[DI] Reference tagged services in config

src/Symfony/Component/DependencyInjection/Argument/TaggedIteratorArgument.php

@@ -0,0 +1,37 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\DependencyInjection\Argument;
+
+/**
+ * Represents a collection of services found by tag name to lazily iterate over.
+ *
+ * @author Roland Franssen <franssen.roland@gmail.com>
+ */
+class TaggedIteratorArgument extends IteratorArgument
+{
+    private $tag;
+
+    /**
+     * @param string $tag
+     */
+    public function __construct($tag)
+    {
+        parent::__construct(array());
+
+        $this->tag = (string) $tag;
+    }
+
+    public function getTag()
+    {
+        return $this->tag;
+    }
+}

src/Symfony/Component/DependencyInjection/CHANGELOG.md

@@ -13,6 +13,7 @@ CHANGELOG
  * deprecated support for top-level anonymous services in XML
  * deprecated case insensitivity of parameter names
  * deprecated the `ResolveDefinitionTemplatesPass` class in favor of `ResolveChildDefinitionsPass`
+ * added `TaggedIteratorArgument` with YAML (`!tagged foo`) and XML (`<service type="tagged"/>`) support
 
 3.3.0
 -----

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

@@ -61,6 +61,7 @@ class PassConfig
             new AutowireRequiredMethodsPass(),
             new ResolveBindingsPass(),
             new AutowirePass(false),
+            new ResolveTaggedIteratorArgumentPass(),
             new ResolveServiceSubscribersPass(),
             new ResolveReferencesToAliasesPass(),
             new ResolveInvalidReferencesPass(),

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

@@ -0,0 +1,38 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\DependencyInjection\Compiler;
+
+use Symfony\Component\DependencyInjection\Argument\TaggedIteratorArgument;
+
+/**
+ * Resolves all TaggedIteratorArgument arguments.
+ *
+ * @author Roland Franssen <franssen.roland@gmail.com>
+ */
+class ResolveTaggedIteratorArgumentPass extends AbstractRecursivePass
+{
+    use PriorityTaggedServiceTrait;
+
+    /**
+     * {@inheritdoc}
+     */
+    protected function processValue($value, $isRoot = false)
+    {
+        if (!$value instanceof TaggedIteratorArgument) {
+            return parent::processValue($value, $isRoot);
+        }
+
+        $value->setValues($this->findAndSortTaggedServices($value->getTag(), $this->container));
+
+        return $value;
+    }
+}

src/Symfony/Component/DependencyInjection/Dumper/XmlDumper.php

@@ -13,6 +13,7 @@ namespace Symfony\Component\DependencyInjection\Dumper;
 
 use Symfony\Component\DependencyInjection\Argument\IteratorArgument;
 use Symfony\Component\DependencyInjection\Argument\ServiceClosureArgument;
+use Symfony\Component\DependencyInjection\Argument\TaggedIteratorArgument;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 use Symfony\Component\DependencyInjection\Parameter;
 use Symfony\Component\DependencyInjection\Reference;
@@ -298,6 +299,9 @@ class XmlDumper extends Dumper
             if (is_array($value)) {
                 $element->setAttribute('type', 'collection');
                 $this->convertParameters($value, $type, $element, 'key');
+            } elseif ($value instanceof TaggedIteratorArgument) {
+                $element->setAttribute('type', 'tagged');
+                $element->setAttribute('tag', $value->getTag());
             } elseif ($value instanceof IteratorArgument) {
                 $element->setAttribute('type', 'iterator');
                 $this->convertParameters($value->getValues(), $type, $element, 'key');

src/Symfony/Component/DependencyInjection/Dumper/YamlDumper.php

@@ -19,6 +19,7 @@ use Symfony\Component\DependencyInjection\Alias;
 use Symfony\Component\DependencyInjection\Argument\ArgumentInterface;
 use Symfony\Component\DependencyInjection\Argument\IteratorArgument;
 use Symfony\Component\DependencyInjection\Argument\ServiceClosureArgument;
+use Symfony\Component\DependencyInjection\Argument\TaggedIteratorArgument;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 use Symfony\Component\DependencyInjection\Definition;
 use Symfony\Component\DependencyInjection\Parameter;
@@ -263,6 +264,9 @@ class YamlDumper extends Dumper
             $value = $value->getValues()[0];
         }
         if ($value instanceof ArgumentInterface) {
+            if ($value instanceof TaggedIteratorArgument) {
+                return new TaggedValue('tagged', $value->getTag());
+            }
             if ($value instanceof IteratorArgument) {
                 $tag = 'iterator';
             } else {

src/Symfony/Component/DependencyInjection/Loader/Configurator/ContainerConfigurator.php

