From 6fe97f9b7ca5b2218a20ce149fb846464abec2a1 Mon Sep 17 00:00:00 2001
From: Ryan Weaver <ryan@thatsquality.com>
Date: Sun, 21 Feb 2016 19:27:26 -0500
Subject: [PATCH] [DependencyInjection] Improving autowiring error messages to
 say *why* something cannot be autowired

---
 .../Compiler/AutowirePass.php                 | 28 +++++++++++++++----
 .../Tests/Compiler/AutowirePassTest.php       | 21 ++++++++++++--
 2 files changed, 40 insertions(+), 9 deletions(-)

diff --git a/src/Symfony/Component/DependencyInjection/Compiler/AutowirePass.php b/src/Symfony/Component/DependencyInjection/Compiler/AutowirePass.php
index ec7880be89b95..aa6f0bf8ad740 100644
--- a/src/Symfony/Component/DependencyInjection/Compiler/AutowirePass.php
+++ b/src/Symfony/Component/DependencyInjection/Compiler/AutowirePass.php
@@ -27,7 +27,7 @@ class AutowirePass implements CompilerPassInterface
     private $reflectionClasses = array();
     private $definedTypes = array();
     private $types;
-    private $notGuessableTypes = array();
+    private $ambiguousServiceTypes = array();
 
     /**
      * {@inheritdoc}
@@ -46,7 +46,7 @@ public function process(ContainerBuilder $container)
         $this->reflectionClasses = array();
         $this->definedTypes = array();
         $this->types = null;
-        $this->notGuessableTypes = array();
+        $this->ambiguousServiceTypes = array();
     }
 
     /**
@@ -197,17 +197,25 @@ private function extractAncestors($id, \ReflectionClass $reflectionClass)
      */
     private function set($type, $id)
     {
-        if (isset($this->definedTypes[$type]) || isset($this->notGuessableTypes[$type])) {
+        if (isset($this->definedTypes[$type])) {
             return;
         }
 
+        // check to make sure the type doesn't match multiple services
         if (isset($this->types[$type])) {
             if ($this->types[$type] === $id) {
                 return;
             }
 
+            // keep an array of all services matching this type
+            if (!isset($this->ambiguousServiceTypes[$type])) {
+                $this->ambiguousServiceTypes[$type] = array(
+                    $this->types[$type],
+                );
+            }
+            $this->ambiguousServiceTypes[$type][] = $id;
+
             unset($this->types[$type]);
-            $this->notGuessableTypes[$type] = true;
 
             return;
         }
@@ -227,8 +235,16 @@ private function set($type, $id)
      */
     private function createAutowiredDefinition(\ReflectionClass $typeHint, $id)
     {
-        if (isset($this->notGuessableTypes[$typeHint->name]) || !$typeHint->isInstantiable()) {
-            throw new RuntimeException(sprintf('Unable to autowire argument of type "%s" for the service "%s".', $typeHint->name, $id));
+        if (isset($this->ambiguousServiceTypes[$typeHint->name])) {
+            $classOrInterface = $typeHint->isInterface() ? 'interface' : 'class';
+            $matchingServices = implode(', ', $this->ambiguousServiceTypes[$typeHint->name]);
+
+            throw new RuntimeException(sprintf('Unable to autowire argument of type "%s" for the service "%s". Multiple services exist for this %s (%s).', $typeHint->name, $id, $classOrInterface, $matchingServices));
+        }
+
+        if (!$typeHint->isInstantiable()) {
+            $classOrInterface = $typeHint->isInterface() ? 'interface' : 'class';
+            throw new RuntimeException(sprintf('Unable to autowire argument of type "%s" for the service "%s". No services were found matching this %s.', $typeHint->name, $id, $classOrInterface));
         }
 
         $argumentId = sprintf('autowired.%s', $typeHint->name);
diff --git a/src/Symfony/Component/DependencyInjection/Tests/Compiler/AutowirePassTest.php b/src/Symfony/Component/DependencyInjection/Tests/Compiler/AutowirePassTest.php
index f1ed72e94a4cd..a0b11ce9d9fd3 100644
--- a/src/Symfony/Component/DependencyInjection/Tests/Compiler/AutowirePassTest.php
+++ b/src/Symfony/Component/DependencyInjection/Tests/Compiler/AutowirePassTest.php
@@ -102,7 +102,7 @@ public function testCompleteExistingDefinitionWithNotDefinedArguments()
 
     /**
      * @expectedException \Symfony\Component\DependencyInjection\Exception\RuntimeException
-     * @expectedExceptionMessage Unable to autowire argument of type "Symfony\Component\DependencyInjection\Tests\Compiler\CollisionInterface" for the service "a".
+     * @expectedExceptionMessage Unable to autowire argument of type "Symfony\Component\DependencyInjection\Tests\Compiler\CollisionInterface" for the service "a". Multiple services exist for this interface (c1, c2).
      */
     public function testTypeCollision()
     {
@@ -119,7 +119,7 @@ public function testTypeCollision()
 
     /**
      * @expectedException \Symfony\Component\DependencyInjection\Exception\RuntimeException
-     * @expectedExceptionMessage Unable to autowire argument of type "Symfony\Component\DependencyInjection\Tests\Compiler\Foo" for the service "a".
+     * @expectedExceptionMessage Unable to autowire argument of type "Symfony\Component\DependencyInjection\Tests\Compiler\Foo" for the service "a". Multiple services exist for this class (a1, a2).
      */
     public function testTypeNotGuessable()
     {
@@ -136,7 +136,7 @@ public function testTypeNotGuessable()
 
     /**
      * @expectedException \Symfony\Component\DependencyInjection\Exception\RuntimeException
-     * @expectedExceptionMessage Unable to autowire argument of type "Symfony\Component\DependencyInjection\Tests\Compiler\A" for the service "a".
+     * @expectedExceptionMessage Unable to autowire argument of type "Symfony\Component\DependencyInjection\Tests\Compiler\A" for the service "a". Multiple services exist for this class (a1, a2).
      */
     public function testTypeNotGuessableWithSubclass()
     {
@@ -151,6 +151,21 @@ public function testTypeNotGuessableWithSubclass()
         $pass->process($container);
     }
 
+    /**
+     * @expectedException \Symfony\Component\DependencyInjection\Exception\RuntimeException
+     * @expectedExceptionMessage Unable to autowire argument of type "Symfony\Component\DependencyInjection\Tests\Compiler\CollisionInterface" for the service "a". No services were found matching this interface.
+     */
+    public function testTypeNotGuessableNoServicesFound()
+    {
+        $container = new ContainerBuilder();
+
+        $aDefinition = $container->register('a', __NAMESPACE__.'\CannotBeAutowired');
+        $aDefinition->setAutowired(true);
+
+        $pass = new AutowirePass();
+        $pass->process($container);
+    }
+
     public function testTypeNotGuessableWithTypeSet()
     {
         $container = new ContainerBuilder();