Merge pull request #760 from soyuka/doc-extension

Change doc to reflect new extensions priorities

Author: soyuka

core/extensions.md

@@ -104,7 +104,7 @@ final class CurrentUserExtension implements QueryCollectionExtensionInterface, Q
 
 ```
 
-Finally register the custom extension:
+Finally, if you're not using the autoconfiguration, you have to register the custom extension with either of those tags:
 
 ```yaml
 # api/config/services.yaml
@@ -114,13 +114,23 @@ services:
 
     'App\Doctrine\CurrentUserExtension':
         tags:
-            - { name: api_platform.doctrine.orm.query_extension.collection, priority: 9 }
+            - { name: api_platform.doctrine.orm.query_extension.collection }
             - { name: api_platform.doctrine.orm.query_extension.item }
 ```
 
-Thanks to the `api_platform.doctrine.orm.query_extension.collection` tag, API Platform will register this service as a collection extension. The `api_platform.doctrine.orm.query_extension.item` do the same thing for items.
+The `api_platform.doctrine.orm.query_extension.collection` tag will register this service as a collection extension.
+The `api_platform.doctrine.orm.query_extension.item` do the same thing for items.
 
-Notice the priority level for the `api_platform.doctrine.orm.query_extension.collection` tag. When an extension implements the `ApiPlatform\Core\Bridge\Doctrine\Orm\Extension\QueryResultCollectionExtensionInterface` or the `ApiPlatform\Core\Bridge\Doctrine\Orm\Extension\QueryResultItemExtensionInterface` interface to return results by itself, any lower priority extension will not be executed. Because the pagination is enabled by default with a priority of 8, the priority of the `app.doctrine.orm.query_extension.current_user` service must be at least 9 to ensure its execution.
+Note that your extensions should have a positive priority if defined. Internal extensions have negative priorities, for reference:
+
+| Service name                                               | Priority | Class                                              |
+|------------------------------------------------------------|------|---------------------------------------------------------|
+| api_platform.doctrine.orm.query_extension.eager_loading (collection) | -8 | ApiPlatform\Core\Bridge\Doctrine\Orm\Extension\EagerLoadingExtension |
+| api_platform.doctrine.orm.query_extension.eager_loading (item) | -8 | ApiPlatform\Core\Bridge\Doctrine\Orm\Extension\EagerLoadingExtension |
+| api_platform.doctrine.orm.query_extension.filter | -16 | ApiPlatform\Core\Bridge\Doctrine\Orm\Extension\FilterExtension |
+| api_platform.doctrine.orm.query_extension.filter_eager_loading | -17 | ApiPlatform\Core\Bridge\Doctrine\Orm\Extension\FilterEagerLoadingExtension |
+| api_platform.doctrine.orm.query_extension.order | -32 | ApiPlatform\Core\Bridge\Doctrine\Orm\Extension\OrderExtension |
+| api_platform.doctrine.orm.query_extension.pagination | -64 | ApiPlatform\Core\Bridge\Doctrine\Orm\Extension\PaginationExtension |
 
 #### Blocking Anonymous Users