Correctly marshall _joinData when patching entities.

When patching belongsToMany associations with existing target records,
and including _joinData, the joinData should be correctly marshalled.

Getting this to work required accepting `accessibleFields` in merge()
and mergeMany(). This allows the internals of the marshaller to
whitelist _joinData and not rely on the entity having it marked as
accessible.

Refs #6971

src/ORM/Marshaller.php

@@ -408,6 +408,7 @@ protected function _loadBelongsToMany($assoc, $ids)
      *   also be set to a string to use a specific validator. Defaults to true/default.
      * * fieldList: A whitelist of fields to be assigned to the entity. If not present
      *   the accessible fields list in the entity will be used.
+     * * accessibleFields: A list of fields to allow or deny in entity accessible fields.
      *
      * @param \Cake\Datasource\EntityInterface $entity the entity that will get the
      * data merged in
@@ -427,6 +428,12 @@ public function merge(EntityInterface $entity, array $data, array $options = [])
             $keys = $entity->extract((array)$this->_table->primaryKey());
         }
 
+        if (isset($options['accessibleFields'])) {
+            foreach ((array)$options['accessibleFields'] as $key => $value) {
+                $entity->accessible($key, $value);
+            }
+        }
+
         $errors = $this->_validate($data + $keys, $options, $isNew);
         $schema = $this->_table->schema();
         $properties = $marshalledAssocs = [];
@@ -501,6 +508,7 @@ public function merge(EntityInterface $entity, array $data, array $options = [])
      * - associated: Associations listed here will be marshalled as well.
      * - fieldList: A whitelist of fields to be assigned to the entity. If not present,
      *   the accessible fields list in the entity will be used.
+     * - accessibleFields: A list of fields to allow or deny in entity accessible fields.
      *
      * @param array|\Traversable $entities the entities that will get the
      *   data merged in
@@ -660,6 +668,7 @@ protected function _mergeJoinData($original, $assoc, $value, $options)
             $nested = (array)$associated['_joinData'];
         }
 
+        $options['accessibleFields'] = ['_joinData' => true];
         $records = $this->mergeMany($original, $value, $options);
         foreach ($records as $record) {
             $hash = spl_object_hash($record);

tests/TestCase/ORM/MarshallerTest.php

@@ -34,6 +34,17 @@ class OpenEntity extends Entity
     ];
 }
 
+/**
+ * Test entity for mass assignment.
+ */
+class Tag extends Entity
+{
+
+    protected $_accessible = [
+        'tag' => true,
+    ];
+}
+
 /**
  * Test entity for mass assignment.
  */
@@ -125,6 +136,7 @@ public function setUp()
         $this->articles = $articles;
         $this->comments = $comments;
         $this->users = $users;
+        $this->tags = $tags;
     }
 
     /**
@@ -625,6 +637,57 @@ public function testBelongsToManyWithMixedJoinData()
         $this->assertEquals(1, $result->tags[1]->_joinData->active);
     }
 
+    /**
+     * Test belongsToMany association with mixed data and _joinData
+     *
+     * @return void
+     */
+    public function testBelongsToManyAddingNewExisting()
+    {
+        $this->tags->entityClass(__NAMESPACE__ . '\Tag');
+        $data = [
+            'title' => 'My title',
+            'body' => 'My content',
+            'author_id' => 1,
+            'tags' => [
+                [
+                    'id' => 1,
+                    '_joinData' => [
+                        'active' => 0,
+                    ]
+                ],
+            ]
+        ];
+        $marshall = new Marshaller($this->articles);
+        $result = $marshall->one($data, ['associated' => ['Tags._joinData']]);
+        $data = [
+            'title' => 'New Title',
+            'tags' => [
+                [
+                    'id' => 1,
+                    '_joinData' => [
+                        'active' => 0,
+                    ]
+                ],
+                [
+                    'id' => 2,
+                    '_joinData' => [
+                        'active' => 1,
+                    ]
+                ]
+            ]
+        ];
+        $result = $marshall->merge($result, $data, ['associated' => ['Tags._joinData']]);
+
+        $this->assertEquals($data['title'], $result->title);
+        $this->assertEquals($data['tags'][0]['id'], $result->tags[0]->id);
+        $this->assertEquals($data['tags'][1]['id'], $result->tags[1]->id);
+        $this->assertNotEmpty($result->tags[0]->_joinData);
+        $this->assertNotEmpty($result->tags[1]->_joinData);
+        $this->assertEquals(0, $result->tags[0]->_joinData->active);
+        $this->assertEquals(1, $result->tags[1]->_joinData->active);
+    }
+
     /**
      * Test belongsToMany association with mixed data and _joinData
      *
@@ -970,6 +1033,34 @@ public function testMergeSimple()
         $this->assertFalse($result->isNew(), 'Should not change the entity state');
     }
 
+    /**
+     * Test merge() with accessibleFields options
+     *
+     * @return void
+     */
+    public function testMergeAccessibleFields()
+    {
+        $data = [
+            'title' => 'My title',
+            'body' => 'New content',
+            'author_id' => 1,
+            'not_in_schema' => true
+        ];
+        $marshall = new Marshaller($this->articles);
+        $entity = new Entity([
+            'title' => 'Foo',
+            'body' => 'My Content'
+        ]);
+        $entity->accessible('*', false);
+        $entity->isNew(false);
+        $entity->clean();
+        $result = $marshall->merge($entity, $data, ['accessibleFields' => ['body' => true]]);
+
+        $this->assertSame($entity, $result);
+        $this->assertEquals(['title' => 'Foo', 'body' => 'New content'], $result->toArray());
+        $this->assertTrue($entity->accessible('body'));
+    }
+
     /**
      * Provides empty values.
      *