Jonathan Nieder <jrnie...@gmail.com> writes:
> Russ Allbery wrote:
>> Jonathan Nieder <jrnie...@gmail.com> writes:
>>> * postrm does not get called until pre-dependencies for the new
>>> version are satisfied. So I think it is impossible for
>>> pre-dependencies to be half-installed here.
>> I believe, from what Ian said, that it's possible if the
>> pre-dependencies of the old version are different than the
>> pre-dependencies of the new version and the upgrade of the
>> pre-dependencies failed.
> The following is only about "postrm upgrade" and "preinst abort-upgrade".
> I don’t follow; could you explain further? The order of operations
> during an upgrade when all goes well is something like this:
> <check pre-dependencies>
> preinst upgrade
> <unpack>
> postrm upgrade
> ... unpack other things ...
> <satisfy dependencies>
> postinst upgrade
> In particular, if postrm fails, then pre-dependencies will have already
> been checked...
Suppose that you have a package foo 1.0-1 with:
Pre-Depends: bar
and a package foo 2.0-1 that has no pre-dependencies. foo and bar are
both currently installed. Now, you:
dpkg -i bar_2.0-1.deb
^C
(or something else bad happens in the middle). bar is now half-installed.
Nothing has happened to foo because attempted upgrades of dependencies and
pre-dependencies do not require deconfiguring packages.
Now you run:
dpkg -i foo_2.0-1.deb
foo 2.0-1 has no pre-dependencies, so the pre-dependency check succeeds.
Installation proceeds and foo 2.0-1 is unpacked, and then the foo 1.0-1
postrm upgrade fails. Error unwind happens and the foo 1.0-1 preinst is
called with abort-upgrade. bar is only half-installed.
--
Russ Allbery (r...@debian.org) <http://www.eyrie.org/~eagle/>
--
To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org
with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org
