Function delete_group_members 

pub async fn delete_group_members(
    infra: &InfraContext<'_>,
    token: &str,
    group_name: &str,
    host_expression: &str,
    dry_run: bool,
) -> Result<(), Error>

Resolve host_expression and remove the resolved nodes from group_name.

With dry_run = true, only the resolution runs — no backend mutation. Errors from the per-node deletion abort the loop and surface to the handler, so a partially completed batch is possible.

Errors

• [Error::InvalidNodeId] / [Error::BadRequest] when host_expression can’t be parsed by crate::service::node_ops::from_hosts_expression_to_xname_vec.
• [Error::BadRequest] when the resolution produces no xnames (a literal “nothing to do” guard).
• [Error::BadRequest] when the caller lacks access to one of the resolved xnames (via crate::service::authorization::validate_user_group_members_access).
• [Error::NetError] / [Error::CsmError] from get_node_metadata_available and per-node delete_member_from_group.