Require combine and reduce scripts in scripted metrics aggregation (#33452)

* Make text message not required in constructor for slack

* Remove unnecessary comments in test file

* Throw exception when reduce or combine is not provided; update tests

* Update integration tests for scripted metrics to always include reduce and combine

* Remove some old changes from previous branches

* Rearrange script presence checks to be earlier in build

* Change null check order in script builder for aggregated metrics; correct test scripts in IT

* Add breaking change details to PR

docs/reference/migration/migrate_7_0/aggregations.asciidoc

@@ -26,3 +26,9 @@ has been removed. `missing_bucket` should be used instead.
 The object used to share aggregation state between the scripts in a Scripted Metric
 Aggregation is now a variable called `state` available in the script context, rather than
 being provided via the `params` object as `params._agg`.
+
+[float]
+==== Make metric aggregation script parameters `reduce_script` and `combine_script` mandatory
+
+The metric aggregation has been changed to require these two script parameters to ensure users are
+explicitly defining how their data is processed.

server/src/main/java/org/elasticsearch/search/aggregations/metrics/ScriptedMetricAggregationBuilder.java

@@ -196,6 +196,14 @@ public class ScriptedMetricAggregationBuilder extends AbstractAggregationBuilder
     protected ScriptedMetricAggregatorFactory doBuild(SearchContext context, AggregatorFactory<?> parent,
             Builder subfactoriesBuilder) throws IOException {
 
+        if (combineScript == null) {
+            throw new IllegalArgumentException("[combineScript] must not be null: [" + name + "]");
+        }
+
+        if(reduceScript == null) {
+            throw new IllegalArgumentException("[reduceScript] must not be null: [" + name + "]");
+        }
+
         QueryShardContext queryShardContext = context.getQueryShardContext();
 
         // Extract params from scripts and pass them along to ScriptedMetricAggregatorFactory, since it won't have
@@ -215,16 +223,14 @@ public class ScriptedMetricAggregationBuilder extends AbstractAggregationBuilder
             ScriptedMetricAggContexts.MapScript.CONTEXT);
         Map<String, Object> mapScriptParams = mapScript.getParams();
 
+
         ScriptedMetricAggContexts.CombineScript.Factory compiledCombineScript;
         Map<String, Object> combineScriptParams;
-        if (combineScript != null) {
-            compiledCombineScript = queryShardContext.getScriptService().compile(combineScript,
-                ScriptedMetricAggContexts.CombineScript.CONTEXT);
-            combineScriptParams = combineScript.getParams();
-        } else {
-            compiledCombineScript = (p, a) -> null;
-            combineScriptParams = Collections.emptyMap();
-        }
+
+        compiledCombineScript = queryShardContext.getScriptService().compile(combineScript,
+            ScriptedMetricAggContexts.CombineScript.CONTEXT);
+        combineScriptParams = combineScript.getParams();
+
         return new ScriptedMetricAggregatorFactory(name, compiledMapScript, mapScriptParams, compiledInitScript,
                 initScriptParams, compiledCombineScript, combineScriptParams, reduceScript,
                 params, queryShardContext.lookup(), context, parent, subfactoriesBuilder, metaData);

server/src/test/java/org/elasticsearch/search/aggregations/metrics/ScriptedMetricAggregatorTests.java

@@ -54,6 +54,8 @@ public class ScriptedMetricAggregatorTests extends AggregatorTestCase {
     private static final Script MAP_SCRIPT = new Script(ScriptType.INLINE, MockScriptEngine.NAME, "mapScript", Collections.emptyMap());
     private static final Script COMBINE_SCRIPT = new Script(ScriptType.INLINE, MockScriptEngine.NAME, "combineScript",
             Collections.emptyMap());
+    private static final Script REDUCE_SCRIPT = new Script(ScriptType.INLINE, MockScriptEngine.NAME, "reduceScript",
+        Collections.emptyMap());
 
