fix for GRAILS-1089

git-svn-id: https://svn.codehaus.org/grails/trunk@4070 1cfb16fd-6d17-0410-8ff1-b7e8e1e2867d

Author: graeme

src/groovy/org/codehaus/groovy/grails/plugins/orm/hibernate/HibernateGrailsPlugin.groovy

@@ -159,16 +159,31 @@ class HibernateGrailsPlugin {
 							else {
 								throw new MissingMethodException(dc.clazz, "addTo${collectionName}", [arg] as Object[])
 							} 
-						    if(prop.bidirectional) {
-						      	obj[prop.otherSide.name] = delegate  
+						    if(prop.bidirectional) {							   
+								if(prop.manyToMany) {                    
+									String name = prop.otherSide.name
+									if(!obj[name]) {
+										obj[name] = GrailsClassUtils.createConcreteCollection(prop.otherSide.type)
+									}
+									obj[prop.otherSide.name].add(delegate)									
+								}   
+								else {
+							      	obj[prop.otherSide.name] = delegate  
+								}
 						    }						    
 							delegate						
 						}   
 						dc.metaClass."removeFrom${collectionName}" = { Object arg ->
 	                         if(otherDomainClass.clazz.isInstance(arg)) {
 		                     	delegate[prop.name]?.remove(arg)
-		                        if(prop.bidirectional) {
-			                         arg[prop.otherSide.name] = null
+		                        if(prop.bidirectional) { 
+									 if(prop.manyToMany) {
+										String name = prop.otherSide.name
+                                       	arg[name]?.remove(delegate)										
+									 }
+									 else {
+										arg[prop.otherSide.name] = null
+									 }			                         
 								}
 							 } 
 							else {

test/groovy/org/codehaus/groovy/grails/orm/hibernate/RelationshipManagementMethodsTests.groovy

@@ -54,6 +54,27 @@ class RelationshipManagementMethodsTests extends org.codehaus.groovy.grails.plug
 
 	}
 
+	void testWithManyToManyRelationship() {
+	    def bookmarkClass = ga.getDomainClass("Bookmark")
+	    def tagClass = ga.getDomainClass("Tag")
+
+        def bookmark = bookmarkClass.newInstance()
+        bookmark.url='http://www.ru'
+
+        def tag = tagClass.newInstance()
+        tag.name = "foo"
+
+        bookmark.addToTags(tag)
+
+        assert bookmark.tags.contains(tag)
+        assert tag.bookmarks.contains(bookmark)
+
+        bookmark.removeFromTags(tag)
+        assert !bookmark.tags.contains(tag)
+        assert !tag.bookmarks.contains(bookmark)
+
+    }
+
 
 	void onSetUp() {
 
@@ -78,6 +99,23 @@ class Address {
 	String number
 	Person person
 }
+class Bookmark {
+	Long id
+	Long version
+
+    String url
+    Set tags = new HashSet()
+    static hasMany = [tags:Tag]
+    static belongsTo = [Tag]
+}
+class Tag {
+	Long id
+	Long version
+
+    String name
+    Set bookmarks = new HashSet()
+    static hasMany = [bookmarks:Bookmark]
+}
 '''
 		)
 	}