@@ -12,6 +12,7 @@
 namespace Symfony\Component\DependencyInjection\Loader\Configurator;
 
 use Symfony\Component\DependencyInjection\Argument\IteratorArgument;
+use Symfony\Component\DependencyInjection\Argument\TaggedIteratorArgument;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
 use Symfony\Component\DependencyInjection\Definition;
 use Symfony\Component\DependencyInjection\Exception\InvalidArgumentException;
@@ -115,6 +116,18 @@ function iterator(array $values)
     return new IteratorArgument(AbstractConfigurator::processValue($values, true));
 }
 
+/**
+ * Creates a lazy iterator by tag name.
+ *
+ * @param string $tag
+ *
+ * @return TaggedIteratorArgument
+ */
+function tagged($tag)
+{
+    return new TaggedIteratorArgument($tag);
+}
+
 /**
  * Creates an expression.
  *

src/Symfony/Component/DependencyInjection/Loader/XmlFileLoader.php

@@ -12,6 +12,7 @@
 namespace Symfony\Component\DependencyInjection\Loader;
 
 use Symfony\Component\Config\Util\XmlUtils;
+use Symfony\Component\DependencyInjection\Argument\TaggedIteratorArgument;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 use Symfony\Component\DependencyInjection\Alias;
 use Symfony\Component\DependencyInjection\Argument\BoundArgument;
@@ -518,6 +519,12 @@ class XmlFileLoader extends FileLoader
                         throw new InvalidArgumentException(sprintf('Tag "<%s>" with type="iterator" only accepts collections of type="service" references in "%s".', $name, $file));
                     }
                     break;
+                case 'tagged':
+                    if (!$arg->getAttribute('tag')) {
+                        throw new InvalidArgumentException(sprintf('Tag "<%s>" with type="tagged" has no or empty "tag" attribute in "%s".', $name, $file));
+                    }
+                    $arguments[$key] = new TaggedIteratorArgument($arg->getAttribute('tag'));
+                    break;
                 case 'string':
                     $arguments[$key] = $arg->nodeValue;
                     break;

src/Symfony/Component/DependencyInjection/Loader/YamlFileLoader.php

@@ -15,6 +15,7 @@ use Symfony\Component\DependencyInjection\Alias;
 use Symfony\Component\DependencyInjection\Argument\ArgumentInterface;
 use Symfony\Component\DependencyInjection\Argument\BoundArgument;
 use Symfony\Component\DependencyInjection\Argument\IteratorArgument;
+use Symfony\Component\DependencyInjection\Argument\TaggedIteratorArgument;
 use Symfony\Component\DependencyInjection\ChildDefinition;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
 use Symfony\Component\DependencyInjection\ContainerInterface;
@@ -726,6 +727,13 @@ class YamlFileLoader extends FileLoader
                     throw new InvalidArgumentException(sprintf('"!iterator" tag only accepts arrays of "@service" references in "%s".', $file));
                 }
             }
+            if ('tagged' === $value->getTag()) {
+                if (!is_string($argument) || !$argument) {
+                    throw new InvalidArgumentException(sprintf('"!tagged" tag only accepts non empty string in "%s".', $file));
+                }
+
+                return new TaggedIteratorArgument($argument);
+            }
             if ('service' === $value->getTag()) {
                 if ($isParameter) {
                     throw new InvalidArgumentException(sprintf('Using an anonymous service in a parameter is not allowed in "%s".', $file));

src/Symfony/Component/DependencyInjection/Loader/schema/dic/services/services-1.0.xsd

@@ -208,6 +208,7 @@
     <xsd:attribute name="name" type="xsd:string" />
     <xsd:attribute name="on-invalid" type="invalid_sequence" />
     <xsd:attribute name="strict" type="boolean" />
+    <xsd:attribute name="tag" type="xsd:string" />
   </xsd:complexType>
 
   <xsd:complexType name="bind" mixed="true">
@@ -233,6 +234,7 @@
     <xsd:attribute name="index" type="xsd:integer" />
     <xsd:attribute name="on-invalid" type="invalid_sequence" />
     <xsd:attribute name="strict" type="boolean" />
+    <xsd:attribute name="tag" type="xsd:string" />
   </xsd:complexType>
 
