This blog post is about fixing the bug #246992: 'arch all package available before arch any dependancy'. What does that mean: we will keep multiple versions of arch all and source packages per suite as long as older arch 'any' package are still available because maybe newer versions haven't been built by the buildds yet. That means that packages from the unstable suite will always be installable in the future.
The old code in make_suite_file_list.py has been replaced by generate_filelist.py and dominate.py. The first one is generating the file lists for apt-ftparchive and the second one removes obsolete packages from the database. The code in make_suite_file_list.py has been written by people that are no longer members of the ftpteam. Its main control function has a nice name: do_da_do_da(). The new script dominate.py still ships with a small function doDaDoDa() as a reminiscence to our forefathers.
My code has been merged into dak and will be activated on ftp-master.debian.org soon. It can't re-add packages that have already been removed in the past but is will make the archive more friendly in the future. Unfortunately it will leave more cruft in the archive that cannot be cleaned fully automatically. We will need your help to find such corner cases. Please report any errors in the archive as a bug report against the virtual package 'ftp.debian.org'.
More information about the topic can be found in ftpteam's wiki.