sysmo-bts
/
generic-poky
9
0
Fork 0
Code Pull Requests Releases Activity

documentation/dev-manual/dev-manual-newbie.xml: edits and enhancements. 

General pass-through for consistency in referencing sections.
Also, added Darren Hart's review comments for the "Submitting a
Change" section.  I added more about the mailing lists and how to
submit a proper commit message.

(From yocto-docs rev: d9c8f5db8c862b1be724915cc43da6d12b88b97d)

Signed-off-by: Scott Rifenbark <scott.m.rifenbark@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
This commit is contained in:
Scott Rifenbark 2011-09-20 06:44:45 -07:00 committed by Richard Purdie
parent 90ccadecc3
commit 421c22d32c
1 changed files with 256 additions and 207 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

463
documentation/dev-manual/dev-manual-newbie.xml
View File

@ -7,12 +7,12 @@
<para>
This chapter helps you understand the Yocto Project as an open source development project.
In general, working in an open-source environment is very different than working in a
In general, working in an open source environment is very different as compared to working in a
proprietary environment.
Additionally, the Yocto Project uses specific tools and constructs as part of its development
environment.
The chapter specifically addresses open source philosophy, licensing issues, code repositories,
the open source distributed version control system Git, and best practices using Yocto Project.
the open source distributed version control system Git, and best practices using the Yocto Project.
</para>
<section id='open-source-philosophy'>
@ -33,23 +33,21 @@
stake in the software project.
The open source environment contains new copyright, licensing, domain, and consumer issues
that differ from the more traditional development environment.
In an open source environment the end-product, source material, and documentation are
In an open source environment, the end-product, source material, and documentation are
all available to the public at no cost.
</para>
<para>
A benchmark example of an open source project is the Linux Kernel, which was initially conceived
and created by Finnish computer science student Linus Torvalds in 1991.
Conversely, a good example of a non-open source project is the Windows family of operating
systems developed by Microsoft Corporation.
Conversely, a good example of a non-open source project is the
<trademark class='registered'>Windows</trademark> family of operating
systems developed by <trademark class='registered'>Microsoft</trademark> Corporation.
</para>
<para>
Wikipedia has a good historical description of the Open Source Philosophy
<ulink url='http://en.wikipedia.org/wiki/Open_source'>here</ulink>.
</para>
<para>
You can also find helpful information on how to participate in the Linux Community
<ulink url='http://ldn.linuxfoundation.org/book/how-participate-linux-community'>here</ulink>.
</para>
@ -66,21 +64,21 @@
From the interface, you can click on any particular item in the "Name" column and
see the URL at the bottom of the page that you need to set up a Git repository for
that particular item.
The ability to create Git repositories of the Yocto Project source allows you to
Having a local Git repository of the Yocto Project files allows you to
make changes, contribute to the history, and ultimately enhance the Yocto Project's
tools, Board Support Packages, and so forth.
</para>
<para>
Conversely, if you are a developer that is not interested in contributing back to the
Yocto Project you have the ability to simply download and extract release tarballs
Yocto Project, you have the ability to simply download and extract release tarballs
and use them within the Yocto Project environment.
All that is required is a particular release of Yocto Project, a kernel, and
your application source code.
</para>
<para>
For any supported release of Yocto Project you can go to the Yocto Project website’s
For any supported release of Yocto Project, you can go to the Yocto Project website’s
<ulink url='http://www.yoctoproject.org/download'>download page</ulink> and get a
tarball of the release.
You can also go to this site to download any supported BSP tarballs.
@ -104,8 +102,9 @@
<imagedata fileref="figures/source-repos.png" align="center" width="6in" depth="4in" />
</para></listitem>
<listitem><para><anchor id='index-downloads' /><emphasis><ulink url='http://autobuilder.yoctoproject.org/downloads/'>Index of /downloads:</ulink></emphasis>
This area contains an index of the Eclipse-plugin, miscellaneous support, poky, pseudo, and
all released versions of Yocto Project in the form of images or tarballs.
This area contains an index of downloads such as
the Eclipse Yocto Plug-in, miscellaneous support, Poky, pseudo, cross-development toolchains,
and all released versions of Yocto Project in the form of images or tarballs.
Downloading and extracting these files does not produce a Git repository but rather
a snapshot of a particular release or image.
[WRITER NOTE: link will be http://downloads.yoctoproject.org.]</para>
@ -130,12 +129,87 @@
<para>
Following is a list of terms and definitions users new to the Yocto Project development
environment might find helpful.
Some terms are universal but are included here just in case:
While some of these terms are universal, the list includes them just in case:
<itemizedlist>
<listitem><para><emphasis>The Yocto Project Files:</emphasis>
<listitem><para><emphasis>Append Files:</emphasis> Files that append build information to
a recipe file.
Information in append files override the information in the similarly-named recipe file.
