn't, respond @qq{no} and check that you configured Git
1845 properly in the previous step. If it does match, respond
1846 @qq{yes}. SSH should then issue another warning:
1849 Warning: Permanently added 'git.sv.gnu.org,140.186.70.72' (RSA) to
1850 the list of known hosts.
1853 The list of known hosts is stored in the file
1854 @file{~/.ssh/known_hosts}.
1856 At this point, you are prompted for your passphrase if you have
1857 one, then Git will attempt a pull.
1859 If @command{git@tie{}pull@tie{}--verbose} fails, you should see
1860 error messages like these:
1863 Permission denied (publickey).
1864 fatal: The remote end hung up unexpectedly
1867 If you get the above error, you may have made a mistake when
1868 registering your SSH key at Savannah. If the key is properly
1869 registered, you probably just need to wait for the Savannah server
1870 to activate it. It usually takes a few minutes for the key to be
1871 active after registering it, but if it still doesn't work after an
1872 hour, ask for help on the mailing list.
1874 If @command{git@tie{}pull@tie{}--verbose} succeeds, the output
1875 will include a @q{From} line that shows @q{ssh} as the protocol:
1878 From ssh://git.sv.gnu.org/srv/git/lilypond
1881 If the protocol shown is not @q{ssh}, check that you configured
1882 Git properly in the previous step.
1886 Test your commit access with a dry run:
1888 @warning{Do not push directly to master; instead, push to staging.
1889 See @ref{Pushing to staging}.}
1892 git push --dry-run --verbose
1895 Note that recent versions of Git (Git 1.6.3 or later) will issue a
1896 big warning if the above command is used. The simplest solution
1897 is to tell Git to push all matching branches by default:
1900 git config push.default matching
1904 Then @code{git@tie{}push} should work as before. For more
1905 details, consult the @code{git@tie{}push} man page.
1909 Repeat the steps from generating an RSA key through to testing
1910 your commit access, for each machine from which you will be
1911 making commits, or you may simply copy the files from your
1912 local @file{~/.ssh} folder to the same folder on the other
1917 @subsubheading Technical details
1921 On Firefox, to view or remove the CAcert root certificate, go to:
1922 Edit > Preferences > Advanced > Encryption > View Certificates >
1923 Authorities > Certificate Name > Root CA > CA Cert Signing
1927 The @command{git@tie{}config} commands above should modify your
1928 local repository's @file{.git/config} file. These lines:
1932 url = git://git.sv.gnu.org/lilypond.git/
1936 should now be changed to:
1940 url = ssh://@var{user}@@git.sv.gnu.org/srv/git/lilypond.git
1944 where @var{user} is your login name on Savannah.
1948 @command{git@tie{}config@tie{}push.default@tie{}matching} command
1949 should add these lines to @file{.git/config}:
1958 Encryption protocols, including ssh, generally do not permit packet
1959 fragmentation to avoid introducing a point of insecurity. This
1960 means that the maximum packet size must not exceed the smallest
1961 MTU (Maximum Transmission Unit) set in the routers along the path.
1962 This smallest MTU is determined by a procedure during call set-up
1963 which relies on the transmission over the path of ICMP packets.
1964 If any of the routers in the path block ICMP packets this mechanism
1965 fails, resulting in the possibility of packets being transmitted
1966 which exceed the MTU of one of the routers. If this happens the
1967 packet is discarded, causing the ssh session to hang, timeout or
1968 terminate with the error message
1971 ssh: connect to host <host ip addr> port 22: Bad file number
1972 fatal: The remote end hung up unexpectedly
1975 depending on precisely when in the proceedings the first large
1976 packet is transmitted. Most routers on the internet have MTU
1977 set to 1500, but routers installed in homes to connect via
1978 broadband may use a slightly smaller MTU for efficient transmission
1979 over ATM. If this problem is encountered a possible work-around is
1980 to set the MTU in the local router to 1500.
1983 @node Pushing to staging
1984 @subsection Pushing to staging
1986 Do not push directly to the git @code{master} branch. Instead,
1987 push to @code{staging}.
