@node Working with source code
@chapter Working with source code
+New contributors should only read @ref{Using lily-git}. Please
+ignore the rest of this chapter.
+
+Advanced contributors will find the rest of this material quite
+useful, particularly if they are working on major new features.
@menu
* Using lily-git::
@end menu
+@c if you change this node name, you'll need to change the @ref in
+@c web/ and/or included/, along with all the translations.
@node Using lily-git
@section Using lily-git
+@command{lily-git.tcl} is a graphical tool to help you access and
+share changes to the lilypond source code.
-If you haven't already, download and install Git. Go to
-@uref{http://git-scm.com/download}, and in the @qq{Binaries}
-section, select the appropriate package for your operating system.
-Windows users should visit
-@uref{http://code.google.com/p/msysgit/downloads/list} and
-download the @file{.exe} file labeled @qq{Full installer for
-official Git}.
+@menu
+* Install and configuration of lily-git.tcl::
+* Daily use of lily-git.tcl::
+@end menu
-Download the lily-git script from:
+@node Install and configuration of lily-git.tcl
+@unnumberedsubsec Install and configuration of @command{lily-git.tcl}
-@c don't change the cgit link below to gitweb; gitweb uses
-@c long filenames like "scripts_auxiliar_lily-git.tcl"
+@subsubheading Lilybuntu
-@example
-@uref{http://git.sv.gnu.org/cgit/lilypond.git/plain/scripts/auxiliar/lily-git.tcl}.
-@end example
+@warning{The rest of this manual assumes that you are using the
+command-line; go to @clicksequence{Applications @click{}
+Accessories @click{} Terminal}.}
-To run the program from the command line, navigate to the
-directory containing @file{lily-git.tcl} and enter:
+@enumerate
+@item
+@code{lily-git.tcl} has already been install for you. Simply type
+(or copy&paste):
@example
+cd
wish lily-git.tcl
@end example
+@item
+Click on the @qq{Get source} button.
-@subsubheading Get source / Update source
-
-When you click the @qq{Get source} button, @command{lily-git} will
-create a directory called @file{lilypond-git/} within your home
-directory, and will download the complete source code into that
+This will create a directory called @file{lilypond-git/} within
+your home directory, and will download the source code into that
directory (around 55Mb). When the process is finished, the
@qq{Command output} window will display @qq{Done}, and the button
label will change to say @qq{Update source}.
+@item
Navigate to the @file{lilypond-git/} directory to view the source
files. You should now be able to modify the source files using
your normal text editor.
+@end enumerate
+
+You should now progress to @ref{Compiling with lilybuntu}.
+
+@warning{Throughout the rest of this manual, most command-line
+input should be entered from @file{~/lilypond-git/}. This is
+referred to as the @emph{top source directory}.}
+
+
+@subsubheading Other operating music systems
+
+@enumerate
+@item
+If you haven't already, download and install Git.
+
+@itemize
+
+@item
+Lilybuntu users: git has already been installed for you.
+
+@item Windows users: download the @code{.exe} file labeled
+@qq{Full installer for official Git} from:
+
+@example
+@uref{http://code.google.com/p/msysgit/downloads/list}
+@end example
+
+@item Other operating systems: either install @command{git} with
+your package manager, or download it from the @qq{Binaries}
+section of:
+
+@example
+@uref{http://git-scm.com/download}
+@end example
+
+@end itemize
+
+
+@item
+Download the @command{lily-git.tcl} script from:
+
+@c don't change the cgit link below to gitweb; gitweb uses
+@c long filenames like "scripts_auxiliar_lily-git.tcl"
+
+@example
+@uref{http://git.sv.gnu.org/cgit/lilypond.git/plain/scripts/auxiliar/lily-git.tcl}
+@end example
+
+@item
+To run the program from the command line, navigate to the
+directory containing @command{lily-git.tcl} and enter:
+
+@example
+wish lily-git.tcl
+@end example
+
+@item
+Go read the lilybuntu instructions, starting from the @qq{get
+source} step.
