Improving the exception message when the bundle name is wrong for the controller in a route

Usually, it is wrong because you've chosen the wrong bundle name in your _controller syntax.
But this also tries to imply that you *might* be missing your bundle initialization in AppKernel
(though I think this is much much less common).

src/Symfony/Bundle/FrameworkBundle/Controller/ControllerNameParser.php

@@ -46,6 +46,7 @@ class ControllerNameParser
      */
     public function parse($controller)
     {
+        $originalController = $controller;
         if (3 != count($parts = explode(':', $controller))) {
             throw new \InvalidArgumentException(sprintf('The "%s" controller is not a valid "a:b:c" controller string.', $controller));
         }
@@ -54,8 +55,24 @@ class ControllerNameParser
         $controller = str_replace('/', '\\', $controller);
         $bundles = array();
 
-        // this throws an exception if there is no such bundle
-        foreach ($this->kernel->getBundle($bundle, false) as $b) {
+        try {
+            // this throws an exception if there is no such bundle
+            $allBundles = $this->kernel->getBundle($bundle, false);
+        } catch (\InvalidArgumentException $e) {
+            $message = sprintf(
+                'The "%s" (from the _controller value "%s") does not exist or is not enabled in your kernel!',
+                $bundle,
+                $originalController
+            );
+
+            if ($alternative = $this->findAlternative($bundle)) {
+                $message .= sprintf(' Did you mean "%s:%s:%s"?', $alternative, $controller, $action);
+            }
+
+            throw new \InvalidArgumentException($message, 0, $e);
+        }
+
+        foreach ($allBundles as $b) {
             $try = $b->getNamespace().'\\Controller\\'.$controller.'Controller';
             if (class_exists($try)) {
                 return $try.'::'.$action.'Action';
@@ -100,4 +117,33 @@ class ControllerNameParser
 
         throw new \InvalidArgumentException(sprintf('Unable to find a bundle that defines controller "%s".', $controller));
     }
+
+    /**
+     * Attempts to find a bundle that is *similar* to the given bundle name
+     *
+     * @param string $nonExistentBundleName
+     * @return string
+     */
+    private function findAlternative($nonExistentBundleName)
+    {
+        $bundleNames = array_map(function ($b) {
+            return $b->getName();
+        }, $this->kernel->getBundles());
+
+        $alternative = null;
+        $shortest = null;
+        foreach ($bundleNames as $bundleName) {
+            // if there's a partial match, return it immediately
+            if (false !== strpos($bundleName, $nonExistentBundleName)) {
+                return $bundleName;
+            }
+
+            $lev = levenshtein($nonExistentBundleName, $bundleName);
+            if ($lev <= strlen($nonExistentBundleName) / 3 && ($alternative === null || $lev < $shortest)) {
+                $alternative = $bundleName;
+            }
+        }
+
+        return $alternative;
+    }
 }

src/Symfony/Bundle/FrameworkBundle/Tests/Controller/ControllerNameParserTest.php

@@ -107,6 +107,36 @@ class ControllerNameParserTest extends TestCase
         );
     }
 
+    /**
+     * @expectedException
+     * @dataProvider getInvalidBundleNameTests
+     */
+    public function testInvalidBundleName($bundleName, $suggestedBundleName)
+    {
+        $parser = $this->createParser();
+
+        try {
+            $parser->parse($bundleName);
+        } catch (\Exception $e) {
+            $this->assertInstanceOf('\InvalidArgumentException', $e, '->parse() throws a \InvalidArgumentException if the bundle does not exist');
+
+            if (false === $suggestedBundleName) {
+                // make sure we don't have a suggestion
+                $this->assertNotContains('Did you mean', $e->getMessage());
+            } else {
+                $this->assertContains(sprintf('Did you mean "%s"', $suggestedBundleName), $e->getMessage());
+            }
+        }
+    }
+
+    public function getInvalidBundleNameTests()
+    {
+        return array(
+            array('FoodBundle:Default:index', 'FooBundle:Default:index'),
+            array('CrazyBundle:Default:index', false),
+        );
+    }
+
     private function createParser()
     {
         $bundles = array(
@@ -121,6 +151,10 @@ class ControllerNameParserTest extends TestCase
             ->expects($this->any())
             ->method('getBundle')
             ->will($this->returnCallback(function ($bundle) use ($bundles) {
+                if (!isset($bundles[$bundle])) {
+                    throw new \InvalidArgumentException(sprintf('Invalid bundle name "%s"', $bundle));
+                }
+
                 return $bundles[$bundle];
             }))
         ;