How to fix the grass7 package available from the ubuntugis-unstable PPA?

Question

Out of the blue, grass stopped functioning this morning on one of the Ubuntu 14.04 systems I use:

$ grass
Starting GRASS GIS...
python: can't open file '/usr/lib/grass70/gui/wxpython/gis_set.py': [Errno 2] No such file or directory
Received EXIT message from GUI.
GRASS is not started. Bye.

After some fussing around I found that the grass meta-package available from the ubuntugis-unstable PPA was updated from 6.4.4 to 7.0.0 two days ago. Since I have this PPA registered in the sources.list file the grass meta-package got automatically upgraded. However, something went wrong, the grass-gui package is still version 6.4.4:

$ dpkg -l | grep grass
ii  grass                                                 7.0.0-1~exp2~trusty                                 all          Geographic Resources Analysis Support System (GRASS GIS)
ii  grass-core                                            7.0.0-1~exp2~trusty                                 amd64        GRASS GIS core components
ii  grass-doc                                             7.0.0-1~exp2~trusty                                 all          GRASS GIS user documentation
ii  grass-gui                                             6.4.4-1~trusty5                                     amd64        GRASS GIS graphical user interfaces
ii  libqgisgrass2.8.0                                     1:2.8.0+20trusty                                    amd64        QGIS - shared grass library
ii  libqgisgrass2.8.1                                     1:2.8.1+20trusty                                    amd64        QGIS - shared grass library
ii  qgis-plugin-grass                                     1:2.8.1+20trusty                                    amd64        GRASS plugin for QGIS
ii  qgis-plugin-grass-common                              1:2.8.1+20trusty                                    all          GRASS plugin for QGIS - architecture-independent data

As it happens, the new grass-gui is marking a number of dependencies that can not be installed:

$ sudo apt-get build-dep grass-gui
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Picking 'grass' as source package instead of 'grass-gui'
Note, selecting 'libtiff5-dev' instead of 'libtiff-dev'
The following packages have unmet dependencies.
 libcairo2-dev : Depends: libcairo2 (= 1.13.0~20140204-0ubuntu1) but 1.13.0~20140204-0ubuntu1.1 is to be installed
                 Depends: libcairo-gobject2 (= 1.13.0~20140204-0ubuntu1) but 1.13.0~20140204-0ubuntu1.1 is to be installed
                 Depends: libfontconfig1-dev (>= 2.2.95) but it is not going to be installed
                 Depends: libglib2.0-dev but it is not going to be installed
 libproj-dev : Depends: libproj0 (= 4.8.0-2ubuntu2) but 4.8.0-4~saucy2 is to be installed
E: Build-dependencies for grass-gui could not be satisfied.

Is there any hope of getting these dependencies installed? Do I need some extra PPA for it? Or should I simply revert back to version 6.4.4?

Answer 1

The GRASS 7 meta-package made available last week had errors that cause this situation. The ubuntugis-unstable PPA maintainers have in consequence removed this meta-package.

In a system where this rogue GRASS 7 meta-package was installed the fix is to remove all its packages and downgrade:

sudo apt-get purge  grass grass-core grass-doc grass-gui

sudo apt-get install grass=6.4.3-3