glitch in upgrade myth to 0.25.2-dmo2

In a Debian testing chroot I just upgraded myth 0.25.2 from dmo1 to
dmo2, along with other upgrades.

During the upgrade aptitude popped up a dialog asking what user I should
use to administer myth on mysql (roughly--it's from memory). "root" was
filled in as the response, with a recommendation to accept it. I did.

I was surprised to see the dialogue, since I had already configured myth
and this is a minor upgrade--just a change in compression, according to
the changelog.

Later, the terminal showed

Failed to connect to database: Access denied for user 'root'@'localhost' (using password: YES) at -e line 5, <> line 1.
dpkg: error processing mythtv-database (--configure):
subprocess installed post-installation script returned error exit status 255

There were a few more failed to connect messages in the logs, and at the
end
dpkg: error processing mythtv (--configure):
dependency problems - leaving unconfigured
Errors were encountered while processing:
mythtv-database
mythtv

Despite this, myth seems to be running fine.

I did fiddle around with account names and passwords, although my notes
do not show any indication that I rejected the default "root" response
earlier.

Any ideas how to make the install go all the way through? Is there any
upgrade code I'm likely to need to execute?

Thanks.
Ross Boylan