poky/documentation/migration-guides/migration-3.4.rst - mdmillerii/openbmc - Gitiles

 .. SPDX-License-Identifier: CC-BY-SA-2.0-UK

 Migration notes for 3.4 (honister)
 ----------------------------------

 This section provides migration information for moving to the Yocto
 Project 3.4 Release (codename "honister") from the prior release.

 Override syntax changes
 ~~~~~~~~~~~~~~~~~~~~~~~

 In this release, the ``:`` character replaces the use of ``_`` to
 refer to an override, most commonly when making a conditional assignment
 of a variable. This means that an entry like::

    SRC_URI_qemux86 = "file://somefile"

 now becomes::

    SRC_URI:qemux86 = "file://somefile"

 since ``qemux86`` is an override. This applies to any use of override
 syntax, so the following::

    SRC_URI_append = " file://somefile"
    SRC_URI_append_qemux86 = " file://somefile2"
    SRC_URI_remove_qemux86-64 = "file://somefile3"
    SRC_URI_prepend_qemuarm = "file://somefile4 "
    FILES_${PN}-ptest = "${bindir}/xyz"
    IMAGE_CMD_tar = "tar"
    BASE_LIB_tune-cortexa76 = "lib"
    SRCREV_pn-bash = "abc"
    BB_TASK_NICE_LEVEL_task-testimage = '0'

 would now become::

    SRC_URI:append = " file://somefile"
    SRC_URI:append:qemux86 = " file://somefile2"
    SRC_URI:remove:qemux86-64 = "file://somefile3"
    SRC_URI:prepend:qemuarm = "file://somefile4 "
    FILES:${PN}-ptest = "${bindir}/xyz"
    IMAGE_CMD:tar = "tar"
    BASE_LIB:tune-cortexa76 = "lib"
    SRCREV:pn-bash = "abc"
    BB_TASK_NICE_LEVEL:task-testimage = '0'

 This also applies to
 :ref:`variable queries to the datastore <bitbake-user-manual/bitbake-user-manual-metadata:functions for accessing datastore variables>`,
 for example using ``getVar`` and similar so ``d.getVar("RDEPENDS_${PN}")``
 becomes ``d.getVar("RDEPENDS:${PN}")``.

 Whilst some of these are fairly obvious such as :term:`MACHINE` and :term:`DISTRO`
 overrides, some are less obvious, for example the packaging variables such as
 :term:`RDEPENDS`, :term:`FILES` and so on taking package names (e.g. ``${PN}``,
 ``${PN}-ptest``) as overrides. These overrides are not always in
 :term:`OVERRIDES` but applied conditionally in specific contexts
 such as packaging. ``task-<taskname>`` is another context specific override, the
 context being specific tasks in that case. Tune overrides are another special
 case where some code does use them as overrides but some does not. We plan to try
 and make the tune code use overrides more consistently in the future.

 There are some variables which do not use override syntax which include the
 suffix to variables in ``layer.conf`` files such as :term:`BBFILE_PATTERN`,
 :term:`SRCREV`\ ``_xxx`` where ``xxx`` is a name from :term:`SRC_URI` and
 :term:`PREFERRED_VERSION`\ ``_xxx``. In particular, ``layer.conf`` suffixes
 may be the same as a :term:`DISTRO` override causing some confusion. We do
 plan to try and improve consistency as these issues are identified.

 To help with migration of layers, a script has been provided in OE-Core.
 Once configured with the overrides used by a layer, this can be run as::

    <oe-core>/scripts/contrib/convert-overrides.py <layerdir>

 .. note::

    Please read the notes in the script as it isn't entirely automatic and it isn't
    expected to handle every case. In particular, it needs to be told which overrides
    the layer uses (usually machine and distro names/overrides) and the result should
    be carefully checked since it can be a little enthusiastic and will convert
    references to ``_append``, ``_remove`` and ``_prepend`` in function and variable
    names.

 For reference, this conversion is important as it allows BitBake to more reliably
 determine what is an override and what is not, as underscores are also used in
 variable names without intending to be overrides. This should allow us to proceed
 with other syntax improvements and simplifications for usability. It also means
 BitBake no longer has to guess and maintain large lookup lists just in case
 e.g. ``functionname`` in ``my_functionname`` is an override, and thus should improve
 efficiency.

 New host dependencies
 ~~~~~~~~~~~~~~~~~~~~~