Append files use the <filename>.bbappend</filename> filename suffix.</para></listitem>
<listitem><para><emphasis>BitBake:</emphasis> The task executor and scheduler used by
the Yocto Project to build images.
For more information on BitBake, see the <ulink url='http://bitbake.berlios.de/manual/'>
BitBake documentation</ulink>.</para></listitem>
<listitem><para><emphasis>Classes:</emphasis> Files that provide for logic encapsulation
and inheritance allowing commonly used patterns to be defined once and easily used
in multiple recipes.
Class files end with the <filename>.bbclass</filename> filename extension.</para></listitem>
<listitem><para><emphasis>Configuration File:</emphasis> Configuration information in the
<filename>.conf</filename> files provides global definitions of variables.
The <filename>conf/local.conf</filename> configuration file in the Yocto Project
build directory defines user-defined variables that affect each build.
The <filename>distro/poky.conf</filename> configuration file also in the
build directory defines Yocto ‘distro’ configuration
variables used only when building with this policy.
Machine configuration files, which
are located throughout the Yocto Project file structure, define
variables for specific hardware and are only used when building for that target
(e.g. the <filename>machine/beagleboard.conf</filename> configuration file defines
variables for the Texas Instruments ARM Cortex-A8 development board).
Configuration files end with a <filename>.conf</filename> filename extension.</para></listitem>
<listitem><para><emphasis>Cross-Development Toolchain:</emphasis> A collection of software development
tools and utilities that allow you to develop software for targeted architectures.
This toolchain contains cross-compilers, linkers, and debuggers that are specific to
an architecure.
You can use the Yocto Project to build cross-development toolchains in tarball form that when
unpacked contain the development tools you need to cross-compile and test your software.
The Yocto Project ships with images that contain toolchains for supported architectures
as well.
Sometimes this toolchain is referred to as the meta-toolchain.</para></listitem>
<listitem><para><emphasis>Image:</emphasis> An image is the result produced when
BitBake processes a given collection of recipes and related metadata.
Images are the binary output that runs on specific hardware and for specific
use cases.
For a list of the supported image types that the Yocto Project provides, see the
"<ulink url='http://www.yoctoproject.org/docs/1.1/poky-ref-manual/poky-ref-manual.html#ref-images'>Reference: Images</ulink>"
appendix in
<ulink url='http://www.yoctoproject.org/docs/1.1/poky-ref-manual/poky-ref-manual.html'>
The Yocto Project Reference Manual</ulink>.</para></listitem>
<listitem><para><emphasis>Layer:</emphasis> A collection of recipes representing the core,
a BSP, or an application stack.</para></listitem>
<listitem><para><emphasis>Metadata:</emphasis> The files that BitBake parses when building an image.
Metadata includes recipes, classes, and configuration files.</para></listitem>
<listitem><para><emphasis>OE-Core:</emphasis> A core set of metadata originating
with OpenEmbedded (OE) that is shared between OE and the Yocto Project.
This metadata is found in the <filename>meta</filename> directory of the Yocto Project
files.</para></listitem>
<listitem><para><emphasis>Package:</emphasis> The packaged output from a baked recipe.
A package is generally the compiled binaries produced from the recipe's sources.
You ‘bake’ something by running it through BitBake.</para></listitem>
<listitem><para><emphasis>Poky:</emphasis> The build tool that the Yocto Project
uses to create images.</para></listitem>
<listitem><para><emphasis>Recipe:</emphasis> A set of instructions for building packages.
A recipe describes where you get source code and which patches to apply.
Recipes describe dependencies for libraries or for other recipes, and they
also contain configuration and compilation options.
Recipes contain the logical unit of execution, the software/images to build, and
use the <filename>.bb</filename> file extension.</para></listitem>
<listitem><para><emphasis>Tasks:</emphasis> Arbitrary groups of software Recipes.
You simply use Tasks to hold recipes that, when built, usually accomplish a single task.
For example, a task could contain the recipes for a company’s proprietary or value-add software.
Or, the task could contain the recipes that enable graphics.
A task is really just another recipe.
Because task files are recipes, they end with the <filename>.bb</filename> filename
extension.</para></listitem>
<listitem><para><emphasis>Upstream:</emphasis> A reference to source code or repositories
that are not local to the development system but located in a master area that is controlled
by the maintainer of the source code.
For example, in order for a developer to work on a particular piece of code, they need to
first get a copy of it from an "upstream" source.</para></listitem>
<listitem><para><emphasis>Yocto Project Files:</emphasis>
This term refers to the directory structure created as a result of downloading
and unpacking a Yocto Project release tarball or setting up a Git repository
by cloning <filename>git://git.yoctoproject.org/poky</filename>.</para>
by cloning <filename>git://git.yoctoproject.org/poky</filename>.
Sometimes the term "the Yocto Project Files structure" is used as well.</para>
<para>The Yocto Project files contain BitBake, Documentation, metadata and
other files that all support the development environment.
