feature #21770 [DI] Allow extensions to create ServiceLocator as services (nicolas-grekas)

This PR was merged into the 3.3-dev branch.

Discussion
----------

[DI] Allow extensions to create ServiceLocator as services

| Q             | A
| ------------- | ---
| Branch?       | master
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

https://github.com/symfony/symfony/pull/21770/files?w=1

With this PR, DI extensions are able to create "service locator" services.
They are easily created as such:
```php
$container->register('my_service_locator', ServiceLocator::class)
    ->addArgument(array(
        'exposed_id' => new ServiceClosureArgument(new Reference('internal_id')),
    ))
```
I already need this in two different PRs to come.

Commits
-------

1d9663326e [DI] Allow creating ServiceLocator-based services in extensions

Author: fabpot

Console/Descriptor/JsonDescriptor.php

@@ -13,6 +13,7 @@
 
 use Symfony\Component\DependencyInjection\Alias;
 use Symfony\Component\DependencyInjection\Argument\ArgumentInterface;
+use Symfony\Component\DependencyInjection\Argument\ServiceClosureArgument;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
 use Symfony\Component\DependencyInjection\Definition;
 use Symfony\Component\DependencyInjection\ParameterBag\ParameterBag;
@@ -388,6 +389,10 @@ private function describeValue($value, $omitTags, $showArguments)
             return $data;
         }
 
+        if ($value instanceof ServiceClosureArgument) {
+            $value = $value->getValues()[0];
+        }
+
         if ($value instanceof Reference) {
             return array(
                 'type' => 'service',

Console/Descriptor/TextDescriptor.php

@@ -16,6 +16,7 @@
 use Symfony\Component\DependencyInjection\Alias;
 use Symfony\Component\DependencyInjection\Argument\ClosureProxyArgument;
 use Symfony\Component\DependencyInjection\Argument\IteratorArgument;
+use Symfony\Component\DependencyInjection\Argument\ServiceClosureArgument;
 use Symfony\Component\DependencyInjection\Argument\ServiceLocatorArgument;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
 use Symfony\Component\DependencyInjection\Definition;
@@ -324,6 +325,9 @@ protected function describeContainerDefinition(Definition $definition, array $op
         $argumentsInformation = array();
         if ($showArguments && ($arguments = $definition->getArguments())) {
             foreach ($arguments as $argument) {
+                if ($argument instanceof ServiceClosureArgument) {
+                    $argument = $argument->getValues()[0];
+                }
                 if ($argument instanceof Reference) {
                     $argumentsInformation[] = sprintf('Service(%s)', (string) $argument);
                 } elseif ($argument instanceof IteratorArgument) {

Console/Descriptor/XmlDescriptor.php

@@ -14,6 +14,7 @@
 use Symfony\Component\DependencyInjection\Alias;
 use Symfony\Component\DependencyInjection\Argument\ClosureProxyArgument;
 use Symfony\Component\DependencyInjection\Argument\IteratorArgument;
+use Symfony\Component\DependencyInjection\Argument\ServiceClosureArgument;
 use Symfony\Component\DependencyInjection\Argument\ServiceLocatorArgument;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
 use Symfony\Component\DependencyInjection\Definition;
@@ -425,6 +426,10 @@ private function getArgumentNodes(array $arguments, \DOMDocument $dom)
                 $argumentXML->setAttribute('key', $argumentKey);
             }
 
+            if ($argument instanceof ServiceClosureArgument) {
+                $argument = $argument->getValues()[0];
+            }
+
             if ($argument instanceof Reference) {
                 $argumentXML->setAttribute('type', 'service');
                 $argumentXML->setAttribute('id', (string) $argument);