feature #21071 [DI] Add "inherit-tags" with configurable defaults + s…

…ame for "public", "tags" & "autowire" (nicolas-grekas, ogizanagi)

This PR was merged into the 3.3-dev branch.

Discussion
----------

[DI] Add "inherit-tags" with configurable defaults + same for "public", "tags" & "autowire"

| Q             | A
| ------------- | ---
| Branch?       | master
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #20048
| License       | MIT
| Doc PR        | -

Instead of making services private by default (#20048), which is going to create a big migration burden that might not be worth it, I'd like to propose the idea of changing the default for the current file.

Having a place to redefine some defaults, this can also be used to enable autowiring for a file, making it much lighter in the end.

This PR handles defaults for "public", "autowired" and "tags". Not sure the other options need a configurable default. Please comment if you think otherwise.

Short example (the feat is more interesting with a longer list of services):
```yaml
services:
    _defaults:
        public: false
        autowire: ['_construct', 'set*']

    foo:
        class: Foo
```

```xml
<?xml version="1.0" encoding="utf-8"?>
<container xmlns="http://symfony.com/schema/dic/services" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://symfony.com/schema/dic/services http://symfony.com/schema/dic/services/services-1.0.xsd">
    <services>
        <defaults public="false">
            <autowire>__construct</autowire>
            <tag name="foo"/>
        </defaults>
    </services>
</container>
```

ping @dunglas @weaverryan

Commits
-------

beec1cf [DI] Allow definitions to inherit tags from parent context
05f24d5 [DI] Add "defaults" tag to XML services configuration
7b4a18b [DI] Add "_defaults" key to Yaml services configuration

src/Symfony/Component/DependencyInjection/CHANGELOG.md

@@ -4,11 +4,13 @@ CHANGELOG
 3.3.0
 -----
 
- * Add "iterator" argument type for lazy iteration over a set of values and services
-
- * Using the `PhpDumper` with an uncompiled `ContainerBuilder` is deprecated and
-   will not be supported anymore in 4.0.
-
+ * 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"
+ * 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
  * deprecated the `DefinitionDecorator` class in favor of `ChildDefinition`
 
 3.2.0

src/Symfony/Component/DependencyInjection/ChildDefinition.php

@@ -22,6 +22,7 @@
 class ChildDefinition extends Definition
 {
     private $parent;
+    private $inheritTags = false;
     private $changes = array();
 
     /**
@@ -54,6 +55,30 @@ public function getChanges()
         return $this->changes;
     }
 
+    /**
+     * Sets whether tags should be inherited from the parent or not.
+     *
+     * @param bool $boolean
+     *
+     * @return $this
+     */
+    public function setInheritTags($boolean)
+    {
+        $this->inheritTags = (bool) $boolean;
+
+        return $this;
+    }
+
+    /**
+     * Returns whether tags should be inherited from the parent or not.
+     *
+     * @return bool
+     */
+    public function getInheritTags()
+    {
+        return $this->inheritTags;
+    }
+
     /**
      * {@inheritdoc}
      */

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

@@ -216,6 +216,15 @@ private function doResolveDefinition(ContainerBuilder $container, ChildDefinitio
         $def->setShared($definition->isShared());
         $def->setTags($definition->getTags());
 
+        // append parent tags when inheriting is enabled
+        if ($definition->getInheritTags()) {
+            foreach ($parentDef->getTags() as $k => $v) {
+                foreach ($v as $v) {
+                    $def->addTag($k, $v);
+                }
+            }
+        }
+
         return $def;
     }
 }

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

@@ -118,28 +118,77 @@ private function parseDefinitions(\DOMDocument $xml, $file)
         }
 
         foreach ($services as $service) {
-            if (null !== $definition = $this->parseDefinition($service, $file)) {
+            if (null !== $definition = $this->parseDefinition($service, $file, $this->getServiceDefaults($xml, $file))) {
                 $this->container->setDefinition((string) $service->getAttribute('id'), $definition);
             }
         }
     }
 