Consequently, you must have the Yocto Project files in place on your development
@ -143,102 +217,31 @@
<para>The name of the top-level directory of the Yocto Project file structure
is derived from the Yocto Project release tarball.
For example, downloading and unpacking <filename>poky-edison-6.0.tar.bz2</filename>
results in a Yocto Project source tree whose Yocto Project source directory is named
results in a Yocto Project file structure whose Yocto Project source directory is named
<filename>poky-edison-6.0</filename>.
If you create a Git repository, then you can name the repository anything you like.</para>
<para>You can find instruction on how to set up the Yocto Project files on your
host development system by reading
the
"<ulink url='http://www.yoctoproject.org/docs/1.1/dev-manual/dev-manual.html#getting-setup'>Getting
Setup</ulink>" section in
<ulink url='http://www.yoctoproject.org/docs/1.1/dev-manual/dev-manual.html'>
The Yocto Project Development Manual</ulink>.</para></listitem>
<listitem><para><emphasis>Yocto Project Build Tree:</emphasis>
This term refers to the area where the Yocto Project builds images.
Setup</ulink>" section.</para></listitem>
<listitem><para><emphasis>Yocto Project Build Directory:</emphasis>
This term refers to the area used by the Yocto Project for builds.
The area is created when you <filename>source</filename> the Yocto Project setup
environment script that is found in the Yocto Project files area.
(e.g. <filename>oe-init-build-env</filename>).
You can create the Yocto Project build tree anywhere you want on your
You can create the Yocto Project build directory anywhere you want on your
development system.
Here is an example that creates the tree in <filename>mybuilds</filename>
Here is an example that creates the directory in <filename>mybuilds</filename>
and names the Yocto Project build directory <filename>YP-6.0</filename>:
<literallayout class='monospaced'>
$ source poky-edison-6.0/oe-init-build-env $HOME/mybuilds/YP-6.0
</literallayout>
If you don't specifically name the build directory, BitBake creates it
If you don't specifically name the directory, BitBake creates it
in the current directory and uses the name <filename>build</filename>.
Also, if you supply an existing directory, then BitBake uses that
directory as the Yocto Project build directory and populates the build tree
directory as the Yocto Project build directory and populates the build hierarchy
beneath it.</para></listitem>
<listitem><para><emphasis>Image</emphasis> - An image is the result produced when
BitBake processes a given collection of recipes and related metadata.
Images are the binary output that runs on specific hardware and for specific
use cases.
For a list of the supported image types that the Yocto Project provides, see the
<ulink url='http://www.yoctoproject.org/docs/1.1/poky-ref-manual/poky-ref-manual.html#ref-images'>
Reference: Images</ulink> appendix in
<ulink url='http://www.yoctoproject.org/docs/1.1/poky-ref-manual/poky-ref-manual.html'>
The Yocto Project Reference Manual</ulink>.</para></listitem>
<listitem><para><emphasis>Recipe</emphasis> - A set of instructions for building packages.
A recipe describes where you get source code and which patches to apply.
Recipes describe dependencies for libraries or for other recipes and they
also contain configuration and compilation options.
Recipes contain the logical unit of execution, the software/images to build, and
use the <filename>.bb</filename> file extension.</para></listitem>
<listitem><para><emphasis>BitBake</emphasis> - The task executor and scheduler used by Yocto Project
to build images.
For more information on BitBake, see the <ulink url='http://bitbake.berlios.de/manual/'>
BitBake documentation</ulink>.</para></listitem>
<listitem><para><emphasis>Package</emphasis> - The packaged output from a baked recipe.
A package is generally the compiled binaries produced from the recipe's sources.
You ‘bake’ something by running it through BitBake.</para></listitem>
<listitem><para><emphasis>Layer</emphasis> - A collection of recipes representing the core,
a BSP, or an application stack.</para></listitem>
<listitem><para><emphasis>Metadata</emphasis> - A term used throughout the Yocto Project
documentation that refers to the files that BitBake parses when building an image.
Metadata includes recipes, classes, and configuration files.</para></listitem>
<listitem><para><emphasis>Meta-Toolchain</emphasis> - A collection of software development
tools and utilities that allow you to develop software for targeted architectures.
These toolchains contain cross-compilers, linkers, and debuggers that are specific to
an architecure.
You can use the Yocto Project to build meta-toolchains in tarball form that when
unpacked contain the development tools you need to cross-compile and test your software.
The Yocto Project ships with images that contain toolchains for supported architectures
as well.</para></listitem>
<listitem><para><emphasis>Configuration File</emphasis>: Configuration information in the
<filename>.conf</filename> files provides global definitions of variables.
The <filename>build/conf/local.conf</filename> configuration file defines user-defined variables
that effect each build.
The <filename>distro/poky.conf</filename> configuration file defines Yocto ‘distro’ configuration
variables used only when building with this policy.
