Get rid of ReferenceUnions entirely

This is the third and final phase in the migration away from ReferenceUnions.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=138778148

javatests/google/registry/model/ImmutableObjectTest.java

@@ -19,7 +19,6 @@ import static com.google.common.collect.Maps.newHashMap;
 import static com.google.common.collect.Sets.newHashSet;
 import static com.google.common.truth.Truth.assertThat;
 import static google.registry.model.ImmutableObject.cloneEmptyToNull;
-import static google.registry.testing.DatastoreHelper.persistActiveContact;
 import static google.registry.testing.DatastoreHelper.persistResource;
 import static google.registry.util.DateTimeUtils.START_OF_TIME;
 
@@ -31,7 +30,6 @@ import com.googlecode.objectify.Key;
 import com.googlecode.objectify.ObjectifyService;
 import com.googlecode.objectify.annotation.Entity;
 import com.googlecode.objectify.annotation.Id;
-import google.registry.model.domain.ReferenceUnion;
 import google.registry.testing.AppEngineRule;
 import google.registry.util.CidrAddressBlock;
 import java.util.ArrayDeque;
@@ -255,6 +253,7 @@ public class ImmutableObjectTest {
 
   /** Subclass of ImmutableObject with keys to other objects. */
   public static class RootObject extends ImmutableObject {
+
     Key<ValueObject> hydrateMe;
 
     @DoNotHydrate
@@ -263,8 +262,6 @@ public class ImmutableObjectTest {
     Map<String, Key<ValueObject>> map;
 
     Set<Key<ValueObject>> set;
-
-    ReferenceUnion<?> referenceUnion;
   }
 
   /** Simple subclass of ImmutableObject. */
@@ -308,11 +305,4 @@ public class ImmutableObjectTest {
     root.set = ImmutableSet.of(Key.create(persistResource(ValueObject.create(1, "foo"))));
     assertThat(root.toHydratedString()).contains("foo");
   }
-
-  @Test
-  public void testToHydratedString_expandsReferenceUnions() {
-    RootObject root = new RootObject();
-    root.referenceUnion = ReferenceUnion.create(Key.create(persistActiveContact("foo")));
-    assertThat(root.toHydratedString()).contains("foo");
-  }
 }

javatests/google/registry/model/domain/DomainApplicationTest.java

@@ -130,10 +130,8 @@ public class DomainApplicationTest extends EntityTestCase {
         domainApplication.asBuilder().setPeriod(Period.create(5, Period.Unit.YEARS)).build());
     verifyIndexing(
         domainApplication,
-        "allContacts.contactId.linked",
         "allContacts.contact",
         "fullyQualifiedDomainName",
-        "nameservers.linked",
         "nsHosts",
         "deletionTime",
         "currentSponsorClientId",

javatests/google/registry/model/domain/DomainResourceTest.java

@@ -23,8 +23,6 @@ import static google.registry.testing.DatastoreHelper.cloneAndSetAutoTimestamps;
 import static google.registry.testing.DatastoreHelper.createTld;
 import static google.registry.testing.DatastoreHelper.newDomainResource;
 import static google.registry.testing.DatastoreHelper.newHostResource;
-import static google.registry.testing.DatastoreHelper.persistActiveContact;
-import static google.registry.testing.DatastoreHelper.persistActiveHost;
 import static google.registry.testing.DatastoreHelper.persistResource;
 import static google.registry.testing.DomainResourceSubject.assertAboutDomains;
 import static google.registry.util.DateTimeUtils.START_OF_TIME;
@@ -174,10 +172,8 @@ public class DomainResourceTest extends EntityTestCase {
   public void testIndexing() throws Exception {
     verifyIndexing(
         domain,
-        "allContacts.contactId.linked",
         "allContacts.contact",
         "fullyQualifiedDomainName",
-        "nameservers.linked",
         "nsHosts",
         "currentSponsorClientId",
         "deletionTime",
@@ -455,28 +451,4 @@ public class DomainResourceTest extends EntityTestCase {
   public void testToHydratedString_notCircular() {
     domain.toHydratedString();  // If there are circular references, this will overflow the stack.
   }
-
-  // TODO(b/28713909): Remove these tests once ReferenceUnion migration is complete.
-  @Test
-  public void testDualSavingOfDesignatedContact() {
-    ContactResource contact = persistActiveContact("time1006");
-    DesignatedContact designatedContact = new DesignatedContact();
-    designatedContact.contact = Key.create(contact);
-    designatedContact.type = Type.ADMIN;
-    DomainResource domainWithContact =
-        domain.asBuilder().setContacts(ImmutableSet.of(designatedContact)).build();
-    assertThat(getOnlyElement(domainWithContact.getContacts()).contactId).isNull();
-    DomainResource reloadedDomain = persistResource(domainWithContact);
-    assertThat(getOnlyElement(reloadedDomain.getContacts()).contactId)
-        .isEqualTo(ReferenceUnion.create(Key.create(contact)));
-  }
-
-  @Test
-  public void testDualSavingOfNameservers() {
-    HostResource host = persistActiveHost("zzz.xxx.yyy");
-    DomainResource domain = newDomainResource("python-django-unchained.com", host);
-    assertThat(domain.nameservers).isNull();
-    DomainResource djangoReloaded = persistResource(domain);
-    assertThat(djangoReloaded.nameservers).containsExactly(ReferenceUnion.create(Key.create(host)));
-  }
 }

