feature symfony#24671 [DI] Handle container.autowiring.strict_mode to opt-out from legacy autowiring (nicolas-grekas)

This PR was merged into the 3.4 branch.

Discussion
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[DI] Handle container.autowiring.strict_mode to opt-out from legacy autowiring

| Q             | A
| ------------- | ---
| Branch?       | 3.4
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

To preserve BC, autowiring still wires things in hybrid 2.8/3.3 modes.
But 2.8 mode is really a foot gun.
I propose to add a new parameter in SF3.4, to opt-out of this 2.8 mode, and enable this strict mode for all new projects.
WDYT?
(see symfony/recipes#221 for corresponding change on Flex recipe)

Commits
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a4a0ae2 [DI] Handle container.autowiring.strict_mode to opt-out from legacy autowiring

Author: nicolas-grekas

src/Symfony/Component/DependencyInjection/Compiler/AutowirePass.php

@@ -34,6 +34,7 @@ class AutowirePass extends AbstractRecursivePass
     private $lastFailure;
     private $throwOnAutowiringException;
     private $autowiringExceptions = array();
+    private $strictMode;
 
     /**
      * @param bool $throwOnAutowireException Errors can be retrieved via Definition::getErrors()
@@ -62,6 +63,7 @@ public function process(ContainerBuilder $container)
     {
         // clear out any possibly stored exceptions from before
         $this->autowiringExceptions = array();
+        $this->strictMode = $container->hasParameter('container.autowiring.strict_mode') && $container->getParameter('container.autowiring.strict_mode');
 
         try {
             parent::process($container);
@@ -290,7 +292,7 @@ private function getAutowiredReference(TypedReference $reference, $deprecationMe
             return new TypedReference($this->types[$type], $type);
         }
 
-        if (isset($this->types[$type])) {
+        if (!$this->strictMode && isset($this->types[$type])) {
             $message = 'Autowiring services based on the types they implement is deprecated since Symfony 3.3 and won\'t be supported in version 4.0.';
             if ($aliasSuggestion = $this->getAliasesSuggestionForType($type = $reference->getType(), $deprecationMessage)) {
                 $message .= ' '.$aliasSuggestion;
@@ -311,7 +313,9 @@ private function getAutowiredReference(TypedReference $reference, $deprecationMe
             return $this->autowired[$type] ? new TypedReference($this->autowired[$type], $type) : null;
         }
 
-        return $this->createAutowiredDefinition($type);
+        if (!$this->strictMode) {
+            return $this->createAutowiredDefinition($type);
+        }
     }
 
     /**