BUG-8445: Guard against NPE

[controller.git] / opendaylight / md-sal / sal-distributed-datastore / src / main / java / org / opendaylight / controller / cluster / datastore / ShardDataTree.java

diff --git a/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/ShardDataTree.java b/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/ShardDataTree.java
index 694be4d1d16ac1e723359531fac964908bfdc3f3..7b317faaee8619bdcd590cbf11ea59ca6e014b61 100644 (file)
--- a/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/ShardDataTree.java
+++ b/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/ShardDataTree.java
@@ -787,8 +787,12 @@ public class ShardDataTree extends ShardDataTreeTransactionParent {
     }
 
     void startCanCommit(final SimpleShardDataTreeCohort cohort) {
-        final SimpleShardDataTreeCohort current = pendingTransactions.peek().cohort;
-        if (!cohort.equals(current)) {
+        final CommitEntry head = pendingTransactions.peek();
+        if (head == null) {
+            LOG.warn("{}: No transactions enqueued while attempting to start canCommit on {}", logContext, cohort);
+            return;
+        }
+        if (!cohort.equals(head.cohort)) {
             LOG.debug("{}: Transaction {} scheduled for canCommit step", logContext, cohort.getIdentifier());
             return;
         }