   <xsd:complexType name="call">
@@ -258,6 +260,7 @@
       <xsd:enumeration value="string" />
       <xsd:enumeration value="constant" />
       <xsd:enumeration value="iterator" />
+      <xsd:enumeration value="tagged" />
     </xsd:restriction>
   </xsd:simpleType>
 

src/Symfony/Component/DependencyInjection/Tests/Compiler/ResolveTaggedIteratorArgumentPassTest.php

@@ -0,0 +1,40 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\DependencyInjection\Tests\Compiler;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\DependencyInjection\Argument\TaggedIteratorArgument;
+use Symfony\Component\DependencyInjection\Compiler\ResolveTaggedIteratorArgumentPass;
+use Symfony\Component\DependencyInjection\ContainerBuilder;
+use Symfony\Component\DependencyInjection\Reference;
+
+/**
+ * @author Roland Franssen <franssen.roland@gmail.com>
+ */
+class ResolveTaggedIteratorArgumentPassTest extends TestCase
+{
+    public function testProcess()
+    {
+        $container = new ContainerBuilder();
+        $container->register('a', 'stdClass')->addTag('foo');
+        $container->register('b', 'stdClass')->addTag('foo', array('priority' => 20));
+        $container->register('c', 'stdClass')->addTag('foo', array('priority' => 10));
+        $container->register('d', 'stdClass')->setProperty('foos', new TaggedIteratorArgument('foo'));
+
+        (new ResolveTaggedIteratorArgumentPass())->process($container);
+
+        $properties = $container->getDefinition('d')->getProperties();
+        $expected = new TaggedIteratorArgument('foo');
+        $expected->setValues(array(new Reference('b'), new Reference('c'), new Reference('a')));
+        $this->assertEquals($expected, $properties['foos']);
+    }
+}

src/Symfony/Component/DependencyInjection/Tests/Fixtures/config/basic.php

@@ -5,9 +5,7 @@ namespace Symfony\Component\DependencyInjection\Loader\Configurator;
 use App\BarService;
 
 return function (ContainerConfigurator $c) {
-
     $s = $c->services();
     $s->set(BarService::class)
         ->args(array(inline('FooClass')));
-
 };

src/Symfony/Component/DependencyInjection/Tests/Fixtures/config/child.php

@@ -5,7 +5,6 @@ namespace Symfony\Component\DependencyInjection\Loader\Configurator;
 use App\BarService;
 
 return function (ContainerConfigurator $c) {
-
     $c->services()
         ->set('bar', 'Class1')
         ->set(BarService::class)
@@ -20,5 +19,4 @@ return function (ContainerConfigurator $c) {
             ->parent('bar')
             ->parent(BarService::class)
     ;
-
 };

src/Symfony/Component/DependencyInjection/Tests/Fixtures/config/defaults.php

@@ -5,7 +5,6 @@ namespace Symfony\Component\DependencyInjection\Loader\Configurator;
 use Symfony\Component\DependencyInjection\Tests\Fixtures\Prototype\Foo;
 
 return function (ContainerConfigurator $c) {
-
     $c->import('basic.php');
 
     $s = $c->services()->defaults()
@@ -19,5 +18,4 @@ return function (ContainerConfigurator $c) {
 
     $s->set(Foo::class)->args(array(ref('bar')))->public();
     $s->set('bar', Foo::class)->call('setFoo')->autoconfigure(false);
-
 };

src/Symfony/Component/DependencyInjection/Tests/Fixtures/config/instanceof.php

@@ -6,7 +6,6 @@ use App\FooService;
 use Symfony\Component\DependencyInjection\Tests\Fixtures\Prototype;
 
 return function (ContainerConfigurator $c) {
-
     $s = $c->services();
     $s->instanceof(Prototype\Foo::class)
         ->property('p', 0)
@@ -20,5 +19,4 @@ return function (ContainerConfigurator $c) {
     $s->load(Prototype::class.'\\', '../Prototype')->exclude('../Prototype/*/*');
 