+    /**
+     * Get service defaults.
+     *
+     * @return array
+     */
+    private function getServiceDefaults(\DOMDocument $xml, $file)
+    {
+        $xpath = new \DOMXPath($xml);
+        $xpath->registerNamespace('container', self::NS);
+
+        if (null === $defaultsNode = $xpath->query('//container:services/container:defaults')->item(0)) {
+            return array();
+        }
+        $defaults = array(
+            'tags' => $this->getChildren($defaultsNode, 'tag'),
+            'autowire' => $this->getChildren($defaultsNode, 'autowire'),
+        );
+
+        foreach ($defaults['tags'] as $tag) {
+            if ('' === $tag->getAttribute('name')) {
+                throw new InvalidArgumentException(sprintf('The tag name for tag "<defaults>" in %s must be a non-empty string.', $file));
+            }
+        }
+        if ($defaultsNode->hasAttribute('public')) {
+            $defaults['public'] = XmlUtils::phpize($defaultsNode->getAttribute('public'));
+        }
+        if ($defaultsNode->hasAttribute('inherit-tags')) {
+            $defaults['inherit-tags'] = XmlUtils::phpize($defaultsNode->getAttribute('inherit-tags'));
+        }
+        if (!$defaultsNode->hasAttribute('autowire')) {
+            foreach ($defaults['autowire'] as $k => $v) {
+                $defaults['autowire'][$k] = $v->textContent;
+            }
+
+            return $defaults;
+        }
+        if ($defaults['autowire']) {
+            throw new InvalidArgumentException(sprintf('The "autowire" attribute cannot be used together with "<autowire>" tags for tag "<defaults>" in %s.', $file));
+        }
+        if (XmlUtils::phpize($defaultsNode->getAttribute('autowire'))) {
+            $defaults['autowire'][] = '__construct';
+        }
+
+        return $defaults;
+    }
+
     /**
      * Parses an individual Definition.
      *
      * @param \DOMElement $service
      * @param string      $file
+     * @param array       $defaults
      *
      * @return Definition|null
      */
-    private function parseDefinition(\DOMElement $service, $file)
+    private function parseDefinition(\DOMElement $service, $file, array $defaults = array())
     {
         if ($alias = $service->getAttribute('alias')) {
             $this->validateAlias($service, $file);
 
             $public = true;
             if ($publicAttr = $service->getAttribute('public')) {
                 $public = XmlUtils::phpize($publicAttr);
+            } elseif (isset($defaults['public'])) {
+                $public = $defaults['public'];
             }
             $this->container->setAlias((string) $service->getAttribute('id'), new Alias($alias, $public));
 
@@ -148,11 +197,24 @@ private function parseDefinition(\DOMElement $service, $file)
 
         if ($parent = $service->getAttribute('parent')) {
             $definition = new ChildDefinition($parent);
+
+            if ($value = $service->getAttribute('inherit-tags')) {
+                $definition->setInheritTags(XmlUtils::phpize($value));
+            } elseif (isset($defaults['inherit-tags'])) {
+                $definition->setInheritTags($defaults['inherit-tags']);
+            }
+            $defaults = array();
         } else {
             $definition = new Definition();
         }
 
-        foreach (array('class', 'shared', 'public', 'synthetic', 'lazy', 'abstract') as $key) {
+        if ($publicAttr = $service->getAttribute('public')) {
+            $definition->setPublic(XmlUtils::phpize($publicAttr));
+        } elseif (isset($defaults['public'])) {
+            $definition->setPublic($defaults['public']);
+        }
+
+        foreach (array('class', 'shared', 'synthetic', 'lazy', 'abstract') as $key) {
             if ($value = $service->getAttribute($key)) {
                 $method = 'set'.$key;
                 $definition->$method(XmlUtils::phpize($value));
@@ -216,7 +278,19 @@ private function parseDefinition(\DOMElement $service, $file)
             $definition->addMethodCall($call->getAttribute('method'), $this->getArgumentsAsPhp($call, 'argument'));
         }
 
-        foreach ($this->getChildren($service, 'tag') as $tag) {
+        $tags = $this->getChildren($service, 'tag');
+
+        if (empty($defaults['tags'])) {
+            // no-op
+        } elseif (!$value = $service->getAttribute('inherit-tags')) {
+            if (!$tags) {
+                $tags = $defaults['tags'];
+            }
+        } elseif (XmlUtils::phpize($value)) {
+            $tags = array_merge($tags, $defaults['tags']);
+        }
+
+        foreach ($tags as $tag) {
             $parameters = array();
             foreach ($tag->attributes as $name => $node) {
                 if ('name' === $name) {
@@ -252,6 +326,8 @@ private function parseDefinition(\DOMElement $service, $file)
             }
 
