undefined symbol: _Py_ZeroStruct when built against current Debian Unstable as of 4-22-2018

[lukefromdc]

Expected behaviour

Caja opens without warnings of python errors, and extensions like Caja Admin extension work

Actual behaviour

If Debian's packaged python-caja (python-caja_1.20.0-1_amd64.deb and python-caja-common_1.20.0-1_all.deb) are used this package works as expected.

On the other hand, a local build against Debian Unstable as of 4-22-208 it does not work, even with the same configuration options, and even if a python-caja tarball from Debian's repo is used rather than downloaded tarball from git

When caja opens I get the errors below from python-caja and python extensions cannot be loaded.
libpython2.7.so.1.0 is present on the system, so it looks like the undefined symbol: _Py_ZeroStruct is the culprit here:

(caja:21735): Caja-Python-WARNING **: 01:23:22.701: g_module_open libpython failed: /libpython2.7.so.1.0: cannot open shared object file: No such file or directory
ImportError: could not import gobject (error was: '/usr/lib/python2.7/dist-packages/gi/_gi.x86_64-linux-gnu.so: undefined symbol: _Py_ZeroStruct')

(caja:21735): Caja-Python-WARNING **: 01:23:22.710: pygobject initialization failed

(caja:21735): Caja-Python-WARNING **: 01:23:22.710: caja_python_init_python failed

Steps to reproduce the behaviour

1: Install MATE including caja 1.21 from git master and caja-extensions git master by local builds with config options
./autogen.sh --prefix=/usr --libdir=/usr/lib/x86_64-linux-gnu --sysconfdir=/etc --enable-shared=yes --disable-maintainer-mode --disable-schemas-compile
into Debian Unstable

2: Build python-caja with these build options or the ones used by Debian, it makes no difference.

3: install Caja Admin and restart caja (my tests were running from terminal)

$: up come the warnings, python extensions are not loaded

MATE general version

1.20/1.21 mix from git master, generally up to date

Package version

1.20.0 as release or 1.20.0+git master 2018-04-23 locally built, both behave the same way as expected.

Linux Distribution

Debian Unstable updated as of 4-22-2018

Link to downstream report of your Distribution

None, the packages distributed by Debian work (perhaps linked against older python 2.7 version?), something changed since they were built.

[monsta]

I can't reproduce it in Debian Testing, but as I build packages using our debian-packages repo, I also have this patch. Can you try it?

g_module_open libpython failed: /libpython2.7.so.1.0: cannot open shared object file: No such file or directory

This looks like it tries to load the library from the root dir, which might be when PYTHON_LIB_LOC is empty (and it is empty without the mentioned patch).

[monsta]

Forgot to mention that it's Debian/Ubuntu-specific patch, and it's needed because of this "fix":
https://bugs.debian.org/770935

[lukefromdc]

That Debian patch works, I now have a working local build of python-caja.

[monsta]

You can close this - it's a Debian/Ubuntu-specific problem, we can't do anything about it here.