     $s->set('foo', FooService::class);
-
 };

src/Symfony/Component/DependencyInjection/Tests/Fixtures/config/php7.php

@@ -5,7 +5,6 @@ namespace Symfony\Component\DependencyInjection\Loader\Configurator;
 use Symfony\Component\DependencyInjection\Tests\Fixtures\Prototype\Foo;
 
 return function (ContainerConfigurator $c) {
-
     $c->parameters()
         ('foo', 'Foo')
         ('bar', 'Bar')
@@ -17,5 +16,4 @@ return function (ContainerConfigurator $c) {
         ('bar', Foo::class)
             ->call('setFoo')
     ;
-
 };

src/Symfony/Component/DependencyInjection/Tests/Fixtures/config/prototype.php

@@ -5,7 +5,6 @@ namespace Symfony\Component\DependencyInjection\Loader\Configurator;
 use Symfony\Component\DependencyInjection\Tests\Fixtures\Prototype;
 
 return function (ContainerConfigurator $c) {
-
     $di = $c->services()->defaults()
         ->tag('baz');
     $di->load(Prototype::class.'\\', '../Prototype')
@@ -20,5 +19,4 @@ return function (ContainerConfigurator $c) {
         ->parent('foo');
     $di->set('foo')->lazy()->abstract();
     $di->get(Prototype\Foo::class)->lazy(false);
-
 };

src/Symfony/Component/DependencyInjection/Tests/Fixtures/config/services9.php

@@ -9,7 +9,6 @@ require_once __DIR__.'/../includes/classes.php';
 require_once __DIR__.'/../includes/foo.php';
 
 return function (ContainerConfigurator $c) {
-
     $p = $c->parameters();
     $p->set('baz_class', 'BazClass');
     $p->set('foo_class', FooClass::class)
@@ -119,4 +118,11 @@ return function (ContainerConfigurator $c) {
     $s->set('lazy_context_ignore_invalid_ref', 'LazyContext')
         ->args(array(iterator(array(ref('foo.baz'), ref('invalid')->ignoreOnInvalid())), iterator(array())));
 
+    $s->set('tagged_iterator_foo', 'Bar')
+        ->private()
+        ->tag('foo');
+
+    $s->set('tagged_iterator', 'Bar')
+        ->public()
+        ->args(array(tagged('foo')));
 };

src/Symfony/Component/DependencyInjection/Tests/Fixtures/containers/container9.php

@@ -4,6 +4,7 @@ require_once __DIR__.'/../includes/classes.php';
 require_once __DIR__.'/../includes/foo.php';
 
 use Symfony\Component\DependencyInjection\Argument\IteratorArgument;
+use Symfony\Component\DependencyInjection\Argument\TaggedIteratorArgument;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
 use Symfony\Component\DependencyInjection\Reference;
@@ -161,5 +162,15 @@ $container
     ->setArguments(array(new IteratorArgument(array(new Reference('foo.baz'), new Reference('invalid', ContainerInterface::IGNORE_ON_INVALID_REFERENCE))), new IteratorArgument(array())))
     ->setPublic(true)
 ;
+$container
+    ->register('tagged_iterator_foo', 'Bar')
+    ->addTag('foo')
+    ->setPublic(false)
+;
+$container
+    ->register('tagged_iterator', 'Bar')
+    ->addArgument(new TaggedIteratorArgument('foo'))
+    ->setPublic(true)
+;
 
 return $container;

src/Symfony/Component/DependencyInjection/Tests/Fixtures/graphviz/services9.dot

@@ -29,6 +29,8 @@ digraph sc {
   node_factory_service_simple [label="factory_service_simple\nBar\n", shape=record, fillcolor="#eeeeee", style="filled"];
   node_lazy_context [label="lazy_context\nLazyContext\n", shape=record, fillcolor="#eeeeee", style="filled"];
   node_lazy_context_ignore_invalid_ref [label="lazy_context_ignore_invalid_ref\nLazyContext\n", shape=record, fillcolor="#eeeeee", style="filled"];
+  node_tagged_iterator_foo [label="tagged_iterator_foo\nBar\n", shape=record, fillcolor="#eeeeee", style="filled"];
+  node_tagged_iterator [label="tagged_iterator\nBar\n", shape=record, fillcolor="#eeeeee", style="filled"];
   node_foo2 [label="foo2\n\n", shape=record, fillcolor="#ff9999", style="filled"];
   node_foo3 [label="foo3\n\n", shape=record, fillcolor="#ff9999", style="filled"];
   node_foobaz [label="foobaz\n\n", shape=record, fillcolor="#ff9999", style="filled"];

