Add support for arrays containing additional database values in list views

[jorrit]

Subject

I am trying to show additional fields in the list view. These fields are not part of the entity. Adding the field is no problem thanks to configureQuery(). However, Doctrine2 returns an array instead of an object when additional columns are present in the result set.

This was discussed previously in sonata-project/SonataDoctrineORMAdminBundle#399 and sonata-project/SonataDoctrineORMAdminBundle#501 with no result. The direction in those issues was to use a DTO. This PR does not add support for DTO's but for the arrays that Doctrine2 returns.

As mentioned briefly in #6198 I found several issues with the method SonataAdminExtension::getValueFromFieldDescription():

• It contains an unused third parameter.
• It is public for no reason.
• The code block if ($fieldDescription->getAssociationAdmin()) { ... } is dysfunctional because it causes $value to be a model instance instead of a field value. Apparently nobody has noticed.

As such, I think it is best to leave this method alone for now and add functionality to renderListElement().

I am targeting this branch, because it is backwards compatible.

Changelog

### Added
- Added support for columns not belonging to the model to the list view.

### Deprecated
- Calling `SonataAdminExtension::getValueFromFieldDescription()`

To do

• Update the documentation;

[jorrit]

@core23 / @VincentLanglet Is there anything I can do to move this forward?

[VincentLanglet]

@core23 Can you review this ?

@jorrit I would say you should ping @greg0ire to dismiss the review if @core23 doesn't answer in the next day(s) ?

(BTW @greg0ire, who else has the right to dismiss a review ?)

[greg0ire]

I don't know…

[VincentLanglet]

I don't know…

I find out it was repository administrators or people with write access :)

[VincentLanglet]

I think we can merge this @greg0ire :)

Requested changes were done

[greg0ire]

Thanks @jorrit !