     private static final Script INIT_SCRIPT_SCORE = new Script(ScriptType.INLINE, MockScriptEngine.NAME, "initScriptScore",
             Collections.emptyMap());
@@ -61,6 +63,8 @@ public class ScriptedMetricAggregatorTests extends AggregatorTestCase {
             Collections.emptyMap());
     private static final Script COMBINE_SCRIPT_SCORE = new Script(ScriptType.INLINE, MockScriptEngine.NAME, "combineScriptScore",
             Collections.emptyMap());
+    private static final Script COMBINE_SCRIPT_NOOP = new Script(ScriptType.INLINE, MockScriptEngine.NAME, "combineScriptNoop",
+        Collections.emptyMap());
 
     private static final Script INIT_SCRIPT_PARAMS = new Script(ScriptType.INLINE, MockScriptEngine.NAME, "initScriptParams",
             Collections.singletonMap("initialValue", 24));
@@ -96,6 +100,14 @@ public class ScriptedMetricAggregatorTests extends AggregatorTestCase {
             Map<String, Object> state = (Map<String, Object>) params.get("state");
             return ((List<Integer>) state.get("collector")).stream().mapToInt(Integer::intValue).sum();
         });
+        SCRIPTS.put("combineScriptNoop", params -> {
+            Map<String, Object> state = (Map<String, Object>) params.get("state");
+            return state;
+        });
+        SCRIPTS.put("reduceScript", params -> {
+            Map<String, Object> state = (Map<String, Object>) params.get("state");
+            return state;
+        });
 
         SCRIPTS.put("initScriptScore", params -> {
             Map<String, Object> state = (Map<String, Object>) params.get("state");
@@ -160,7 +172,7 @@ public class ScriptedMetricAggregatorTests extends AggregatorTestCase {
             }
             try (IndexReader indexReader = DirectoryReader.open(directory)) {
                 ScriptedMetricAggregationBuilder aggregationBuilder = new ScriptedMetricAggregationBuilder(AGG_NAME);
-                aggregationBuilder.mapScript(MAP_SCRIPT); // map script is mandatory, even if its not used in this case
+                aggregationBuilder.mapScript(MAP_SCRIPT).combineScript(COMBINE_SCRIPT_NOOP).reduceScript(REDUCE_SCRIPT);
                 ScriptedMetric scriptedMetric = search(newSearcher(indexReader, true, true), new MatchAllDocsQuery(), aggregationBuilder);
                 assertEquals(AGG_NAME, scriptedMetric.getName());
                 assertNotNull(scriptedMetric.aggregation());
@@ -169,9 +181,6 @@ public class ScriptedMetricAggregatorTests extends AggregatorTestCase {
         }
     }
 