+
+@end enumerate
+
+@advanced{the @qq{Get source} button does not fetch the entire
+history of the git repository, so utilities like @command{gitk}
+will only be able to display the most recent additions. As you
+continue to work with @command{lily-git.tcl}, the @qq{Update
+source} button will take any new additions and add it to whatever
+is currently in your repository's history.}
+
+
+@node Daily use of lily-git.tcl
+@unnumberedsubsec Daily use of @command{lily-git.tcl}
+
+@warning{Only work on one set of changes at once. Do not start
+work on any new changes until your first set has been accepted.}
-@subsubheading New local commit
+@subsubheading 1. Update source
+
+At the beginning of each session of lilypond work, you should
+click the @qq{Update source} button to get the latest changes to
+the source code.
+
+@warning{In some rare and unfortunate circumstances, this will
+result in a @emph{merge conflict}. If this occurs, follow the
+instructions for @qq{Abort changes}, below. Your work will not be
+lost.}
+
+
+@subsubheading 2a. New local commit
A single commit typically represents one logical set of related
changes (such as a bug-fix), and may incorporate changes to
multiple files at the same time.
-When you're finished making the changes for your first commit,
-click the @qq{New local commit} button. This will open the
-@qq{Git Commit Message} window. The message header is required,
-and the message body is optional. See @ref{Commits and patches}
-for more information regarding commits and commit messages.
+When you're finished making the changes for a commit, click the
+@qq{New local commit} button. This will open the @qq{Git Commit
+Message} window. The message header is required, and the message
+body is optional.
After entering a commit message, click @qq{OK} to finalize the
commit.
+@advanced{for more information regarding commits and commit
+messages, see @ref{Commits and patches}.}
+
-@subsubheading Amend previous commit
+@subsubheading 2b. Amend previous commit
You can go back and make changes to the most recent commit with
the @qq{Amend previous commit} button. This is useful if a
-mistake is found after you've clicked the @qq{New local commit}
-button. To amend the most recent commit, edit the source files as
-needed and click the button. The earlier version of the commit is
-not saved, but is replaced by the new one.
+mistake is found after you have clicked the @qq{New local commit}
+button.
-Note that this does not update patch files; if you have a patch
-file from an earlier version of the commit, you will need to make
-another patch set when using this feature. The old patch file is
-not saved, but is replaced by the new one.
+To amend the most recent commit, re-edit the source files as
+needed and then click the @qq{Amend previous commit} button. The
+earlier version of the commit is not saved, but is replaced by the
+new one.
+@warning{This does not update the patch @strong{files}; if you
+have a patch file from an earlier version of the commit, you will
+need to make another patch set when using this feature. The old
+patch file will not be saved, but will be replaced by the new one
+after you click on @qq{Make patch set}.}
-@subsubheading Make patch set
+
+@subsubheading 3. Make patch set
Before making a patch set from any commits, you should click the
@qq{Update source} button to make sure the commits are based on
the most recent remote snapshot.
-When you click the @qq{Make patch set} button, @command{lily-git}
-will produce patch files for any new commits, saving them to the
-current directory. The command output will display the name of
-the new patch files near the end of the output:
+When you click the @qq{Make patch set} button,
+@command{lily-git.tcl} will produce patch files for any new
+commits, saving them to the current directory. The command output
+will display the name of the new patch files near the end of the
+output:
@example
0001-CG-add-lily-git-instructions.patch
Done.
@end example
-Send patch files to your mentor if you have one. Otherwise, write
-an email (must be less than 64 KB) to
-@email{lilypond-devel@@gnu.org} briefly explaining your work, with
-the patch files attached. Translators should send patches to
+Send patch files to the appropriate place:
+
+@itemize
+@item
+If you have a mentor, send it to them via email.
