@node Starting with git
@chapter Starting with git
+To complete or present in another form the introduction to Git usage
+in this chapter, it may be a good idea to look for Git documentation
+at @uref{http://git-scm.com/documentation},
+
@menu
* Getting the source code::
* Updating the source code::
* Sharing your changes::
-* Other interesting Git commands::
+* Advanced git stuff::
* Git on Windows::
+* Development inside VirtualBox (compiling on Windows)::
@end menu
@node Git introduction
@subsection Git introduction
-The source code is kept in a git respository. This allows us to
+The source code is kept in a Git respository. This allows us to
track changes to files, and for multiple people to work on the
-same set of files (generally) without any problems.
+same set of files efficiently.
@warning{These instructions assume that you are using the
-command-line version of git 1.5 or higher. Windows users should
+command-line version of Git 1.5 or higher. Windows users should
skip to @ref{Git on Windows}.}
To get the main source code and documentation,
-@example
+@c WARNING: when updating the commands below, please
+@c update the other flavors in the two next nodes
+@c and in Introduction to Git concepts
+@smallexample
mkdir lilypond; cd lilypond
git init-db
git remote add -f -t master -m master origin git://git.sv.gnu.org/lilypond.git/
git checkout -b master origin/master
-@end example
+@end smallexample
@node Website source code
To get the website (including translations),
-@example
+@smallexample
mkdir lilypond-web ; cd lilypond-web
git init-db
git remote add -f -t web -m web origin git://git.sv.gnu.org/lilypond.git/
git checkout -b web origin/web
-@end example
+@end smallexample
@node Documentation translations source code
To translate the documentation (@emph{not} the website),
-@c TODO this runs off the side of the page in pdf. :(
-@example
+@smallexample
mkdir lilypond-translation; cd lilypond-translation
git init-db
git remote add -f -t lilypond/translation -m lilypond/translation origin git://git.sv.gnu.org/lilypond.git/
git checkout -b lilypond/translation origin/lilypond/translation
-@end example
+@end smallexample
@node Other branches
@item @code{gub}:
This stores the Grand Unified Binary, our cross-platform building
-tool.
+tool.
@c TODO: merge the gub stuff with this CG.
For more info, see @uref{http://lilypond.org/gub}. The git
location is:
ssh://git.sv.gnu.org/srv/git/lilypond.git
@end example
-@warning{The @code{git://} and @code{ssh://} URLs are intended for
-advanced git users.}
+Using HTTP protocol is slowest, so it is not recommended unless both
+SSH and Git protocols fail, which happens e.g. if you connect to
+internet through a router that filters out Git and/or SSH connections.
@node Git user configuration
@subsection Git user configuration
To configure git to automatically use your name and email address
-for patches,
+for commits and patches,
@example
git config --global user.name "MYNAME"
* Importance of updating::
* Update command::
* Resolving conflicts::
-* Technical notes::
@end menu
@node Importance of updating
@subsection Importance of updating
-In a large project like LilyPond, contributors sometimes edit the
-same file at the same time. As long as everybody updates their
-version of the file with the most recent changes (@qq{pull}ing),
-there are generally no problems with this multiple-person editing.
-However, serious problems can arise if you do not pull before
-attempting commit.
+In a large project like LilyPond, contributors sometimes edit the same
+file at the same time. As long as everybody updates their version of
+the file with the most recent changes (@emph{pulling}), there are
+generally no problems with this multiple-person editing. However,
+boring problems can arise if you do not pull before attempting commit,
+e.g. you may encounter a conflict; in this case, see @ref{Resolving
+conflicts}.
@node Update command
the remote @code{git.sv.gnu.org} repository:
@example
-git pull origin
+git pull -r
@end example
together. When this happens, you must manually merge the two
versions.
+If you need some documentation to understand and resolve conflicts,
+see paragraphs @emph{How conflicts are presented} and @emph{How to
+resolve conflicts} in @command{git merge} man page.