 The ``lz4c``, ``pzstd`` and ``zstd`` commands are now required to be
 installed on the build host to support LZ4 and Zstandard compression
 functionality. These are typically provided by ``lz4`` and ``zstd``
 packages in most Linux distributions. Alternatively they are available
 as part of :term:`buildtools` tarball if your distribution does not provide
 them. For more information see
 :ref:`ref-manual/system-requirements:required packages for the build host`.

 Removed recipes
 ~~~~~~~~~~~~~~~

 The following recipes have been removed in this release:

 - ``assimp``: problematic from a licensing perspective and no longer
   needed by anything else
 - ``clutter-1.0``: legacy component moved to meta-gnome
 - ``clutter-gst-3.0``: legacy component moved to meta-gnome
 - ``clutter-gtk-1.0``: legacy component moved to meta-gnome
 - ``cogl-1.0``: legacy component moved to meta-gnome
 - ``core-image-clutter``: removed along with clutter
 - ``linux-yocto``: removed version 5.4 recipes (5.14 and 5.10 still
   provided)
 - ``mklibs-native``: not actively tested and upstream mklibs still
   requires Python 2
 - ``mx-1.0``: obsolete (last release 2012) and isn't used by anything in
   any known layer
 - ``packagegroup-core-clutter``: removed along with clutter

 Removed classes
 ~~~~~~~~~~~~~~~

 - ``clutter``: moved to meta-gnome along with clutter itself
 - ``image-mklibs``: not actively tested and upstream mklibs still
   requires Python 2
 - ``meta``: no longer useful. Recipes that need to skip installing
   packages should inherit :ref:`ref-classes-nopackages` instead.

 Prelinking disabled by default
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

 Recent tests have shown that prelinking works only when PIE is not
 enabled (see `here <https://rlbl.me/prelink-1>`__ and `here <https://rlbl.me/prelink-2>`__),
 and as PIE is both a desirable security feature, and the only
 configuration provided and tested by the Yocto Project, there is
 simply no sense in continuing to enable prelink.

 There's also a concern that no one is maintaining the code, and there
 are open bugs (including :yocto_bugs:`this serious one </show_bug.cgi?id=14429>`).
 Given that prelink does intricate address arithmetic and rewriting
 of binaries the best option is to disable the feature. It is recommended
 that you consider disabling this feature in your own configuration if
 it is currently enabled.

 Virtual runtime provides
 ~~~~~~~~~~~~~~~~~~~~~~~~

 Recipes shouldn't use the ``virtual/`` string in :term:`RPROVIDES` and
 :term:`RDEPENDS` --- it is confusing because ``virtual/`` has no special
 meaning in :term:`RPROVIDES` and :term:`RDEPENDS` (unlike in the
 corresponding build-time :term:`PROVIDES` and :term:`DEPENDS`).

 Tune files moved to architecture-specific directories
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

 The tune files found in ``conf/machine/include`` have now been moved
 into their respective architecture name directories under that same
 location; e.g. x86 tune files have moved into an ``x86`` subdirectory,
 MIPS tune files have moved into a ``mips`` subdirectory, etc.
 The ARM tunes have an extra level (``armv8a``, ``armv8m``, etc.) and
 some have been renamed to make them uniform with the rest of the tunes.
 See :yocto_git:`this commit </poky/commit/?id=1d381f21f5f13aa0c4e1a45683ed656ebeedd37d>`
 for reference.

 If you have any references to tune files (e.g. in custom machine
 configuration files) they will need to be updated.

 Extensible SDK host extension
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

 For a normal SDK, some layers append to :term:`TOOLCHAIN_HOST_TASK`
 unconditionally which is fine, until the eSDK tries to override the
 variable to its own values. Instead of installing packages specified
 in this variable it uses native recipes instead --- a very different
 approach. This has led to confusing errors when binaries are added
 to the SDK but not relocated.

 To avoid these issues, a new :term:`TOOLCHAIN_HOST_TASK_ESDK` variable has
 been created. If you wish to extend what is installed in the host
 portion of the eSDK then you will now need to set this variable.

 Package/recipe splitting
 ~~~~~~~~~~~~~~~~~~~~~~~~

 - ``perl-cross`` has been split out from the main ``perl`` recipe to
   its own ``perlcross`` recipe for maintenance reasons. If you have
   bbappends for the perl recipe then these may need extending.

