Bug#59194: apt-get update overall % not correct

[Peter Maydell <maydell@tao-group.com>]

Package: apt
Version: 0.3.18

If I do an apt-get update, the progress indicator line includes
two percentage counts. I presume that the one on the left is intended
to show total progress, and the other one shows progress with this
package. However, the total progress meter is broken, in that
it appears to be incremented such that it reaches 100% as each Packages
file is downloaded. At this point it drops back down to something like
80% and starts counting upwards again.

It looks to me as if the start point of the count is correct for
each package (hence dropping down to ~80% or whatever) but the
end point is miscalculated so it's 100% rather than what it ought
to be at the end of the package.

This is particularly obvious if you're getting Packages files from
a slow remote archive.

The percentage meters for the actual apt-get dist-upgrade seem to
be counting correctly.

This might be the same bug as #44379 ("apt-get counting again") 
and perhaps #55820 ("apt grossly misestimates download") but neither
of those bug reports provide sufficient detail that I can be sure
of this, so I'm submitting this bug.

Peter Maydell