Bug#799361: preseed: always sets preseed_unspecified_at_boot (since fix for #759290)

[Philip Hands <phil@hands.com>]

Package: preseed
Severity: minor

Since #759290 is archived, I'll send this again as a new report.

Regarding this commit:

  http://anonscm.debian.org/cgit/d-i/preseed.git/commit/?id=f2e7bae02caec5a66e25d5af7aab90eb7648deca

The attempted fix here mangles the logic of the if statement.

The &&'s after the db_get's are about checking that the setting is set,
you cannot invert those and get a useful result.

I'm now unsure how to fix this without reintroducing #759290.

One could restore the if statement, with an empty then, but I think that
the real bug is that we don't have a test for the DHCP provided preseed,
so the real fix would be to add such a test to the if as it was before.

In case you're wondering why one should care, the result is that the
touch /var/run/preseed_unspecified_at_boot is always run now, which
means that preseed scripts that use that to determine what to do if the
user didn't specify a preseed at boot, but rather did so when prompted
during the install, will do the wrong thing.

This feature is useful if one wants to have a demo preseed setup that
can notice that the user was a newbie, and will then drop into a more
interactive tutorial, for example.

Cheers, Phil.