1989 You will not see your patch on @code{origin/master} until some
1990 automatic tests have been run. These tests are run every couple
1991 of hours; please wait at least 12 hours before wondering if your
1992 patch has been lost. Note that you can check the commits on
1993 @code{origin/staging} by looking at the git web interface on
1996 @subsubheading If your work is in a patch file
1998 Assuming that your patch is in a file called
1999 @file{0001-my-patch.patch}, and you are currently on git master,
2003 git checkout staging
2005 git am 0001-my-patch.patch
2007 git push origin staging
2011 @warning{Do not skip the @command{gitk} step; a quick 5-second
2012 check of the visual history can save a great deal of frustration
2013 later on. You should only see that @command{staging} is only 1
2014 commit ahead of @code{origin/staging}.}
2016 @subsubheading If your work is in a branch
2018 If you are working on branches and your work in is
2019 @code{my_branch_name}, then do:
2022 git checkout staging
2024 git merge my_branch_name
2026 git push origin staging
2029 @warning{Do not skip the @command{gitk} step; a quick 5-second
2030 check of the visual history can save a great deal of frustration
2031 later on. You should see that @code{staging} is only ahead of
2032 @code{origin/staging} by the commits from your branch.}
2036 @node Git on Windows
2037 @section Git on Windows
2039 @warning{We heavily recommend that development be done with our
2040 virtual machine @ref{Lilydev}.}
2042 @c Some of this may duplicate stuff in other sections
2043 @c But it is probably best for windows users to have it all together
2044 @c If necessary, clear this up later -td
2046 TODO: Decide what to do with this... Pare it down? Move
2047 paragraphs next to analogous Unix instructions? -mp
2049 @subsection Background to nomenclature
2051 Git is a system for tracking the changes made to source files by a
2052 distributed set of editors. It is designed to work without a
2053 master repository, but we have chosen to have a master repository
2054 for LilyPond files. Editors hold a local copy of the master
2055 repository together with any changes they have made locally.
2056 Local changes are held in a local @q{branch}, of which there may
2057 be several, but these instructions assume you are using just one.
2058 The files visible in the local repository always correspond to
2059 those on the currently @q{checked out} local branch.
2061 Files are edited on a local branch, and in that state the changes
2062 are said to be @q{unstaged}. When editing is complete, the
2063 changes are moved to being @q{staged for commit}, and finally the
2064 changes are @q{committed} to the local branch. Once committed,
2065 the changes (called a @q{commit}) are given a unique 40-digit
2066 hexadecimal reference number called the @q{Committish} or @q{SHA1
2067 ID} which identifies the commit to Git. Such committed changes
2068 can be sent to the master repository by @q{pushing} them (if you
2069 have write permission) or by sending them by email to someone who
2070 has, either as a complete file or as a @q{diff} or @q{patch}
2071 (which send just the differences from the master repository).
2073 @subsection Installing git
2076 @uref{http://code.google.com/p/msysgit/downloads/list} (note, not
2077 msysGit, which is for Git developers and not PortableGit, which is
2078 not a full git installation) and install it.
2080 Note that most users will not need to install SSH. That is not
2081 required until you have been granted direct push permissions to
2082 the master git repository.
2084 Start Git by clicking on the desktop icon. This will bring up a
2085 command line bash shell. This may be unfamiliar to Windows users.
2086 If so, follow these instructions carefully. Commands are entered
2087 at a $ prompt and are terminated by keying a newline.
2089 @subsection Initialising Git
2091 Decide where you wish to place your local Git repository, creating
2092 the folders in Windows as necessary. Here we call the folder to
2093 contain the repository @code{[path]/Git}, but if you intend using
2094 Git for other projects a directory name like @code{lilypond-git}
2095 might be better. You will need to have space for around
2098 Start the Git bash shell by clicking on the desk-top icon
2099 installed with Git and type
2105 to position the shell at your new Git repository.
2107 Note: if [path] contains folders with names containing spaces use
2119 to initialize your Git repository.
2121 Then type (all on one line; the shell will wrap automatically)
2124 git remote add -ft master origin git://git.sv.gnu.org/lilypond.git
2127 to download the lilypond master files.
2129 @warning{Be patient! Even on a broadband connection this can take
2130 10 minutes or more. Wait for lots of [new tag] messages and the $
2133 We now need to generate a local copy of the downloaded files in a
2134 new local branch. Your local branch needs to have a name. It is
2135 usual to call it @q{master} and we shall do that here.
