TINKERPOP-3144 Close traversal on failure (#3075)

* Close traversal for failure

* close-iterator-in-abstract-op

Author: langrp

gremlin-server/src/main/java/org/apache/tinkerpop/gremlin/server/op/AbstractEvalOpProcessor.java

@@ -40,6 +40,7 @@
 import org.apache.tinkerpop.gremlin.server.GraphManager;
 import org.apache.tinkerpop.gremlin.server.Settings;
 import org.apache.tinkerpop.gremlin.server.util.MetricManager;
+import org.apache.tinkerpop.gremlin.structure.util.CloseableIterator;
 import org.apache.tinkerpop.gremlin.structure.util.TemporaryException;
 import org.apache.tinkerpop.gremlin.util.function.ThrowingConsumer;
 import org.apache.tinkerpop.gremlin.util.iterator.IteratorUtils;
@@ -269,6 +270,8 @@ protected void evalOpInternal(final Context ctx, final Supplier<GremlinExecutor>
                     } catch (Exception ex) {
                         if (managedTransactionsForRequest) attemptRollback(msg, ctx.getGraphManager(), settings.strictTransactionManagement);
 
+                        CloseableIterator.closeIterator(itty);
+
                         // wrap up the exception and rethrow. the error will be written to the client by the evalFuture
                         // as it will completeExceptionally in the GremlinExecutor
                         throw new RuntimeException(ex);

gremlin-server/src/main/java/org/apache/tinkerpop/gremlin/server/op/session/SessionOpProcessor.java

@@ -48,6 +48,7 @@
 import org.apache.tinkerpop.gremlin.structure.Graph;
 import org.apache.tinkerpop.gremlin.structure.io.graphson.GraphSONMapper;
 import org.apache.tinkerpop.gremlin.structure.io.graphson.GraphSONVersion;
+import org.apache.tinkerpop.gremlin.structure.util.CloseableIterator;
 import org.apache.tinkerpop.gremlin.structure.util.TemporaryException;
 import org.apache.tinkerpop.gremlin.util.function.ThrowingConsumer;
 import org.apache.tinkerpop.shaded.jackson.databind.ObjectMapper;
@@ -423,6 +424,8 @@ private void iterateBytecodeTraversal(final Context context) throws Exception {
                     if (ex instanceof UndeclaredThrowableException)
                         t = t.getCause();
 
+                    CloseableIterator.closeIterator(traversal);
+
                     // if any exception in the chain is TemporaryException or Failure then we should respond with the
                     // right error code so that the client knows to retry
                     final Optional<Throwable> possibleSpecialException = determineIfSpecialException(ex);

gremlin-server/src/main/java/org/apache/tinkerpop/gremlin/server/op/traversal/TraversalOpProcessor.java

@@ -47,6 +47,7 @@
 import org.apache.tinkerpop.gremlin.server.util.MetricManager;
 import org.apache.tinkerpop.gremlin.server.util.TraverserIterator;
 import org.apache.tinkerpop.gremlin.structure.Graph;
+import org.apache.tinkerpop.gremlin.structure.util.CloseableIterator;
 import org.apache.tinkerpop.gremlin.structure.util.TemporaryException;
 import org.apache.tinkerpop.gremlin.util.function.ThrowingConsumer;
 import org.slf4j.Logger;
@@ -227,6 +228,8 @@ private void iterateBytecodeTraversal(final Context context) throws Exception {
                     if (ex instanceof UndeclaredThrowableException)
                         t = t.getCause();
 
+                    CloseableIterator.closeIterator(traversal);
+
                     // if any exception in the chain is TemporaryException or Failure then we should respond with the
                     // right error code so that the client knows to retry
                     final Optional<Throwable> possibleSpecialException = determineIfSpecialException(ex);