Release 5.2 (walnascar)

Migration notes for 5.2 (walnascar)

This section provides migration information for moving to the Yocto Project 5.2 Release (codename “walnascar”) from the prior release.

debug-tweaks removed from IMAGE_FEATURES

The debug-tweaks image feature is now removed because it was too vague about what it achieved: an image on which the root user can login without a password.

To achieve the same result, the features previously added by debug-tweaks should be manually added to the IMAGE_FEATURES variable. These are:

  • allow-empty-password

  • allow-root-login

  • empty-root-password

  • post-install-logging

Such a statement would be:

IMAGE_FEATURES += "allow-empty-password allow-root-login empty-root-password post-install-logging"

See the list of available image features in the Image Features section of the Yocto Project Reference Manual.

Supported kernel versions

The OLDEST_KERNEL setting is XXX in this release, meaning that out the box, older kernels are not supported. See 4.3 migration notes for details.

Supported distributions

Compared to the previous releases, running BitBake is supported on new GNU/Linux distributions:

On the other hand, some earlier distributions are no longer supported:

See all supported distributions.

Go language changes

Rust language changes

  • Recipes inheriting the cargo do not install libraries by default anymore. This behavior can be controlled by the CARGO_INSTALL_LIBRARIES variable.

systemd changes

  • Support for split-usr and unmerged-usr are now removed after Systemd was updated to version 255. This option allowed installing Systemd in a system where directories such as /lib, /sbin or /bin are not merged into /usr.

    As a consequence, the systemd recipe no longer contains the usrmerge PACKAGECONFIG option as it is now implied by default.

  • systemd.bbclass: If a systemd service file had referred to other service files by starting them via Also, the other service files were automatically added to the FILES variable of the same package. Example:

    a.service contains:

    [Install]
Also=b.service

    If a.service is packaged in package A, b.service was automatically packaged into package A as well. This happened even if b.service was explicitly added to package B using FILES and SYSTEMD_SERVICE variables. This prevented such services from being packaged into different packages. Therefore, this automatic behavior has been removed for service files (but not for socket files). Now all service files must be explicitly added to FILES.

Multiconfig changes

The value of BB_CURRENT_MC was changed from default to an empty string for the default multiconfig configuration to avoid needing to map the values within BitBake. This was already not happening in some cases so this fixes some obscure bugs.

Any logic based on BB_CURRENT_MC equalling to default by default should be changed to be equal to an empty string.

Virtual toolchain provider changes

Support was added for virtual providers on a per-recipe basis for specific key toolchain providers listed in BB_VIRTUAL_RECIPE_PROVIDERS. As part of that support, the cross providers were simplified to remove the triplet prefix (TARGET_PREFIX, SDK_PREFIX and HOST_PREFIX) and generalise the naming. Here are examples of how references to these variables can be changed to use the new cross syntax:

virtual/${HOST_PREFIX}binutils -> virtual/cross-binutils
virtual/${TARGET_PREFIX}binutils -> virtual/cross-binutils

virtual/${HOST_PREFIX}gcc -> virtual/cross-cc
virtual/${TARGET_PREFIX}gcc -> virtual/cross-cc
virtual/${SDK_PREFIX}gcc -> virtual/nativesdk-cross-cc

virtual/${HOST_PREFIX}compilerlibs -> virtual/compilerlibs
virtual/${TARGET_PREFIX}compilerlibs -> virtual/compilerlibs
virtual/nativesdk-${SDK_PREFIX}compilerlibs -> virtual/nativesdk-compilerlibs

virtual/${TARGET_PREFIX}g++ -> virtual/cross-c++

A PREFERRED_PROVIDER assignment can be transformed as follows:

PREFERRED_PROVIDER_virtual/${TARGET_PREFIX}binutils -> PREFERRED_PROVIDER_virtual/cross-binutils
PREFERRED_PROVIDER_virtual/${SDK_PREFIX}binutils -> PREFERRED_PROVIDER_virtual/cross-binutils:class-nativesdk
PREFERRED_PROVIDER_virtual/${SDK_PREFIX}g++ -> PREFERRED_PROVIDER_virtual/nativesdk-cross-c++

The above examples should cover most cases, but there might be situations where replacing is not as straightforward. For more examples, see the commit “classes/recipes: Switch virtual/XXX-gcc to virtual/cross-cc (and c++/binutils)” in OpenEmbedded-Core (OE-Core).

Recipe changes

Removed variables

The following variables have been removed:

  • PACKAGE_SNAP_LIB_SYMLINKS: related to an unmaintained and obsolete “micro” distro.

  • SETUPTOOLS_INSTALL_ARGS: obsolete and unused variable.

  • BB_DANGLINGAPPENDS_WARNONLY: support for only warning the user when a .bbappend file doesn’t apply to the original recipe has been dropped. See the Appending Other Layers Metadata With Your Layer section of the Yocto Project Development Tasks Manual for alternatives to this variable.

Removed recipes

The following recipes have been removed in this release:

Removed classes

The following classes have been removed in this release:

  • migrate_localcount.bbclass: obsolete class for which code was already removed in 2012.

Miscellaneous changes

  • ZSTD_COMPRESSION_LEVEL is now a plain integer number instead of a dash-prefixed command-line option (e.g. it should be set to 3 rather than -3).