 - The ``wayland`` recipe now packages its binaries in a
   ``wayland-tools`` package rather than putting them into
   ``wayland-dev``.

 - Xwayland has been split out of the xserver-xorg tree and thus is now
   in its own ``xwayland`` recipe. If you need Xwayland in your image
   then you may now need to add it explicitly.

 - The ``rpm`` package no longer has ``rpm-build`` in its :term:`RRECOMMENDS`;
   if by chance you still need rpm package building functionality in
   your image and you have not already done so then you should add
   ``rpm-build`` to your image explicitly.

 - The Python ``statistics`` standard module is now packaged in its own
   ``python3-statistics`` package instead of ``python3-misc`` as
   previously.

 Image / SDK generation changes
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

 - Recursive dependencies on the :ref:`ref-tasks-build` task are now disabled when
   building SDKs. These are generally not needed; in the unlikely event
   that you do encounter problems then it will probably be as a result of
   missing explicit dependencies that need to be added.

 - Errors during "complementary" package installation (e.g. for ``*-dbg``
   and ``*-dev`` packages) during image construction are no longer
   ignored. Historically some of these packages had installation problems,
   that is no longer the case. In the unlikely event that you see errors
   as a result, you will need to fix the installation/packaging issues.

 - When building an image, only packages that will be used in building
   the image (i.e. the first entry in :term:`PACKAGE_CLASSES`) will be
   produced if multiple package types are enabled (which is not a typical
   configuration). If in your CI system you need to have the original
   behaviour, use ``bitbake --runall build <target>``.

 - The ``-lic`` package is no longer automatically added to
   :term:`RRECOMMENDS` for every other package when
   :term:`LICENSE_CREATE_PACKAGE` is set to "1". If you wish all license
   packages to be installed corresponding to packages in your image, then
   you should instead add the new ``lic-pkgs`` feature to
   :term:`IMAGE_FEATURES`.

 Miscellaneous
 ~~~~~~~~~~~~~

 - Certificates are now properly checked when BitBake fetches sources
   over HTTPS. If you receive errors as a result for your custom recipes,
   you will need to use a mirror or address the issue with the operators
   of the server in question.

 - ``avahi`` has had its GTK+ support disabled by default. If you wish to
   re-enable it, set ``AVAHI_GTK = "gtk3"`` in a bbappend for the
   ``avahi`` recipe or in your custom distro configuration file.

 - Setting the ``BUILD_REPRODUCIBLE_BINARIES`` variable to "0" no longer
   uses a strangely old fallback date of April 2011, it instead disables
   building reproducible binaries as you would logically expect.

 - Setting noexec/nostamp/fakeroot varflags to any value besides "1" will
   now trigger a warning. These should be either set to "1" to enable, or
   not set at all to disable.

 - The previously deprecated ``COMPRESS_CMD`` and
   ``CVE_CHECK_CVE_WHITELIST`` variables have been removed. Use
   :term:`CONVERSION_CMD` and ``CVE_CHECK_WHITELIST`` (replaced by
   :term:`CVE_CHECK_IGNORE` in version 4.0) respectively
   instead.

 - The obsolete ``oe_machinstall`` function previously provided in the
   :ref:`ref-classes-utils` class has been removed. For
   machine-specific installation it is recommended that you use the
   built-in override support in the fetcher or overrides in general
   instead.

 - The ``-P`` (``--clear-password``) option can no longer be used with
   ``useradd`` and ``usermod`` entries in :term:`EXTRA_USERS_PARAMS`.
   It was being implemented using a custom patch to the ``shadow`` recipe
   which clashed with a ``-P`` option that was added upstream in
   ``shadow`` version 4.9, and in any case is fundamentally insecure.
   Hardcoded passwords are still supported but they need to be hashed, see
   examples in :term:`EXTRA_USERS_PARAMS`.
	.. SPDX-License-Identifier: CC-BY-SA-2.0-UK

	Migration notes for 3.4 (honister)
	----------------------------------

	This section provides migration information for moving to the Yocto
	Project 3.4 Release (codename "honister") from the prior release.

	Override syntax changes
	~~~~~~~~~~~~~~~~~~~~~~~

