Function deploy_verify_node 

pub async fn deploy_verify_node(
    declared: &Declared,
    project: &str,
    node: VerifyNode,
    master: Option<VerifyMasterSurfaces<'_>>,
    master_reader: &dyn TreeReader,
    backup: Option<&BackupNode<'_>>,
    opts: &VerifyOptions,
) -> Result<DeployVerifyResult, CoreError>

deploy verify over one node or both (D-12, V6).

Master is deploy_verify unchanged. Backup runs the backup checks only: the redundancy check (peerConnected and not syncPending), the mode, the REST read-back of the render, and the backup’s files against the master’s live copy, read through master_reader (a warn when backup has no file transport). Both runs the master’s six checks, then the backup’s. Like deploy_verify it never waits, never resyncs and never writes: the backup is reached through BackupNode, which has no write to express, and the master only through reads.

master is required for Master and Both, backup for Backup and Both; a missing one is CoreError::InvalidInput.