Embed a Collection of Forms Error: Could not determine access type for property

Short version:

I just ran into this problem and solved it by adding a setter for the affected property:

Could not determine access type for property "tagList"

public function setTagList(Array $tagList)
{
    $this->tagList = $tagList;
}

---

Long version:

The error message is signaling that Symfony is trying to modify the object's state, but cannot figure out how to actually make the change due to the way its class is set up.

Taking a look at Symfony's internals, we can see that Symfony gives you 5 chances to give it access and picks the best one in this order from top to bottom:

1. A setter method named setProperty() with one argument:

This is the first thing Symfony checks for and is the most explicit way to achieve this. As far as I'm aware this is the best practice:

class Entity {

    protected $tagList;

    //...

    public function getTagList()
    {
        return $this->tagList;
    }

    //...
}

2. A combined getter and setter in one method with one argument:

It's important to realize that this method will also be accessed by Symfony in order to get the object's state. Since those method calls don't include an argument, the argument in this method must be optional.

class Entity {

    protected $tagList;

    //...

    public function tagList($tags = null)
    {
        if($reps){
            $this->tagList = $tags;
        } else {
            return $this->tagList;
        }
    }

    //...
}

3. The affected property being declared as public:

   class Entity {
   
       public $tagList;
       //... other properties here
   }
   

4. A __set magic method:

This will affect all properties rather than just the one you intended.

class Entity {

    public $tagList;

    //...

    public function __set($name, $value){
        $this->$name = $value;
    }
    //...
}

5. A __call magic method (in some cases):

I wasn't able to confirm this, but the internal code suggests this is possible when magic is enabled on PropertyAccessor's construction.

---

Only using one of the above strategies is required.

Could you please try to implement code from this URL?

http://docs.doctrine-project.org/projects/doctrine-orm/en/latest/reference/association-mapping.html#owning-and-inverse-side-on-a-manytomany-association

First, please try to change mapped/inverse sides, and remove $service->addTag($this); from Tag::addService method.