[libcamera-devel] [PATCH] meson: Use x.y soname versioning

[Laurent Pinchart]

Hi Kieran,

On Mon, May 01, 2023 at 01:25:14PM +0100, Kieran Bingham wrote:
> Quoting Laurent Pinchart (2023-05-01 12:55:56)
> > Hi Kieran,
> > 
> > Thank you for the patch.
> > 
> > On Mon, May 01, 2023 at 12:44:52PM +0100, Kieran Bingham via libcamera-devel wrote:
> > > Now that we identify ABI breakages,
> > 
> > Can you explain how so ? Ideally I'd like a script in the utils/
> > directory to handle the ABI checks.
> 
> I have this snippet in a local Makefile.
> 
> """
> VERSION:=$(shell ./utils/gen-version.sh)
> abi-dump:
> 	echo Version : $(VERSION)
> 	mkdir -p abi/$(VERSION)/
> 	meson abi/build \
> 		-Ddocumentation=disabled \
> 		-Dcam=disabled \
> 		-Dqcam=disabled \
> 		-Dgstreamer=disabled \
> 		-Dlc-compliance=disabled \
> 		-Dtracing=disabled \
> 		-Dpipelines=
> 	ninja -C abi/build
> 	DESTDIR=$(shell pwd)/abi/$(VERSION)/ ninja -C abi/build install
> 	cat libcamera-abi-dump.xml.in | sed 's/VERSION/$(VERSION)/g' > libcamera-abi-dump.xml
> 	abi-compliance-checker \
> 		-lib libcamera \
> 		-v1 $(VERSION) \
> 		-dump libcamera-abi-dump.xml \
> 		-dump-path ./abi/v$(VERSION).abi.dump
> 
> RELEASE_ABI=$(shell ./utils/semver get release $(VERSION))
> abi-check:
> 	abi-compliance-checker -l libcamera \
> 		-old abi/v$(RELEASE_ABI).abi.dump \
> 		-new abi/v$(VERSION).abi.dump
> """
> 
> Where 'libcamera-abi-dump.xml.in' contains:
> 
> """
> <version>VERSION</version>
> <headers>abi/VERSION/usr/local/include/</headers>
> <libs>abi/VERSION/usr/local/lib/</libs>
> """
> 
> The main issue is storing (or regenerating) previous versions of the ABI
> dump files to compare against.
> 
> The abi-check produces an HTML 'report' which likely needs to be read by
> the caller, or have something scrape for the detail, so there's still a
> lot of manual steps involved for now.

I'm not concerned about the storage of ABI dump files at the moment.
What I'd like to see is the method to test for ABI breakage to be
documented in the source tree, scripted, and automated. The current
meson.build states

# When automatic ABI based detection is used to increment the version, this
# will bump the minor number (x.y).

I'm fine having a semi-manual process to start with, if it is documented
and can be replicated.

> > > provide incremental releases which
> > > can support backwards compatible linkage across release points that have
> > > a compatible ABI.
> > > 
> > > Introduction of this commit does not convey that libcamera now has a
> > > stable API, but that patch releases with a common minor number
> > > (0.minor.patch) may potentially be used by applications without
> > > recompilation and linkage against new releases.
> > > 
> > > Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
> > > ---
> > >  meson.build | 10 ++++------
> > >  1 file changed, 4 insertions(+), 6 deletions(-)
> > > 
> > > diff --git a/meson.build b/meson.build
> > > index 6e363a906c69..4afe7d1624a7 100644
> > > --- a/meson.build
> > > +++ b/meson.build
> > > @@ -56,15 +56,13 @@ if libcamera_version != project_version
> > >      libcamera_git_version += '-nvm'
> > >  endif
> > >  
> > > -# Until we make ABI compatible releases, the full libcamera version is used as
> > > -# the soname. No ABI/API compatibility is guaranteed between releases (x.y.z).
> > > -#
> > > -# When automatic ABI based detection is used to increment the version, this
> > > -# will bump the minor number (x.y).
> > > +# The major and minor libcamera version components are used as the soname.
> > > +# No ABI/API compatibility is guaranteed between releases (x.y).
> > >  #
> > >  # When we declare a stable ABI/API we will provide a 1.0 release and the
> > >  # soversion at that point will be the 'major' release value (x).
> > > -libcamera_soversion = libcamera_version
> > > +semver = libcamera_version.split('.')
> > > +libcamera_soversion = semver[0] + '.' + semver[1]
> > >  
> > >  summary({ 'Sources': libcamera_git_version, }, section : 'Versions')
> > >  

-- 
Regards,

Laurent Pinchart