Add marker interface for plugin applications

Author: graemerocher

grails-core/src/main/groovy/grails/boot/GrailsPluginApplication.groovy

@@ -0,0 +1,26 @@
+/*
+ * Copyright 2016 the original author or authors.
+ *
+ * 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.
+ */
+package grails.boot
+
+/**
+ * A marker interface for applications that are also plugins
+ *
+ * @author Graeme Rocher
+ * @since 3.0.17
+ */
+interface GrailsPluginApplication {
+
+}

grails-web-boot/src/main/groovy/org/grails/compiler/boot/BootInitializerClassInjector.groovy

@@ -1,5 +1,6 @@
 package org.grails.compiler.boot
 
+import grails.boot.GrailsPluginApplication
 import grails.boot.config.GrailsAutoConfiguration
 import grails.compiler.ast.AstTransformer
 import grails.compiler.ast.GlobalClassInjectorAdapter
@@ -56,7 +57,7 @@ class BootInitializerClassInjector extends GlobalClassInjectorAdapter {
         // don't generate for plugins
         if( classNode.getNodeMetaData('isPlugin') ) return
 
-        if(GrailsASTUtils.isAssignableFrom(GRAILS_CONFIGURATION_CLASS_NODE, classNode)) {
+        if(GrailsASTUtils.isAssignableFrom(GRAILS_CONFIGURATION_CLASS_NODE, classNode) && !GrailsASTUtils.isSubclassOfOrImplementsInterface(classNode, GrailsPluginApplication.name)) {
             def methods = classNode.getMethods("main")
             for(MethodNode mn in methods) {
                 if(Modifier.isStatic(mn.modifiers) && Modifier.isPublic(mn.modifiers)) {