DATACMNS-1082 - Skip synthetic constructors.

Constructor discovery no longer considers synthetic constructors for preferred constructor.

Original pull request: #225

Author: strelok1

src/main/java/org/springframework/data/mapping/model/PreferredConstructorDiscoverer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2011-2015 by the original author(s).
+ * Copyright 2011-2017 by the original author(s).
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -32,6 +32,7 @@
  * Helper class to find a {@link PreferredConstructor}.
  * 
  * @author Oliver Gierke
+ * @author Roman Rodov
  */
 public class PreferredConstructorDiscoverer<T, P extends PersistentProperty<P>> {
 
@@ -73,6 +74,11 @@ protected PreferredConstructorDiscoverer(TypeInformation<T> type, PersistentEnti
 
 			PreferredConstructor<T, P> preferredConstructor = buildPreferredConstructor(candidate, type, entity);
 
+			// Synthetic constructors should not be considered
+			if (preferredConstructor.getConstructor().isSynthetic()) {
+				continue;
+			}
+
 			// Explicitly defined constructor trumps all
 			if (preferredConstructor.isExplicitlyAnnotated()) {
 				this.constructor = preferredConstructor;

src/test/java/org/springframework/data/mapping/PreferredConstructorDiscovererUnitTests.java

@@ -32,6 +32,7 @@
  * Unit tests for {@link PreferredConstructorDiscoverer}.
  * 
  * @author Oliver Gierke
+ * @author Roman Rodov
  */
 public class PreferredConstructorDiscovererUnitTests<P extends PersistentProperty<P>> {
 
@@ -97,6 +98,34 @@ public void discoversInnerClassConstructorCorrectly() {
 		assertThat(constructor.isEnclosingClassParameter(parameter), is(true));
 	}
 
+	@Test // DATACMNS-1082
+	public void skipsSyntheticConstructor() {
+
+		PersistentEntity<SyntheticConstructor, P> entity = new BasicPersistentEntity<SyntheticConstructor, P>(
+				ClassTypeInformation.from(SyntheticConstructor.class));
+		PreferredConstructorDiscoverer<SyntheticConstructor, P> discoverer = //
+				new PreferredConstructorDiscoverer<SyntheticConstructor, P>(entity);
+
+		PreferredConstructor<SyntheticConstructor, P> constructor = discoverer.getConstructor();
+
+		PersistenceConstructor annotation = constructor.getConstructor().getAnnotation(PersistenceConstructor.class);
+		assertNotNull("The preferred constructor should have 'PersistenctConstructor' annotation.", annotation);
+		assertFalse("The preferred constructor must not be synthetic", constructor.getConstructor().isSynthetic());
+	}
+
+	static class SyntheticConstructor {
+		@PersistenceConstructor
+		private SyntheticConstructor(String x) {}
+
+		class InnerSynthetic {
+			// Compiler will generate a synthetic constructor since
+			// SyntheticConstructor() is private.
+			InnerSynthetic() {
+				new SyntheticConstructor("");
+			}
+		}
+	}
+
 	static class EntityWithoutConstructor {
 
 	}