cinnamon depends on xapp python package which is not provided

[George Shuklin]

Traceback (most recent call last):
  File "/usr/share/cinnamon-screensaver/cinnamon-screensaver-main.py", line 17, in <module>
    from util import utils
  File "/usr/share/cinnamon-screensaver/util/utils.py", line 7, in <module>
    import xapp.os
ModuleNotFoundError: No module named 'xapp'

ProblemType: Bug
DistroRelease: Ubuntu 17.10
Package: cinnamon-screensaver 3.4.1-1ubuntu1
ProcVersionSignature: Ubuntu 4.12.0-11.12-generic 4.12.5
Uname: Linux 4.12.0-11-generic x86_64
ApportVersion: 2.20.6-0ubuntu6
Architecture: amd64
CurrentDesktop: X-Cinnamon
Date: Wed Aug 23 14:00:32 2017
DistributionChannelDescriptor:
 # This is a distribution channel descriptor
 # For more information see http://wiki.ubuntu.com/DistributionChannelDescriptor
 canonical-oem-somerville-xenial-amd64-20160624-2
EcryptfsInUse: Yes
InstallationDate: Installed on 2017-06-22 (62 days ago)
InstallationMedia: Ubuntu 16.04 "Xenial" - Build amd64 LIVE Binary 20160624-10:47
SourcePackage: cinnamon-screensaver
UpgradeStatus: No upgrade log present (probably fresh install)

[Chris Routh (routhinator)]

Confirming this issue on 17.10 preview.

[George Shuklin (george-shuklin)]

I'd like to point that exceptions in screensaver is a security issue as they leave desktops unlocked after suspend/resume and timeouts.