Object replication for PHP5

Today with YII development program, a bug changed the night, finally found that the problem in the object replication mechanism, PHP5 before the object copy only need $object_a = $object _b can, but PHP5 this is a shallow copy, and pointers, not real data replication, such as change $object the value of the _b, the $object_a will change as well, so $object_a = Clone $object _b, so $object_a will not follow the change.

However, there is a problem, clone is also PHP5 only, so if the design object replication, then PHP5 as a demarcation version, compatibility issues need to be noted.

Note: Yii2.0 supports PHP5 and above by default, so this issue is not covered in Yii2, and does not include the Yii 1.X version.

Object replication for PHP5