             $definition->setAutowiredMethods($autowireTags);
+        } elseif (!$service->hasAttribute('autowire') && !empty($defaults['autowire'])) {
+            $definition->setAutowiredMethods($defaults['autowire']);
         }
 
         if ($value = $service->getAttribute('decorates')) {

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

@@ -52,6 +52,7 @@ class YamlFileLoader extends FileLoader
         'configurator' => 'configurator',
         'calls' => 'calls',
         'tags' => 'tags',
+        'inherit_tags' => 'inherit_tags',
         'decorates' => 'decorates',
         'decoration_inner_name' => 'decoration_inner_name',
         'decoration_priority' => 'decoration_priority',
@@ -148,9 +149,56 @@ private function parseDefinitions($content, $file)
         if (!is_array($content['services'])) {
             throw new InvalidArgumentException(sprintf('The "services" key should contain an array in %s. Check your YAML syntax.', $file));
         }
+        if (isset($content['services']['_defaults'])) {
+            if (!is_array($defaults = $content['services']['_defaults'])) {
+                throw new InvalidArgumentException(sprintf('Service defaults must be an array, "%s" given in "%s".', gettype($defaults), $file));
+            }
+            if (isset($defaults['alias']) || isset($defaults['class']) || isset($defaults['factory'])) {
+                @trigger_error('Giving a service the "_defaults" name is deprecated since Symfony 3.3 and will be forbidden in 4.0. Rename your service.', E_USER_DEPRECATED);
+                $defaults = array();
+            } else {
+                $defaultKeys = array('public', 'tags', 'inherit_tags', 'autowire');
+                unset($content['services']['_defaults']);
+
+                foreach ($defaults as $key => $default) {
+                    if (!in_array($key, $defaultKeys)) {
+                        throw new InvalidArgumentException(sprintf('The configuration key "%s" cannot be used to define a default value in "%s". Allowed keys are "%s".', $key, $file, implode('", "', $defaultKeys)));
+                    }
+                }
+                if (isset($defaults['tags'])) {
+                    if (!is_array($tags = $defaults['tags'])) {
+                        throw new InvalidArgumentException(sprintf('Parameter "tags" in "_defaults" must be an array in %s. Check your YAML syntax.', $file));
+                    }
+
+                    foreach ($tags as $tag) {
+                        if (!is_array($tag)) {
+                            $tag = array('name' => $tag);
+                        }
+
+                        if (!isset($tag['name'])) {
+                            throw new InvalidArgumentException(sprintf('A "tags" entry in "_defaults" is missing a "name" key in %s.', $file));
+                        }
+                        $name = $tag['name'];
+                        unset($tag['name']);
+
+                        if (!is_string($name) || '' === $name) {
+                            throw new InvalidArgumentException(sprintf('The tag name in "_defaults" must be a non-empty string in %s.', $file));
+                        }
+
+                        foreach ($tag as $attribute => $value) {
+                            if (!is_scalar($value) && null !== $value) {
+                                throw new InvalidArgumentException(sprintf('Tag "%s", attribute "%s" in "_defaults" must be of a scalar-type in %s. Check your YAML syntax.', $name, $attribute, $file));
+                            }
+                        }
+                    }
+                }
+            }
+        } else {
+            $defaults = array();
+        }
 
         foreach ($content['services'] as $id => $service) {
-            $this->parseDefinition($id, $service, $file);
+            $this->parseDefinition($id, $service, $file, $defaults);
         }
     }
 
