Function verify_blobs 

pub fn verify_blobs(
    plan: &Plan,
    blobs: &BTreeMap<Digest, Vec<u8>>,
) -> Result<(), RkError>

Refuse where a blob the plan names is missing from the store or no longer digests to the name it is filed under.

The store files a blob by its digest and reads it back by filename alone, so this is what turns that filename into a claim the bytes have to keep. It runs before any staging, so a corrupted store costs the target nothing.

Errors

A refusal with Reason::StateDrift naming every digest whose bytes are missing or altered, collected in one pass.