Fix order and beef up test

Author: jasontedor

core/src/main/java/org/elasticsearch/index/shard/IndexShard.java

@@ -2065,8 +2065,8 @@ public void acquireReplicaOperationPermit(final long operationPrimaryTerm, final
                                     getLocalCheckpoint(),
                                     globalCheckpoint,
                                     globalCheckpoint);
-                            getEngine().seqNoService().resetLocalCheckpoint(globalCheckpoint);
                             updateGlobalCheckpointOnReplica(globalCheckpoint);
+                            getEngine().seqNoService().resetLocalCheckpoint(getGlobalCheckpoint());
                             getEngine().getTranslog().rollGeneration();
                         });
                         globalCheckpointUpdated = true;

core/src/test/java/org/elasticsearch/index/shard/IndexShardTests.java

@@ -692,13 +692,19 @@ private void finish() {
         closeShards(indexShard);
     }
 
-    public void testThrowbackLocalCheckpointOnReplica() throws IOException, InterruptedException {
+    public void testThrowBackLocalCheckpointOnReplica() throws IOException, InterruptedException {
         final IndexShard indexShard = newStartedShard(false);
 
         // most of the time this is large enough that most of the time there will be at least one gap
         final int operations = 1024 - scaledRandomIntBetween(0, 1024);
         indexOnReplicaWithGaps(indexShard, operations, Math.toIntExact(SequenceNumbersService.NO_OPS_PERFORMED));
 
+        final long globalCheckpointOnReplica =
+                randomIntBetween(
+                        Math.toIntExact(SequenceNumbersService.NO_OPS_PERFORMED),
+                        Math.toIntExact(indexShard.getLocalCheckpoint()));
+        indexShard.updateGlobalCheckpointOnReplica(globalCheckpointOnReplica);
+
         final int globalCheckpoint =
                 randomIntBetween(
                         Math.toIntExact(SequenceNumbersService.NO_OPS_PERFORMED),
@@ -721,9 +727,9 @@ public void onFailure(Exception e) {
                 ThreadPool.Names.SAME);
 
         latch.await();
-        assertThat(indexShard.getLocalCheckpoint(), equalTo((long) globalCheckpoint));
+        assertThat(indexShard.getLocalCheckpoint(), equalTo(Math.max(globalCheckpoint, globalCheckpointOnReplica)));
 
-        // ensure that after the local checkpoint throwback and indexing again, the local checkpoint advances
+        // ensure that after the local checkpoint throw back and indexing again, the local checkpoint advances
         final Result result = indexOnReplicaWithGaps(indexShard, operations, Math.toIntExact(indexShard.getLocalCheckpoint()));
         assertThat(indexShard.getLocalCheckpoint(), equalTo((long) result.localCheckpoint));