How can I install all packages when apt-get dist-upgrade does nothing?

Question

On my Debian system (Raspian Raspberry Pi), some packages were kept back. I tried sudo apt-get dist-upgrade, but this did not result in an upgrade.

$ sudo apt-get upgrade -y
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Calculating upgrade... Done
The following packages have been kept back:
  libalgorithm-diff-xs-perl libdbd-mysql-perl libdbi-perl libfile-fcntllock-perl
  liblocale-gettext-perl libnet-libidn-perl libnet-ssleay-perl
  libterm-readkey-perl libtext-charwidth-perl libtext-iconv-perl
  libtext-soundex-perl
0 upgraded, 0 newly installed, 0 to remove and 11 not upgraded.
$ sudo apt-get dist-upgrade
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Calculating upgrade... Done
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.

There are no holds on packages. The following gives no output.

$ dpkg --get-selections | grep hold

What is causing the block to these packages, and how can I upgrade them?

Solution

As per jordanm's comment, it was likely missing dependencies (perl-based) in the testing repository. I tried again a few days later and it seemed to work.

$ sudo apt-get dist-upgrade
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Calculating upgrade... Done
The following packages will be REMOVED:
  libperl5.18
The following NEW packages will be installed:
  docutils-common docutils-doc libalgorithm-c3-perl libcgi-pm-perl libclass-c3-perl
  libclass-c3-xs-perl libdata-optlist-perl libdata-section-perl libfcgi-perl
  libmodule-build-perl libmodule-signature-perl libmro-compat-perl
  libpackage-constants-perl libparams-util-perl libperl5.20 libpod-readme-perl
  libregexp-common-perl libsoftware-license-perl libsub-exporter-perl
  libsub-install-perl libtext-template-perl libwebp5 libwebpdemux1 libwebpmux1
  php-aws-sdk-doc php-guzzle-doc python-docutils python-guzzle-sphinx-theme
  python-jinja2 python-markupsafe python-pil python-pygments python-roman
  python-sphinx sphinx-common sphinx-doc
The following packages will be upgraded:
  elinks libalgorithm-diff-xs-perl libdbd-mysql-perl libdbi-perl
  libfile-fcntllock-perl liblocale-gettext-perl libnet-libidn-perl
  libnet-ssleay-perl libterm-readkey-perl libtext-charwidth-perl libtext-iconv-perl
  libtext-soundex-perl perl perl-base perl-modules php-aws-sdk php-guzzle
17 upgraded, 36 newly installed, 1 to remove and 0 not upgraded.
Need to get 0 B/15.0 MB of archives.
After this operation, 25.0 MB of additional disk space will be used.
Do you want to continue? [Y/n] 

Comments

[jordanm]

Are you running testing? Their dependencies probably can not be satisfied.

[Sparhawk]

@jordanm Yes, it's Jessie/testing. I understood testing to mean that it was a fully-featured repository, if slightly unstable. Are you suggesting otherwise?

[Sparhawk]

@jordanm Please write it up as an answer and I'll upvote/accept. I've provided my own answer which will provide as an addendum (it probably should just be a comment to yours, but I need the formatting).