add test and cleanup

modules/lang-painless/src/main/java/org/elasticsearch/painless/NeedsScore.java

@@ -1,3 +1,21 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
 package org.elasticsearch.painless;
 
 /** Marker interface that a generated {@link Executable} uses the {@code _score} value */

modules/lang-painless/src/main/java/org/elasticsearch/painless/PainlessScriptEngineService.java

@@ -215,11 +215,10 @@ public class PainlessScriptEngineService extends AbstractComponent implements Sc
 
             /**
              * Whether or not the score is needed.
-             * @return Always true as it's assumed score is needed.
              */
             @Override
             public boolean needsScores() {
-                return true;
+                return compiledScript.compiled() instanceof NeedsScore;
             }
         };
     }

modules/lang-painless/src/main/java/org/elasticsearch/painless/Writer.java

@@ -138,9 +138,9 @@ class Writer extends PainlessParserBaseVisitor<Void> {
         // apply marker interface NeedsScore if we use the score!
         final String interfaces[];
         if (metadata.scoreValueUsed) {
-          interfaces = new String[] { WriterConstants.NEEDS_SCORE_TYPE.getInternalName() };
+            interfaces = new String[] { WriterConstants.NEEDS_SCORE_TYPE.getInternalName() };
         } else {
-          interfaces = null;
+            interfaces = null;
         }
         writer.visit(version, access, name, null, base, interfaces);
         writer.visitSource(source, null);

modules/lang-painless/src/test/java/org/elasticsearch/painless/NeedsScoreTests.java

@@ -0,0 +1,61 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.elasticsearch.painless;
+
+import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.index.IndexService;
+import org.elasticsearch.script.CompiledScript;
+import org.elasticsearch.script.ScriptService.ScriptType;
+import org.elasticsearch.script.SearchScript;
+import org.elasticsearch.search.lookup.SearchLookup;
+import org.elasticsearch.test.ESSingleNodeTestCase;
+
+import java.util.Collections;
+
+/**
+ * Test that needsScores() is reported correctly depending on whether _score is used
+ */
+// TODO: can we test this better? this is a port of the ExpressionsTests method.
+public class NeedsScoreTests extends ESSingleNodeTestCase {
+
+    public void testNeedsScores() {
+        IndexService index = createIndex("test", Settings.EMPTY, "type", "d", "type=double");
+
+        PainlessScriptEngineService service = new PainlessScriptEngineService(Settings.EMPTY);
+        SearchLookup lookup = new SearchLookup(index.mapperService(), index.fieldData(), null);
+
+        Object compiled = service.compile("1.2", Collections.emptyMap());
+        SearchScript ss = service.search(new CompiledScript(ScriptType.INLINE, "randomName", "painless", compiled), lookup, Collections.<String, Object>emptyMap());
+        assertFalse(ss.needsScores());
+
+        compiled = service.compile("input.doc['d'].value", Collections.emptyMap());
+        ss = service.search(new CompiledScript(ScriptType.INLINE, "randomName", "painless", compiled), lookup, Collections.<String, Object>emptyMap());
+        assertFalse(ss.needsScores());
+
+        compiled = service.compile("1/_score", Collections.emptyMap());
+        ss = service.search(new CompiledScript(ScriptType.INLINE, "randomName", "painless", compiled), lookup, Collections.<String, Object>emptyMap());
+        assertTrue(ss.needsScores());
+
+        compiled = service.compile("input.doc['d'].value * _score", Collections.emptyMap());
+        ss = service.search(new CompiledScript(ScriptType.INLINE, "randomName", "painless", compiled), lookup, Collections.<String, Object>emptyMap());
+        assertTrue(ss.needsScores());
+    }
+
+}