[Pkg-kde-extras] Bug#762950: digikam: Removes all images from database when docker.io is running

[Austin Clements]

Package: digikam
Version: 4:4.1.0-1+b1
Severity: important

Dear Maintainer,

Digikam has a serious incompatibility with docker.io due to the
particular way the docker daemon manages mounts.  If the docker daemon
is running and the user starts Digikam, Digikam will delete all album
metadata from its database, dissociate all images in the database from
their albums, and show the user an empty album tree.  If the user then
stops the docker daemon and restarts digikam, the album tree will
appear, but all images will be gone.

This happens when the user's album root is under / because docker
creates a second mount point for / that is not readable by digikam.
E.g., when docker is running, my mount table contains

/dev/disk/by-uuid/86efd6d8-2751-47e1-a6d7-2c7bf04f974b on / type ext4 (rw,noatime,errors=remount-ro,data=ordered)
/dev/disk/by-uuid/86efd6d8-2751-47e1-a6d7-2c7bf04f974b on /var/lib/docker/aufs type ext4 (rw,noatime,errors=remount-ro,data=ordered)

where /var/lib/docker (and hence /var/lib/docker/aufs) has permissions
0700 and is owned by root:root.  When digikam starts, it finds the
/var/lib/docker/aufs mount point when scanning for album locations and
outputs the following error:

digikam(4915)/digikam (core) Digikam::CollectionScanner::scanAlbum: Folder does not exist or is not readable: "/var/lib/docker/aufs/home/USER/img/digicam" 

This causes it to delete all rows from the Albums table and NULL out
the album column from the entire Images table (I would expect it to
delete all rows from Images given the delete_album trigger; I'm not
sure why this doesn't happen, but the images are as good as gone once
their album column is NULL).

I can think of a few potential fixes for this.  The most specific fix
would be to handle the case where an album root is mounted multiple
times and some mounts are inaccessible.  A more general fix might be
to be less trigger happy when deleting albums when the folder cannot
be accessed.

-- System Information:
Debian Release: jessie/sid
  APT prefers testing
  APT policy: (900, 'testing')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 3.14-1-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_US.utf8, LC_CTYPE=en_US.utf8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash

Versions of packages digikam depends on:
ii  digikam-data          4:4.1.0-1
ii  digikam-private-libs  4:4.1.0-1+b1
ii  kde-runtime           4:4.13.1-1
ii  libc6                 2.19-7
ii  libgcc1               1:4.9.1-4
ii  libgphoto2-6          2.5.4-1
ii  libgphoto2-port10     2.5.4-1
ii  libkdcraw23           4:4.13.1-1
ii  libkdecore5           4:4.13.3-1
ii  libkdeui5             4:4.13.3-1
ii  libkexiv2-11          4:4.13.1-1
ii  libkhtml5             4:4.13.3-1
ii  libkio5               4:4.13.3-1
ii  libkipi11             4:4.13.3-1
ii  libknotifyconfig4     4:4.13.3-1
ii  libkparts4            4:4.13.3-1
ii  libopencv-core2.4     2.4.9+dfsg-1+b1
ii  libopencv-imgproc2.4  2.4.9+dfsg-1+b1
ii  libphonon4            4:4.7.1-1
ii  libqt4-dbus           4:4.8.5+git121-g2a9ea11+dfsg-1
ii  libqt4-sql            4:4.8.5+git121-g2a9ea11+dfsg-1
ii  libqt4-sql-sqlite     4:4.8.5+git121-g2a9ea11+dfsg-1
ii  libqt4-xml            4:4.8.5+git121-g2a9ea11+dfsg-1
ii  libqtcore4            4:4.8.5+git121-g2a9ea11+dfsg-1
ii  libqtgui4             4:4.8.5+git121-g2a9ea11+dfsg-1
ii  libsolid4             4:4.13.3-1
ii  libstdc++6            4.9.1-4
ii  libthreadweaver4      4:4.13.3-1
ii  perl                  5.20.0-4
ii  phonon                4:4.7.1-1

Versions of packages digikam recommends:
ii  ffmpegthumbs                        4:4.10.5-1+b1
ii  google-chrome-stable [www-browser]  36.0.1985.125-1
ii  iceweasel [www-browser]             30.0-2
ii  kipi-plugins                        4:4.1.0-1+b1
ii  w3m [www-browser]                   0.5.3-16

Versions of packages digikam suggests:
pn  digikam-doc     <none>
ii  systemsettings  4:4.11.3-3

-- no debconf information