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<chapter id='migration'>
<title>Migrating to a Newer Yocto Project Release</title>

    <para>
        This chapter provides information you can use to migrate work to a 
        newer Yocto Project release.  You can find the same information in the 
        release notes for a given release.
    </para>

<section id='moving-to-the-yocto-project-1.3-release'>
    <title>Moving to the Yocto Project 1.3 Release</title>

    <para>
        This section provides migration information for moving to the 
        Yocto Project 1.3 Release.
    </para>

    <section id='1.3-local-configuration'>
        <title>Local Configuration</title>

        <para>
            Differences include changes for 
            <link linkend='var-SSTATE_MIRRORS'><filename>SSTATE_MIRRORS</filename></link>
            and <filename>bblayers.conf</filename>.
        </para>

        <section id='migration-1.3-sstate-mirrors'>
            <title>SSTATE_MIRRORS</title>

            <para>
                The shared state cache (sstate-cache) as pointed to by 
                <link linkend='var-SSTATE_DIR'><filename>SSTATE_DIR</filename></link> by default 
                now has two-character subdirectories to prevent there being an issue with too 
                many files in the same directory.
                Also, native sstate-cache packages will go into a subdirectory named using 
                the distro ID string. 
                If you copy the newly structured sstate-cache to a mirror location 
                (either local or remote) and then point to it in 
                <link linkend='var-SSTATE_MIRRORS'><filename>SSTATE_MIRRORS</filename></link>,
                you need to append "PATH" to the end of the mirror URL so that 
                the path used by BitBake before the mirror substitution is 
                appended to the path used to access the mirror. 
                Here is an example:
                <literallayout class='monospaced'>
     SSTATE_MIRRORS = "file://.* http://someserver.tld/share/sstate/PATH"
                </literallayout>
            </para>
        </section>

        <section id='migration-1.3-bblayers-conf'>
            <title>bblayers.conf</title>

            <para>
                The <filename>meta-yocto</filename> layer has been split into 
                two parts: <filename>meta-yocto</filename> and 
                <filename>meta-yocto-bsp</filename>, corresponding to the 
                Poky reference distro configuration and the reference
                hardware Board Support Packages (BSPs), respectively. 
                When running BitBake or Hob for the first time after upgrading, 
                your <filename>conf/bblayers.conf</filename> file will be 
                updated to handle this change and you will be asked to 
                re-run/restart for the changes to take effect.
            </para>
        </section>
    </section>

    <section id='1.3-recipes'>
        <title>Recipes</title>

        <para>
            Differences include changes for the following:
            <itemizedlist>
                <listitem><para>Python function whitespace</para></listitem>
                <listitem><para><filename>proto=</filename> in <filename>SRC_URI</filename></para></listitem>
                <listitem><para><filename>nativesdk</filename></para></listitem>
                <listitem><para>Task recipes</para></listitem>
                <listitem><para><filename>IMAGE_FEATURES</filename></para></listitem>
                <listitem><para>Removed recipes</para></listitem>
            </itemizedlist>
        </para>

        <section id='migration-1.3-python-function-whitespace'>
            <title>Python Function Whitespace</title>

            <para>
                All Python functions must now use four spaces for indentation. 
                Previously, an inconsistent mix of spaces and tabs existed,
                which made extending these functions using 
                <filename>_append</filename> or <filename>_prepend</filename>
                complicated given that Python treats whitespace as 
                syntactically significant. 
                If you are defining or extending any Python functions (e.g.
                <filename>populate_packages</filename>, <filename>do_unpack</filename>,
                <filename>do_patch</filename> and so forth) in custom recipes
                or classes, you need to ensure you are using consistent 
                four-space indentation.
            </para>
        </section>

        <section id='migration-1.3-proto=-in-src-uri'>
            <title>proto= in SRC_URI</title>

            <para>
                Any use of <filename>proto=</filename> in 
                <link linkend='var-SRC_URI'><filename>SRC_URI</filename></link>
                needs to be changed to <filename>protocol=</filename>.
                In particular, this applies to the following URIs:
                <itemizedlist>
                    <listitem><para><filename>svn://</filename></para></listitem>
                    <listitem><para><filename>bzr://</filename></para></listitem>
                    <listitem><para><filename>hg://</filename></para></listitem>
                    <listitem><para><filename>osc://</filename></para></listitem>
                </itemizedlist>
                Other URIs were already using <filename>protocol=</filename>.
                This change improves consistency.
            </para>
        </section>

        <section id='migration-1.3-nativesdk'>
            <title>nativesdk</title>

            <para>
                The suffix <filename>nativesdk</filename> is now implemented
                as a prefix, which simplifies a lot of the packaging code for 
                <filename>nativesdk</filename> recipes. 
                All custom <filename>nativesdk</filename> recipes and any 
                references need to be updated to use 
                <filename>nativesdk-*</filename> instead of 
                <filename>*-nativesdk</filename>.
            </para>
        </section>

