Re: [ANNOUNCE] libgpiod v1.6 released

[Bartosz Golaszewski <brgl@xxxxxxxx>]

On Mon, Oct 12, 2020 at 5:18 PM SZ Lin (林上智) <SZ.Lin@xxxxxxxx> wrote:
>
> Hi,
>
> <snip>
>
> > I personally don't care much about how desktop distros handle this - I'm mostly
> > interested in bespoke embedded distros built with yocto or buildroot. I'm Cc'ing
> > SZ Lin who maintains the libgpiod debian package.
>
> Nowadays, many embedded distros are derived from Debian, such as Raspberry Pi OS
> (previously called Raspbian). Moreover, the meta-debian [1] provides the recipes for the
> Poky build system to build images using Debian source packages within the Yocto project [2].
>
> [1] https://github.com/meta-debian/meta-debian
> [2] https://www.yoctoproject.org/learn-items/deby-reproducible-and-maintainable-embedded-linux-environment-with-poky/
>
> >
> > SZ Lin: libgpiod will get a new major release in the following months
> > - the API will become v2.x and ABI v3.x - do you think it's important to make it
> > possible for two major versions of libgpiod to live together in a single system? I
>
> It's possible, but I think it's *no strongly needed* and there are no other Debian
> packages depend on libgpiod, as shown below.
>
> ===
> apt rdepends libgpiod2
> libgpiod2
> Reverse Depends:
>   Depends: libgpiod-dev (= 1.5.2-1)
>   Depends: python3-libgpiod (= 1.5.2-1)
>   Depends: gpiod (>= 1.5.1)
> ===
>
> All of the above binary packages are built from the same (libgpiod) source package.
>
> > would like to avoid having to rename everything and use libgpiod2.0
> > everywhere - this information is already stored in the API version. Does debian
> > support something like yocto's virtual providers maybe? How do you see this for
> > a desktop distro.
>
> I'm not familiar with Yocto's mechanism, but in this case, the ABI changes seem that
> are not backward-compatible; we normally require changing the SONAME of the library
> and the shared library package name.
>

For the SONAME it's clear: current libgpiod.so.2 will become
libgpiod.so.3. For the library package name: this is already handled
by distros - for instance the package in debian is called libgpiod2. I
guess it will become libgpiod3 then. I think we're good in that regard
then.

Bartosz