The <filename>machine/beagleboard.conf</filename> configuration file defines variables
for the Beagleboard and are only used when building for that target
(i.e. Texas Instruments ARM Cortex-A8 development board).
Configuration files end with a <filename>.conf</filename> filename extension.</para></listitem>
<listitem><para><emphasis>Classes</emphasis> - Files that provide for logic encapsulation
and inheritance allowing commonly used patterns to be defined once and easily used
in multiple recipes.
Class files end with the <filename>.bbclass</filename> filename extension.</para></listitem>
<listitem><para><emphasis>Append Files</emphasis> - Files that append build information to
a recipe file.
Information in append files override the information in the similarly-named recipe file.
Append files use the <filename>.bbappend</filename> filename suffix.</para></listitem>
<listitem><para><emphasis>Tasks</emphasis> - Arbitrary groups of software Recipes.
You simply use Tasks to hold recipes that when built usually accomplish a single task.
For example, a task could contain the recipes for a company’s proprietary or value-add software.
Or the task could contain the recipes that enable graphics.
A task is really just another recipe.
Because task files are recipes, they end with the <filename>.bb</filename> filename
extension.</para></listitem>
<listitem><para><emphasis>OE-Core</emphasis> - A core set of metadata originating
with OpenEmbedded (OE) that is shared between OE and the Yocto Project.
This metadata is found in the <filename>meta</filename> directory of the Yocto Project
files.</para></listitem>
<listitem><para><emphasis>Upstream</emphasis> - A reference to source code or repositories
that are not local to the development system but located in a master area that is controlled
by the maintainer of the source code.
For example, in order for a developer to work on a particular piece of code they need to
first get a copy of it from an "upstream" source.</para></listitem>
</itemizedlist>
</para>
</section>
@ -247,9 +250,9 @@
<title>Licensing</title>
<para>
Because open source projects are open to the public they have different licensing structures in place.
Because open source projects are open to the public, they have different licensing structures in place.
License evolution for both Open Source and Free Software has an interesting history.
If you are interested in the history you can find basic information here:
If you are interested in this history, you can find basic information here:
<itemizedlist>
<listitem><para><ulink url='http://en.wikipedia.org/wiki/Open-source_license'>Open source license history</ulink>
</para></listitem>
@ -275,13 +278,13 @@
When you build an image using Yocto Project, the build process uses a known list of licenses to
ensure compliance.
Once the build completes, the list of all licenses found and used during the build are
kept in the resulting build directory at
<filename>&lt;build_directory&gt;/tmp/deploy/images/licenses</filename>.
kept in the Yocto Project build directory at
<filename>tmp/deploy/images/licenses</filename>.
If a module requires a license that is not in the base list, the build process
generates a warning during the build.
These tools make it easier for a developer to be certain of the licenses with which
their shipped products must comply.
However, it is still up to the developer to resolve potential licensing issues.
However, even with these tools it is still up to the developer to resolve potential licensing issues.
</para>
<para>
@ -292,14 +295,13 @@
for a standard format for communicating the components, licenses, and copyrights
associated with a software package.
<ulink url='http://opensource.org'>OSI</ulink> is a corporation dedicated to the Open Source
Definition and the effort for reviewing
and approving licenses that are OSD-conformant.
Definition and the effort for reviewing and approving licenses that are OSD-conformant.
</para>
<para>
You can find a list of the combined SPDX and OSI licenses that the Yocto Project uses
<ulink url='http://git.yoctoproject.org/cgit/cgit.cgi/poky/tree/meta/files/common-licenses'>here</ulink>.
The wiki page discusses the license infrastructure used by the Yocto Project.
This wiki page discusses the license infrastructure used by the Yocto Project.
</para>
</section>
@ -320,7 +322,7 @@
You do not have to be an expert in Git to be functional.
A good place to look for instruction on a minimal set of Git commands is
<ulink url='http://git-scm.com/documentation'>here</ulink>.
If you need to download Git you can do so
If you need to download Git, you can do so
<ulink url='http://git-scm.com/download'>here</ulink>.
</para>
@ -332,7 +334,7 @@
This methodology also allows for an environment in which you can do lots of
experimentation on your project as you develop changes or new features.
For example, you can create a “branch”, experiment with some feature, and then
if you like the feature you incorporate the branch into the tree.
if you like the feature, you incorporate the branch into the tree.
If you don’t, you cut the branch off by deleting it.
</para>
@ -347,55 +349,63 @@
omits the many arguments they support.
See the Git documentation for complete descriptions and strategies on how to use these commands:
<itemizedlist>
<listitem><para><emphasis><filename>git init</filename></emphasis> – Initializes an empty Git repository.
<listitem><para><emphasis><filename>git init</filename>:</emphasis> Initializes an empty Git repository.
You cannot use Git commands unless you have a <filename>.git</filename> repository.</para></listitem>
<listitem><para><emphasis><filename>git clone</filename></emphasis> – Creates a clone of a repository.