        <section id='migration-1.3-task-recipes'>
            <title>Task Recipes</title>

            <para>
                "Task" recipes are now known as "Package groups" and have 
                been renamed from <filename>task-*.bb</filename> to 
                <filename>packagegroup-*.bb</filename>. 
                Existing references to the previous <filename>task-*</filename>
                names should work in most cases as there is an automatic 
                upgrade path for most packages.
                However, you should update references in your own recipes and 
                configurations as they could be removed in future releases. 
                You should also rename any custom <filename>task-*</filename>
                recipes to <filename>packagegroup-*</filename>, and change 
                them to inherit <filename>packagegroup</filename> instead of 
                <filename>task</filename>, as well as taking the opportunity 
                to remove anything now handled by 
                <filename>packagegroup.bbclass</filename>, such as providing
                <filename>-dev</filename> and <filename>-dbg</filename>
                packages, setting 
                <link linkend='var-LIC_FILES_CHKSUM'><filename>LIC_FILES_CHKSUM</filename></link>, 
                and so forth.
                See the 
                "<link linkend='ref-classes-packagegroup'>Package Groups - packagegroup.bbclass</link>"
                section for further details.
            </para>
        </section>

        <section id='migration-1.3-image-features'>
            <title>IMAGE_FEATURES</title>

            <para>
                Image recipes that previously included "apps-console-core" 
                in <link linkend='var-IMAGE_FEATURES'><filename>IMAGE_FEATURES</filename></link>
                should now include "splash" instead to enable the boot-up 
                splash screen.
                Retaining "apps-console-core" will still include the splash 
                screen generates a warning.
                The "apps-x11-core" and "apps-x11-games" 
                <filename>IMAGE_FEATURES</filename> features have been removed.
            </para>
        </section>

        <section id='migration-1.3-removed-recipes'>
            <title>Removed Recipes</title>

            <para>
                The following recipes have been removed. 
                For most of them, it is unlikely that you would have any 
                references to them in your own metadata.
                However, you should check your metadata against this list to be sure:
                <itemizedlist>
                    <listitem><para><emphasis><filename>libx11-trim</filename></emphasis>: 
                        Replaced by <filename>libx11</filename>, which has a negligible 
                        size difference with modern Xorg.</para></listitem>
                    <listitem><para><emphasis><filename>xserver-xorg-lite</filename></emphasis>: 
                        Use <filename>xserver-xorg</filename>, which has a negligible 
                        size difference when DRI and GLX modules are not installed.</para></listitem>
                    <listitem><para><emphasis><filename>xserver-kdrive</filename></emphasis>: 
                        Effectively unmaintained for many years.</para></listitem>
                    <listitem><para><emphasis><filename>mesa-xlib</filename></emphasis>: 
                        No longer serves any purpose.</para></listitem>
                    <listitem><para><emphasis><filename>galago</filename></emphasis>: 
                        Replaced by telepathy.</para></listitem>
                    <listitem><para><emphasis><filename>gail</filename></emphasis>: 
                        Functionality was integrated into GTK+ 2.13.</para></listitem>
                    <listitem><para><emphasis><filename>eggdbus</filename></emphasis>: 
                        No longer needed.</para></listitem>
                    <listitem><para><emphasis><filename>gcc-*-intermediate</filename></emphasis>: 
                        The build has been restructured to avoid the need for 
                        this step.</para></listitem>
                    <listitem><para><emphasis><filename>libgsmd</filename></emphasis>: 
                        Unmaintained for many years.
                        Functionality now provided by 
                        <filename>ofono</filename> instead.</para></listitem>
                    <listitem><para><emphasis>contacts, dates, tasks, eds-tools</emphasis>: 
                        Largely unmaintained PIM application suite.
                        It has been moved to <filename>meta-gnome</filename>
                        in <filename>meta-openembedded</filename>.</para></listitem>
                </itemizedlist>
                In addition to the previously listed changes, the 
                <filename>meta-demoapps</filename> directory has also been removed
                because the recipes in it were not being maintained and many 
                had become obsolete or broken.
                Additionally, these recipes were not parsed in the default configuration.
                Many of these recipes are already provided in an updated and 
                maintained form within OpenEmbedded community layers such as 
                <filename>meta-oe</filename> and <filename>meta-gnome</filename>.
                For the remainder, you can now find them in the 
                <filename>meta-extras</filename> repository, which is in the 
                Yocto Project source repositories.
            </para>
        </section>        
    </section>
</section>
</chapter>
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