+
+
+@node Sharing your changes
+@section Sharing your changes
+
+@menu
+* Producing a patch::
+* Committing directly::
+@end menu
+
+
+@node Producing a patch
+@subsection Producing a patch
+
+Once you have finished editing your files, checked that your changes
+meet the @ref{Code style}, and/or @ref{Documentation policy}, properly
+set up your name and email in @ref{Git user configuration}, and
+checked that the entire thing compiles, you may:
+
@example
-FIXME: what the mao should people do?!?! Personally, I just break
-down and cry. -gp
+git commit -a
+git format-patch origin
@end example
+The commit should include a brief message describing the change.
+This consists of a one-line summary describing the change, and
+if necessary a blank line followed by several lines giving the
+details:
+
+@example
+Did household chores.
-@node Technical notes
-@subsection Technical notes
+I hung up the wet laundry and then washed the car. I also
+vacuumed the floors, rinsed the dirty dishes, fed the cat, and
+recalibrated the temporal flux machine.
+@end example
-TODO: I'm not going to bother with this section. -gp
+If the change is to the documentation only then the one-line
+summary should be prefixed with @qq{Docs: }.
-Let's explain a bit of Git vocabulary. The @code{git pull origin}
-command is just a shortcut for this command:
+If you added a file to the source code, you must add it to git
+with:
@example
-git pull git://git.sv.gnu.org/lilypond.git/ MY-BRANCH:origin/MY-BRANCH
+git add FILENAME
@end example
-A commit is a set of changes made to the sources; it also includes
-the committish of the parent commit, the name and e-mail of the
-author (the person who wrote the changes), the name and e-mail of
-the committer (the person who brings these changes into the git
-repository), and a commit message.
+@noindent
+(and possibly modify the @file{GNUmakefile})
-A committish is the SHA1 checksum of a commit, a number made of 40
-hexadecimal digits, which acts as the internal unique identifier
-for this commit. To refer to a particular revision, don't use
-vague references like the (approximative) date, simply
-copy'n'paste the committish.
+These commands will produce one or more files named
+@file{0001-xyz}, @file{0002-abc}, etc. in the top directory of the
+git tree. Send an email to @email{lilypond-devel@@gnu.org} with
+these files attached, and a developer will review and apply the
+patches to the main repository.
-A branch is a tree (in the mathematical or computer science sense)
-of commits, and the topmost commit of this branch is called a
-head.
-The @q{git fetch} command above has created a branch called
-@code{origin/web} in your local Git repository. As this branch is
-a copy of the remote branch web from git.sv.gnu.org LilyPond
-repository, it is called a @qq{remote branch,} and is meant to track
-the changes on the branch from git.sv.gnu.org: it will be updated
-every time you run @q{git pull} or @q{git fetch} with this branch
-reference as argument, e.g. by using .git/remotes/web remote file
-when running @q{git fetch web}.
-
-The @q{git checkout} command above has created a branch named @q{web}. At
-the beginning, this branch is identical to @q{origin/web,} but it will
-differ as soon as you make changes, e.g. adding newly translated
-pages. Whenever you pull, you merge the changes from origin/web and
-your web branch since the last pulling. If you do not have push
-(i.e. @qq{write}) access on git.sv.gnu.org, your web branch will always
-differ from origin/web. In this case, remember that other people
-working like you on the remote web branch of
-git://git.sv.gnu.org/lilypond.git/ know nothing about your own web
-branch: this means that whenever you use a committish or make a patch,
-others expect you to take the latest commit of origin/web branch as a
-reference.
-
-This README tries to explain most of Git commands needed for
-translating the web site. However, you are invited to read
-further documentation to make git more familiar to you; for
-instance, take a look at @uref{http://git.or.cz/gitwiki/},
-especially GitDocumentation and GitGlossary; a good alternative to
-reading the wiki is reading the first two chapters of Git User's
-Manual at
-@uref{http://www.kernel.org/pub/software/scm/git/docs/user-manual.html}
+@node Committing directly
+@subsection Committing directly
+
+Most contributors do not have permission to commit directly. If you
+do, make sure you have set up your name and email in @ref{Git user
+configuration}, then edit @file{.git/config}: change the line
+
+@example
+url = git://git.sv.gnu.org/lilypond.git/
+@end example
+@noindent
+into
+@example
+url = ssh://@var{user}@@git.sv.gnu.org/srv/git/lilypond.git
+@end example
-@node Sharing your changes
-@section Sharing your changes
+@noindent
+where @var{user} is your login name on Savannah.