2140 git checkout -b master origin/master
2143 This creates a second branch called @q{master}. You will see two
2144 warnings (ignore these), and a message advising you that your
2145 local branch @q{master} has been set up to track the remote
2146 branch. You now have two branches, a local branch called
2147 @q{master}, and a tracking branch called @q{origin/master}, which
2148 is a shortened form of @q{remotes/origin/master}.
2150 Return to Windows Explorer and look in your Git repository. You
2151 should see lots of folders. For example, the LilyPond
2152 documentation can be found in [path]/Git/Documentation/.
2154 The Git bash shell is terminated by typing @code{exit} or by
2155 clicking on the usual Windows close-window widget.
2159 Almost all subsequent work will use the Git Graphical User
2160 Interface, which avoids having to type command line commands. To
2161 start Git GUI first start the Git bash shell by clicking on the
2162 desktop icon, and type
2169 The Git GUI will open in a new window. It contains four panels
2170 and 7 pull-down menus. At this stage do not use any of the
2171 commands under Branch, Commit, Merge or Remote. These will be
2174 The top panel on the left contains the names of files which you
2175 are in the process of editing (Unstaged Changes), and the lower
2176 panel on the left contains the names of files you have finished
2177 editing and have staged ready for committing (Staged Changes). At
2178 present, these panels will be empty as you have not yet made any
2179 changes to any file. After a file has been edited and saved the
2180 top panel on the right will display the differences between the
2181 edited file selected in one of the panels on the left and the last
2182 version committed on the current branch.
2184 The panel at bottom right is used to enter a descriptive message
2185 about the change before committing it.
2187 The Git GUI is terminated by entering CNTL-Q while it is the
2188 active window or by clicking on the usual Windows close-window
2191 @subsection Personalising your local git repository
2193 Open the Git GUI, click on
2199 and enter your name and email address in the left-hand (Git
2200 Repository) panel. Leave everything else unchanged and save it.
2202 Note that Windows users must leave the default setting for line
2203 endings unchanged. All files in a git repository must have lines
2204 terminated by just a LF, as this is required for Merge to work,
2205 but Windows files are terminated by CRLF by default. The git
2206 default setting causes the line endings of files in a Windows git
2207 repository to be flipped automatically between LF and CRLF as
2208 required. This enables files to be edited by any Windows editor
2209 without causing problems in the git repository.
2211 @subsection Checking out a branch
2213 At this stage you have two branches in your local repository,
2214 both identical. To see them click on
2220 You should have one local branch called @q{master} and one
2221 tracking branch called @q{origin/master}. The latter is your
2222 local copy of the @q{remotes/origin/master} branch in the master
2223 LilyPond repository. The local @q{master} branch is where you
2224 will make your local changes.
2226 When a particular branch is selected, i.e., checked out, the files
2227 visible in your repository are changed to reflect the state of the
2228 files on that branch.
2230 @subsection Updating files from @q{remote/origin/master}
2232 Before starting the editing of a file, ensure your local
2233 repository contains the latest version of the files in the remote
2234 repository by first clicking
2237 Remote -> Fetch from -> origin
2243 This will place the latest version of every file, including all
2244 the changes made by others, into the @q{origin/master} branch of
2245 the tracking branches in your git repository. You can see these
2246 files by checking out this branch, but you must @emph{never} edit
2247 any files while this branch is checked out. Check out your local
2248 @q{master} branch again.
2250 You then need to merge these fetched files into your local
2251 @q{master} branch by clicking on
2254 Merge -> Local Merge
2258 and if necessary select the local @q{master} branch.
2260 Note that a merge cannot be completed if you have made any local
2261 changes which have not yet been committed.
2263 This merge will update all the files in the @q{master} branch to
2264 reflect the current state of the @q{origin/master} branch. If any
2265 of the changes conflict with changes you have made yourself
2266 recently you will be notified of the conflict (see below).
2268 @subsection Editing files
2270 First ensure your @q{master} branch is checked out, then simply
2271 edit the files in your local Git repository with your favourite
2272 editor and save them back there. If any file contains non-ASCII
2273 characters ensure you save it in UTF-8 format. Git will detect
2274 any changes whenever you restart Git GUI and the file names will
2275 then be listed in the Unstaged Changes panel. Or you can click
2276 the Rescan button to refresh the panel contents at any time. You
2277 may break off and resume editing any time.
