Merge branch 'stable-2.16' into stable-3.0

* stable-2.16:
  Ignore change deletion events for owners-autoassign

Change-Id: If7f9457dee71a3c752f279084b3fa3ee258fb99a

owners-autoassign/src/main/java/com/googlesource/gerrit/owners/common/GitRefListener.java

diff --git a/owners-autoassign/src/main/java/com/googlesource/gerrit/owners/common/GitRefListener.java b/owners-autoassign/src/main/java/com/googlesource/gerrit/owners/common/GitRefListener.java
index 4a34958..48f55a5 100644
--- a/owners-autoassign/src/main/java/com/googlesource/gerrit/owners/common/GitRefListener.java
+++ b/owners-autoassign/src/main/java/com/googlesource/gerrit/owners/common/GitRefListener.java
@@ -84,6 +84,11 @@
 
   @Override
   public void onGitReferenceUpdated(Event event) {
+    if (event.isDelete()) {
+      logger.debug("Ref-update event on ref %s is a deletion: ignoring", event.getRefName());
+      return;
+    }
+
     AccountInfo updaterAccountInfo = event.getUpdater();
     CurrentUser currentUser = currentUserProvider.get();
     if (currentUser.isIdentifiedUser()) {
@@ -137,9 +142,6 @@
     try {
       ChangeApi cApi = changes.id(cId.id);
       ChangeInfo change = cApi.get();
-      if (change == null) {
-        return;
-      }
       PatchList patchList = getPatchList(event, change);
       if (patchList != null) {
         PathOwners owners = new PathOwners(accounts, repository, change.branch, patchList);