+
+If you have not already done so, you should generate and upload a
+SSH key: open @uref{https://savannah.gnu.org/my/} in your browser,
+go to @q{Account Configuration}, then to something like
+@q{Edit SSH Keys}, and follow the instructions on that page.
+
+You may then:
+
+@example
+git push origin
+@end example
+
+Note that recent versions of Git (Git 1.6.3 or later) will issue a
+big warning if the above command is used. The simplest solution
+is to add a new section to @file{.git/config} that looks like
+this:
+
+@example
+[push]
+ default = matching
+@end example
+
+@noindent
+Then @code{git push origin} will work as before. For more
+details, consult the @code{git push} man page.
+
+
+@node Advanced git stuff
+@section Advanced git stuff
+
+@warning{This section is not necessary for normal contributors;
+these commands are presented for information for people interested
+in learning more about git.}
+
+
+It is possible to work with several branches on the same local Git
+repository; this is especially useful for translators who may have to
+deal with both @code{lilypond/translation} and a stable branch,
+e.g. @code{stable/2.12}.
+
+Some Git commands are introduced first, then a workflow with several
+Git branches of LilyPond source code is presented.
@menu
-* Producing a patch::
-* Committing directly::
+* Introduction to Git concepts::
+* Git commands for managing several branches::
+* Working on LilyPond sources with several branches::
+* Git log::
+* Applying git patches::
+* Reverting all local changes::
@end menu
-@node Producing a patch
-@subsection Producing a patch
+@node Introduction to Git concepts
+@subsection Introduction to Git concepts
-Once you have finished editing your files, checked that your
-changes meet the @ref{Code style} and/or @ref{Documentation
-policy}, and checked that the entire thing compiles, you may
+A bit of Git vocabulary will be explained below. The following is
+just introduction material; for better understanding of Git concepts,
+you are invited to read further documentation, especially Git
+Community Book at @uref{http://book.git-scm.com/}.
+
+The @code{git pull origin} command above is just a shortcut for this
+command:
@example
-git commit -a
-git format-patch origin
+git pull git://git.sv.gnu.org/lilypond.git/ @var{branch}:origin/@var{branch}
@end example
-Send an email to @email{lilypond-devel@@gnu.org} with the diff as
-an attachment.
+@noindent
+where @code{@var{branch}} is typically @code{master}, @code{web} or
+@code{lilypond/translation}; if you do not know or remember, see
+@ref{Getting the source code} to remember which commands you issued or
+which source code you wanted to get.
+
+A @emph{commit} is a set of changes made to the sources; it also
+includes the committish of the parent commit, the name and e-mail of
+the @emph{author} (the person who wrote the changes), the name and
+e-mail of the @emph{committer} (the person who brings these changes
+into the Git repository), and a commit message.
+
+A @emph{committish} is the SHA1 checksum of a commit, a number made of
+40 hexadecimal digits, which acts as the internal unique identifier
+for this commit. To refer to a particular revision, don't use vague
+references like the (approximative) date, simply copy and paste the
+committish.
+
+A @emph{branch} is nothing more than a pointer to a particular commit,
+which is called the @emph{head} of the branch; when referring to a
+branch, one often acutally thinks about its head and the ancestor
+commits of the head.
+
+Now we will explain the two last commands you used to get the source
+code from Git -- see @ref{Getting the source code}.
+@example
+git remote add -f -t @var{branch} -m @var{branch} origin git://git.sv.gnu.org/lilypond.git/
+git checkout -b @var{branch} origin/@var{branch}
+@end example
-@node Committing directly
-@subsection Committing directly
+The @command{git remote} has created a branch called
+@code{origin/@var{branch}} in your local Git repository. As this
+branch is a copy of the remote branch web from git.sv.gnu.org LilyPond
+repository, it is called a @emph{remote branch}, and is meant to track
+the changes on the branch from git.sv.gnu.org: it will be updated
+every time you run @command{git pull origin} or @command{git fetch
+origin}.
