Instead of patching apt, wouldn't it be easier to ship a script like do-release-upgrade (eg. do-lts-upgrade --component=xorg --component=linux --target=quantal) which does all the necessary magic? It could even do something like
1. trigger package downloads only
2. force-remove the old packages
3. install the new packages
That would circumvent any solver and possible brakages due to that.
Instead of patching apt, wouldn't it be easier to ship a script like do-release-upgrade (eg. do-lts-upgrade --component=xorg --component=linux --target=quantal) which does all the necessary magic? It could even do something like
1. trigger package downloads only
2. force-remove the old packages
3. install the new packages
That would circumvent any solver and possible brakages due to that.