avoid arrayList allocation

platform/projectModel-impl/src/com/intellij/openapi/roots/impl/RootModelBase.java

@@ -1,17 +1,5 @@
 /*
- * Copyright 2000-2015 JetBrains s.r.o.
- *
- * Licensed 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.
+ * Copyright 2000-2017 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
  */
 package com.intellij.openapi.roots.impl;
 
@@ -206,7 +194,7 @@ public abstract class RootModelBase implements ModuleRootModel {
   @NotNull
   public Module[] getModuleDependencies(boolean includeTests) {
     OrderEntry[] entries = getOrderEntries();
-    List<Module> result = new ArrayList<>(entries.length);
+    List<Module> result = null;
 
     for (OrderEntry entry : entries) {
       if (entry instanceof ModuleOrderEntry) {
@@ -214,13 +202,16 @@ public abstract class RootModelBase implements ModuleRootModel {
         if (includeTests || scope.isForProductionCompile() || scope.isForProductionRuntime()) {
           Module module = ((ModuleOrderEntry)entry).getModule();
           if (module != null) {
+            if (result == null) {
+              result = new SmartList<>();
+            }
             result.add(module);
           }
         }
       }
     }
 
-    return result.isEmpty() ? Module.EMPTY_ARRAY : ContainerUtil.toArray(result, new Module[result.size()]);
+    return result == null ? Module.EMPTY_ARRAY : ContainerUtil.toArray(result, new Module[result.size()]);
   }
 
   private static class CollectDependentModules extends RootPolicy<List<String>> {