Adding joinData to the target relation array wehn using matching

The scenario that c41f40cd was wondering about came to be sooner than
expected.

src/ORM/Association/BelongsToMany.php

@@ -249,9 +249,13 @@ class BelongsToMany extends Association {
  * @param array $row
  * @return array
  */
-	public function transformRow($row) {
+	public function transformRow($row, $joined = false) {
+		$alias = $this->junction()->alias();
+		if ($joined) {
+			$row[$this->target()->alias()]['_joinData'] = $row[$alias];
+			unset($row[$alias]);
+		}
 		$row = $this->_transformRow($row);
-		unset($row[$this->junction()->alias()]);
 		return $row;
 	}
 

src/ORM/ResultSet.php

@@ -404,7 +404,7 @@ class ResultSet implements Countable, Iterator, Serializable, JsonSerializable {
 				$results[$alias] = $entity;
 			}
 
-			$results = $instance->transformRow($results);
+			$results = $instance->transformRow($results, $assoc['canBeJoined']);
 		}
 
 		foreach ($presentAliases as $alias => $present) {

tests/TestCase/ORM/QueryTest.php

@@ -659,7 +659,8 @@ class QueryTest extends TestCase {
 				'published' => 'Y',
 				'tags' => [
 					'id' => 3,
-					'name' => 'tag3'
+					'name' => 'tag3',
+					'_joinData' => ['article_id' => 2, 'tag_id' => 3]
 				]
 			]
 		];
@@ -681,7 +682,8 @@ class QueryTest extends TestCase {
 				'published' => 'Y',
 				'tags' => [
 					'id' => 2,
-					'name' => 'tag2'
+					'name' => 'tag2',
+					'_joinData' => ['article_id' => 1, 'tag_id' => 2]
 				]
 			]
 		];
@@ -719,7 +721,8 @@ class QueryTest extends TestCase {
 					'published' => 'Y',
 					'tags' => [
 						'id' => 2,
-						'name' => 'tag2'
+						'name' => 'tag2',
+						'_joinData' => ['article_id' => 1, 'tag_id' => 2]
 					]
 				]
 			]
@@ -1873,7 +1876,6 @@ class QueryTest extends TestCase {
 		$table->belongsTo('Tags');
 		TableRegistry::get('Tags')->belongsToMany('Articles');
 		$results = $table->find()->contain(['Articles', 'Tags.Articles'])->hydrate(false)->toArray();
-		debug($results);
 	}
 
 }