From 0d527052cbc73d177d23efcda1e53f28ec9aedf5 Mon Sep 17 00:00:00 2001 From: Richard Purdie Date: Thu, 29 Jul 2021 23:09:45 +0100 Subject: migration-guides: Add start of 3.4 guide with override migration notes (From yocto-docs rev: e60019c81e63250feaee4937873a90042074030b) Signed-off-by: Richard Purdie Reviewed-by: Quentin Schulz Reviewed-by: Michael Opdenacker Signed-off-by: Richard Purdie --- documentation/migration-guides/index.rst | 1 + documentation/migration-guides/migration-3.4.rst | 76 ++++++++++++++++++++++++ 2 files changed, 77 insertions(+) create mode 100644 documentation/migration-guides/migration-3.4.rst (limited to 'documentation') diff --git a/documentation/migration-guides/index.rst b/documentation/migration-guides/index.rst index 6304e6318c..287b553195 100644 --- a/documentation/migration-guides/index.rst +++ b/documentation/migration-guides/index.rst @@ -12,6 +12,7 @@ to move to one release of the Yocto Project from the previous one. .. toctree:: migration-general + migration-3.4 migration-3.3 migration-3.2 migration-3.1 diff --git a/documentation/migration-guides/migration-3.4.rst b/documentation/migration-guides/migration-3.4.rst new file mode 100644 index 0000000000..6fa1ab20cb --- /dev/null +++ b/documentation/migration-guides/migration-3.4.rst @@ -0,0 +1,76 @@ +Release 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 +----------------------- + +This release requires changes to the metadata to indicate where overrides are +being used in variable key names. This is done with the ``:`` character replacing +the use of ``_`` previously. This means that an entry like:: + + SRC_URI_qemux86 = "file://somefile" + +becomes:: + + SRC_URI:qemux86 = "file://somefile" + +since ``qemux86`` is an override. This applies to any use of override syntax so:: + + 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' + +becomes:: + + 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 `, +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-`` 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. + +To help with migration of layers there is a script in OE-Core. Once configured +with the overrides used by a layer, this can be run as:: + + /scripts/contrib/convert-overrides.py + +.. 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 variables names. + +For reference, this conversion is important as it allows BitBake to know what is +an override and what is not. 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 ``functionname`` in +``my_functionname`` is an override and this should improve efficiency. -- cgit v1.2.3-54-g00ecf