feature #21223 [DI] Deprecate case insentivity of service identifiers…

… (nicolas-grekas)

This PR was merged into the 3.3-dev branch.

Discussion
----------

[DI] Deprecate case insentivity of service identifiers

| Q             | A
| ------------- | ---
| Branch?       | master
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | minor (see UPGRADE note)
| Deprecations? | yes
| Tests pass?   | yes
| Fixed tickets | #21193
| License       | MIT
| Doc PR        | -

As discussed in linked RFC.

Commits
-------

d08f110 [DI] Deprecate case insentivity of service identifiers

UPGRADE-3.3.md

@@ -10,6 +10,10 @@ ClassLoader
 DependencyInjection
 -------------------
 
+ * The `Reference` and `Alias` classes do not make service identifiers lowercase anymore.
+
+ * Case insensitivity of service identifiers is deprecated and will be removed in 4.0.
+
  * Using the `PhpDumper` with an uncompiled `ContainerBuilder` is deprecated and
    will not be supported anymore in 4.0.
 

UPGRADE-4.0.md

@@ -22,6 +22,10 @@ Debug
 DependencyInjection
 -------------------
 
+ * Service identifiers are now case sensitive.
+
+ * The `Reference` and `Alias` classes do not make service identifiers lowercase anymore.
+
  * Using the `PhpDumper` with an uncompiled `ContainerBuilder` is not supported
    anymore.
 

src/Symfony/Component/DependencyInjection/Alias.php

@@ -22,7 +22,12 @@ class Alias
      */
     public function __construct($id, $public = true)
     {
-        $this->id = strtolower($id);
+        if (!is_string($id)) {
+            $type = is_object($id) ? get_class($id) : gettype($id);
+            $id = (string) $id;
+            @trigger_error(sprintf('Non-string identifiers are deprecated since Symfony 3.3 and won\'t be supported in 4.0 for Alias to "%s" ("%s" given.) Cast it to string beforehand.', $id, $type), E_USER_DEPRECATED);
+        }
+        $this->id = $id;
         $this->public = $public;
     }
 

src/Symfony/Component/DependencyInjection/CHANGELOG.md

@@ -4,10 +4,12 @@ CHANGELOG
 3.3.0
 -----
 
+ * deprecated case insensitivity of service identifiers
  * added "iterator" argument type for lazy iteration over a set of values and services
  * added "closure-proxy" argument type for turning services' methods into lazy callables
  * added file-wide configurable defaults for service attributes "public", "tags",
-   "autowire" and a new "inherit-tags"
+   "autowire" and "inherit-tags"
+ * added "inherit-tags" service attribute to control tags' inheritance from parent context
  * made the "class" attribute optional, using the "id" as fallback
  * using the `PhpDumper` with an uncompiled `ContainerBuilder` is deprecated and
    will not be supported anymore in 4.0

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

@@ -51,12 +51,13 @@ public function process(ContainerBuilder $container)
     private function updateDefinition(ContainerBuilder $container, $id, Definition $definition, array $resolveClassPassChanges, array $previous = array())
     {
         // circular reference
-        if (isset($previous[$id])) {
+        $lcId = strtolower($id);
+        if (isset($previous[$lcId])) {
             return;
         }
 
         $factory = $definition->getFactory();
-        if (null === $factory || (!isset($resolveClassPassChanges[$id]) && null !== $definition->getClass())) {
+        if (null === $factory || (!isset($resolveClassPassChanges[$lcId]) && null !== $definition->getClass())) {
             return;
         }
 
@@ -69,9 +70,9 @@ private function updateDefinition(ContainerBuilder $container, $id, Definition $
             }
         } else {
             if ($factory[0] instanceof Reference) {
-                $previous[$id] = true;
+                $previous[$lcId] = true;
                 $factoryDefinition = $container->findDefinition((string) $factory[0]);
-                $this->updateDefinition($container, strtolower($factory[0]), $factoryDefinition, $resolveClassPassChanges, $previous);
+                $this->updateDefinition($container, $factory[0], $factoryDefinition, $resolveClassPassChanges, $previous);
                 $class = $factoryDefinition->getClass();
             } else {
                 $class = $factory[0];
@@ -96,7 +97,7 @@ private function updateDefinition(ContainerBuilder $container, $id, Definition $
                 }
             }
 
-            if (null !== $returnType && (!isset($resolveClassPassChanges[$id]) || $returnType !== $resolveClassPassChanges[$id])) {
+            if (null !== $returnType && (!isset($resolveClassPassChanges[$lcId]) || $returnType !== $resolveClassPassChanges[$lcId])) {
                 @trigger_error(sprintf('Relying on its factory\'s return-type to define the class of service "%s" is deprecated since Symfony 3.3 and won\'t work in 4.0. Set the "class" attribute to "%s" on the service definition instead.', $id, $returnType), E_USER_DEPRECATED);
             }
             $definition->setClass($returnType);

