have to update on a regular basis...why?

[Colin Law]

On 8 March 2015 at 09:43, Tom H <tomh0665 at gmail.com> wrote:
> On Sun, Mar 8, 2015 at 5:22 AM, Colin Law <clanlaw at gmail.com> wrote:
>> On 8 March 2015 at 08:58, Tom H <tomh0665 at gmail.com> wrote:
>
>>> 2) The package that you're installing has been updated and your cached
>>> list of available packages has the incorrect version
>>
>> Again I would not have expected that to give a not found message.
>
> I'm not sure about that. I can't remember at the moment what the error
> message is when you try to install a package that's not in the cache
> or where the cache doesn't correspond to the archive. And I just got
> in to my office and can't test right now.

If it is not in the cache of the repo contents (so it has been added
since the apt update was last run) then I would expect it not to be
found -
$ sudo apt install some-unknown-app
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Unable to locate package some-unknown-app

but having thought about it some more, if the version has been
updated, then running install without running update would try to
install the old version of the package, which might well no longer be
in the repo, so this may well explain Thufir's problem.  I guess that
it is saying not that it cannot find the package (as in my example
above) but that it cannot find a particular version of the package -
namely the old one.

@Thufir - is that what you see?  Cannot find a particular version of
the package?

Colin