src/Symfony/Component/DependencyInjection/Tests/Fixtures/php/services9.php

@@ -56,6 +56,8 @@ class ProjectServiceContainer extends Container
             'new_factory' => 'getNewFactoryService',
             'new_factory_service' => 'getNewFactoryServiceService',
             'service_from_static_method' => 'getServiceFromStaticMethodService',
+            'tagged_iterator' => 'getTaggedIteratorService',
+            'tagged_iterator_foo' => 'getTaggedIteratorFooService',
         );
         $this->privates = array(
             'configurator_service' => true,
@@ -63,6 +65,7 @@ class ProjectServiceContainer extends Container
             'factory_simple' => true,
             'inlined' => true,
             'new_factory' => true,
+            'tagged_iterator_foo' => true,
         );
         $this->aliases = array(
             'Psr\\Container\\ContainerInterface' => 'service_container',
@@ -337,6 +340,18 @@ class ProjectServiceContainer extends Container
         return $this->services['service_from_static_method'] = \Bar\FooClass::getInstance();
     }
 
+    /**
+     * Gets the public 'tagged_iterator' shared service.
+     *
+     * @return \Bar
+     */
+    protected function getTaggedIteratorService()
+    {
+        return $this->services['tagged_iterator'] = new \Bar(new RewindableGenerator(function () {
+            return new \EmptyIterator();
+        }, 0));
+    }
+
     /**
      * Gets the private 'configurator_service' shared service.
      *
@@ -404,6 +419,16 @@ class ProjectServiceContainer extends Container
         return $instance;
     }
 
+    /**
+     * Gets the private 'tagged_iterator_foo' shared service.
+     *
+     * @return \Bar
+     */
+    protected function getTaggedIteratorFooService()
+    {
+        return $this->services['tagged_iterator_foo'] = new \Bar();
+    }
+
     /**
      * Gets the default parameters.
      *

src/Symfony/Component/DependencyInjection/Tests/Fixtures/php/services9_as_files.txt

@@ -235,6 +235,27 @@ use Symfony\Component\DependencyInjection\Argument\RewindableGenerator;
 
 return $this->services['service_from_static_method'] = \Bar\FooClass::getInstance();
 
+    [Container%s/getTaggedIteratorService.php] => <?php
+
+use Symfony\Component\DependencyInjection\Argument\RewindableGenerator;
+
+// This file has been auto-generated by the Symfony Dependency Injection Component for internal use.
+// Returns the public 'tagged_iterator' shared service.
+
+return $this->services['tagged_iterator'] = new \Bar(new RewindableGenerator(function () {
+    yield 0 => ${($_ = isset($this->services['foo']) ? $this->services['foo'] : $this->load(__DIR__.'/getFooService.php')) && false ?: '_'};
+    yield 1 => ${($_ = isset($this->services['tagged_iterator_foo']) ? $this->services['tagged_iterator_foo'] : $this->services['tagged_iterator_foo'] = new \Bar()) && false ?: '_'};
+}, 2));
+
+    [Container%s/getTaggedIteratorFooService.php] => <?php
+
+use Symfony\Component\DependencyInjection\Argument\RewindableGenerator;
+
+// This file has been auto-generated by the Symfony Dependency Injection Component for internal use.
+// Returns the private 'tagged_iterator_foo' shared service.
+
+return $this->services['tagged_iterator_foo'] = new \Bar();
+
     [Container%s/Container.php] => <?php
 
 use Symfony\Component\DependencyInjection\Argument\RewindableGenerator;
@@ -292,9 +313,12 @@ class Container%s extends Container
             'method_call1' => __DIR__.'/getMethodCall1Service.php',
             'new_factory_service' => __DIR__.'/getNewFactoryServiceService.php',
             'service_from_static_method' => __DIR__.'/getServiceFromStaticMethodService.php',
+            'tagged_iterator' => __DIR__.'/getTaggedIteratorService.php',
+            'tagged_iterator_foo' => __DIR__.'/getTaggedIteratorFooService.php',
         );
         $this->privates = array(
             'factory_simple' => true,
+            'tagged_iterator_foo' => true,
         );
         $this->aliases = array(
             'alias_for_alias' => 'foo',

src/Symfony/Component/DependencyInjection/Tests/Fixtures/php/services9_compiled.php

