Bug#803936: goplay: not installable using aptitude with "apt-xapian-index.postinst: update-python-modules: not found"

[twied]

Package: goplay
Severity: grave
Justification: renders package unusable

Dear Maintainer,

goplay failed to install using aptitude with "apt-xapian-index.postinst:
update-python-modules: not found":

# aptitude install goplay
The following NEW packages will be installed:
  apt-xapian-index{a} goplay libept1.4.16{a} libfltk-images1.3{a} libfltk1.3{a}
python-xapian{a}
The following packages are RECOMMENDED but will NOT be installed:
  games-thumbnails
0 packages upgraded, 6 newly installed, 0 to remove and 0 not upgraded.
Need to get 0 B/1275 kB of archives. After unpacking 4128 kB will be used.
Do you want to continue? [Y/n/?]
Selecting previously unselected package python-xapian.
(Reading database ... 211875 files and directories currently installed.)
Preparing to unpack .../python-xapian_1.2.21-2.1_amd64.deb ...
Unpacking python-xapian (1.2.21-2.1) ...
Selecting previously unselected package apt-xapian-index.
Preparing to unpack .../apt-xapian-index_0.47_all.deb ...
Unpacking apt-xapian-index (0.47) ...
Selecting previously unselected package libept1.4.16:amd64.
Preparing to unpack .../libept1.4.16_1.0.14+b1_amd64.deb ...
Unpacking libept1.4.16:amd64 (1.0.14+b1) ...
Preparing to unpack .../libfltk1.3_1.3.3-4_amd64.deb ...
Unpacking libfltk1.3:amd64 (1.3.3-4) ...
Selecting previously unselected package libfltk-images1.3:amd64.
Preparing to unpack .../libfltk-images1.3_1.3.3-4_amd64.deb ...
Unpacking libfltk-images1.3:amd64 (1.3.3-4) ...
Selecting previously unselected package goplay.
Preparing to unpack .../goplay_0.9.1_amd64.deb ...
Unpacking goplay (0.9.1) ...
Processing triggers for man-db (2.7.4-1) ...
Processing triggers for menu (2.1.47) ...
Processing triggers for mime-support (3.59) ...
Processing triggers for desktop-file-utils (0.22-1) ...
Setting up python-xapian (1.2.21-2.1) ...
Setting up apt-xapian-index (0.47) ...
apt-xapian-index: Building new index in background...
/var/lib/dpkg/info/apt-xapian-index.postinst: 43: /var/lib/dpkg/info/apt-
xapian-index.postinst: update-python-modules: not found
dpkg: error processing package apt-xapian-index (--configure):
 subprocess installed post-installation script returned error exit status 127
Setting up libept1.4.16:amd64 (1.0.14+b1) ...
Setting up libfltk1.3:amd64 (1.3.3-4) ...
Setting up libfltk-images1.3:amd64 (1.3.3-4) ...
dpkg: dependency problems prevent configuration of goplay:
 goplay depends on apt-xapian-index; however:
  Package apt-xapian-index is not configured yet.

dpkg: error processing package goplay (--configure):
 dependency problems - leaving unconfigured
Processing triggers for libc-bin (2.19-22) ...
Errors were encountered while processing:
 apt-xapian-index
 goplay
======  How can you help?  (doc: https://wiki.debian.org/how-can-i-help )
======

-----  Show old opportunities as well as new ones: how-can-i-help --old  -----
E: Sub-process /usr/bin/dpkg returned an error code (1)
Failed to perform requested operation on package.  Trying to recover:
Setting up apt-xapian-index (0.47) ...
apt-xapian-index: Building new index in background...
/var/lib/dpkg/info/apt-xapian-index.postinst: 43: /var/lib/dpkg/info/apt-
xapian-index.postinst: update-python-modules: not found
dpkg: error processing package apt-xapian-index (--configure):
 subprocess installed post-installation script returned error exit status 127
dpkg: dependency problems prevent configuration of goplay:
 goplay depends on apt-xapian-index; however:
  Package apt-xapian-index is not configured yet.

dpkg: error processing package goplay (--configure):
 dependency problems - leaving unconfigured
Errors were encountered while processing:
 apt-xapian-index
 goplay



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

Kernel: Linux 4.2.0-1-amd64 (SMP w/4 CPU cores)
Locale: LANG=de_DE.UTF-8, LC_CTYPE=de_DE.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)