Allowing Entity to get errors in nested entities

Cake/ORM/Entity.php

@@ -605,7 +605,11 @@ public function errors($field = null, $errors = null) {
 		}
 
 		if (is_string($field) && $errors === null) {
-			return isset($this->_errors[$field]) ? $this->_errors[$field] : [];
+			$errors = isset($this->_errors[$field]) ? $this->_errors[$field] : [];
+			if (!$errors) {
+				$errors = $this->_nestedErrors($field);
+			}
+			return $errors;
 		}
 
 		if (!is_array($field)) {
@@ -619,6 +623,39 @@ public function errors($field = null, $errors = null) {
 		return $this;
 	}
 
+/**
+ * Auxiliary method for getting errors in nested entities
+ *
+ * @param string field the field in this entity to check for errors
+ * @return array errors in nested entity if any
+ */
+	protected function _nestedErrors($field) {
+		if (!isset($this->_properties[$field])) {
+			return [];
+		}
+
+		$value = $this->_properties[$field];
+		if (is_scalar($value) || (is_object($value) && !($value instanceof self))) {
+			return [];
+		}
+
+		if ($value instanceof self) {
+			return $value->errors();
+		}
+
+		$errors = [];
+		if (is_array($value) || $value instanceof \Traversable) {
+			foreach ($value as $k => $v) {
+				if (!($v instanceof self)) {
+					break;
+				}
+				$errors[$k] = $v->errors();
+			}
+		}
+
+		return $errors;
+	}
+
 /**
  * Stores whether or not a property value can be changed or set in this entity.
  * The special property '*' can also be marked as accessible or protected, meaning

Cake/Test/TestCase/ORM/EntityTest.php

@@ -781,6 +781,38 @@ public function testErrors() {
 		$this->assertEquals($errors, $entity->errors());
 	}
 
+/**
+ * Tests that it is possible to get errors for nested entities
+ *
+ * @return void
+ */
+	public function testErrorsDeep() {
+		$entity = new Entity;
+		$entity2 = new Entity;
+		$entity3 = new Entity;
+		$entity->set('foo', 'bar');
+		$entity->set('thing', 'baz');
+		$entity->set('user', $entity2);
+		$entity->set('owner', $entity3);
+
+		$entity->errors('thing', ['this is a mistake']);
+		$entity2->errors(['a' => ['error1'], 'b' => ['error2']]);
+		$entity3->errors(['c' => ['error3'], 'd' => ['error4']]);
+
+		$expected = ['a' => ['error1'], 'b' => ['error2']];
+		$this->assertEquals($expected, $entity->errors('user'));
+
+		$expected = ['c' => ['error3'], 'd' => ['error4']];
+		$this->assertEquals($expected, $entity->errors('owner'));
+
+		$entity->set('multiple', [$entity2, $entity3]);
+		$expected = [
+			['a' => ['error1'], 'b' => ['error2']],
+			['c' => ['error3'], 'd' => ['error4']]
+		];
+		$this->assertEquals($expected, $entity->errors('multiple'));
+	}
+
 /**
  * Tests that changing the value of a property will remove errors
  * stored for it