feature #32582 [Routing] Deprecate ServiceRouterLoader and ObjectRouteLoader in favor of ContainerLoader and ObjectLoader (fancyweb)

This PR was merged into the 4.4 branch.

Discussion
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[Routing] Deprecate ServiceRouterLoader and ObjectRouteLoader in favor of ContainerLoader and ObjectLoader

| Q             | A
| ------------- | ---
| Branch?       | 4.4
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | yes
| Tests pass?   | yes
| Fixed tickets | symfony/symfony#30926 (comment)
| License       | MIT
| Doc PR        | -

This PR aims at deprecating some things to have a more consistent code.

### ServiceRouterLoader

1. This class actually fetches an object from a container. In symfony/symfony#30926 (comment), it was suggested that it should be renamed to `ContainerRouteLoader`. Actually I think it's better to rename it to `ContainerLoader` since all others route loaders does not have "Route" in their name. Let's be consistent!

2. This class is in a `DependencyInjection` sub directory for historical reasons. Let's remove that! It accepts any PSR-11 container.

### ObjectRouteLoader

1. This class has "Route" in its name too. Let's rename it!

2. This class is supposed to be an abstract implementation for "object" loaders to reuse, but in its code it has a lot of references to "services". Let's remove those references! That means renaming some methods, altering messages, etc.. That also means removing the `supports` method from it to let extending classes implement it.

3. IMHO, this abstract implementation is useless. We sould just deprecate the whole class and move the implemention in the `ContainerLoader` class.

Commits
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154810119d [Routing] Deprecate ServiceRouterLoader and ObjectRouteLoader in favor of ContainerLoader and ObjectLoader

Author: nicolas-grekas

CHANGELOG.md

@@ -10,6 +10,7 @@ CHANGELOG
  * The `ControllerResolver` and `DelegatingLoader` classes have been marked as `final`
  * Added support for configuring chained cache pools
  * Deprecated booting the kernel before running `WebTestCase::createClient()`
+ * Deprecated `routing.loader.service`, use `routing.loader.container` instead.
 
 4.3.0
 -----

Resources/config/routing.xml

@@ -41,6 +41,11 @@
         </service>
 
         <service id="routing.loader.service" class="Symfony\Component\Routing\Loader\DependencyInjection\ServiceRouterLoader">
+            <argument type="service" id="service_container" />
+            <deprecated>The "%service_id%" service is deprecated since Symfony 4.4, use "routing.loader.container" instead.</deprecated>
+        </service>
+
+        <service id="routing.loader.container" class="Symfony\Component\Routing\Loader\ContainerLoader">
             <tag name="routing.loader" />
             <argument type="service" id="service_container" />
         </service>

composer.json

@@ -27,7 +27,7 @@
         "symfony/polyfill-mbstring": "~1.0",
         "symfony/filesystem": "^3.4|^4.0|^5.0",
         "symfony/finder": "^3.4|^4.0|^5.0",
-        "symfony/routing": "^4.3|^5.0"
+        "symfony/routing": "^4.4|^5.0"
     },
     "require-dev": {
         "doctrine/cache": "~1.0",