OK, I start with my 100% `stable` (`jessie`) system up-to-date. IOW,
after `apt-get update`, `apt-get upgrade` reports that there are no
candidates for upgrading:
% sudo apt-get 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.
Now, I add to my `/etc/apt/sources.list` file the last two lines shown below:
deb http://http.us.debian.org/debian jessie
main contrib non-free
deb-src http://http.us.debian.org/debian jessie
main contrib
deb http://http.us.debian.org/debian jessie-updates
main contrib
deb-src http://http.us.debian.org/debian jessie-updates
main contrib
deb http://security.debian.org/ jessie/updates
main contrib non-free
deb-src http://security.debian.org/ jessie/updates
main contrib non-free
deb http://http.us.debian.org/debian stretch
main contrib non-free
deb-src http://http.us.debian.org/debian stretch
main contrib
Also, I set the contents of my `/etc/apt/preferences` file to this
(the file was empty before):
Package: *
Pin: release a=stable
(BTW, both my `/etc/apt/sources.list.d` and `/etc/apt/preferences.d`
directories are empty.)
Then, I re-run `apt-get update`.
Given the contents of my `/etc/apt/preferences` file, which specifies
that everything should be pinned at `stable`, I expected that the two
new lines in my `/etc/apt/sources.list` would be essentially
irrelevant. In particular, I expected that `apt-get upgrade` would
still report that there was nothing to upgrade.
To my surprise, this is far from the case: the `apt-get upgrade`
dialog reports: "962 upgraded, 0 newly installed, 0 to remove and 590
not upgraded."
How come there are any upgrades at all (let alone hundreds of them)
when `/etc/apt/preferences` requires that everything sould be pinned
at `stable`?
Thanks in advance!
kj
P.S. FWIW, ultimately, what I want to perform a very controlled,
tightly-targeted upgrade of my R-related packages (i.e. `r-base` and
friends) to `stretch`/`testing`. IOW, I want to keep the non-`jessie`
packages installed in my system to the absolute minimum that is
compatible with upgrading R to `stretch`/`testing`.
I thought that setting my `/etc/apt/preferences` file as shown below,
coupled with the `/etc/apt/sources.list` file shown earlier, would do
the trick:
Package: *
Pin: release a=stable
Package: r-*
Pin: release a=testing
But my complete failure to predict the results of the experiment
described in the main part of this post tells me that I probably have
the whole thing wrong.