javatests/google/registry/model/schema.txt

@@ -189,7 +189,6 @@ enum google.registry.model.contact.PostalInfo$Type {
 class google.registry.model.domain.DesignatedContact {
   com.googlecode.objectify.Key<google.registry.model.contact.ContactResource> contact;
   google.registry.model.domain.DesignatedContact$Type type;
-  google.registry.model.domain.ReferenceUnion<google.registry.model.contact.ContactResource> contactId;
 }
 enum google.registry.model.domain.DesignatedContact$Type {
   ADMIN;
@@ -218,7 +217,6 @@ class google.registry.model.domain.DomainApplication {
   java.util.List<google.registry.model.smd.EncodedSignedMark> encodedSignedMarks;
   java.util.Set<com.googlecode.objectify.Key<google.registry.model.host.HostResource>> nsHosts;
   java.util.Set<google.registry.model.domain.DesignatedContact> allContacts;
-  java.util.Set<google.registry.model.domain.ReferenceUnion<google.registry.model.host.HostResource>> nameservers;
   java.util.Set<google.registry.model.domain.secdns.DelegationSignerData> dsData;
   java.util.Set<google.registry.model.eppcommon.StatusValue> status;
   org.joda.money.Money auctionPrice;
@@ -245,7 +243,6 @@ class google.registry.model.domain.DomainBase {
   java.lang.String tld;
   java.util.Set<com.googlecode.objectify.Key<google.registry.model.host.HostResource>> nsHosts;
   java.util.Set<google.registry.model.domain.DesignatedContact> allContacts;
-  java.util.Set<google.registry.model.domain.ReferenceUnion<google.registry.model.host.HostResource>> nameservers;
   java.util.Set<google.registry.model.domain.secdns.DelegationSignerData> dsData;
   java.util.Set<google.registry.model.eppcommon.StatusValue> status;
   org.joda.time.DateTime deletionTime;
@@ -274,7 +271,6 @@ class google.registry.model.domain.DomainResource {
   java.util.Set<com.googlecode.objectify.Key<google.registry.model.host.HostResource>> nsHosts;
   java.util.Set<google.registry.model.domain.DesignatedContact> allContacts;
   java.util.Set<google.registry.model.domain.GracePeriod> gracePeriods;
-  java.util.Set<google.registry.model.domain.ReferenceUnion<google.registry.model.host.HostResource>> nameservers;
   java.util.Set<google.registry.model.domain.secdns.DelegationSignerData> dsData;
   java.util.Set<google.registry.model.eppcommon.StatusValue> status;
   java.util.Set<java.lang.String> subordinateHosts;
@@ -307,9 +303,6 @@ enum google.registry.model.domain.Period$Unit {
   MONTHS;
   YEARS;
 }
-class google.registry.model.domain.ReferenceUnion {
-  com.googlecode.objectify.Key<T> linked;
-}
 enum google.registry.model.domain.launch.ApplicationStatus {
   ALLOCATED;
   INVALID;