On 2019-05-10 13:45 -0500, David Wright wrote: > On Fri 10 May 2019 at 20:14:20 (+0200), Sven Joachim wrote: >> On 2019-05-08 13:14 -0500, David Wright wrote: >> >> > I'm trying to ascertain what APT::Default-Release can do for me, >> > and what it constrains. In the output that follows, why does >> > APT::Default-Release prevent firefox from being upgraded? >> >> Because stretch-updates ≢ stretch, see bug #173215[1] (with >> -proposed-updates rather than -updates). > > Thanks for the reply. (I had just pointed out elsewhere that no answer > had been forthcoming, so you've made a liar of me!) > > Perhaps a note to that effect might have been added to man apt.conf > which was written (or revised) 14 years after the bug surfaced. > > Does this mean APT::Default-Release is a security risk,
Not really, but if you don't have entries for newer releases in your sources.list, then APT::Default-Release is unnecessary. Personally I find it clearer to use explicit pinning in apt-preferences. > or is > the behaviour of stretch/updates different from that of > stretch-updates because of the slash? (I don't find the deb lines > in sources.list easy to parse as a human.) It's because the Codename (and Release) fields are different: stable/updates on the security mirror uses "Codename: stretch" while stable-updates uses "Codename: stretch-updates". Yes, this is confusing. Cheers, Sven