	In this release, the ``:`` character replaces the use of ``_`` to
	refer to an override, most commonly when making a conditional assignment
	of a variable. This means that an entry like::

	SRC_URI_qemux86 = "file://somefile"

	now becomes::

	SRC_URI:qemux86 = "file://somefile"

	since ``qemux86`` is an override. This applies to any use of override
	syntax, so the following::

	SRC_URI_append = " file://somefile"
	SRC_URI_append_qemux86 = " file://somefile2"
	SRC_URI_remove_qemux86-64 = "file://somefile3"
	SRC_URI_prepend_qemuarm = "file://somefile4 "
	FILES_${PN}-ptest = "${bindir}/xyz"
	IMAGE_CMD_tar = "tar"
	BASE_LIB_tune-cortexa76 = "lib"
	SRCREV_pn-bash = "abc"
	BB_TASK_NICE_LEVEL_task-testimage = '0'

	would now become::

	SRC_URI:append = " file://somefile"
	SRC_URI:append:qemux86 = " file://somefile2"
	SRC_URI:remove:qemux86-64 = "file://somefile3"
	SRC_URI:prepend:qemuarm = "file://somefile4 "
	FILES:${PN}-ptest = "${bindir}/xyz"
	IMAGE_CMD:tar = "tar"
	BASE_LIB:tune-cortexa76 = "lib"
	SRCREV:pn-bash = "abc"
	BB_TASK_NICE_LEVEL:task-testimage = '0'

	This also applies to
	:ref:`variable queries to the datastore <bitbake-user-manual/bitbake-user-manual-metadata:functions for accessing datastore variables>`,
	for example using ``getVar`` and similar so ``d.getVar("RDEPENDS_${PN}")``
	becomes ``d.getVar("RDEPENDS:${PN}")``.

	Whilst some of these are fairly obvious such as :term:`MACHINE` and :term:`DISTRO`
	overrides, some are less obvious, for example the packaging variables such as
	:term:`RDEPENDS`, :term:`FILES` and so on taking package names (e.g. ``${PN}``,
	``${PN}-ptest``) as overrides. These overrides are not always in
	:term:`OVERRIDES` but applied conditionally in specific contexts
	such as packaging. ``task-<taskname>`` is another context specific override, the
	context being specific tasks in that case. Tune overrides are another special
	case where some code does use them as overrides but some does not. We plan to try
	and make the tune code use overrides more consistently in the future.

	There are some variables which do not use override syntax which include the
	suffix to variables in ``layer.conf`` files such as :term:`BBFILE_PATTERN`,
	:term:`SRCREV`\ ``_xxx`` where ``xxx`` is a name from :term:`SRC_URI` and
	:term:`PREFERRED_VERSION`\ ``_xxx``. In particular, ``layer.conf`` suffixes
	may be the same as a :term:`DISTRO` override causing some confusion. We do
	plan to try and improve consistency as these issues are identified.

	To help with migration of layers, a script has been provided in OE-Core.
	Once configured with the overrides used by a layer, this can be run as::

	<oe-core>/scripts/contrib/convert-overrides.py <layerdir>

	.. note::

	Please read the notes in the script as it isn't entirely automatic and it isn't
	expected to handle every case. In particular, it needs to be told which overrides
	the layer uses (usually machine and distro names/overrides) and the result should
	be carefully checked since it can be a little enthusiastic and will convert
	references to ``_append``, ``_remove`` and ``_prepend`` in function and variable
	names.

	For reference, this conversion is important as it allows BitBake to more reliably
	determine what is an override and what is not, as underscores are also used in
	variable names without intending to be overrides. This should allow us to proceed
	with other syntax improvements and simplifications for usability. It also means
	BitBake no longer has to guess and maintain large lookup lists just in case
	e.g. ``functionname`` in ``my_functionname`` is an override, and thus should improve
	efficiency.

