Bug#946355: glib2.0: Please make autopkgtests cross-test-friendly

[Steve Langasek]

Package: glib2.0
Version: 2.63.1-2
Severity: minor
Tags: patch
User: ubuntu-devel at lists.ubuntu.com
Usertags: origin-ubuntu focal ubuntu-patch

Dear maintainers,

In Ubuntu, we are in the process of moving the i386 architecture to a
compatibility-only layer on amd64, and therefore we are also moving our
autopkgtest infrastructure to test i386 binaries in a cross-environment.

This requires changes to some tests so that they are cross-aware and can do
the right thing.

The glib2.0 tests currently fail in this environment, because there are
build tests that do not invoke the toolchain in a cross-aware manner.  I've
verified that the attached patch lets the tests successfully build (and run)
i386 tests on an amd64 host.

Note that upstream autopkgtest doesn't currently set DEB_HOST_ARCH so this
is a complete no-op in Debian for the moment.  Support for cross-testing in
autopkgtest is currently awaiting review at
https://salsa.debian.org/ci-team/autopkgtest/merge_requests/69 and once
landed, will still have no effect unless autopkgtest is invoked with a '-a'
option.  So this change should be safe to land in your package despite this
not being upstream in autopkgtest.

Unfortunately in the case of glib2.0, this is an incomplete solution for
cross-testing compatibility, because in addition to the build tests, glib2.0
has two other tests that depend on libglib2.0-tests and this package is not
cross-installable because dh-python causes it to have a dependency on
python3:any but on python3.7, and it's impossible to install the
foreign-arch (i386) version of python3.7.  There is discussion on the
autopkgtest MP about how to filter out some tests when cross-testing, which
may wind up being a solution, but I think this is also a bug in dh-python
that it generates a dependency on same-arch python3.7, so I think this patch
is worth inclusion in glib2.0 as-is.

Thanks for considering,
-- 
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 glib2.0-2.63.1/debian/tests/build glib2.0-2.63.1/debian/tests/build
--- glib2.0-2.63.1/debian/tests/build	2019-11-18 05:59:35.000000000 -0800
+++ glib2.0-2.63.1/debian/tests/build	2019-12-06 21:31:37.000000000 -0800
@@ -34,6 +34,13 @@
 WORKDIR=$(mktemp -d)
 trap "rm -rf $WORKDIR" 0 INT QUIT ABRT PIPE TERM
 cd $WORKDIR
+
+if [ -n "${DEB_HOST_GNU_TYPE:-}" ]; then
+    CROSS_COMPILE="$DEB_HOST_GNU_TYPE-"
+else
+    CROSS_COMPILE=
+fi
+
 cat <<EOF > glib.c
 #include <glib.h>
 
@@ -119,7 +126,7 @@
             ;;
     esac
 
-    gcc $cflags -o ${lib}-$mode ${lib}.c `pkg-config $pcflags --cflags --libs ${packages}`
+    ${CROSS_COMPILE}gcc $cflags -o ${lib}-$mode ${lib}.c `${CROSS_COMPILE}pkg-config $pcflags --cflags --libs ${packages}`
     echo "build ($lib, $mode): OK"
     [ -x ${lib}-$mode ]
     foo=bar ./${lib}-$mode