During collaboration this command allows you to create a local repository that is on
<listitem><para><emphasis><filename>git clone</filename>:</emphasis> Creates a clone of a repository.
During collaboration, this command allows you to create a local repository that is on
equal footing with a fellow developer’s repository.</para></listitem>
<listitem><para><emphasis><filename>git add</filename></emphasis> – Adds updated file contents to the index that
<listitem><para><emphasis><filename>git add</filename>:</emphasis> Adds updated file contents
to the index that
Git uses to track changes.
All files that have changed must be added before they can be committed.</para></listitem>
<listitem><para><emphasis><filename>git commit</filename></emphasis> – Creates a “commit” that documents
You must add all files that have changed before you can commit them.</para></listitem>
<listitem><para><emphasis><filename>git commit</filename>:</emphasis> Creates a “commit” that documents
the changes you made.
Commits are used for historical purposes, for determining if a maintainer of a project
will allow the change, and for ultimately pushing the change from your local Git repository
into the project’s upstream (or master) repository.</para></listitem>
<listitem><para><emphasis><filename>git status</filename></emphasis> – Reports any modified files that
<listitem><para><emphasis><filename>git status</filename>:</emphasis> Reports any modified files that
possibly need added and committed.</para></listitem>
<listitem><para><emphasis><filename>git checkout &lt;branch-name&gt;</filename></emphasis> - Changes
your working branch. This command is analogous to “cd”.</para></listitem>
<listitem><para><emphasis><filename>git checkout –b &lt;working-branch&gt;</filename></emphasis> - Creates
<listitem><para><emphasis><filename>git checkout &lt;branch-name&gt;</filename>:</emphasis> Changes
your working branch.
This command is analogous to “cd”.</para></listitem>
<listitem><para><emphasis><filename>git checkout –b &lt;working-branch&gt;</filename>:</emphasis> Creates
a working branch on your local machine where you can isolate work.
It is a good idea to use local branches when adding specific features or changes.
This way if you don’t like what you have done you can easily get rid of the work.</para></listitem>
<listitem><para><emphasis><filename>git branch</filename></emphasis> – Reports existing branches and
<listitem><para><emphasis><filename>git branch</filename>:</emphasis> Reports existing branches and
tells you which branch in which you are currently working.</para></listitem>
<listitem><para><emphasis><filename>git branch -D &lt;branch-name&gt;</filename></emphasis> –
Deletes an existing branch. You need to be in a branch other than the one you are deleting
<listitem><para><emphasis><filename>git branch -D &lt;branch-name&gt;</filename>:</emphasis>
Deletes an existing branch.
You need to be in a branch other than the one you are deleting
in order to delete &lt;branch-name&gt;.</para></listitem>
<listitem><para><emphasis><filename>git pull</filename></emphasis> – Retrieves information from an upstream Git
<listitem><para><emphasis><filename>git pull</filename>:</emphasis> Retrieves information
from an upstream Git
repository and places it in your local Git repository.
You use this command to make sure you are synchronized with the upstream repository
from which the project’s maintainer uses to pull changes into the master repository.</para></listitem>
<listitem><para><emphasis><filename>git push</filename></emphasis> – Sends all your local changes you
have committed to an upstream Git repository.
You use this command to make sure you are synchronized with the repository
from which you are basing changes (.e.g. the master repository).</para></listitem>
<listitem><para><emphasis><filename>git push</filename>:</emphasis> Sends all your local changes you
have committed to an upstream Git repository (e.g. a contribution repository).
The maintainer of the project draws from these repositories when adding your changes to the
project’s master repository.</para></listitem>
<listitem><para><emphasis><filename>git merge</filename></emphasis> – Combines or adds changes from one
<listitem><para><emphasis><filename>git merge</filename>:</emphasis> Combines or adds changes from one
local branch of your repository with another branch.
When you create a local Git repository the default branch is named “master”.
When you create a local Git repository, the default branch is named “master”.
A typical workflow is to create a temporary branch for isolated work, make and commit your
changes, switch to the master branch, merge the changes from the temporary branch into the
master branch, and then delete the temporary branch</para></listitem>
<listitem><para><emphasis><filename>git cherry-pick</filename></emphasis> – Choose and apply specific
changes, switch to your local master branch, merge the changes from the temporary branch into the
local master branch, and then delete the temporary branch.</para></listitem>
<listitem><para><emphasis><filename>git cherry-pick</filename>:</emphasis> Choose and apply specific
commits from one branch into another branch.
There are times when you might not be able to merge all the changes in one branch with
another but need to pick out certain ones.</para></listitem>
<listitem><para><emphasis><filename>gitk</filename></emphasis> – Provides a GUI view of the branches
<listitem><para><emphasis><filename>gitk</filename>:</emphasis> Provides a GUI view of the branches
and changes in your local Git repository.