	New host dependencies
	~~~~~~~~~~~~~~~~~~~~~

	The ``lz4c``, ``pzstd`` and ``zstd`` commands are now required to be
	installed on the build host to support LZ4 and Zstandard compression
	functionality. These are typically provided by ``lz4`` and ``zstd``
	packages in most Linux distributions. Alternatively they are available
	as part of :term:`buildtools` tarball if your distribution does not provide
	them. For more information see
	:ref:`ref-manual/system-requirements:required packages for the build host`.

	Removed recipes
	~~~~~~~~~~~~~~~

	The following recipes have been removed in this release:

	- ``assimp``: problematic from a licensing perspective and no longer
	needed by anything else
	- ``clutter-1.0``: legacy component moved to meta-gnome
	- ``clutter-gst-3.0``: legacy component moved to meta-gnome
	- ``clutter-gtk-1.0``: legacy component moved to meta-gnome
	- ``cogl-1.0``: legacy component moved to meta-gnome
	- ``core-image-clutter``: removed along with clutter
	- ``linux-yocto``: removed version 5.4 recipes (5.14 and 5.10 still
	provided)
	- ``mklibs-native``: not actively tested and upstream mklibs still
	requires Python 2
	- ``mx-1.0``: obsolete (last release 2012) and isn't used by anything in
	any known layer
	- ``packagegroup-core-clutter``: removed along with clutter

	Removed classes
	~~~~~~~~~~~~~~~

	- ``clutter``: moved to meta-gnome along with clutter itself
	- ``image-mklibs``: not actively tested and upstream mklibs still
	requires Python 2
	- ``meta``: no longer useful. Recipes that need to skip installing
	packages should inherit :ref:`ref-classes-nopackages` instead.

	Prelinking disabled by default
	~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

	Recent tests have shown that prelinking works only when PIE is not
	enabled (see `here <https://rlbl.me/prelink-1>`__ and `here <https://rlbl.me/prelink-2>`__),
	and as PIE is both a desirable security feature, and the only
	configuration provided and tested by the Yocto Project, there is
	simply no sense in continuing to enable prelink.

	There's also a concern that no one is maintaining the code, and there
	are open bugs (including :yocto_bugs:`this serious one </show_bug.cgi?id=14429>`).
	Given that prelink does intricate address arithmetic and rewriting
	of binaries the best option is to disable the feature. It is recommended
	that you consider disabling this feature in your own configuration if
	it is currently enabled.

	Virtual runtime provides
	~~~~~~~~~~~~~~~~~~~~~~~~

	Recipes shouldn't use the ``virtual/`` string in :term:`RPROVIDES` and
	:term:`RDEPENDS` --- it is confusing because ``virtual/`` has no special
	meaning in :term:`RPROVIDES` and :term:`RDEPENDS` (unlike in the
	corresponding build-time :term:`PROVIDES` and :term:`DEPENDS`).

	Tune files moved to architecture-specific directories
	~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

	The tune files found in ``conf/machine/include`` have now been moved
	into their respective architecture name directories under that same
	location; e.g. x86 tune files have moved into an ``x86`` subdirectory,
	MIPS tune files have moved into a ``mips`` subdirectory, etc.
	The ARM tunes have an extra level (``armv8a``, ``armv8m``, etc.) and
	some have been renamed to make them uniform with the rest of the tunes.
	See :yocto_git:`this commit </poky/commit/?id=1d381f21f5f13aa0c4e1a45683ed656ebeedd37d>`
	for reference.

	If you have any references to tune files (e.g. in custom machine
	configuration files) they will need to be updated.

	Extensible SDK host extension
	~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

	For a normal SDK, some layers append to :term:`TOOLCHAIN_HOST_TASK`
	unconditionally which is fine, until the eSDK tries to override the
	variable to its own values. Instead of installing packages specified
	in this variable it uses native recipes instead --- a very different
	approach. This has led to confusing errors when binaries are added
	to the SDK but not relocated.

	To avoid these issues, a new :term:`TOOLCHAIN_HOST_TASK_ESDK` variable has
	been created. If you wish to extend what is installed in the host
	portion of the eSDK then you will now need to set this variable.