+
+@item
+New contributors should send the patch attached to an email to
+@email{frogs@@lilynet.net}. Please add @qq{[PATCH]} to the
+subject line.
+
+@item
+Translators should send patches to
@email{translations@@lilynet.net}.
+@item
+More experienced contributors should upload the patch for
+web-based review. This requires additional software and use of
+the command-line; see @ref{Uploading a patch for review}.
+
+@end itemize
+
@subsubheading The @qq{Abort changes -- Reset to origin} button
Using the Git program directly (as opposed to using the
-@command{lily-git} GUI) allows you to have much greater control
+@command{lily-git.tcl} GUI) allows you to have much greater control
over the contributing process. You should consider using Git if
you want to work on complex projects, or if you want to work on
multiple projects concurrently.
@warning{Throughout the rest of this manual, all command-line
input should be entered from the top directory of the Git
repository being discussed (eg. @file{~/lilypond-git/}). This is
-referred to as a @emph{top source directory}.}
+referred to as the @emph{top source directory}.}
Before downloading a copy of the main LilyPond repository, you
should configure some basic settings with the
* Making commits::
* Commit messages::
* Making patches::
+* Uploading a patch for review::
@end menu
@example
-# Please enter the commit message for your changes. Lines starting
+# Please enter the commit message for your changes. Lines starting
# with '#' will be ignored, and an empty message aborts the commit.
# On branch master
# Changes to be committed:
@node Making patches
@unnumberedsubsubsec Making patches
-
If you want to share your changes with other contributors and
developers, you need to generate @emph{patches} from your commits.
+We prefer it if you follow the instructions in
+@ref{Uploading a patch for review}. However, we present an
+alternate method here.
+
You should always run @command{git@tie{}pull@tie{}-r} (translators
should leave off the @code{-r}) before doing this to ensure that
your patches are as current as possible.
reviewed, the developers may push one or more of them to the main
repository or discuss them with you.
-@seealso
-If your patch includes a significant amount of code, you may want
-to see @ref{Adding or modifying features}, especially @emph{Post
-patch for comments}.
+@node Uploading a patch for review
+@unnumberedsubsubsec Uploading a patch for review
+
+Any non-trivial change should be uploaded to our @qq{Rietveld}
+code review website:
+
+@example
+@uref{http://codereview.appspot.com/}
+@end example
+
+@subsubheading Initial setup
+
+@enumerate
+
+@item
+You must have a gmail account.
+
+@item
+Install @command{git-cl} by entering:
+
+@example
+git clone git://neugierig.org/git-cl.git
+@end example
+
+@item
+Add the @file{git-cl/} directory to your PATH, or create a
+symbolic link to the @command{git-cl} and @command{upload.py}
+scripts in one of your PATH directories (such as
+@file{$HOME/bin}).
+
+
+@item
+Move into the top source directory and then configure
+@command{git cl}. If you do not understand any question, just
+answer with a newline (CR).
+
+@example
+cd $HOME/lilypond-git/
+git cl config
+@end example
+
+The @qq{CC list} question should be answered with:
+
+@example
+lilypond-devel@@gnu.org
+@end example
+
+@end enumerate
+
+@subsubheading Uploading patch set
+
+@warning{Unless you are familiar with branches, only work on one
+set of changes at once.}
+
+There are two methods, depending on your git setup.
+
+@itemize
+@item
+@strong{Master branch}: (easy option, and used in @command{lily-git.tcl})
+
+If you added your patch to @code{master}, then:
+
+@example
+git pull -r
+git cl upload origin/master
+@end example
+
+If you have git push ability, make sure that you @emph{remove}
+your patch (with @command{git rebase} or @command{git reset})
+before pushing other stuff.
