Incremental advances collide with same-version artifacts that reached the
destination through another lineage — the stable -> rc bootstrap seed and
native rc builds are not byte-identical to edge's builds of the same
version. A collision means the package has not moved in the source since,
so keep the destination's published copy and continue; the hard failure
also aborted before the db rebuild and sync, leaving the advance half-done.
Also stop advancing pinned packages into rc: eligibility deferred to
package_builds_for_mirror, whose OMARCHY_RC_PINS gate is never set during
an advance, so edge's omarchy/omarchy-settings looked movable — and could
have overtaken an in-flight RC pin under a fresh filename.
Ryan Hughes
2b15c13e86