Temporarily add null handling for autorenew billing events

These shouldn't ever be null, but we have some bad data in production
for prober TLDs left over from the Registry 2.0 transition. Ignoring
null values here is required to finish cleanup for this old data, which
currently cannot even be deleted because it's throwing an NPE when
trying to update these values.

This commit will be reverted after the bad data is cleaned up, likely
sometime next week.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=158546840

java/google/registry/flows/domain/DomainFlowUtils.java

@@ -36,6 +36,7 @@ import static google.registry.util.DateTimeUtils.END_OF_TIME;
 import static google.registry.util.DateTimeUtils.isAtOrAfter;
 import static google.registry.util.DateTimeUtils.leapSafeAddYears;
 import static google.registry.util.DomainNameUtils.ACE_PREFIX;
+import static google.registry.util.FormattingLogger.getLoggerForCallerClass;
 
 import com.google.common.base.CharMatcher;
 import com.google.common.base.Joiner;
@@ -63,6 +64,7 @@ import google.registry.model.EppResource;
 import google.registry.model.billing.BillingEvent;
 import google.registry.model.billing.BillingEvent.Flag;
 import google.registry.model.billing.BillingEvent.Reason;
+import google.registry.model.billing.BillingEvent.Recurring;
 import google.registry.model.contact.ContactResource;
 import google.registry.model.domain.DesignatedContact;
 import google.registry.model.domain.DesignatedContact.Type;
@@ -104,6 +106,7 @@ import google.registry.model.registry.label.ReservationType;
 import google.registry.model.registry.label.ReservedList;
 import google.registry.model.reporting.HistoryEntry;
 import google.registry.model.tmch.ClaimsListShard;
+import google.registry.util.FormattingLogger;
 import google.registry.util.Idn;
 import java.math.BigDecimal;
 import java.util.HashSet;
@@ -118,6 +121,8 @@ import org.joda.time.DateTime;
 /** Static utility functions for domain flows. */
 public class DomainFlowUtils {
 
+  private static final FormattingLogger logger = getLoggerForCallerClass();
+
   /** Map from launch phases to the equivalent tld states. */
   private static final ImmutableMap<LaunchPhase, TldState> LAUNCH_PHASE_TO_TLD_STATE =
       ImmutableMap.of(
@@ -506,9 +511,17 @@ public class DomainFlowUtils {
       ofy().save().entity(updatedAutorenewPollMessage);
     }
 
-    ofy().save().entity(ofy().load().key(domain.getAutorenewBillingEvent()).now().asBuilder()
+    Recurring recurring = ofy().load().key(domain.getAutorenewBillingEvent()).now();
-        .setRecurrenceEndTime(newEndTime)
+    // TODO(b/27472322): Revert handling of recurring being null once bad data is cleaned from prod.
-        .build());
+    // It shouldn't ever actually be null, and we only have some null data left because of issues
+    // dating back to the Registry 2.0 migration.
+    if (recurring == null) {
+      logger.warningfmt(
+          "Domain name %s has null autorenew billing event; ignoring. Domain key: %s.",
+          domain.getFullyQualifiedDomainName(), Key.create(domain));
+    } else {
+      ofy().save().entity(recurring.asBuilder().setRecurrenceEndTime(newEndTime).build());
+    }
   }
 
   /**

javatests/google/registry/flows/domain/DomainDeleteFlowTest.java

@@ -492,6 +492,20 @@ public class DomainDeleteFlowTest extends ResourceFlowTestCase<DomainDeleteFlow,
     assertThat(domain.getTransferData()).isEqualTo(TransferData.EMPTY);
   }
 
+  //TODO(b/27472322): Delete test handling recurring being null once bad data is cleaned from prod.
+  @Test
+  public void testSuccess_nullAutorenewBillingEvent_isIgnore() throws Exception {
+    setClientIdForFlow("TheRegistrar");
+    setupSuccessfulTest();
+    ofy().deleteWithoutBackup().key(domain.getAutorenewBillingEvent()).now();
+    ofy().clearSessionCache();
+    clock.advanceOneMilli();
+    runFlowAssertResponse(readFile("domain_delete_response_pending.xml"));
+    // If the previous statement doesn't throw an error, then the test is successful.
+    assertThat(ofy().load().key(reloadResourceByForeignKey().getAutorenewBillingEvent()).now())
+        .isNull();
+  }
+
   @Test
   public void testSuccess_pendingTransfer() throws Exception {
     setClientIdForFlow("TheRegistrar");