Bug#1094709: apt modernize-sources should fail when it doesn't do the conversion faithfully

[Helmut Grohne <helmut@subdivi.de>]

Package: apt
Version: 2.9.26
Severity: important

Hi Julian,

apt modernizes should not silently discard relevant aspects of your
sources.list in the conversion process. An example where this happens
is:

| deb [target-=Contents-deb] http://deb.debian.org/debian-debug/ unstable-debug main

While it would be nice to have it perform a successful conversion here,
more crucially it should fail when it cannot convert it without
discarding the [target=-Contents-deb]. If it solves 90% of the common
cases, that feels good enough to me, but it really should give up in the
other ones.

Helmut