-    /**
-     * without combine script, the "states" map should contain a list of the size of the number of documents matched
-     */
     public void testScriptedMetricWithoutCombine() throws IOException {
         try (Directory directory = newDirectory()) {
             int numDocs = randomInt(100);
@@ -182,15 +191,28 @@ public class ScriptedMetricAggregatorTests extends AggregatorTestCase {
             }
             try (IndexReader indexReader = DirectoryReader.open(directory)) {
                 ScriptedMetricAggregationBuilder aggregationBuilder = new ScriptedMetricAggregationBuilder(AGG_NAME);
-                aggregationBuilder.initScript(INIT_SCRIPT).mapScript(MAP_SCRIPT);
-                ScriptedMetric scriptedMetric = search(newSearcher(indexReader, true, true), new MatchAllDocsQuery(), aggregationBuilder);
-                assertEquals(AGG_NAME, scriptedMetric.getName());
-                assertNotNull(scriptedMetric.aggregation());
-                @SuppressWarnings("unchecked")
-                Map<String, Object> agg = (Map<String, Object>) scriptedMetric.aggregation();
-                @SuppressWarnings("unchecked")
-                List<Integer> list = (List<Integer>) agg.get("collector");
-                assertEquals(numDocs, list.size());
+                aggregationBuilder.initScript(INIT_SCRIPT).mapScript(MAP_SCRIPT).reduceScript(REDUCE_SCRIPT);
+                IllegalArgumentException exception = expectThrows(IllegalArgumentException.class,
+                    () -> search(newSearcher(indexReader, true, true), new MatchAllDocsQuery(), aggregationBuilder));
+                assertEquals(exception.getMessage(), "[combineScript] must not be null: [scriptedMetric]");
+            }
+        }
+    }
+
+    public void testScriptedMetricWithoutReduce() throws IOException {
+        try (Directory directory = newDirectory()) {
+            int numDocs = randomInt(100);
+            try (RandomIndexWriter indexWriter = new RandomIndexWriter(random(), directory)) {
+                for (int i = 0; i < numDocs; i++) {
+                    indexWriter.addDocument(singleton(new SortedNumericDocValuesField("number", i)));
+                }
+            }
+            try (IndexReader indexReader = DirectoryReader.open(directory)) {
+                ScriptedMetricAggregationBuilder aggregationBuilder = new ScriptedMetricAggregationBuilder(AGG_NAME);
+                aggregationBuilder.initScript(INIT_SCRIPT).mapScript(MAP_SCRIPT).combineScript(COMBINE_SCRIPT);
+                IllegalArgumentException exception = expectThrows(IllegalArgumentException.class,
+                    () -> search(newSearcher(indexReader, true, true), new MatchAllDocsQuery(), aggregationBuilder));
+                assertEquals(exception.getMessage(), "[reduceScript] must not be null: [scriptedMetric]");
             }
         }
     }
@@ -208,7 +230,8 @@ public class ScriptedMetricAggregatorTests extends AggregatorTestCase {
             }
             try (IndexReader indexReader = DirectoryReader.open(directory)) {
                 ScriptedMetricAggregationBuilder aggregationBuilder = new ScriptedMetricAggregationBuilder(AGG_NAME);
-                aggregationBuilder.initScript(INIT_SCRIPT).mapScript(MAP_SCRIPT).combineScript(COMBINE_SCRIPT);
+                aggregationBuilder.initScript(INIT_SCRIPT).mapScript(MAP_SCRIPT)
+                    .combineScript(COMBINE_SCRIPT).reduceScript(REDUCE_SCRIPT);
                 ScriptedMetric scriptedMetric = search(newSearcher(indexReader, true, true), new MatchAllDocsQuery(), aggregationBuilder);
                 assertEquals(AGG_NAME, scriptedMetric.getName());
                 assertNotNull(scriptedMetric.aggregation());
@@ -230,7 +253,8 @@ public class ScriptedMetricAggregatorTests extends AggregatorTestCase {
             }
             try (IndexReader indexReader = DirectoryReader.open(directory)) {
                 ScriptedMetricAggregationBuilder aggregationBuilder = new ScriptedMetricAggregationBuilder(AGG_NAME);
-                aggregationBuilder.initScript(INIT_SCRIPT_SCORE).mapScript(MAP_SCRIPT_SCORE).combineScript(COMBINE_SCRIPT_SCORE);
+                aggregationBuilder.initScript(INIT_SCRIPT_SCORE).mapScript(MAP_SCRIPT_SCORE)
+                    .combineScript(COMBINE_SCRIPT_SCORE).reduceScript(REDUCE_SCRIPT);
                 ScriptedMetric scriptedMetric = search(newSearcher(indexReader, true, true), new MatchAllDocsQuery(), aggregationBuilder);
                 assertEquals(AGG_NAME, scriptedMetric.getName());
                 assertNotNull(scriptedMetric.aggregation());
@@ -250,7 +274,8 @@ public class ScriptedMetricAggregatorTests extends AggregatorTestCase {
 
