Force comparator to add comment (json -> json_array)

I know, this is REALLY nasty but that was the only way I've found to
make it work properly.

lib/Doctrine/DBAL/Schema/Comparator.php

@@ -435,6 +435,13 @@ public function diffColumn(Column $column1, Column $column2)
             }
         }
 
+        // This is a very nasty hack to make comparator work with the legacy json_array type, which should be killed in v3
+        if ($this->isALegacyJsonComparison($properties1['type'], $properties2['type'])) {
+            array_shift($changedProperties);
+
+            $changedProperties[] = 'comment';
+        }
+
         if ($properties1['default'] != $properties2['default'] ||
             // Null values need to be checked additionally as they tell whether to create or drop a default value.
             // null != 0, null != false, null != '' etc. This affects platform's table alteration SQL generation.
@@ -497,6 +504,21 @@ public function diffColumn(Column $column1, Column $column2)
         return array_unique($changedProperties);
     }
 
+    /**
+     * TODO: kill with fire on v3.0
+     *
+     * @deprecated
+     */
+    private function isALegacyJsonComparison(Types\Type $one, Types\Type $other) : bool
+    {
+        if ( ! $one instanceof Types\JsonType || ! $other instanceof Types\JsonType) {
+            return false;
+        }
+
+        return ( ! $one instanceof Types\JsonArrayType && $other instanceof Types\JsonArrayType)
+            || ( ! $other instanceof Types\JsonArrayType && $one instanceof Types\JsonArrayType);
+    }
+
     /**
      * Finds the difference between the indexes $index1 and $index2.
      *