+
+@item
+@strong{Separate branch}: (complicated option)
+
+Ensure your changes are committed in a separate branch, which
+should differ from the reference branch to be used by just the
+changes to be uploaded. If the reference branch is to be
+origin/master, ensure this is up-to-date. If necessary, use git
+rebase to rebase the branch containing the changes to the head of
+origin/master. Finally, check out branch with the changes and
+enter the command:
+
+@example
+git cl upload <reference SHA1 ID>
+@end example
+
+@noindent
+where <reference SHA1 ID> is the SHA1 ID of the commit to be used
+as a reference source for the patch. Generally, this will be the
+SHA1 ID of origin/master, and in that case the command:
+
+@example
+git cl upload origin/master
+@end example
+
+@noindent
+can be used.
+
+@end itemize
+
+After prompting for your Google email address and password, the
+patch set will be posted to Rietveld, and you will be given a URL
+for your patch.
+
+@subsubheading Announcing your patch set
+
+You should then announce the patch by logging into the code review
+issue webpage and using @qq{Publish + Mail Comments} to add a
+(mostly bogus) comment to your issue. The text of your comment
+will be sent to our developer mailing list.
+
+@subsubheading Revisions
+
+As revisions are made in response to comments, successive patch sets
+for the same issue can be uploaded by reissuing the git-cl command
+with the modified branch checked out.
+
+Sometimes in response to comments on revisions, the best way to
+work may require creation of a new branch in git. In order to
+associate the new branch with an existing Rietveld issue,
+the following command can be used:
+
+@example
+git cl issue issue-number
+@end example
+
+@noindent
+where @code{issue-number} is the number of the existing Rietveld
+issue.
+
+@subsubheading Resetting git cl
+
+If @command{git cl} becomes confused, you can @qq{reset} it by
+running:
+
+@example
+git cl issue 0
+@end example
@node Advanced Git procedures
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
+referring to a branch, one often actually thinks about its head
and the ancestor commits of the head.
Now we will explain the two last commands you used to get the
The commands above don't only bring you the latest version of the
-sources, but also the full history of revisions (revisons, also
+sources, but also the full history of revisions (revisions, also
called commits, are changes made to the sources), stored in the
@file{.git} directory. You can browse this history with
@item
-After your membership has been activated and you’ve configured Git
+After your membership has been activated and you've configured Git
to use SSH, test the connection with:
@example
@end example
@end itemize
+@knownissues
+Encryption protocols, including ssh, generally do not permit packet
+fragmentation to avoid introducing a point of insecurity. This
+means that the maximum packet size must not exceed the smallest
+MTU (Maximum Transmission Unit) set in the routers along the path.
+This smallest MTU is determined by a procedure during call set-up
+which relies on the transmission over the path of ICMP packets.
+If any of the routers in the path block ICMP packets this mechanism
+fails, resulting in the possibility of packets being transmitted
+which exceed the MTU of one of the routers. If this happens the
+packet is discarded, causing the ssh session to hang, timeout or
+terminate with the error message
+
+@example
+ssh: connect to host <host ip addr> port 22: Bad file number
+fatal: The remote end hung up unexpectedly
+@end example
+
+depending on precisely when in the proceedings the first large
+packet is transmitted. Most routers on the internet have MTU
+set to 1500, but routers installed in homes to connect via
+broadband may use a slightly smaller MTU for efficient transmission
+over ATM. If this problem is encountered a possible work-around is
+to set the MTU in the local router to 1500.
+
@node Git on Windows
@section Git on Windows
Git is a system for tracking the changes made to source files by a
distributed set of editors. It is designed to work without a
-master repository, but we have chosen to have a master respository
+master repository, but we have chosen to have a master repository
for LilyPond files. Editors hold a local copy of the master
repository together with any changes they have made locally.
Local changes are held in a local @q{branch}, of which there may
@subsection Git GUI
Almost all subsequent work will use the Git Graphical User
-Interface, which avoids having to type command line commands. To
+Interface, which avoids having to type command line commands. To
start Git GUI first start the Git bash shell by clicking on the
desktop icon, and type
projects / lilypond.git / blobdiff