             try (IndexReader indexReader = DirectoryReader.open(directory)) {
                 ScriptedMetricAggregationBuilder aggregationBuilder = new ScriptedMetricAggregationBuilder(AGG_NAME);
-                aggregationBuilder.initScript(INIT_SCRIPT_PARAMS).mapScript(MAP_SCRIPT_PARAMS).combineScript(COMBINE_SCRIPT_PARAMS);
+                aggregationBuilder.initScript(INIT_SCRIPT_PARAMS).mapScript(MAP_SCRIPT_PARAMS)
+                    .combineScript(COMBINE_SCRIPT_PARAMS).reduceScript(REDUCE_SCRIPT);
                 ScriptedMetric scriptedMetric = search(newSearcher(indexReader, true, true), new MatchAllDocsQuery(), aggregationBuilder);
 
                 // The result value depends on the script params.
@@ -270,8 +295,8 @@ public class ScriptedMetricAggregatorTests extends AggregatorTestCase {
             try (IndexReader indexReader = DirectoryReader.open(directory)) {
                 ScriptedMetricAggregationBuilder aggregationBuilder = new ScriptedMetricAggregationBuilder(AGG_NAME);
                 Map<String, Object> aggParams = Collections.singletonMap(CONFLICTING_PARAM_NAME, "blah");
-                aggregationBuilder.params(aggParams).initScript(INIT_SCRIPT_PARAMS).mapScript(MAP_SCRIPT_PARAMS).
-                    combineScript(COMBINE_SCRIPT_PARAMS);
+                aggregationBuilder.params(aggParams).initScript(INIT_SCRIPT_PARAMS).mapScript(MAP_SCRIPT_PARAMS)
+                    .combineScript(COMBINE_SCRIPT_PARAMS).reduceScript(REDUCE_SCRIPT);
 
                 IllegalArgumentException ex = expectThrows(IllegalArgumentException.class, () ->
                     search(newSearcher(indexReader, true, true), new MatchAllDocsQuery(), aggregationBuilder)
@@ -289,7 +314,8 @@ public class ScriptedMetricAggregatorTests extends AggregatorTestCase {
             }
             try (IndexReader indexReader = DirectoryReader.open(directory)) {
                 ScriptedMetricAggregationBuilder aggregationBuilder = new ScriptedMetricAggregationBuilder(AGG_NAME);
-                aggregationBuilder.initScript(INIT_SCRIPT_SELF_REF).mapScript(MAP_SCRIPT);
+                aggregationBuilder.initScript(INIT_SCRIPT_SELF_REF).mapScript(MAP_SCRIPT)
+                    .combineScript(COMBINE_SCRIPT_PARAMS).reduceScript(REDUCE_SCRIPT);
 
                 IllegalArgumentException ex = expectThrows(IllegalArgumentException.class, () ->
                     search(newSearcher(indexReader, true, true), new MatchAllDocsQuery(), aggregationBuilder)
@@ -309,7 +335,8 @@ public class ScriptedMetricAggregatorTests extends AggregatorTestCase {
             }
             try (IndexReader indexReader = DirectoryReader.open(directory)) {
                 ScriptedMetricAggregationBuilder aggregationBuilder = new ScriptedMetricAggregationBuilder(AGG_NAME);
-                aggregationBuilder.initScript(INIT_SCRIPT).mapScript(MAP_SCRIPT_SELF_REF);
+                aggregationBuilder.initScript(INIT_SCRIPT).mapScript(MAP_SCRIPT_SELF_REF)
+                    .combineScript(COMBINE_SCRIPT_PARAMS).reduceScript(REDUCE_SCRIPT);
 
