[RFC] Expose resource in processor context

[VincentLanglet]

Q	A
Branch?	main
Tickets	Closes #..., closes #...
License	MIT
Doc PR	api-platform/docs#...

When writing a route with a custom input like

new Patch(
      uriTemplate: '/users/{uuid}/verify',
      input: UserVerifyInput::class,
      processor: UserProcessor::class,
),

with an input like

class UserVerifyInput { public string $code; }

I didn't find an easy way to access to the User resource (in order to modify it), resolved by the URL.
The $context['previous_data'] doesn't fulfill this job because it's a cloned data so if we try to modify/flush the data it does nothing and if we try to modify/persist/flush the data we get an EntityCollision error with doctrine.

The data request attribute coming from the ReadProvider is later overridden by the DeserializeListener which are generating the Input. Too bad API platform doesn't keep a reference to this resource somewhere no ?
I would save an extra query in the processor

$entityManager->find($context['previous_data']->getId());

So what about adding a resource key in the request/context ?
When trying locally it works for me with the ReadProvider + WriteListener changes, but I dunno if

• I should update ApiPlatformController too ?
• I should update ObjectMapperProvider too ?
• There is another place to update.

Also, you might want to challenge the naming.

[VincentLanglet]

Seems like my issue is related to use_symfony_listeners: true.

Without, the context has a data key witch map to the resource (which is also in the request)
With, the context has lost this key.

[VincentLanglet]

Let's start with an issue