minor #18691 [DX][DI] Make failed autowiring error messages more explicit (lemoinem)

This PR was merged into the 2.8 branch.

Discussion
----------

[DX][DI] Make failed autowiring error messages more explicit

| Q             | A
| ------------- | ---
| Branch?       | 2.8
| Bug fix?      | no (better DX integration)
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #18658
| License       | MIT
| Doc PR        | N/A

This is the PR improving the auto wiring error messages.
Two errors messages have augmented:

If a type-hint does not match any existing type and a service for this type cannot be automatically created, the error message now says so, instead of simply saying the type cannot be autowired.

If a type-hint matches multiple services and none of them provides an  autowiringType for it, the error message now says so and list the candidate services, instead of simply saying the type cannot be autowired.

Commits
-------

2ac81f9 Make failed autowiring error messages more explicit

Author: fabpot

Compiler/AutowirePass.php

@@ -105,7 +105,7 @@ private function completeDefinition($id, Definition $definition)
                     $this->populateAvailableTypes();
                 }
 
-                if (isset($this->types[$typeHint->name])) {
+                if (isset($this->types[$typeHint->name]) && !isset($this->notGuessableTypes[$typeHint->name])) {
                     $value = new Reference($this->types[$typeHint->name]);
                 } else {
                     try {
@@ -190,22 +190,26 @@ private function populateAvailableType($id, Definition $definition)
      */
     private function set($type, $id)
     {
-        if (isset($this->definedTypes[$type]) || isset($this->notGuessableTypes[$type])) {
+        if (isset($this->definedTypes[$type])) {
             return;
         }
 
-        if (isset($this->types[$type])) {
-            if ($this->types[$type] === $id) {
-                return;
-            }
+        if (!isset($this->types[$type])) {
+            $this->types[$type] = $id;
 
-            unset($this->types[$type]);
-            $this->notGuessableTypes[$type] = true;
+            return;
+        }
 
+        if ($this->types[$type] === $id) {
             return;
         }
 
-        $this->types[$type] = $id;
+        if (!isset($this->notGuessableTypes[$type])) {
+            $this->notGuessableTypes[$type] = true;
+            $this->types[$type] = (array) $this->types[$type];
+        }
+
+        $this->types[$type][] = $id;
     }
 
     /**
@@ -220,8 +224,14 @@ 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->notGuessableTypes[$typeHint->name])) {
+            throw new RuntimeException(sprintf('Unable to autowire argument of type "%s" for the service "%s". Several services implementing this type have been declared: "%s".', $typeHint->name, $id, implode('", "', $this->types[$typeHint->name])));
+        }
+
+        $noAvailableDefinitionMessage = sprintf('Unable to autowire argument of type "%s" for the service "%s". This type cannot be instantiated automatically and no service implementing this type is declared.', $typeHint->name, $id);
+
+        if (!$typeHint->isInstantiable()) {
+            throw new RuntimeException($noAvailableDefinitionMessage);
         }
 
         $argumentId = sprintf('autowired.%s', $typeHint->name);
@@ -230,7 +240,12 @@ private function createAutowiredDefinition(\ReflectionClass $typeHint, $id)
         $argumentDefinition->setPublic(false);
 
         $this->populateAvailableType($argumentId, $argumentDefinition);
-        $this->completeDefinition($argumentId, $argumentDefinition);
+
+        try {
+            $this->completeDefinition($argumentId, $argumentDefinition);
+        } catch (RuntimeException $e) {
+            throw new RuntimeException($noAvailableDefinitionMessage, 0, $e);
+        }
 
         return new Reference($argumentId);
     }

Tests/Compiler/AutowirePassTest.php

@@ -103,7 +103,7 @@ 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". Several services implementing this type have been declared: "c1", "c2".
      */
     public function testTypeCollision()
     {
@@ -120,7 +120,7 @@ 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". Several services implementing this type have been declared: "a1", "a2".
      */
     public function testTypeNotGuessable()
     {
@@ -137,7 +137,7 @@ 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". Several services implementing this type have been declared: "a1", "a2".
      */
     public function testTypeNotGuessableWithSubclass()
     {
@@ -207,6 +207,21 @@ public function testCreateDefinition()
         $this->assertEquals(__NAMESPACE__.'\Lille', $lilleDefinition->getClass());
     }
 
+    /**
+     * @expectedException \Symfony\Component\DependencyInjection\Exception\RuntimeException
+     * @expectedExceptionMessage Unable to autowire argument of type "Symfony\Component\DependencyInjection\Tests\Compiler\CollisionInterface" for the service "a". This type cannot be instantiated automatically and no service implementing this type is declared.
+     */
+    public function testCreateNonInstanciable()
+    {
+        $container = new ContainerBuilder();
+
+        $aDefinition = $container->register('a', __NAMESPACE__.'\CannotBeAutowired');
+        $aDefinition->setAutowired(true);
+
+        $pass = new AutowirePass();
+        $pass->process($container);
+    }
+
     public function testResolveParameter()
     {
         $container = new ContainerBuilder();