@@ -160,10 +208,11 @@ private function parseDefinitions($content, $file)
      * @param string $id
      * @param array  $service
      * @param string $file
+     * @param array  $defaults
      *
      * @throws InvalidArgumentException When tags are invalid
      */
-    private function parseDefinition($id, $service, $file)
+    private function parseDefinition($id, $service, $file, array $defaults)
     {
         if (is_string($service) && 0 === strpos($service, '@')) {
             $this->container->setAlias($id, substr($service, 1));
@@ -178,7 +227,7 @@ private function parseDefinition($id, $service, $file)
         static::checkDefinition($id, $service, $file);
 
         if (isset($service['alias'])) {
-            $public = !array_key_exists('public', $service) || (bool) $service['public'];
+            $public = array_key_exists('public', $service) ? (bool) $service['public'] : !empty($defaults['public']);
             $this->container->setAlias($id, new Alias($service['alias'], $public));
 
             foreach ($service as $key => $value) {
@@ -192,6 +241,12 @@ private function parseDefinition($id, $service, $file)
 
         if (isset($service['parent'])) {
             $definition = new ChildDefinition($service['parent']);
+
+            $inheritTag = isset($service['inherit_tags']) ? $service['inherit_tags'] : (isset($defaults['inherit_tags']) ? $defaults['inherit_tags'] : null);
+            if (null !== $inheritTag) {
+                $definition->setInheritTags($inheritTag);
+            }
+            $defaults = array();
         } else {
             $definition = new Definition();
         }
@@ -212,8 +267,9 @@ private function parseDefinition($id, $service, $file)
             $definition->setLazy($service['lazy']);
         }
 
-        if (isset($service['public'])) {
-            $definition->setPublic($service['public']);
+        $public = isset($service['public']) ? $service['public'] : (isset($defaults['public']) ? $defaults['public'] : null);
+        if (null !== $public) {
+            $definition->setPublic($public);
         }
 
         if (isset($service['abstract'])) {
@@ -262,27 +318,38 @@ private function parseDefinition($id, $service, $file)
             }
         }
 
-        if (isset($service['tags'])) {
-            if (!is_array($service['tags'])) {
+        $tags = isset($service['tags']) ? $service['tags'] : array();
+
+        if (!isset($defaults['tags'])) {
+            // no-op
+        } elseif (!isset($service['inherit_tags'])) {
+            if (!isset($service['tags'])) {
+                $tags = $defaults['tags'];
+            }
+        } elseif ($service['inherit_tags']) {
+            $tags = array_merge($tags, $defaults['tags']);
+        }
+
+        if (null !== $tags) {
+            if (!is_array($tags)) {
                 throw new InvalidArgumentException(sprintf('Parameter "tags" must be an array for service "%s" in %s. Check your YAML syntax.', $id, $file));
             }
 
-            foreach ($service['tags'] as $tag) {
+            foreach ($tags as $tag) {
                 if (!is_array($tag)) {
                     $tag = array('name' => $tag);
                 }
 
                 if (!isset($tag['name'])) {
                     throw new InvalidArgumentException(sprintf('A "tags" entry is missing a "name" key for service "%s" in %s.', $id, $file));
                 }
+                $name = $tag['name'];
+                unset($tag['name']);
 
-                if (!is_string($tag['name']) || '' === $tag['name']) {
+                if (!is_string($name) || '' === $name) {
                     throw new InvalidArgumentException(sprintf('The tag name for service "%s" in %s must be a non-empty string.', $id, $file));
                 }
 
-                $name = $tag['name'];
-                unset($tag['name']);
-
                 foreach ($tag as $attribute => $value) {
                     if (!is_scalar($value) && null !== $value) {
                         throw new InvalidArgumentException(sprintf('A "tags" attribute must be of a scalar-type for service "%s", tag "%s", attribute "%s" in %s. Check your YAML syntax.', $id, $name, $attribute, $file));
@@ -303,11 +370,12 @@ private function parseDefinition($id, $service, $file)
             $definition->setDecoratedService($service['decorates'], $renameId, $priority);
         }
 
-        if (isset($service['autowire'])) {
-            if (is_array($service['autowire'])) {
-                $definition->setAutowiredMethods($service['autowire']);
+        $autowire = isset($service['autowire']) ? $service['autowire'] : (isset($defaults['autowire']) ? $defaults['autowire'] : null);
+        if (null !== $autowire) {
+            if (is_array($autowire)) {
+                $definition->setAutowiredMethods($autowire);
             } else {
-                $definition->setAutowired($service['autowire']);
+                $definition->setAutowired($autowire);
             }
         }