@@ -49,9 +49,12 @@ class ProjectServiceContainer extends Container
             'method_call1' => 'getMethodCall1Service',
             'new_factory_service' => 'getNewFactoryServiceService',
             'service_from_static_method' => 'getServiceFromStaticMethodService',
+            'tagged_iterator' => 'getTaggedIteratorService',
+            'tagged_iterator_foo' => 'getTaggedIteratorFooService',
         );
         $this->privates = array(
             'factory_simple' => true,
+            'tagged_iterator_foo' => true,
         );
         $this->aliases = array(
             'alias_for_alias' => 'foo',
@@ -339,6 +342,19 @@ class ProjectServiceContainer extends Container
         return $this->services['service_from_static_method'] = \Bar\FooClass::getInstance();
     }
 
+    /**
+     * Gets the public 'tagged_iterator' shared service.
+     *
+     * @return \Bar
+     */
+    protected function getTaggedIteratorService()
+    {
+        return $this->services['tagged_iterator'] = new \Bar(new RewindableGenerator(function () {
+            yield 0 => ${($_ = isset($this->services['foo']) ? $this->services['foo'] : $this->getFooService()) && false ?: '_'};
+            yield 1 => ${($_ = isset($this->services['tagged_iterator_foo']) ? $this->services['tagged_iterator_foo'] : $this->services['tagged_iterator_foo'] = new \Bar()) && false ?: '_'};
+        }, 2));
+    }
+
     /**
      * Gets the private 'factory_simple' shared service.
      *
@@ -353,6 +369,16 @@ class ProjectServiceContainer extends Container
         return $this->services['factory_simple'] = new \SimpleFactoryClass('foo');
     }
 
+    /**
+     * Gets the private 'tagged_iterator_foo' shared service.
+     *
+     * @return \Bar
+     */
+    protected function getTaggedIteratorFooService()
+    {
+        return $this->services['tagged_iterator_foo'] = new \Bar();
+    }
+
     /**
      * {@inheritdoc}
      */

src/Symfony/Component/DependencyInjection/Tests/Fixtures/xml/services9.xml

@@ -133,6 +133,12 @@
       </argument>
       <argument type="iterator"/>
     </service>
+    <service id="tagged_iterator_foo" class="Bar" public="false">
+      <tag name="foo"/>
+    </service>
+    <service id="tagged_iterator" class="Bar" public="true">
+      <argument type="tagged" tag="foo"/>
+    </service>
     <service id="Psr\Container\ContainerInterface" alias="service_container" public="false"/>
     <service id="Symfony\Component\DependencyInjection\ContainerInterface" alias="service_container" public="false"/>
     <service id="alias_for_foo" alias="foo" public="true"/>

src/Symfony/Component/DependencyInjection/Tests/Fixtures/yaml/services9.yml

@@ -145,6 +145,16 @@ services:
     alias_for_alias:
         alias: 'foo'
         public: true
+    tagged_iterator_foo:
+        class: Bar
+        tags:
+            - { name: foo }
+        public: false
+    tagged_iterator:
+        class: Bar
+        arguments:
+            - !tagged foo
+        public: true
     Psr\Container\ContainerInterface:
         alias: service_container
         public: false

src/Symfony/Component/Yaml/Inline.php

@@ -774,8 +774,8 @@ class Inline
         $nextOffset += strspn($value, ' ', $nextOffset);
 
         // Is followed by a scalar
-        if (!isset($value[$nextOffset]) || !in_array($value[$nextOffset], array('[', '{'), true)) {
-            // Manage scalars in {@link self::evaluateScalar()}
+        if ((!isset($value[$nextOffset]) || !in_array($value[$nextOffset], array('[', '{'), true)) && 'tagged' !== $tag) {
+            // Manage non-whitelisted scalars in {@link self::evaluateScalar()}
             return;
         }
 

src/Symfony/Component/Yaml/Parser.php

@@ -698,6 +698,8 @@ class Parser
             if ('' !== $matches['tag']) {
                 if ('!!binary' === $matches['tag']) {
                     return Inline::evaluateBinaryScalar($data);
+                } elseif ('tagged' === $matches['tag']) {
+                    return new TaggedValue(substr($matches['tag'], 1), $data);
                 } elseif ('!' !== $matches['tag']) {
                     @trigger_error(sprintf('Using the custom tag "%s" for the value "%s" is deprecated since version 3.3. It will be replaced by an instance of %s in 4.0.', $matches['tag'], $data, TaggedValue::class), E_USER_DEPRECATED);
                 }