[Pkg-xen-devel] Bug#975062: Python 3 (pygrub) in 4.14 packages

[Hans van Kranenburg]

Package: src:xen
Version: 4.14.0-1~exp1
Control: submitter -1 ehem+debian at m5p.com
X-Debbugs-CC: ehem+debian at m5p.com, ijackson at chiark.greenend.org.uk

Hi, I think this should be in a bug report in the BTS to track it in a
better way.

----8<---- Forwarded Message ----8<----
Subject: [Pkg-xen-devel] Python 3 in 4.14 packages
Date: Sat, 26 Sep 2020 22:44:25 -0700
From: Elliott Mitchell <ehem+debian at m5p.com>
To: pkg-xen-devel at alioth-lists.debian.net

I was trying to test `pygrub` and found the Python 3 version is
definitely broken in the 4.14 packages.  I was able to get the script to
display the help message by adding "/usr/lib/xen-4.14/lib/<triplet>" to
sys.path.

The existing line:
sys.path.insert(1, sys.path[0] + '/../lib/python')

Is distinctly odd, usually this is better expressed:
sys.path.append(os.path.join(sys.path[0], "libexec"))

(though I suppose we can assume Linux, but this is Bad Practice)

The way some portions of `pygrub` are packaged are distinctly odd.
Certainly xc.so and xs.so are linked to core Xen libraries and need to be
version-specific.  Yet libfsimage.so appears independant of the Xen
version and should likely track `pygrub`, rather than matching the system
Xen version.

---->8---- Forwarded Message ---->8----

I also have a little snippet from IRC, which is about this, where Ian
reports that he's seen it working.

https://salsa.debian.org/xen-team/debian-xen/-/snippets/500

So, apparently there are cases in which pygrub 'works' and in which it
does not, and apparently using pygrub with "amd64 kernel and Xen tools
but i386 userland" is problematic, and I remember some remarks which I
can't find back about that that use case was probably already broken
always, in the past.

I wanted to find out about this and set up some test cases to reproduce
things (I've never used pygrub yet), but that obviously did not happen
yet. I have some stuff going on in my personal life that is taking up a
lot of time currently. What is rather easy for *me* is to help
organizing the work and managing todo lists etc, but not learning new
stuff ATM.

So, my current questions are:

1. Is pygrub a blocker for having Xen 4.14 in unstable? Because that
should be our first team-goal now.
2. What exactly is going on, can we make a list/table/whatever about in
which cases pygrub 'does not work' (in more detail, how does it fail).
3. pygrub keeps being the thing that always causes problems. What would
be your (asking anyone who wants to think along) ideas about which
well-defined situations/test-cases we should have to execute instead of
having the users report problems after big package changes?

Hans

P.S. Next message after the commercials will be on #968965 which is the
other biggest issue for Xen 4.14 in unstable now.