                 IllegalArgumentException ex = expectThrows(IllegalArgumentException.class, () ->
                     search(newSearcher(indexReader, true, true), new MatchAllDocsQuery(), aggregationBuilder)
@@ -326,7 +353,8 @@ public class ScriptedMetricAggregatorTests extends AggregatorTestCase {
             }
             try (IndexReader indexReader = DirectoryReader.open(directory)) {
                 ScriptedMetricAggregationBuilder aggregationBuilder = new ScriptedMetricAggregationBuilder(AGG_NAME);
-                aggregationBuilder.initScript(INIT_SCRIPT).mapScript(MAP_SCRIPT).combineScript(COMBINE_SCRIPT_SELF_REF);
+                aggregationBuilder.initScript(INIT_SCRIPT).mapScript(MAP_SCRIPT)
+                    .combineScript(COMBINE_SCRIPT_SELF_REF).reduceScript(REDUCE_SCRIPT);
 
                 IllegalArgumentException ex = expectThrows(IllegalArgumentException.class, () ->
                     search(newSearcher(indexReader, true, true), new MatchAllDocsQuery(), aggregationBuilder)

server/src/test/java/org/elasticsearch/search/aggregations/metrics/ScriptedMetricIT.java

@@ -153,6 +153,14 @@ public class ScriptedMetricIT extends ESIntegTestCase {
                 return newAggregation;
             });
 
+            scripts.put("no-op aggregation", vars -> {
+                return (Map<String, Object>) vars.get("state");
+            });
+
+            scripts.put("no-op list aggregation", vars -> {
+                return  (List<List<?>>) vars.get("states");
+            });
+
             // Equivalent to:
             //
             // newaggregation = [];
@@ -188,6 +196,11 @@ public class ScriptedMetricIT extends ESIntegTestCase {
                 Integer sum = 0;
 
                 List<Map<String, Object>> states = (List<Map<String, Object>>) vars.get("states");
+
+                if(states == null) {
+                    return newAggregation;
+                }
+
                 for (Map<String, Object> state : states) {
                     List<?> list = (List<?>) state.get("list");
                     if (list != null) {
@@ -328,10 +341,14 @@ public class ScriptedMetricIT extends ESIntegTestCase {
 
     public void testMap() {
         Script mapScript = new Script(ScriptType.INLINE, CustomScriptPlugin.NAME, "state['count'] = 1", Collections.emptyMap());
+        Script combineScript =
+            new Script(ScriptType.INLINE, CustomScriptPlugin.NAME, "no-op aggregation", Collections.emptyMap());
+        Script reduceScript = new Script(ScriptType.INLINE, CustomScriptPlugin.NAME,
+            "no-op list aggregation", Collections.emptyMap());
 
         SearchResponse response = client().prepareSearch("idx")
                 .setQuery(matchAllQuery())
-                .addAggregation(scriptedMetric("scripted").mapScript(mapScript))
+                .addAggregation(scriptedMetric("scripted").mapScript(mapScript).combineScript(combineScript).reduceScript(reduceScript))
                 .get();
         assertSearchResponse(response);
         assertThat(response.getHits().getTotalHits(), equalTo(numDocs));
@@ -369,10 +386,18 @@ public class ScriptedMetricIT extends ESIntegTestCase {
         Map<String, Object> aggregationParams = Collections.singletonMap("param2", 1);
 
         Script mapScript = new Script(ScriptType.INLINE, CustomScriptPlugin.NAME, "state[param1] = param2", scriptParams);
+        Script combineScript =
+            new Script(ScriptType.INLINE, CustomScriptPlugin.NAME, "no-op aggregation", Collections.emptyMap());
+        Script reduceScript = new Script(ScriptType.INLINE, CustomScriptPlugin.NAME,
+            "no-op list aggregation", Collections.emptyMap());
 
