{
  definitions,
  lib,
}:
let
  assertValid =
    data:
    let
      assertions = validationAssertions data;
      failures = lib.filter (assertion: !assertion.assertion) assertions;
    in
    assert lib.assertMsg (lib.all (assertion: assertion.assertion) assertions) (
      lib.concatMapStringsSep "\n" (assertion: assertion.message) failures
    );
    data;

  validationAssertions =
    data:
    lib.concatLists (
      lib.mapAttrsToList (
        registryName: registry:
        let
          entries = flattenRegistryEntries registryName data.${registryName};
        in
        map (check: {
          assertion = check.assertion entries;
          inherit (check) message;
        }) registry.checks
      ) definitions
    );

  flattenRegistryEntries =
    registryName: data:
    lib.concatLists (
      lib.mapAttrsToList (
        host: entries:
        lib.mapAttrsToList (entry: value: {
          path = "registry.${registryName}.${host}.${entry}";
          inherit host entry value;
        }) entries
      ) data
    );
in
assertValid