2279 The changes you have made may be displayed in diff form in the top
2280 right-hand panel of Git GUI by clicking on the file name shown in
2281 one of the left panels.
2283 When your editing is complete, move the files from being Unstaged
2284 to Staged by clicking the document symbol to the left of each
2285 name. If you change your mind it can be moved back by clicking on
2286 the ticked box to the left of the name.
2288 Finally the changes you have made may be committed to your
2289 @q{master} branch by entering a brief message in the Commit
2290 Message box and clicking the Commit button.
2292 If you wish to amend your changes after a commit has been made,
2293 the original version and the changes you made in that commit may
2294 be recovered by selecting
2297 Commit -> Amend Last Commit
2301 or by checking the Amend Last Commit radio button at bottom right.
2302 This will return the changes to the Staged state, so further
2303 editing made be carried out within that commit. This must only be
2304 done @emph{before} the changes have been Pushed or sent to your
2305 mentor for Pushing - after that it is too late and corrections
2306 have to be made as a separate commit.
2309 @subsection Sending changes to @q{remotes/origin/master}
2311 If you do not have write access to @q{remotes/origin/master} you
2312 will need to send your changes by email to someone who does.
2314 First you need to create a diff or patch file containing your
2315 changes. To create this, the file must first be committed. Then
2316 terminate the Git GUI. In the git bash shell first cd to your Git
2323 if necessary, then produce the patch with
2326 git format-patch origin
2329 This will create a patch file for all the locally committed files
2330 which differ from @q{origin/master}. The patch file can be found
2331 in [path]/Git and will have a name formed from the commit message.
2333 @subsection Resolving merge conflicts
2335 As soon as you have committed a changed file your local
2336 @code{master} branch has diverged from @code{origin/master}, and
2337 will remain diverged until your changes have been committed in
2338 @code{remotes/origin/master} and Fetched back into your
2339 @code{origin/master} branch. Similarly, if a new commit has been
2340 made to @code{remotes/origin/master} by someone else and Fetched,
2341 your local @code{master} branch is divergent. You can detect a
2342 divergent branch by clicking on
2345 Repository -> Visualise all branch history
2348 This opens up a very useful new window called @q{gitk}. Use this
2349 to browse all the commits made by yourself and others.
2351 If the diagram at top left of the resulting window does not show
2352 your @code{master} tag on the same node as the
2353 @code{remotes/origin/master} tag your branch has diverged from
2354 @code{origin/master}. This is quite normal if files you have
2355 modified yourself have not yet been Pushed to
2356 @code{remotes/origin/master} and Fetched, or if files modified and
2357 committed by others have been Fetched since you last Merged
2358 @code{origin/master} into your local @code{master} branch.
2360 If a file being merged from @code{origin/master} differs from one
2361 you have modified in a way that cannot be resolved automatically
2362 by git, Merge will report a Conflict which you must resolve by
2363 editing the file to create the version you wish to keep.
2365 This could happen if the person updating
2366 @code{remotes/origin/master} for you has added some changes of his
2367 own before committing your changes to
2368 @code{remotes/origin/master}, or if someone else has changed the
2369 same file since you last fetched the file from
2370 @code{remotes/origin/master}.
2372 Open the file in your editor and look for sections which are
2375 [to be completed when I next have a merge conflict to be sure I
2376 give the right instructions -td]
2379 @subsection Other actions
2381 The instructions above describe the simplest way of using git on
2382 Windows. Other git facilities which may usefully supplement these
2386 @item Using multiple local branches (Create, Rename, Delete)
2387 @item Resetting branches
2388 @item Cherry-picking commits
2389 @item Pushing commits to @w{remote/origin/master}
2390 @item Using gitk to review history
2393 Once familiarity with using git on Windows has been gained the
2394 standard git manuals can be used to learn about these.
2397 @node Repository directory structure
2398 @section Repository directory structure
2401 @c TODO: integrate the roadmap better
2402 @verbatiminclude ROADMAP
2405 @node Other Git documentation
2406 @section Other Git documentation
2410 Official git man pages:
2411 @uref{http://www.kernel.org/pub/software/scm/git/docs/}
2414 More in-depth tutorials: @uref{http://git-scm.com/documentation}
2417 Book about git: @uref{http://progit.org/,Pro Git}
2420 Github help: @uref{http://help.github.com/}
2421 (very highly recommended by Graham)