This command is a good way to see where things have diverged in your local repository.</para></listitem>
<listitem><para><emphasis><filename>git log</filename></emphasis> – Reports a history of your changes to the
This command is a good way to graphically see where things have diverged in your
local repository.</para></listitem>
<listitem><para><emphasis><filename>git log</filename>:</emphasis> Reports a history of your changes to the
repository.</para></listitem>
<listitem><para><emphasis><filename>git diff</filename>:</emphasis> Displays line-by-line differences
between your local working files and the same files in the upstream Git repository that your
branch currently tracks.</para></listitem>
</itemizedlist>
</para>
</section>
@ -407,14 +417,16 @@
This section provides some overview on workflows using Git.
In particular, the information covers basic practices that describe roles and actions in a
collaborative development environment.
Again, if you are familiar with this type of development environment you might want to just skip the section.
Again, if you are familiar with this type of development environment, you might want to just
skip the section.
</para>
<para>
The Yocto Project files are maintained using Git in a "master" branch whose Git history
tracks every change and whose structure provides branches for all diverging functionality.
Although there is no need to use Git, This practice is typical for open-source projects.
For the Yocto Project a key individual called the "maintainer" is responsible for "master".
Although there is no need to use Git, many open source projects do so.
For the Yocto Project, a key individual called the "maintainer" is responsible for "master"
branch of the Git repository.
The "master" branch is the “upstream” repository where the final builds of the project occur.
The maintainer is responsible for allowing changes in from other developers and for
organizing the underlying branch structure to reflect release strategies and so forth.
@ -432,7 +444,7 @@
Developers (including contributing community members) create and maintain cloned repositories
of the upstream "master" branch.
These repositories are local to their development platforms and are used to develop changes.
When a developer is satisfied with a particular feature or change they “push” the changes
When a developer is satisfied with a particular feature or change, they “push” the changes
to the appropriate "contrib" repository.
</para>
@ -468,53 +480,53 @@
The following list describes some of these practices.
For more detailed information about these strategies see
<ulink url='http://www.kernel.org/pub/software/scm/git/docs/gitworkflows.html'>Git Workflows</ulink>.
<itemizedlist>
<listitem><para><emphasis>Make Small Changes</emphasis> - It is best to keep your changes you commit
small as compared to bundling many disparate changes into a single commit.
This practice not only keeps things manageable but also allows the maintainer
to more easily include or refuse changes.</para>
<para>It is also good practice to leave the repository in a state that allows you to
still successfully build your project.</para></listitem>
<listitem><para><emphasis>Use Branches Liberally</emphasis> - It is very easy to create, use, and
delete local branches in your working Git repository.
You can name these branches anything you like.
It is helpful to give them names associated with the particular feature or change
on which you are working.
Once you are done with a feature or change you simply discard the branch.</para></listitem>
<listitem><para><emphasis>Merge Changes</emphasis> - The <filename>git merge</filename>
command allows you to take the
changes from one branch and fold them into another branch.
This process is especially helpful when more than a single developer might be working
on different parts of the same feature.
Merging changes also automatically identifies any collisions or “conflicts”
that might happen resulting from the same lines of code being altered by two different
developers.</para></listitem>
<listitem><para><emphasis>Manage Branches</emphasis> - Because branches are easy to use, you should
use a system where branches indicate varying levels of code readiness.
For example, you can have a “work” branch to develop in, a “test” branch where the code or
change is tested, a “stage” branch where changes are ready to be committed, and so forth.
As your project develops, you can merge code across the branches to reflect ever-increasing
stable states of the development.</para></listitem>
<listitem><para><emphasis>Use Push and Pull</emphasis> - The push-pull workflow is based on the
concept of developers “pushing” local commits to a remote repository, which is
usually a contribution repository.
It is also based on the developers “pulling” known states of the project down into their
local development repositories.
This workflow easily allows you to pull changes submitted by other developers from the
upstream repository into your work area ensuring that you have the most recent software
on which to develop.
The Yocto Project has two scripts named <filename>create-pull-request</filename> and
<filename>send-pull-request</filename> that ship with the release to facilitate this
workflow.
You can find these scripts in the local Yocto Project files Git repository in
<filename>scripts</filename>.</para></listitem>
<listitem><para><emphasis>Patch Workflow</emphasis> - This workflow allows you to notify the
maintainer through an email that you have a change (or patch) you would like considered
for the "master" branch of the Git repository.
To send this type of change you format the patch and then send the email using the Git commands
<filename>git format-patch</filename> and <filename>git send-email</filename>.
You can find information on how to submit later in this chapter.</para></listitem>
</itemizedlist>
<itemizedlist>
<listitem><para><emphasis>Make Small Changes:</emphasis> It is best to keep your changes you commit
small as compared to bundling many disparate changes into a single commit.
