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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 from the prior 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 issues rising
                from 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 consists of two parts
                that correspond to the Poky reference distribution and the
                reference hardware Board Support Packages (BSPs), respectively:
                <filename>meta-yocto</filename> and
                <filename>meta-yocto-bsp</filename>.
                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 or 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 but 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
                <ulink url='&YOCTO_DOCS_DEV_URL;#metadata'>Metadata</ulink>.
                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 the 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
                <ulink url='&YOCTO_DOCS_DEV_URL;#source-repositories'>Source Repositories</ulink>.
            </para>
        </section>
    </section>
</section>

<section id='moving-to-the-yocto-project-1.4-release'>
    <title>Moving to the Yocto Project 1.4 Release</title>

    <para>
        This section provides migration information for moving to the
        Yocto Project 1.4 Release from the prior release.
    </para>

    <para>
        Here is the raw text from Paul:
        <literallayout class='monospaced'>
* BitBake  - Fix continuation on last line of a comment: if a comment ends in a line continuation (\) then the next line must also be a comment; any instance where this is not the case will now trigger a warning. Either remove the continuation character or make the next line a comment as well.

* BitBake - The runtime package specific variables (RDEPENDS, RRECOMMENDS, RSUGGESTS, RPROVIDES, RCONFLICTS, RREPLACES, FILES, ALLOW_EMPTY, and the pre/post install/uninstall script functions pkg_preinst, pkg_postinst, pkg_prerm, and pkg_postrm) should always have a package name override, for example RDEPENDS_${PN} for the main package instead of RDEPENDS; there are now stricter checks at parse time to ensure this is done in all recipes.

* Build Behavior - Shared state code has been optimised to avoid running tasks that are not really needed; for example, bitbake -c rootfs some-image from shared state will no longer populate the target sysroot since that is not necessary - the system just needs to extract the output package contents, re-create the packages and construct the root filesystem. This is unlikely to cause any problems unless you have missing declared dependencies.

* Proxies and Fetching Source - A new oe-git-proxy script has been added to replace previous methods of handling proxies and fetching source from Git. See meta-yocto/conf/site.conf.sample for information on how to use this script.

* Build Behavior - When scanning for files in SRC_URI, the system now uses FILESOVERRIDES instead of OVERRIDES for the directory names. All of the sensible values previously in OVERRIDES are now in FILESOVERRIDES as well, however if you relied upon an additional value you added to OVERRIDES you may now need to add it to FILESOVERRIDES (unless you are already adding it via the MACHINEOVERRIDES or DISTROOVERRIDES variables, where this is appropriate).

* Remote Debugging - Support for remote debugging with the Eclipse IDE has been split out into a separate image feature (eclipse-debug) corresponding to the packagegroup-core-eclipse-debug package group. (Previously this was included in the tools-debug image feature which corresponds to the packagegroup-core-tools-debug package group.)

* Variables - SANITY_TESTED_DISTROS now uses a distro ID composed of the host distributor ID followed by the release, rather than the description field being used previously (so "Ubuntu 12.10" becomes "Ubuntu-12.10"). If you aren't setting this variable (or are setting it to "") you don't need to worry about this.

* Items Removed
- mesa-dri renamed to mesa
- Gtk+ DirectFB support has been removed since it is no longer supported in upstream Gtk+ as of version 2.18
- linux-yocto 3.0 kernel has been removed and a version 3.8 has been added
- mesa-xlib removed - no longer useful
- polkit removed - now in the meta-oe layer
- libmusicbrainz removed - now in the meta-multimedia layer
- zeroconf removed - now in the meta-networking layer
- web removed - unmaintained and superseded by web-webkit
- gtkhtml2 removed - now in the meta-oe layer
- clutter-box2d removed - now in the meta-oe layer
- orinoco-conf removed - obsolete
- matchbox-stroke removed - was never more than a proof-of-concept
- update-modules removed - no longer used (kernel module postinstall/postrm scripts can now do the same task without the use of this script)
- zypper / libzypp / sat-solver removed - these have been functionally replaced with Smart (python-smartpm) when RPM packaging is used and package management is enabled on the target.
- libcanberra removed - now in the meta-gnome layer
- metacity removed - now in the meta-gnome layer
- gupnp removed - now in the meta-multimedia layer
- libgdata removed - now in the meta-gnome layer
- gthumb removed - now in the meta-gnome layer
- mutter removed - never used by anything else and recipe was very old
- gypsy removed - now in the meta-oe layer
- matchbox-wm-2 / matchbox-theme-sato-2 removed - unmaintained (matchbox-wm / matchbox-theme-sato still provided)
- lsbsetup removed - functionality now provided by lsbtest
- evolution-data-server removed - now in the meta-gnome layer
- xf86bigfontproto removed - disabled by default upstream since 2007, nothing uses it
- evieext removed - removed from xserver in 2008
- xf86rushproto removed - dependency in xserver was spurious and was removed in 2005
- libxfontcache / xfontcacheproto removed - removed from the Xorg server in 2008
- libxp / libxprintapputil / libxprintutil / printproto removed - the XPrint server was removed from Xorg in 2008
- libxtrap / xtrapproto removed - functionality was broken upstream so it was removed
        </literallayout>
    </para>
</section>
</chapter>
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