Make domain update flow handle null auth data (#2530)

It's valid for the auth data to be null (although it only happens 10 times
across our entire registry), so the domain update flow should not fail out with
a NullPointerException when the existing state of the data is null and the
update isn't adding that data either.

BUG=http://b/359264787

core/src/test/java/google/registry/flows/domain/DomainUpdateFlowTest.java

@@ -104,8 +104,10 @@ import google.registry.model.contact.Contact;
 import google.registry.model.domain.DesignatedContact;
 import google.registry.model.domain.DesignatedContact.Type;
 import google.registry.model.domain.Domain;
+import google.registry.model.domain.DomainAuthInfo;
 import google.registry.model.domain.DomainHistory;
 import google.registry.model.domain.secdns.DomainDsData;
+import google.registry.model.eppcommon.AuthInfo.PasswordAuth;
 import google.registry.model.eppcommon.Trid;
 import google.registry.model.host.Host;
 import google.registry.model.poll.PendingActionNotificationResponse.DomainPendingActionNotificationResponse;
@@ -264,6 +266,38 @@ class DomainUpdateFlowTest extends ResourceFlowTestCase<DomainUpdateFlow, Domain
     doSuccessfulTest("generic_success_response_no_cltrid.xml");
   }
 
+  @Test
+  void testSuccess_noExistingAuthData() throws Exception {
+    setEppInput("domain_update_no_auth_change.xml");
+    persistReferencedEntities();
+    persistDomain();
+    persistResource(
+        reloadResourceByForeignKey()
+            .asBuilder()
+            .setAuthInfo(DomainAuthInfo.create(PasswordAuth.create(null)))
+            .build());
+    assertMutatingFlow(true);
+    runFlowAssertResponse(loadFile("generic_success_response.xml"));
+    Domain domain = reloadResourceByForeignKey();
+    // Check that the domain was updated. These values came from the xml.
+    assertAboutDomains()
+        .that(domain)
+        .hasStatusValue(CLIENT_HOLD)
+        .and()
+        .hasAuthInfoPwd(null)
+        .and()
+        .hasOneHistoryEntryEachOfTypes(DOMAIN_CREATE, DOMAIN_UPDATE)
+        .and()
+        .hasLastEppUpdateTime(clock.nowUtc())
+        .and()
+        .hasLastEppUpdateRegistrarId("TheRegistrar")
+        .and()
+        .hasNoAutorenewEndTime();
+    assertNoBillingEvents();
+    assertDomainDnsRequests("example.tld");
+    assertLastHistoryContainsResource(reloadResourceByForeignKey());
+  }
+
   @Test
   void testSuccess_cachingDisabled() throws Exception {
     boolean origIsCachingEnabled = RegistryConfig.isEppResourceCachingEnabled();

core/src/test/java/google/registry/testing/DomainSubject.java

@@ -29,6 +29,7 @@ import google.registry.model.eppcommon.AuthInfo;
 import google.registry.testing.TruthChainer.And;
 import google.registry.tmch.LordnTaskUtils.LordnPhase;
 import java.util.Set;
+import javax.annotation.Nullable;
 import org.joda.time.DateTime;
 
 /** Truth subject for asserting things about {@link Domain} instances. */
@@ -65,7 +66,7 @@ public final class DomainSubject extends AbstractEppResourceSubject<Domain, Doma
     return hasValue(lordnPhase, actual.getLordnPhase(), "lordnPhase");
   }
 
-  public And<DomainSubject> hasAuthInfoPwd(String pw) {
+  public And<DomainSubject> hasAuthInfoPwd(@Nullable String pw) {
     AuthInfo authInfo = actual.getAuthInfo();
     return hasValue(pw, authInfo == null ? null : authInfo.getPw().getValue(), "has auth info pw");
   }

core/src/test/resources/google/registry/flows/domain/domain_update_no_auth_change.xml

@@ -0,0 +1,26 @@
+<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
+  <command>
+    <update>
+      <domain:update
+       xmlns:domain="urn:ietf:params:xml:ns:domain-1.0">
+        <domain:name>example.tld</domain:name>
+        <domain:add>
+          <domain:ns>
+            <domain:hostObj>ns2.example.foo</domain:hostObj>
+          </domain:ns>
+          <domain:contact type="tech">mak21</domain:contact>
+          <domain:status s="clientHold"
+           lang="en">Payment overdue.</domain:status>
+        </domain:add>
+        <domain:rem>
+          <domain:ns>
+            <domain:hostObj>ns1.example.foo</domain:hostObj>
+          </domain:ns>
+          <domain:contact type="tech">sh8013</domain:contact>
+          <domain:status s="clientUpdateProhibited"/>
+        </domain:rem>
+      </domain:update>
+    </update>
+    <clTRID>ABC-12345</clTRID>
+  </command>
+</epp>