Sometimes (for the LinuxPolicy), excuses don't have enough information
when they are processed. They need to defer some of their work until
another excuse has been evaluated and then perhaps get invalidated.
Introduce the concept of "external invalidation" to deal with this. A
policy can keep references to other excuses around, and then invalidate
them later (when processing another one). The excuse finder needs to
know this happened to remove the excuse from the list of "actionable
excuses".
For example. The Linux policy invalidates linux-foo if linux-meta-foo is
invalid. If linux-foo is encountered first, we will not yet know if
linux-meta-foo is going to be invalid. We effectively defer the
evaluation until after linux-meta-foo has been dealt with, and then we
know whether we need to invalidate linux-foo or not.
For packages with lots of reverse dependencies, new versions of those reverse
dependencies may keep on showing up in testing. If migration is blocked until
the results for these new version, migration may take extremely long. If there
are results for the current trigger but for the previous version of the reverse
dependency, use those until the fresh resuts are available.
Similar for the reference runs.
Hint to allow smooth update, even if the section isn't allowed in the
configuration.
Note that this takes the source name and the source version IN TESTING
of the binaries that must be allowed to stay around to allow a smooth
update.
Currently, britney only schedules reference runs when they don't exist. It does
strip out runs against older versions of the autopkgtest, but the current version
may exist for a while and the reference run can be old. So, add an option to
ignore old results.
When the architecture are read from the Release file, they are not
defined in the config file.
Adding 'all' as an architecture will not give the correct result. To
avoid confusion, explicitly check for this and error out if it is added.
We only want to add packages which conflict in testing, but don't
conflict in unstable. For those, the newer version (from unstable)
probably fixes the conflict.
When an arch:all binary is uninstallable on a non-nobreakall arch, don't
block it, but still mark it as uninstallable, so the autopkgtest policy
knows not to schedule tests for it.