         SearchResponse response = client().prepareSearch("idx")
             .setQuery(matchAllQuery())
-            .addAggregation(scriptedMetric("scripted").params(aggregationParams).mapScript(mapScript))
+            .addAggregation(scriptedMetric("scripted")
+                .params(aggregationParams)
+                .mapScript(mapScript)
+                .combineScript(combineScript)
+                .reduceScript(reduceScript))
             .get();
         assertSearchResponse(response);
         assertThat(response.getHits().getTotalHits(), equalTo(numDocs));
@@ -423,7 +448,11 @@ public class ScriptedMetricIT extends ESIntegTestCase {
                                 .initScript(
                                     new Script(ScriptType.INLINE, CustomScriptPlugin.NAME, "vars.multiplier = 3", Collections.emptyMap()))
                                 .mapScript(new Script(ScriptType.INLINE, CustomScriptPlugin.NAME,
-                                    "state.list.add(vars.multiplier)", Collections.emptyMap())))
+                                    "state.list.add(vars.multiplier)", Collections.emptyMap()))
+                                .combineScript(new Script(ScriptType.INLINE, CustomScriptPlugin.NAME,
+                                    "no-op aggregation", Collections.emptyMap()))
+                                .reduceScript(new Script(ScriptType.INLINE, CustomScriptPlugin.NAME,
+                                    "no-op list aggregation", Collections.emptyMap())))
                 .get();
         assertSearchResponse(response);
         assertThat(response.getHits().getTotalHits(), equalTo(numDocs));
@@ -466,6 +495,8 @@ public class ScriptedMetricIT extends ESIntegTestCase {
         Script mapScript = new Script(ScriptType.INLINE, CustomScriptPlugin.NAME, "state.list.add(1)", Collections.emptyMap());
         Script combineScript =
             new Script(ScriptType.INLINE, CustomScriptPlugin.NAME, "sum state values as a new aggregation", Collections.emptyMap());
+        Script reduceScript = new Script(ScriptType.INLINE, CustomScriptPlugin.NAME,
+            "no-op list aggregation", Collections.emptyMap());
 
         SearchResponse response = client()
                 .prepareSearch("idx")
@@ -474,7 +505,8 @@ public class ScriptedMetricIT extends ESIntegTestCase {
                         scriptedMetric("scripted")
                                 .params(params)
                                 .mapScript(mapScript)
-                                .combineScript(combineScript))
+                                .combineScript(combineScript)
+                                .reduceScript(reduceScript))
                 .execute().actionGet();
         assertSearchResponse(response);
         assertThat(response.getHits().getTotalHits(), equalTo(numDocs));
@@ -519,6 +551,8 @@ public class ScriptedMetricIT extends ESIntegTestCase {
             Collections.emptyMap());
         Script combineScript =
             new Script(ScriptType.INLINE, CustomScriptPlugin.NAME, "sum state values as a new aggregation", Collections.emptyMap());
+        Script reduceScript = new Script(ScriptType.INLINE, CustomScriptPlugin.NAME,
+            "no-op list aggregation", Collections.emptyMap());
 
         SearchResponse response = client()
                 .prepareSearch("idx")
@@ -528,7 +562,8 @@ public class ScriptedMetricIT extends ESIntegTestCase {
                                 .params(params)
                                 .initScript(initScript)
                                 .mapScript(mapScript)
-                                .combineScript(combineScript))
+                                .combineScript(combineScript)
+                                .reduceScript(reduceScript))
                 .get();
         assertSearchResponse(response);
         assertThat(response.getHits().getTotalHits(), equalTo(numDocs));
@@ -713,6 +748,8 @@ public class ScriptedMetricIT extends ESIntegTestCase {
         Script initScript = new Script(ScriptType.INLINE, CustomScriptPlugin.NAME, "vars.multiplier = 3", Collections.emptyMap());
         Script mapScript = new Script(ScriptType.INLINE, CustomScriptPlugin.NAME, "state.list.add(vars.multiplier)",
             Collections.emptyMap());
+        Script combineScript =
+            new Script(ScriptType.INLINE, CustomScriptPlugin.NAME, "no-op aggregation", Collections.emptyMap());
         Script reduceScript = new Script(ScriptType.INLINE, CustomScriptPlugin.NAME,
             "sum all states' state.list values as a new aggregation", Collections.emptyMap());
 
