Merge pull request #221 from ebean-orm/feature/220-followup

For #220, detect unexpected OneToMany initialisation cases

Author: rbygrave

ebean-agent/src/main/java/io/ebean/enhance/entity/ConstructorDeferredCode.java

@@ -189,7 +189,7 @@ private boolean kotlinEmptyList(String owner, String name, String desc) {
    */
   boolean consumeVisitFieldInsn(int opcode, String owner, String name, String desc) {
     if (opcode == PUTFIELD) {
-      if (state == State.MAYBE_UNSUPPORTED && meta.isConsumeInitMany(name)) {
+      if (meta.isConsumeInitMany(name) && unsupportedInitialisation()) {
         // a OneToMany/ManyToMany is initialised in an unsupported manor
         meta.addUnsupportedInitMany(name);
         flush();
@@ -221,6 +221,15 @@ boolean consumeVisitFieldInsn(int opcode, String owner, String name, String desc
     return false;
   }
 
+  /**
+   * Return true when a OneToMany or ManyToMany is not initialised in a supported manor.
+   */
+  private boolean unsupportedInitialisation() {
+    return state == State.MAYBE_UNSUPPORTED
+      || state == State.UNSET // proceeded by GETSTATIC field bytecode like Collections.EMPTY_LIST
+      || state == State.INVOKE_SPECIAL && !isConsumeManyType(); // e.g. new BeanList()
+  }
+
   boolean consumeVisitLabel(Label label) {
     if (state == State.KT_CHECKCAST) {
       codes.add(new DeferredLabel(label));

test/src/test/java/test/model/WithInitialisedCollections2.java

@@ -26,6 +26,11 @@ public class WithInitialisedCollections2 extends BaseEntity {
   @OneToMany(cascade = CascadeType.PERSIST)
   Map<Long,Contact> mapCollEmpty = Collections.emptyMap();
 
+  // @OneToMany final List<Contact> listCollNotValidInitialisation0 = new io.ebean.common.BeanList<>();
+  // @OneToMany final List<Contact> listCollNotValidInitialisation1 = Collections.EMPTY_LIST;
+  // @OneToMany final List<Contact> listCollNotValidInitialisation2 = List.of(new Contact("junk"));
+  // @OneToMany final List<Contact> listCollNotValidInitialisation3 = Collections.unmodifiableList(Collections.emptyList());
+
   @Transient
   List<String> transientList = List.of();
   @Transient