This practice not only keeps things manageable but also allows the maintainer
to more easily include or refuse changes.</para>
<para>It is also good practice to leave the repository in a state that allows you to
still successfully build your project.</para></listitem>
<listitem><para><emphasis>Use Branches Liberally:</emphasis> It is very easy to create, use, and
delete local branches in your working Git repository.
You can name these branches anything you like.
It is helpful to give them names associated with the particular feature or change
on which you are working.
Once you are done with a feature or change, simply discard the branch.</para></listitem>
<listitem><para><emphasis>Merge Changes:</emphasis> The <filename>git merge</filename>
command allows you to take the
changes from one branch and fold them into another branch.
This process is especially helpful when more than a single developer might be working
on different parts of the same feature.
Merging changes also automatically identifies any collisions or “conflicts”
that might happen as a result of the same lines of code being altered by two different
developers.</para></listitem>
<listitem><para><emphasis>Manage Branches:</emphasis> Because branches are easy to use, you should
use a system where branches indicate varying levels of code readiness.
For example, you can have a “work” branch to develop in, a “test” branch where the code or
change is tested, a “stage” branch where changes are ready to be committed, and so forth.
As your project develops, you can merge code across the branches to reflect ever-increasing
stable states of the development.</para></listitem>
<listitem><para><emphasis>Use Push and Pull:</emphasis> The push-pull workflow is based on the
concept of developers “pushing” local commits to a remote repository, which is
usually a contribution repository.
This workflow is also based on developers “pulling” known states of the project down into their
local development repositories.
The workflow easily allows you to pull changes submitted by other developers from the
upstream repository into your work area ensuring that you have the most recent software
on which to develop.
The Yocto Project has two scripts named <filename>create-pull-request</filename> and
<filename>send-pull-request</filename> that ship with the release to facilitate this
workflow.
You can find these scripts in the local Yocto Project files Git repository in
<filename>scripts</filename>.</para></listitem>
<listitem><para><emphasis>Patch Workflow:</emphasis> This workflow allows you to notify the
maintainer through an email that you have a change (or patch) you would like considered
for the "master" branch of the Git repository.
To send this type of change you format the patch and then send the email using the Git commands
<filename>git format-patch</filename> and <filename>git send-email</filename>.
You can find information on how to submit later in this chapter.</para></listitem>
</itemizedlist>
</para>
</section>
@ -532,7 +544,7 @@
<para>
Sometimes it is helpful to submit, investigate, or track a bug against the Yocto Project itself
such as when discovering an issue with some component of the build system that acts contrary
to the documentation or expectations.
to the documentation or your expectations.
You can find information
for Bugzilla configuration and bug tracking procedures specific to the Yocto Project
<ulink url='https://wiki.yoctoproject.org/wiki/Bugzilla_Configuration_and_Bug_Tracking'>here</ulink>.
@ -548,7 +560,7 @@
<para>
Here are some things to remember when dealing with bugs against the Yocto Project:
<itemizedlist>
<listitem><para>The Yocto Project follows a naming bug-naming convention:
<listitem><para>The Yocto Project follows a bug-naming convention:
<filename>[YOCTO #&lt;number&gt;]</filename>, where <filename>&lt;number&gt;</filename> is the
assigned defect ID used in Bugzilla.
So, for example, a valid way to refer to a defect when creating a commit comment
@ -567,8 +579,34 @@
<para>
Contributions to the Yocto Project are very welcome.
You should send patches to the Yocto Project mailing list to get them in front of the
Yocto Project Maintainer.
You should send patches to the appropriate Yocto Project mailing list to get them
in front of the Yocto Project Maintainer.
For a list of the Yocto Project mailing lists, see the
"<ulink url='http://www.yoctoproject.org/docs/1.1/poky-ref-manual/poky-ref-manual.html#resources-mailinglist'>Mailing lists</ulink>" section in
<ulink url='http://www.yoctoproject.org/docs/1.1/poky-ref-manual/poky-ref-manual.html'> The
Yocto Project Reference Manual</ulink>.
</para>
<para>
Following is some guidance on which mailing list to use for what type of defect:
<itemizedlist>
<listitem><para>For defects against the Yocto Project build system Poky, send
your patch to the
<ulink url='http://lists.yoctoproject.org/listinfo/poky'></ulink> mailing list.
This mailing list corresponds to issues that are not specific to the Yocto Project but
are part of the OE-core.
For example, a defect against anything in the <filename>meta</filename> layer
or the BitBake Manual could be sent to this mailing list.</para></listitem>
<listitem><para>For defects against Yocto-specific layers, tools, and Yocto Project
documentation use the
<ulink url='http://lists.yoctoproject.org/listinfo/yocto'></ulink> mailing list.
This mailing list corresponds to Yocto-specific areas such as
<filename>meta-yocto</filename>, <filename>meta-intel</filename>,
<filename>linux-yocto</filename>, and <filename>documentation</filename>.</para></listitem>
</itemizedlist>
</para>
<para>
When you send a patch, be sure to include a "signed-off-by:"
line in the same style as required by the Linux kernel.
