Handle field without mappedBy

[VincentLanglet]

Subject

I am targeting this branch, because BC.

Closes #6218.

Changelog

### Fixed
- Allow to use AdminType with unidirectional field.

[jordisala1991]

Thank you @VincentLanglet

[haivala]

I think because of this there should be release 3.72.1

[VincentLanglet]

I think because of this there should be release 3.72.1

I'll make a release today. But it will be 3.73

[haivala]

thank you!

[cjgordon]

Hi @VincentLanglet

I believe this breaks admins using doctrine MongoDB and embedded collections as there is no mappedBy attribute for these mappings.

Example mapping:

     /**
      * @MongoDB\EmbedMany(targetDocument="Comment")
      */
     private $comments;

Break happens on: ObjectManipulator.php line 56 with error message: 'Notice: Undefined index: mappedBy'

I believe you just need to add a check to ensure that if the mappedBy property is not present that instance is returned. I have tested this myself and it has resolved the issue.

        if (!isset($parentFieldDescription->getAssociationMapping()['mappedBy'])) {
            return $instance;
        }
        
        $mappedBy = $parentFieldDescription->getAssociationMapping()['mappedBy'];

Cheers
Chris

[VincentLanglet]

HI @cjgordon.

if (!isset($parentFieldDescription->getAssociationMapping()['mappedBy'])) {
    return $instance;
}

$mappedBy = $parentFieldDescription->getAssociationMapping()['mappedBy'];

Could be a better way to write this, since isset(null) is false.

As a quick fix, do you want to make the PR ?

Also could you dump the $parentFieldDescription->getAssociationMapping() value ? To know if there is something similar to mappedBy in order to provide the same feature to mongoDB than I provided to doctrine orm.

[cjgordon]

@VincentLanglet I'll do a PR for this on the weekend.

[VincentLanglet]

I done this @cjgordon #6297

[cjgordon]

Excellent thank you. Apologies for being slack on this.