Weston versioning (Re: [PATCH weston 6/6] libweston: do not use weston version in libweston.pc)

[Jan Engelhardt]

On Thursday 2016-07-14 17:33, Emil Velikov wrote:
>
>The keypoint here is that one should _not_ need to uninstall
>libdb-4_5-devel in order to have libdb-4_8-devel and vice-versa.
>This is what parallel installability is all about (afaict).

It is indeed what it is about.
But is it _necessary_ to have? No (IMO).
Convenient? Possibly.

Perhaps I am biased because all packages that can be built can be
built in a clean namespace where the "right" devel versions are
installed. Whether that is in a source-based distro (what a weird name,
all distros are using source somewhere) or not.

>If you look closely at some (many?) of the GTK/Qt based applications
>you'll see that they support multiple versions of the respective
>toolkit. Some even support multiple version of GTK _and_ Qt at the
>same time. This is exactly what's happening (being suggested) here.

I will argue that they are slow moving targets (you can add wxWidgets
to the list). That's not the kind of bell that was sounded for
libweston ("be at 27 soon").

>The alternative is to follow the current GTK approach and
>(un)intentionally break API/ABI _between minors_. Which is a serious
>no go, imho.

An AxI break is (to be) communicated by SONAME change. If they do
that for a tarball minor, well let them. What's in a release number
anyway? The Linux kernel also "changes their ABI" between minors.

>IMHO the alias suggestion sounds quite reasonable, yet afaict
>pkg-config does not support it. Have you mentioned/suggested it to the
>pkgconfig developers ?

Nope.

>TL;DR
>* libdb is a classic example of _not_ parallel installable library and
>the OpenSuse packaging shows the efforts needed to make it one (sort
>of).

The only effort was parallel runtime installability.