Bug#944144: openems: FTBFS when multiple python3 versions are supported

[Steve Langasek]

Package: openems
Version: 0.0.35+git20190103.6a75e98+dfsg.1-1
Severity: important
Tags: patch
User: ubuntu-devel at lists.ubuntu.com
Usertags: origin-ubuntu focal ubuntu-patch

Hi Ruben,

The openems package is set up in a way to iterate over all
currently-supported versions of python3 in the archive in order to build its
extension for them.  However, while it build-depends on python3-all, it
actually builds binary extensions, and therefore should build-depend on
python3-all-dev instead.  It is entirely accidental that the package
currently builds at all, since it does not build-depend on python3-dev but
python3-dev happens to get pulled in indirectly.

The attached patch fixes the source to build-depend on python3-all-dev,
which ensures that headers are available for building against all supported
versions of the python3 interpreter, not just the current one.

This issue was discovered in Ubuntu, where the transition to python3.8 has
begun with the addition of 3.8 as a supported version.  The python3-defaults
which adds python3.8 as supported is currently in Debian experimental.  When
this python3-defaults reaches unstable, this will become a serious bug in
Debian.

Thanks,
-- 
Steve Langasek                   Give me a lever long enough and a Free OS
Debian Developer                   to set it on, and I can move the world.
Ubuntu Developer                                   https://www.debian.org/
slangasek at ubuntu.com                                     vorlon at debian.org
-------------- next part --------------
diff -Nru openems-0.0.35+git20190103.6a75e98+dfsg.1/debian/control openems-0.0.35+git20190103.6a75e98+dfsg.1/debian/control
--- openems-0.0.35+git20190103.6a75e98+dfsg.1/debian/control	2019-10-19 10:20:44.000000000 -0700
+++ openems-0.0.35+git20190103.6a75e98+dfsg.1/debian/control	2019-11-04 13:32:32.000000000 -0800
@@ -18,7 +18,7 @@
                cython3,
                chrpath,
                dh-python,
-               python3-all,
+               python3-all-dev,
                txt2man
 Standards-Version: 4.4.1
 Vcs-Browser: https://salsa.debian.org/science-team/openems