Deep clone Doctrine entity with related entities

There is also a module that will do this called DeepCopy:

https://github.com/myclabs/DeepCopy

$deepCopy = new DeepCopy();
$myCopy   = $deepCopy->copy($myObject);

You can also add filters to customize the copy process.

I wasnt able to use DeepClone (it require php 7.1+), so I founded more simple way to clone relations in entity __clone method

$this->tags = new ArrayCollection($this->tags->toArray());

You have to implement a __clone() method in your entities that sets the id to null and clones the relations if desired. Because if you keep the id in the related object it assumes that your new entity A has a relation to the existing entities B and C.

Clone-method for A:

public function __clone() {
    if ($this->id) {
        $this->setId(null);
        $this->B = clone $this->B;
        $this->C = clone $this->C;
    }
}

Clone-method for B and C:

public function __clone() {
    if ($this->id) {
        $this->setId(null);
    }
}

https://groups.google.com/forum/?fromgroups=#!topic/doctrine-user/Nu2rayrDkgQ

https://doctrine-orm.readthedocs.org/en/latest/cookbook/implementing-wakeup-or-clone.html

Based on the comment of coder4show a clone-method for a OneToMany relationship on A where $this->M is OneToMany and therefore an ArrayCollection:

public function __clone() {
    if ($this->id) {
        $this->setId(null);

        // cloning the relation M which is a OneToMany
        $mClone = new ArrayCollection();
        foreach ($this->M as $item) {
            $itemClone = clone $item;
            $itemClone->setA($this);
            $mClone->add($itemClone);
        }
        $this->M = $mClone;
    }
}