Add support for not nullable mappings

[CoalaJoe]

Feature Request

Q	A
New Feature	yes
RFC	yes/no
BC Break	no

Summary

I am using an entity that acts like a file object. Simple representation here:

class MediaObject
{
  /** @Vich\UploadableField(mapping="media_object", fileNameProperty="filename") */
  private ?SymfonyFile $file;

  protected string $filename;
  // ...
  public function __construct() {
    $this->file = null;
    $this->filename = '';
  }
  // ...
  public function setFilename(string $filename) {
    $this->filename = $filename;
  }
  // ...
}

This object is only valid as long as the file exists. So if I now want to remove the entity:

$em->remove($mediaObject);

I will be greeted with this Exception: Expected argument of type "string", "null" given at property path "filename"..

The question now is:

• Do we update the current logic to handle non-nullable properties like:

if ($property->isNullable()) {
  $this->getAccessor()->setValue($propertyName, null);
}

• Do we create a new Annotation or mechanic that disables setting of null.

[garak]

What about this?

class MediaObject
{
  /** @Vich\UploadableField(mapping="media_object", fileNameProperty="filename") */
  private ?SymfonyFile $file;

  protected string $filename;
  // ...
  public function __construct() {
    $this->file = null;
    $this->filename = '';
  }
  // ...
  public function setFilename(?string $filename) {
    $this->filename = $filename;
  }
  // ...
}

[CoalaJoe]

I think this might generate an error, assigning null to a typed property that is not nullable. But my current workaround is essentially this:

public function setFilename(?string $filename) {
  $this->filename = (string) $filename;
}

This is something I can currently live with. I added the workaround into my tests and easily can remove them later.

But none the less, I think as typed properties and the type system of php advances, we have to update this repository.

[garak]

What about making property nullable?

[CoalaJoe]

This would not solve my problem.

I see 2 problems:

1. Why do we update the value with null without checking if it is possible.
2. Why do we clean up the properties, when the entity is being removed anyway.

[garak]

This seems reasonable to me.
Feel free to open a PR.