+
+The @command{git checkout} command has created a branch named
+@code{@var{branch}}. At the beginning, this branch is identical to
+@code{origin/@var{branch}}, but it will differ as soon as you make
+changes, e.g. adding newly translated pages or editing some
+documentation or code source file. Whenever you pull, you merge the
+changes from @code{origin/@var{branch}} and @code{@var{branch}} since
+the last pulling. If you do not have push (i.e. @qq{write}) access on
+git.sv.gnu.org, your @code{@var{branch}} will always differ from
+@code{origin/@var{branch}}. In this case, remember that other people
+working like you with the remote branch @code{@var{branch}} of
+git://git.sv.gnu.org/lilypond.git/ (called @code{origin/@var{branch}}
+on your local repository) know nothing about your own
+@code{@var{branch}}: this means that whenever you use a committish or
+make a patch, others expect you to take the latest commit of
+@code{origin/@var{branch}} as a reference.
+
+Finally, please remember to read the man page of every Git command you
+will find in this manual in case you want to discover alternate
+methods or just understand how it works.
+
+
+@node Git commands for managing several branches
+@subsection Git commands for managing several branches
+
+@subsubheading Listing branches and remotes
+
+You can get the exact path or URL of all remotes with
+running
+
+@example
+git remote -v
+@end example
-Most contributors do not have permission to commit directly. If
-you do, edit @file{.git/config}:
+To list Git branches on your local repositories, run
@example
-%% Change this line:
- url = git://git.sv.gnu.org/lilypond.git/
-%% into something like this:
- url = ssh://gpercival@@git.sv.gnu.org/srv/git/lilypond.git
+git branch # list local branches only
+git branch -r # list remote branches
+git branch -a # list all branches
@end example
-TODO: upload ssh key to somewhere?
-You may then
+@subsubheading Checking out branches
+
+To know the currently checked out branch, i.e. the branch whose source
+files are present in your working tree, read the first line of the
+output of
@example
-git push
+git status
@end example
+@noindent
+The currently checked out branch is also marked with an asterisk in
+the output of @command{git branch}.
-@node Other interesting Git commands
-@section Other interesting Git commands
+You can check out another branch @code{@var{other_branch}}, i.e. check
+out @code{@var{other_branch}} to the working tree, by running
-@menu
-* Git log::
-* Applying git patches::
-@end menu
+@example
+git checkout @var{other_branch}
+@end example
+
+Note that it is possible to check out another branch while having
+uncommitted changes, but it is not recommended unless you know what
+you are doing; it is recommended to run @command{git status} to check
+this kind of issue before checking out another branch.
+
+
+@subsubheading Merging branches
+
+To merge branch @code{@var{foo}} into branch @code{@var{bar}}, i.e. to
+@qq{add} all changes made in branch @code{@var{foo}} to branch
+@code{@var{bar}}, run
+
+@example
+git checkout @var{bar}
+git merge @var{foo}
+@end example
+
+If any conflict happens, see @ref{Resolving conflicts}.
+
+There are common usage cases for merging: as a translator, you will
+often want to merge @code{master} into @code{lilypond/translation}; on
+the other hand, the Translations meister wants to merge
+@code{lilypond/translation} into @code{master} whenever he has checked
+that @code{lilypond/translation} builds successfully.
+
+
+@node Working on LilyPond sources with several branches
+@subsection Working on LilyPond sources with several branches
+
+@subsubheading Fetching new branches from git.sv.gnu.org
+
+To fetch and check out a new branch named @code{@var{branch}} on
+git.sv.gnu.org, run from top of the Git repository
+
+@example
+git config --add remote.origin.fetch +refs/heads/@var{branch}:refs/remotes/origin/@var{branch}
+git checkout --track -b @var{branch} origin/@var{branch}
+@end example
+
+After this, you can pull @code{@var{branch}} from git.sv.gnu.org with
+
+@example
+git pull origin
+@end example
+
+Note that this command generally fetches all branches you added with
+@command{git remote add} (when you initialized the repository) or
+@command{git config --add}, i.e. it updates all remote branches from
+remote @code{origin}, then it merges the remote branch tracked by
+current branch into current branch. For example, if your current
+branch is @code{master} --- which is the case if you got the sources
+with the commands described in @ref{Main source code} and did not
+issue any @command{git checkout} command --- @code{origin/master} will
+be merged into @code{master}.
