Re: [PATCH RFC] docs: Add minimum version depencency policy document

[Jan Beulich <jbeulich@xxxxxxxx>]

On 30.09.2020 14:57, George Dunlap wrote:
> --- /dev/null
> +++ b/docs/policies/dependency-versions.rst
> @@ -0,0 +1,76 @@
> +.. SPDX-License-Identifier: CC-BY-4.0
> +
> +Build and runtime dependencies
> +==============================
> +
> +Xen depends on other programs and libraries to build and to run.
> +Chosing a minimum version of these tools to support requires a careful
> +balance: Supporting older versions of these tools or libraries means
> +that Xen can compile on a wider variety of systems; but means that Xen
> +cannot take advantage of features available in newer versions.
> +Conversely, requiring newer versions means that Xen can take advantage
> +of newer features, but cannot work on as wide a variety of systems.

I think "cannot take advantage" is too strict here: It may be more
cumbersome (and as a result to ugly to maintain), but it ought to
generally be possible. IOW how about adding "easily"?

> +Specific distro versions supported in this release
> +--------------------------------------------------
> +
> +======== ==================
> +Distro   Supported releases
> +======== ==================
> +Debian   10 (Buster)
> +Ubuntu   20.10 (Groovy Gorilla), 20.04 (Focal Fossa), 18.04 (Bionic Beaver), 
> 16.04 (Xenial Xerus)
> +OpenSUSE Leap 15.2
> +SLES     SLES 11, 12, 15

SLE 11 has all support packs in LTSS mode already, so as long as this
mode is what's equivalent to or even less than "Maintenance updates"
in what you did say for RHEL, it may want dropping. (Personally I'd
prefer if we remained sufficiently compatible, but I realize I may be
the only one.)

Additionally in service packs things like compiler or binutils versions
often get updated, so e.g. "SLES 11" alone is not sufficient to know
what's meant to be supported, it would likely need to be "SLES 11 SP4"
and alike, just like you also specify a minor version for some of the
other distros. SLES versions not yet in LTSS at this point are, if I'm
not mistaken, 12 SP5, 15 SP1, and 15 SP2.

Jan