Undeprecate the single-colon notation for controllers

This notation is the only way to support controllers as services in the 3.4
LTS version.
This deprecation has only a very small benefit for the Symfony codebase (the
amount of code involved is very small), but has a huge cost for the community
which cannot avoid this deprecation without dropping support for the LTS or
making crazy logic to switch routing files (as they cannot switch things
inline in YAML or XML files).
This deprecation will be delayed until a future 5.x version, when the current
LTS will be 4.4 (which supports the new notation).

UPGRADE-5.0.md

@@ -30,7 +30,7 @@ EventDispatcher
 FrameworkBundle
 ---------------
 
- * Removed support for `bundle:controller:action` and `service:action` syntaxes to reference controllers. Use `serviceOrFqcn::method`
+ * Removed support for `bundle:controller:action` syntax to reference controllers. Use `serviceOrFqcn::method`
    instead where `serviceOrFqcn` is either the service ID when using controllers as services or the FQCN of the controller.
 
    Before:
@@ -40,11 +40,6 @@ FrameworkBundle
        path: /
        defaults:
            _controller: FrameworkBundle:Redirect:redirect
-
-   service_controller:
-       path: /
-       defaults:
-           _controller: app.my_controller:myAction
    ```
 
    After:
@@ -54,11 +49,6 @@ FrameworkBundle
        path: /
        defaults:
            _controller: Symfony\Bundle\FrameworkBundle\Controller\RedirectController::redirectAction
-
-   service_controller:
-       path: /
-       defaults:
-           _controller: app.my_controller::myAction
    ```
 
  * Removed `Symfony\Bundle\FrameworkBundle\Controller\ControllerNameParser`.

src/Symfony/Component/HttpKernel/CHANGELOG.md

@@ -6,7 +6,7 @@ CHANGELOG
 
  * added orphaned events support to `EventDataCollector`
  * `ExceptionListener` now logs exceptions at priority `0` (previously logged at `-128`)
- * Deprecated `service:action` syntax with a single colon to reference controllers. Use `service::method` instead.
+ * Added support for using `service::method` to reference controllers, making it consistent with other cases. It is recommended over the `service:action` syntax with a single colon, which will be deprecated in the future.
  * Added the ability to profile individual argument value resolvers via the
    `Symfony\Component\HttpKernel\Controller\ArgumentResolver\TraceableValueResolver`
 

src/Symfony/Component/HttpKernel/Controller/ContainerControllerResolver.php

@@ -36,7 +36,7 @@ class ContainerControllerResolver extends ControllerResolver
     {
         if (1 === substr_count($controller, ':')) {
             $controller = str_replace(':', '::', $controller);
-            @trigger_error(sprintf('Referencing controllers with a single colon is deprecated since Symfony 4.1. Use %s instead.', $controller), E_USER_DEPRECATED);
+            // TODO deprecate this in 5.1
         }
 
         return parent::createController($controller);

src/Symfony/Component/HttpKernel/Tests/Controller/ContainerControllerResolverTest.php

@@ -19,10 +19,6 @@ use Symfony\Component\HttpKernel\Controller\ContainerControllerResolver;
 
 class ContainerControllerResolverTest extends ControllerResolverTest
 {
-    /**
-     * @group legacy
-     * @expectedDeprecation Referencing controllers with a single colon is deprecated since Symfony 4.1. Use foo::action instead.
-     */
     public function testGetControllerServiceWithSingleColon()
     {
         $service = new ControllerTestService('foo');