Bug#878818: ovito: FTBFS - Testsuite fails because executed with python3.5 instead of 3.6

[Gilles Filippini]

Source: ovito
Version: 2.9.0+dfsg1-2
Severity: serious
Tags: patch
Justification: FTBFS

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Hash: SHA256

Hi,

With the ongoing python3.6 transition ovito is built with both python3.5 and 3.6. The latter being the defaut.
This makes the testsuite fails with:
make[1]: Entering directory '/<<BUILDDIR>>/ovito-2.9.0+dfsg1/obj-x86_64-linux-gnu'

Running tests...
/usr/bin/ctest --force-new-ctest-process -j1
Test project /<<BUILDDIR>>/ovito-2.9.0+dfsg1/obj-x86_64-linux-gnu
        Start   1: affine_transformation_modifier.py
  1/184 Test   #1: affine_transformation_modifier.py ......................   Passed    0.39 sec
        Start   2: affine_transformation_modifier.py_extern
  2/184 Test   #2: affine_transformation_modifier.py_extern ...............***Failed    0.13 sec
Traceback (most recent call last):
  File "affine_transformation_modifier.py", line 1, in <module>
    from ovito.io import *
  File "/<<BUILDDIR>>/ovito-2.9.0+dfsg1/obj-x86_64-linux-gnu/lib/ovito/plugins/python/ovito/__init__.py", line 17, in <module>
    import ovito.plugins.PyScript
ImportError: Python version mismatch: module was compiled for version 3.6, while the interpreter is running version 3.5.

        Start   3: ambient_occlusion_modifier.py
  3/184 Test   #3: ambient_occlusion_modifier.py ..........................   Passed    0.29 sec
        Start   4: ambient_occlusion_modifier.py_extern
  4/184 Test   #4: ambient_occlusion_modifier.py_extern ...................***Failed    0.13 sec
Traceback (most recent call last):
  File "ambient_occlusion_modifier.py", line 1, in <module>
    import ovito
  File "/<<BUILDDIR>>/ovito-2.9.0+dfsg1/obj-x86_64-linux-gnu/lib/ovito/plugins/python/ovito/__init__.py", line 17, in <module>
    import ovito.plugins.PyScript
ImportError: Python version mismatch: module was compiled for version 3.6, while the interpreter is running version 3.5.
...

An easy workaround is to tell cmake to use the default python3 interpreter instead of the first one it finds.
Patch attached.

Thanks,

_g.


- -- System Information:
Debian Release: buster/sid
  APT prefers testing
  APT policy: (500, 'testing')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 4.12.0-1-amd64 (SMP w/2 CPU cores)
Locale: LANG=fr_FR.UTF-8, LC_CTYPE=fr_FR.UTF-8 (charmap=UTF-8), LANGUAGE=fr_FR.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

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diff -Nru ovito-2.9.0+dfsg1/debian/changelog ovito-2.9.0+dfsg1/debian/changelog
--- ovito-2.9.0+dfsg1/debian/changelog	2017-08-10 19:44:59.000000000 +0200
+++ ovito-2.9.0+dfsg1/debian/changelog	2017-10-16 12:24:21.000000000 +0200
@@ -1,3 +1,10 @@
+ovito (2.9.0+dfsg1-2.1) UNRELEASED; urgency=medium
+
+  * Non-maintainer upload.
+  * Force using default Python 3 interpreter
+
+ -- Gilles Filippini <pini at debian.org>  Mon, 16 Oct 2017 12:24:21 +0200
+
 ovito (2.9.0+dfsg1-2) unstable; urgency=medium
 
   * [cdb5bde] Fix FTBFS on archs, where char is unsigned. (Closes: #871248)
diff -Nru ovito-2.9.0+dfsg1/debian/rules ovito-2.9.0+dfsg1/debian/rules
--- ovito-2.9.0+dfsg1/debian/rules	2017-08-06 23:51:10.000000000 +0200
+++ ovito-2.9.0+dfsg1/debian/rules	2017-10-16 12:24:17.000000000 +0200
@@ -5,6 +5,7 @@
 	dh $@ --parallel
 
 extra_flags += \
+	-DPYTHON_EXECUTABLE=/usr/bin/python3 \
 	-DOVITO_BUILD_DOCUMENTATION=TRUE \
 	-DOVITO_BUILD_PLUGIN_SCRIPTING=TRUE \
 	-DOVITO_BUILD_PLUGIN_NETCDF=TRUE \