Currently, "6.6 Details of unpack phase of installation or upgrade" says
at number 4:

,----
| The new package's files are unpacked, overwriting any that may be on
| the system already, for example any from the old version of the same
| package or from another package. Backups of the old files are kept
| temporarily, and if anything goes wrong the package management system
| will attempt to put them back as part of the error unwind.
`----

But the other parts of this error-unwind are not explained.  The first
thing seems to be that new-postrm is called with "abort-upgrade", and I
guess that old-postinst is called with "configure" afterwards, but I
don't know (since my postrm failed...)

Regards, Frank

fails
Reply-To:

#425523 - debian-policy: Should describe error-unwind in case "dpkg-deb -x"
fails
http://bugs.debian.org/425523

Hi Frank,

It's the same as if the new-preinst failed in the previous step, except
that dpkg will take care of un-doing its own file manipulations.

I have a relevant document:
http://justinpryzby.com/debian/dpkg/

I just add a note to this effect in my doc (at some point I also had
things out of order, and hadn't re-uploaded the doc since fixing that).

Cheers
Justin