In order to eliminate some race conditions around updating the
summary{,.sig} file on the server, and to decouple signing the summary
from signing commits, and to support peer to peer mirrors of content
from multiple upstream collections: add support for unsigned summary
files.
This relaxes the requirement for gpg-verify-summary=true iff
collection-id is set in a remote’s local configuration. It depends on
some pending libostree changes to verify the ref for each commit using
the commit’s signed metadata. See
https://github.com/ostreedev/ostree/issues/983.
Metadata storage has moved from the summary file to a new
ostree-metadata well-known branch on each repository, since this can be
signed for each update and for each collection separately. If the
collection-id is set in a remote’s local configuration, flatpak will
retrieve all repository metadata from this branch rather than from the
summary file. If collection-id is unset, it will ignore this branch and
continue to use the summary file, which will continue to be updated (and
externally signed as summary.sig) for backwards compatibility.
Signed-off-by: Philip Withnall <withnall@endlessm.com>
