MGS1042: a remote spell does not match its digest

The registry answered, but with bytes other than the ones magus.lock pins for the import:

[error] [MGS1042] remote spell ghcr.io/o/r/spells/x: the registry served bytes that do
not match the pin: oci: manifest does not match the digest its reference pins: ...
served sha256:<actual>

Why

The digest is the only proof that the code about to run is the code the workspace chose when it last ran the update charm. A registry is content-addressed, so a mismatch means the host, a proxy, or something between them changed the bytes. magus cannot tell which, so it loads nothing and caches nothing. Only the imports of that spell fail; the rest of the workspace still loads.

What to do

Do not rewrite the lock to the reported value until you know why it differs. Pull the same digest from another network (magus spell pull <path> pulls exactly what the lock pins), or ask the publisher for the digest their publish printed. See Remote spells.

Offline

With MAGUS_OFFLINE set, magus never pulls, so a cached copy under $XDG_CACHE_HOME/magus/spells/ that no longer matches its pin fails with this code rather than being refetched:

[error] [MGS1042] remote spell ghcr.io/o/r/spells/x: the cached copy does not match the
pin and MAGUS_OFFLINE forbids a fresh pull: src/ does not match the layer

Something edited the cache. Unset MAGUS_OFFLINE once so magus replaces the entry, or delete the sha256-<digest> directory it names and load again with a network.