@@ -724,6 +761,7 @@ public class ScriptedMetricIT extends ESIntegTestCase {
                                 .params(params)
                                 .initScript(initScript)
                                 .mapScript(mapScript)
+                                .combineScript(combineScript)
                                 .reduceScript(reduceScript))
                 .get();
         assertSearchResponse(response);
@@ -752,6 +790,8 @@ public class ScriptedMetricIT extends ESIntegTestCase {
 
         Script mapScript = new Script(ScriptType.INLINE, CustomScriptPlugin.NAME, "state.list.add(vars.multiplier)",
             Collections.emptyMap());
+        Script combineScript =
+            new Script(ScriptType.INLINE, CustomScriptPlugin.NAME, "no-op aggregation", Collections.emptyMap());
         Script reduceScript = new Script(ScriptType.INLINE, CustomScriptPlugin.NAME,
             "sum all states' state.list values as a new aggregation", Collections.emptyMap());
 
@@ -762,6 +802,7 @@ public class ScriptedMetricIT extends ESIntegTestCase {
                         scriptedMetric("scripted")
                                 .params(params)
                                 .mapScript(mapScript)
+                                .combineScript(combineScript)
                                 .reduceScript(reduceScript))
                 .get();
         assertSearchResponse(response);
@@ -980,6 +1021,11 @@ public class ScriptedMetricIT extends ESIntegTestCase {
      */
     public void testDontCacheScripts() throws Exception {
         Script mapScript = new Script(ScriptType.INLINE, CustomScriptPlugin.NAME, "state['count'] = 1", Collections.emptyMap());
+        Script combineScript =
+            new Script(ScriptType.INLINE, CustomScriptPlugin.NAME, "no-op aggregation", Collections.emptyMap());
+        Script reduceScript = new Script(ScriptType.INLINE, CustomScriptPlugin.NAME,
+            "no-op list aggregation", Collections.emptyMap());
+
         assertAcked(prepareCreate("cache_test_idx").addMapping("type", "d", "type=long")
                 .setSettings(Settings.builder().put("requests.cache.enable", true).put("number_of_shards", 1).put("number_of_replicas", 1))
                 .get());
@@ -994,7 +1040,7 @@ public class ScriptedMetricIT extends ESIntegTestCase {
 
         // Test that a request using a script does not get cached
         SearchResponse r = client().prepareSearch("cache_test_idx").setSize(0)
-                .addAggregation(scriptedMetric("foo").mapScript(mapScript)).get();
+                .addAggregation(scriptedMetric("foo").mapScript(mapScript).combineScript(combineScript).reduceScript(reduceScript)).get();
         assertSearchResponse(r);
 
         assertThat(client().admin().indices().prepareStats("cache_test_idx").setRequestCache(true).get().getTotal().getRequestCache()
@@ -1006,10 +1052,17 @@ public class ScriptedMetricIT extends ESIntegTestCase {
     public void testConflictingAggAndScriptParams() {
         Map<String, Object> params = Collections.singletonMap("param1", "12");
         Script mapScript = new Script(ScriptType.INLINE, CustomScriptPlugin.NAME, "state.list.add(1)", params);
+        Script combineScript =
+            new Script(ScriptType.INLINE, CustomScriptPlugin.NAME, "no-op aggregation", Collections.emptyMap());
+        Script reduceScript = new Script(ScriptType.INLINE, CustomScriptPlugin.NAME,
+            "no-op list aggregation", Collections.emptyMap());
 
         SearchRequestBuilder builder = client().prepareSearch("idx")
             .setQuery(matchAllQuery())
-            .addAggregation(scriptedMetric("scripted").params(params).mapScript(mapScript));
+            .addAggregation(scriptedMetric("scripted")
+                .params(params).mapScript(mapScript)
+                .combineScript(combineScript)
+                .reduceScript(reduceScript));
 
         SearchPhaseExecutionException ex = expectThrows(SearchPhaseExecutionException.class, builder::get);
         assertThat(ex.getCause().getMessage(), containsString("Parameter name \"param1\" used in both aggregation and script parameters"));