An archive had no removal, so an unassigned one failed as an orphan and
aborted every apply after: a module with tools could not be unassigned,
and a race between two pushes froze a machine against every change.
The record now keeps what an archive unpacked: its files, the
directories the host made inside its path, whether the host made the
path itself, and the parents it made to reach it. Removal takes exactly
that away, directories only once empty, never one that was there
before; a directory that is the host's alone is renamed aside first so a
reader sees the whole bundle or none of it. Whatever cannot be removed
is said and forgotten, never fatal.
A directory found before the archive is no longer swapped away with
what was in it: the archive is moved in file by file, and one that would
write over a file the mesh did not put there is refused before anything
moves. A record from before this change learns its files from the
archive's bytes on the next apply; one already orphaned is left in
place, said and forgotten. A former target is still left in place: the
version before is what a rollback starts (ADR 0141).
The host delivers its own successor as an archive whose target is a new
directory each version, and since mesh-host 63 the record keeps a resource's
former target for the next apply to remove. An archive has no removal (issue
162), so the first host that replaced itself under that rule refused its own
former version at the first step of every apply, and all four machines applied
nothing from then on. A former target nobody dropped is forgotten and said;
an archive the declaration dropped still refuses.