+
+
+@subsubheading Local clones, or having several working trees
+
+If you play with several Git branches, e.g. @code{master},
+@code{lilypond/translation}, @code{stable/2.12}), you may want to have
+one source and build tree for each branch; this is possible with
+subdirectories of your local Git repository, used as local cloned
+subrepositories. To create a local clone for the branch named
+@code{@var{branch}}, run
+
+@example
+git checkout @var{branch}
+git clone -l -s -n . @var{subdir}
+cd @var{subdir}
+git reset --hard
+@end example
+
+Note that @code{@var{subdir}} must be a directory name which does not
+already exist. In @code{@var{subdir}}, you can use all Git commands
+to browse revisions history, commit and uncommit changes; to update
+the cloned subrepository with changes made on the main repository, cd
+into @code{@var{subdir}} and run @command{git pull}; to send changes
+made on the subrepository back to the main repository, run
+@command{git push} from @code{@var{subdir}}. Note that only one
+branch (the currently checked out branch) is created in the
+subrepository by default; it is possible to have several branches in a
+subrepository and do usual operations (checkout, merge, create,
+delete...) on these branches, but this possibility is not detailed
+here.
+
+When you push @code{@var{branch}} from @code{@var{subdir}} to the main
+repository, and @code{@var{branch}} is checked out in the main
+repository, you must save uncommitted changes (see @command{git
+stash}) and do @command{git reset --hard} in the main repository in
+order to apply pushed changes in the working tree of the main
+repository.
@node Git log
@warning{The @code{gitk} command may require a separate @code{gitk} package,
available in the appropriate distribution's repositories.}
+
@node Applying git patches
@subsection Applying git patches
-Well-formed git patches should be committed with
+Well-formed git patches created with @code{git format-patch}
+should be committed with the following command:
+
+@example
+git am @var{patch}
+@end example
+
+Patches created without @code{git format-patch} can be applied in
+two steps. The first step is to apply the patch to the working
+tree:
@example
-git am
+git apply @var{patch}
@end example
-Patches created without @code{git format-patch} should be
-committed with
+@noindent
+The second step is to commit the changes and give credit to the
+author of the patch. This can be done with the following command:
@example
-git apply
+git commit -a --author="First Last <user@@example.net>"
@end example
+@node Reverting all local changes
+@subsection Reverting all local changes
+
+Sometimes git will become hopelessly confused, and you just want
+to get back to a known, stable state. This command destroys any
+local changes you have made, but at least you get back to the
+current online version:
+
+@example
+git reset --hard origin/master
+@end example
+
@node Git on Windows
@section Git on Windows
@subsection Installing git
Obtain Git from
-@uref{http://code.google.com/p/msysgit/downloads/list}.
-(Note, not msysGit, which is for Git developers) and
-install.
+@uref{http://code.google.com/p/msysgit/downloads/list}
+(note, not msysGit, which is for Git developers and not PortableGit,
+which is not a full git installation) and
+install it.
+
+Note that most users will not need to install SSH. That is not
+required until you have been granted direct push permissions to
+the master git repository.
Start Git by clicking on the desktop icon.
This will bring up a command line bash shell. This may be
call the folder to contain the repository [path]/Git.
You will need to have space for around 150Mbytes.
-In the git bash shell type
+Start the Git bash shell by clicking on the desk-top icon installed
+with Git and type
@example
cd [path]/Git
left-hand (Git Repository) panel. Leave everything
else unchanged and save it.
+Note that Windows users must leave the default setting for line
+endings unchanged. All files in a git repository must have lines
+terminated by just a LF, as this is required for Merge to work, but
+Windows files are terminated by CRLF by default. The git default
+setting causes the line endings of files in a Windows git repository
+to be flipped automatically between LF and CRLF as required. This
+enables files to be edited by any Windows editor without causing
+problems in the git repository.
+
@subsection Checking out a branch
At this stage you have two branches in your local repository,
Once familiarity with using git on Windows has been gained the
standard git manuals can be used to learn about these.
+
+
+@node Development inside VirtualBox (compiling on Windows)
+@section Development inside VirtualBox (compiling on Windows)
+
+
+
+
projects / lilypond.git / blobdiff