Function assess_read_compat 

pub fn assess_read_compat(
    mover: &MoverIdentity,
    workloads: &[WorkloadIdentity],
    source_read_only: bool,
) -> MoverReadCompat

Assess whether a backup mover can read the source PVC’s files, given the workload pods mounting it. See the module docs for the conservative posture; the result is deterministic (independent of workloads ordering).

source_read_only is the source mount’s effective readOnly (Source::readOnly, default true). It is load-bearing rather than incidental: the module’s whole fsGroup posture rests on the mount being read-only, and a writable source invalidates every group comparison below — see UnknownReason::FsGroupMayApply.