Re: [OE-core] [PATCH v3 3/3] bitbake-config-build: add a plugin for config fragments

[Richard Purdie <richard.purdie@linuxfoundation.org>]

On Mon, 2024-11-18 at 17:26 +0100, Alexander Kanavin via lists.openembedded.org wrote:
> From: Alexander Kanavin <alex@linutronix.de>
> 
> This allows fine-tuning local configurations with pre-frabricated
> configuration snippets in a structured, controlled way. It's also
> an important building block for bitbake-setup.
> 
> There are three (and a half) operations (list/enable/disable/disable all), and here's the 'list' output:
> 
> alex@Zen2:/srv/storage/alex/yocto/build-64$ bitbake-config-build list-fragments
> NOTE: Starting bitbake server...
> Available fragments in selftest layer located in /srv/work/alex/poky/meta-selftest:
> 
> selftest/test-fragment	(disabled)	This is a configuration fragment intended for testing in oe-selftest context
> selftest/more-fragments-here/test-another-fragment	(disabled)	This is a second configuration fragment intended for testing in oe-selftest context
> 
> The tool requires that each fragment contains a one-line summary, and one or more
> lines of description, as BB_CONF_FRAGMENT_SUMMARY[layerid/fragmentname] style metadata.
> 
> Signed-off-by: Alexander Kanavin <alex@linutronix.de>
> ---
>  .../test-another-fragment.conf                |   3 +
>  .../conf/fragments/test-fragment.conf         |   3 +
>  meta/lib/bbconfigbuild/configfragments.py     | 147 ++++++++++++++++++
>  meta/lib/oeqa/selftest/cases/bblayers.py      |  31 ++++
>  4 files changed, 184 insertions(+)
>  create mode 100644 meta-selftest/conf/fragments/more-fragments-here/test-another-fragment.conf
>  create mode 100644 meta-selftest/conf/fragments/test-fragment.conf
>  create mode 100644 meta/lib/bbconfigbuild/configfragments.py
> 
> diff --git a/meta-selftest/conf/fragments/more-fragments-here/test-another-fragment.conf b/meta-selftest/conf/fragments/more-fragments-here/test-another-fragment.conf
> new file mode 100644
> index 00000000000..cf9ba6a6132
> --- /dev/null
> +++ b/meta-selftest/conf/fragments/more-fragments-here/test-another-fragment.conf
> @@ -0,0 +1,3 @@
> +BB_CONF_FRAGMENT_SUMMARY[selftest/more-fragments-here/test-another-fragment] = "This is a second configuration fragment intended for testing in oe-selftest context"
> +BB_CONF_FRAGMENT_DESCRIPTION[selftest/more-fragments-here/test-another-fragment] = "It defines another variable that can be checked inside the test."
> +SELFTEST_FRAGMENT_ANOTHER_VARIABLE = "someothervalue"

One thing which is still bugging me about this and causing some of my
hesitation to merge things is the repeat of the name in the file path
and in the flag name itself. This is going to be a pain to keep in sync
over time.

I've been wondering if:

a) We should have some of variable that gets expanded. Similar examples
are THIDDIR, LAYERDIR, FILE_DIRNAME and FILE but all those have
problems.

-or-

b) Whether the fragment inclusion code should do a rename of any 
BB_CONF_FRAGMENT_SUMMARY -> BB_CONF_FRAGMENT_SUMMARY[<name>] during
parsing. We could list the variables that need processing as parameters
to the addfragments directive or in a variable.

Of the two, I can see b) possibly working. We've never had a) work in a
way that I've liked.

Does anyone have any thoughts on this?

Cheers,

Richard