Remove per-domain nameserver restrictions in reserved lists

This also removes the related setting on the Registry entity. We never used
either of these, and keeping them around in our codebase just adds complexity
for no purpose. We already achieve the goals of this feature by restricting
nameservers on entire TLDs and by registry-locking important domain names.

This is also two fewer things we'll have to worry about carrying over to the new
schema in Registry 3.0.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=243816241

java/google/registry/model/registry/label/ReservedList.java

@@ -21,20 +21,16 @@ import static google.registry.config.RegistryConfig.getDomainLabelListCacheDurat
 import static google.registry.model.common.EntityGroupRoot.getCrossTldKey;
 import static google.registry.model.ofy.ObjectifyService.ofy;
 import static google.registry.model.registry.label.ReservationType.FULLY_BLOCKED;
-import static google.registry.model.registry.label.ReservationType.NAMESERVER_RESTRICTED;
 import static google.registry.util.CollectionUtils.nullToEmpty;
 import static java.util.concurrent.TimeUnit.MILLISECONDS;
 import static org.joda.time.DateTimeZone.UTC;
 
-import com.google.common.base.Joiner;
 import com.google.common.base.Splitter;
 import com.google.common.cache.CacheBuilder;
 import com.google.common.cache.CacheLoader;
 import com.google.common.cache.LoadingCache;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSet;
-import com.google.common.collect.Sets;
-import com.google.common.net.InternetDomainName;
 import com.google.common.util.concurrent.UncheckedExecutionException;
 import com.googlecode.objectify.Key;
 import com.googlecode.objectify.annotation.Embed;
@@ -47,7 +43,6 @@ import google.registry.model.registry.label.DomainLabelMetrics.MetricsReservedLi
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
-import java.util.Set;
 import java.util.concurrent.ExecutionException;
 import javax.annotation.Nullable;
 import org.joda.time.DateTime;
@@ -74,18 +69,6 @@ public final class ReservedList
 
     ReservationType reservationType;
 
-    /**
-     * Contains a comma-delimited list of the fully qualified hostnames of the nameservers that can
-     * be set on a domain with this label (only applicable to NAMESERVER_RESTRICTED).
-     *
-     * <p>A String field is persisted because Objectify 4 does not allow multi-dimensional
-     * collections in embedded entities.
-     *
-     * @see <a
-     *     href="https://github.com/objectify/objectify-legacy-wiki/blob/v4/Entities.wiki#embedding.">Embedding</a>
-     */
-    String allowedNameservers;
-
     /** Mapper for use with @Mapify */
     static class LabelMapper implements Mapper<String, ReservedListEntry> {
 
@@ -95,41 +78,14 @@ public final class ReservedList
       }
     }
 
-    /**
-     * Creates a {@link ReservedListEntry} from label, reservation type, and optionally additional
-     * restrictions
-     *
-     * <p>The additional restricitno can be the authCode for anchor tenant or the allowed
-     * nameservers (in a colon-separated string) for nameserver-restricted domains.
-     */
+    /** Creates a {@link ReservedListEntry} from a label, reservation type, and optional comment. */
     public static ReservedListEntry create(
-        String label,
-        ReservationType reservationType,
-        @Nullable String allowedNameservers,
-        @Nullable String comment) {
-      ReservedListEntry.Builder entry =
-          new ReservedListEntry.Builder()
-              .setLabel(label)
-              .setComment(comment)
-              .setReservationType(reservationType);
-      checkArgument(
-          (reservationType == NAMESERVER_RESTRICTED) ^ (allowedNameservers == null),
-          "Allowed nameservers must be specified for NAMESERVER_RESTRICTED reservations only");
-      if (allowedNameservers != null) {
-        entry.setAllowedNameservers(
-            ImmutableSet.copyOf(Splitter.on(':').trimResults().split(allowedNameservers)));
-      }
-      return entry.build();
-    }
-
-    private static void checkNameserversAreValid(Set<String> nameservers) {
-      // A domain name with fewer than two parts cannot be a hostname, as a nameserver should be.
-      nameservers.forEach(
-          (ns) ->
-              checkArgument(
-                  InternetDomainName.from(ns).parts().size() >= 3,
-                  "%s is not a valid nameserver hostname",
-                  ns));
+        String label, ReservationType reservationType, @Nullable String comment) {
+      return new ReservedListEntry.Builder()
+          .setLabel(label)
+          .setReservationType(reservationType)
+          .setComment(comment)
+          .build();
     }
 
     @Override
@@ -137,10 +93,6 @@ public final class ReservedList
       return reservationType;
     }
 
-    public ImmutableSet<String> getAllowedNameservers() {
-      return ImmutableSet.copyOf(Splitter.on(',').splitToList(allowedNameservers));
-    }
-
     @Override
     public ReservedListEntry.Builder asBuilder() {
       return new ReservedListEntry.Builder(clone(this));
@@ -156,12 +108,6 @@ public final class ReservedList
         super(instance);
       }
 
-      ReservedListEntry.Builder setAllowedNameservers(Set<String> allowedNameservers) {
-        checkNameserversAreValid(allowedNameservers);
-        getInstance().allowedNameservers = Joiner.on(',').join(allowedNameservers);
-        return this;
-      }
-
       ReservedListEntry.Builder setReservationType(ReservationType reservationType) {
         getInstance().reservationType = reservationType;
         return this;
@@ -225,22 +171,6 @@ public final class ReservedList
         .collect(toImmutableSet());
   }
 
-  /**
-   * Returns the set of nameservers that can be set on the given domain.
-   *
-   * <p>The allowed nameservers are the intersection of all allowed nameservers for the given domain
-   * across all reserved lists. Returns an empty set if not applicable, i. e. the label for the
-   * domain is not set with {@code NAMESERVER_RESTRICTED} reservation type.
-   */
-  public static ImmutableSet<String> getAllowedNameservers(InternetDomainName domainName) {
-    return getReservedListEntries(domainName.parts().get(0), domainName.parent().toString())
-        .stream()
-        .filter((entry) -> entry.reservationType == NAMESERVER_RESTRICTED)
-        .map(ReservedListEntry::getAllowedNameservers)
-        .reduce((types1, types2) -> Sets.intersection(types1, types2).immutableCopy())
-        .orElse(ImmutableSet.of());
-  }
-
   /**
    * Helper function to retrieve the entries associated with this label and TLD, or an empty set if
    * no such entry exists.
@@ -327,8 +257,7 @@ public final class ReservedList
         "Could not parse line in reserved list: %s", originalLine);
     String label = parts.get(0);
     ReservationType reservationType = ReservationType.valueOf(parts.get(1));
-    String restrictions = (parts.size() > 2) ? parts.get(2) : null;
-    return ReservedListEntry.create(label, reservationType, restrictions, comment);
+    return ReservedListEntry.create(label, reservationType, comment);
   }
 
   @Override