	Package/recipe splitting
	~~~~~~~~~~~~~~~~~~~~~~~~

	- ``perl-cross`` has been split out from the main ``perl`` recipe to
	its own ``perlcross`` recipe for maintenance reasons. If you have
	bbappends for the perl recipe then these may need extending.

	- The ``wayland`` recipe now packages its binaries in a
	``wayland-tools`` package rather than putting them into
	``wayland-dev``.

	- Xwayland has been split out of the xserver-xorg tree and thus is now
	in its own ``xwayland`` recipe. If you need Xwayland in your image
	then you may now need to add it explicitly.

	- The ``rpm`` package no longer has ``rpm-build`` in its :term:`RRECOMMENDS`;
	if by chance you still need rpm package building functionality in
	your image and you have not already done so then you should add
	``rpm-build`` to your image explicitly.

	- The Python ``statistics`` standard module is now packaged in its own
	``python3-statistics`` package instead of ``python3-misc`` as
	previously.

	Image / SDK generation changes
	~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

	- Recursive dependencies on the :ref:`ref-tasks-build` task are now disabled when
	building SDKs. These are generally not needed; in the unlikely event
	that you do encounter problems then it will probably be as a result of
	missing explicit dependencies that need to be added.

	- Errors during "complementary" package installation (e.g. for ``*-dbg``
	and ``*-dev`` packages) during image construction are no longer
	ignored. Historically some of these packages had installation problems,
	that is no longer the case. In the unlikely event that you see errors
	as a result, you will need to fix the installation/packaging issues.

	- When building an image, only packages that will be used in building
	the image (i.e. the first entry in :term:`PACKAGE_CLASSES`) will be
	produced if multiple package types are enabled (which is not a typical
	configuration). If in your CI system you need to have the original
	behaviour, use ``bitbake --runall build <target>``.

	- The ``-lic`` package is no longer automatically added to
	:term:`RRECOMMENDS` for every other package when
	:term:`LICENSE_CREATE_PACKAGE` is set to "1". If you wish all license
	packages to be installed corresponding to packages in your image, then
	you should instead add the new ``lic-pkgs`` feature to
	:term:`IMAGE_FEATURES`.

	Miscellaneous
	~~~~~~~~~~~~~

	- Certificates are now properly checked when BitBake fetches sources
	over HTTPS. If you receive errors as a result for your custom recipes,
	you will need to use a mirror or address the issue with the operators
	of the server in question.

	- ``avahi`` has had its GTK+ support disabled by default. If you wish to
	re-enable it, set ``AVAHI_GTK = "gtk3"`` in a bbappend for the
	``avahi`` recipe or in your custom distro configuration file.

	- Setting the ``BUILD_REPRODUCIBLE_BINARIES`` variable to "0" no longer
	uses a strangely old fallback date of April 2011, it instead disables
	building reproducible binaries as you would logically expect.

	- Setting noexec/nostamp/fakeroot varflags to any value besides "1" will
	now trigger a warning. These should be either set to "1" to enable, or
	not set at all to disable.

	- The previously deprecated ``COMPRESS_CMD`` and
	``CVE_CHECK_CVE_WHITELIST`` variables have been removed. Use
	:term:`CONVERSION_CMD` and ``CVE_CHECK_WHITELIST`` (replaced by
	:term:`CVE_CHECK_IGNORE` in version 4.0) respectively
	instead.

	- The obsolete ``oe_machinstall`` function previously provided in the
	:ref:`ref-classes-utils` class has been removed. For
	machine-specific installation it is recommended that you use the
	built-in override support in the fetcher or overrides in general
	instead.

	- The ``-P`` (``--clear-password``) option can no longer be used with
	``useradd`` and ``usermod`` entries in :term:`EXTRA_USERS_PARAMS`.
	It was being implemented using a custom patch to the ``shadow`` recipe
	which clashed with a ``-P`` option that was added upstream in
	``shadow`` version 4.9, and in any case is fundamentally insecure.
	Hardcoded passwords are still supported but they need to be hashed, see
	examples in :term:`EXTRA_USERS_PARAMS`.