[fwiw, due to the way the bug was reassigned, it's entirely possible
that none of the maintainers actually saw your original query - all that
the mailing list received was
https://lists.debian.org/deity/2017/02/msg00051.html ]
On 2017-03-27 12:51, Markus Lindberg wrote:
Could anyone at least point me in the right direction?
So far as I can tell, what you're seeing is expected behaviour.
"apt-get install foo/jessie-backports" says "install foo from
jessie-backports but otherwise respect apt's policy on which release
packages should be installed from", so will not pull in any other
packages from backports unless you've added explicit pinning to make
that happen.
"apt-get install -t jessie-backports foo", otoh, temporarily modifies
apt's policy to give backports a higher priority, at which point
dependencies from backports will be eligible for installation if
required.
Hopefully an apt maintainer can comment on whether I've missed anything
in the above.
Regards,
Adam