Adding this line signifies the developer has agreed to the Developer's Certificate of Origin 1.1
@ -611,33 +649,38 @@
<para>
In a collaborative environment, it is necessary to have some sort of standard
or method through which you submit changes.
Otherwise, things would get quite chaotic.
Otherwise, things could get quite chaotic.
</para>
<para>
When you form a commit you must follow certain standards established by the
When you form a commit, you must follow certain standards established by the
Yocto Project development team.
For each commit, do the following:
For each commit, you must provide a single-line summary of the change and you
almost always provide a more detailed description of what you did (i.e. the body
of the commit).
The only exceptions for not providing a detailed description would be if your
change is a simple, self-explanatory change that needs no description.
Here are the Yocto Project commit message guidelines:
<itemizedlist>
<listitem><para>Provide a single-line, short summary of the change.
This summary is typically viewable by source control systems.
Thus, providing something short and descriptive that gives the reader
a summary of the change is useful when viewing a list of many commits.
</para></listitem>
<listitem><para>If the change addresses a specific bug or issue that is
associated with a bug-tracking ID, prefix the single-line commit summary
with the bug or issue ID.
For example, the Yocto Project tracks bugs using a bug-naming convention.
Any commits that address a bug must use a commit summary line in the
following form:
<literallayout class='monospaced'>
YOCTO #&lt;bug-id&gt;: &lt;Brief 40-character or less summary of the change&gt;
</literallayout></para></listitem>
<listitem><para>For the body of the commit message, provide detailed information
that describes what you changed, why you made the change, and the approach
you used.
Provide as much detail as you want in the body of the commit message.
Provide as much detail as you can in the body of the commit message.
</para></listitem>
<listitem><para>If the change addresses a specific bug or issue that is
associated with a bug-tracking ID, prefix your detailed description
with the bug or issue ID.
For example, the Yocto Project tracks bugs using a bug-naming convention.
Any commits that address a bug must start with the bug ID in the description
as follows:
<literallayout class='monospaced'>
YOCTO #&lt;bug-id&gt;: &lt;Detailed description of commit&gt;
</literallayout></para></listitem>
</itemizedlist>
</para>
@ -655,7 +698,7 @@
<listitem><para>Stage your commit (or change) by using the <filename>git add</filename>
command.</para></listitem>
<listitem><para>Commit the change by using the <filename>git commit</filename>
command and push it to the upstream "contrib" repository.
command and push it to the "contrib" repository.
Be sure to provide a commit message that follows the project’s commit standards
as described earlier.</para></listitem>
<listitem><para>Notify the maintainer that you have pushed a change by making a pull
@ -696,12 +739,13 @@
<listitem><para>Commit the change by using the
<filename>git commit --signoff</filename> command.
Using the <filename>--signoff</filename> option identifies you as the person
making the change.</para>
making the change and also satisfies the Developer's Certificate of
Origin (DCO) shown earlier.</para>
<para>When you form a commit you must follow certain standards established by the
Yocto Project development team.
See the
<link linkend='how-to-submit-a-change'>How to Submit a Change</link> section
earlier for Yocto Project commit message standards.</para></listitem>
See the earlier section
"<link linkend='how-to-submit-a-change'>How to Submit a Change</link>"
for Yocto Project commit message standards.</para></listitem>
<listitem><para>Format the commit into an email messsage.
To format commits, use the <filename>git format-patch</filename> command.
When you provide the command, you must include a revision list or a number of patches
@ -714,9 +758,11 @@
</literallayout></para>
<para>After the command is run, the current directory contains a
numbered <filename>.patch</filename> file for the commit.</para>
<para>If you provide several commits as part of the command, it produces a numbered
<para>If you provide several commits as part of the command,
the <filename>git format-patch</filename> command produces a numbered
series of files in the current directory – one for each commit.
For information on the <filename>git format-patch</filename> command use the
For information on the <filename>git format-patch</filename> command,
see <filename>GIT_FORMAT_PATCH(1)</filename> displayed using the
<filename>man git-format-patch</filename> command.</para></listitem>
<listitem><para>Import the files into your mail client by using the
<filename>git send-email</filename> command.
@ -728,7 +774,10 @@
<filename>msmtp</filename>, <filename>sendmail</filename>, or through a direct
<filename>smtp</filename> configuration in your Git <filename>config</filename>
file.</para>
<para>The <filename>git send-email</filename> command has several options that let you
<para>The <filename>git send-email</filename> command is the preferred method
for sending your patches since there is no risk of compromising whitespace
in the body of the message, which can occur when you use your own mail client.
The command also has several options that let you
specify recipients and perform further editing of the email message.
For information on how to use the <filename>git send-email</filename> command,
use the <filename>man git-send-email</filename> command.</para></listitem>