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

@@ -31,8 +31,8 @@ public function process(ContainerBuilder $container)
                 continue;
             }
             if (preg_match('/^[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*+(?:\\\\[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*+)*+$/', $id)) {
-                $this->changes[$id] = $container->getCaseSensitiveId($id);
-                $definition->setClass($this->changes[$id]);
+                $this->changes[strtolower($id)] = $id;
+                $definition->setClass($id);
             }
         }
     }

src/Symfony/Component/DependencyInjection/Container.php

@@ -70,6 +70,11 @@ class Container implements ResettableContainerInterface
     protected $aliases = array();
     protected $loading = array();
 
+    /**
+     * @internal
+     */
+    protected $normalizedIds = array();
+
     private $underscoreMap = array('_' => '', '.' => '_', '\\' => '_');
     private $envCache = array();
 
@@ -164,7 +169,7 @@ public function setParameter($name, $value)
      */
     public function set($id, $service)
     {
-        $id = strtolower($id);
+        $id = $this->normalizeId($id);
 
         if ('service_container' === $id) {
             throw new InvalidArgumentException('You cannot set service "service_container".');
@@ -215,8 +220,8 @@ public function has($id)
                 return true;
             }
 
-            if (--$i && $id !== $lcId = strtolower($id)) {
-                $id = $lcId;
+            if (--$i && $id !== $normalizedId = $this->normalizeId($id)) {
+                $id = $normalizedId;
                 continue;
             }
 
@@ -254,7 +259,7 @@ public function get($id, $invalidBehavior = self::EXCEPTION_ON_INVALID_REFERENCE
         // Attempt to retrieve the service by checking first aliases then
         // available services. Service IDs are case insensitive, however since
         // this method can be called thousands of times during a request, avoid
-        // calling strtolower() unless necessary.
+        // calling $this->normalizeId($id) unless necessary.
         for ($i = 2;;) {
             if ('service_container' === $id) {
                 return $this;
@@ -273,8 +278,8 @@ public function get($id, $invalidBehavior = self::EXCEPTION_ON_INVALID_REFERENCE
 
             if (isset($this->methodMap[$id])) {
                 $method = $this->methodMap[$id];
-            } elseif (--$i && $id !== $lcId = strtolower($id)) {
-                $id = $lcId;
+            } elseif (--$i && $id !== $normalizedId = $this->normalizeId($id)) {
+                $id = $normalizedId;
                 continue;
             } elseif (!$this->methodMap && !$this instanceof ContainerBuilder && __CLASS__ !== static::class && method_exists($this, $method = 'get'.strtr($id, $this->underscoreMap).'Service')) {
                 // We only check the convention-based factory in a compiled container (i.e. a child class other than a ContainerBuilder,
@@ -329,7 +334,7 @@ public function get($id, $invalidBehavior = self::EXCEPTION_ON_INVALID_REFERENCE
      */
     public function initialized($id)
     {
-        $id = strtolower($id);
+        $id = $this->normalizeId($id);
 
         if ('service_container' === $id) {
             return false;
@@ -426,6 +431,34 @@ protected function getEnv($name)
         return $this->envCache[$name] = $this->getParameter("env($name)");
     }
 
+    /**
+     * Returns the case sensitive id used at registration time.
+     *
+     * @param string $id
+     *
+     * @return string
+     *
+     * @internal
+     */
+    public function normalizeId($id)
+    {
+        if (!is_string($id)) {
+            $type = is_object($id) ? get_class($id) : gettype($id);
+            $id = (string) $id;
+            @trigger_error(sprintf('Non-string service identifiers are deprecated since Symfony 3.3 and won\'t be supported in 4.0 for service "%s" ("%s" given.) Cast it to string beforehand.', $id, $type), E_USER_DEPRECATED);
+        }
+        if (isset($this->normalizedIds[$normalizedId = strtolower($id)])) {
+            $normalizedId = $this->normalizedIds[$normalizedId];
+            if ($id !== $normalizedId) {
+                @trigger_error(sprintf('Service identifiers will be made case sensitive in Symfony 4.0. Using "%s" instead of "%s" is deprecated since version 3.3.', $id, $normalizedId), E_USER_DEPRECATED);
+            }
+        } else {
+            $normalizedId = $this->normalizedIds[$normalizedId] = $id;
+        }
+
+        return $normalizedId;
+    }
+
     private function __clone()
     {
     }