[Form] Output a more usable error when PropertyPath has tried to find adders and getters, but failed to find them

src/Symfony/Component/Form/Tests/Util/PropertyPathCollectionTest.php

@@ -12,6 +12,7 @@
 namespace Symfony\Component\Form\Tests\Util;
 
 use Symfony\Component\Form\Util\PropertyPath;
+use Symfony\Component\Form\Util\FormUtil;
 
 class PropertyPathCollectionTest_Car
 {
@@ -72,6 +73,11 @@ class PropertyPathCollectionTest_CarOnlyRemover
     public function getAxes() {}
 }
 
+class PropertyPathCollectionTest_CarNoAdderAndRemover
+{
+    public function getAxes() {}
+}
+
 class PropertyPathCollectionTest_CompositeCar
 {
     public function getStructure() {}
@@ -195,4 +201,47 @@ abstract class PropertyPathCollectionTest extends \PHPUnit_Framework_TestCase
 
         $path->setValue($car, $axesAfter);
     }
+
+    /**
+     * @dataProvider noAdderRemoverData
+     */
+    public function testNoAdderAndRemoverThrowsSensibleError($path, $message)
+    {
+        $car = $this->getMock(__CLASS__ . '_CarNoAdderAndRemover');
+        $axesBefore = $this->getCollection(array(1 => 'second', 3 => 'fourth'));
+        $axesAfter = $this->getCollection(array(0 => 'first', 1 => 'second', 2 => 'third'));
+
+        try {
+            $path->setValue($car, $axesAfter);
+            $this->fail('An expected exception was not thrown!');
+        } catch (\Symfony\Component\Form\Exception\InvalidPropertyException $e) {
+            $this->assertEquals(str_replace("{class}", get_class($car), $message), $e->getMessage());
+        }
+    }
+
+    public function noAdderRemoverData()
+    {
+        $data = array();
+
+        $propertyPath = new PropertyPath('axes');
+        $expectedMessage = sprintf(
+            'Neither element "axes" nor method "setAxes()" exists in class '
+                .'"{class}", nor could adders and removers be found based on the '
+                .'guessed singulars: %s (provide a singular by suffixing the '
+                .'property path with "|{singular}" to override the guesser)',
+            implode(', ', (array) $singulars = FormUtil::singularify('Axes'))
+        );
+        $data[] = array($propertyPath, $expectedMessage);
+
+        $propertyPath = new PropertyPath('axes|boo');
+        $expectedMessage = sprintf(
+            'Neither element "axes" nor method "setAxes()" exists in class '
+                .'"{class}", nor could adders and removers be found based on the '
+                .'passed singular: %s',
+            'boo'
+        );
+        $data[] = array($propertyPath, $expectedMessage);
+
+        return $data;
+    }
 }

src/Symfony/Component/Form/Util/PropertyPath.php

@@ -437,6 +437,8 @@ class PropertyPath implements \IteratorAggregate, PropertyPathInterface
      */
     protected function writeProperty(&$objectOrArray, $property, $singular, $isIndex, $value)
     {
+        $adderRemoverError = null;
+
         if ($isIndex) {
             if (!$objectOrArray instanceof \ArrayAccess && !is_array($objectOrArray)) {
                 throw new InvalidPropertyException(sprintf('Index "%s" cannot be modified in object of type "%s" because it doesn\'t implement \ArrayAccess', $property, get_class($objectOrArray)));
@@ -446,8 +448,14 @@ class PropertyPath implements \IteratorAggregate, PropertyPathInterface
         } elseif (is_object($objectOrArray)) {
             $reflClass = new ReflectionClass($objectOrArray);
 
+            // The plural form is the last element of the property path
+            $plural = $this->camelize($this->elements[$this->length - 1]);
+
+            // Any of the two methods is required, but not yet known
+            $singulars = null !== $singular ? array($singular) : (array) FormUtil::singularify($plural);
+
             if (is_array($value) || $value instanceof Traversable) {
-                $methods = $this->findAdderAndRemover($reflClass, $singular);
+                $methods = $this->findAdderAndRemover($reflClass, $singulars);
                 if (null !== $methods) {
                     // At this point the add and remove methods have been found
                     $itemsToAdd = is_object($value) ? clone $value : $value;
@@ -480,6 +488,13 @@ class PropertyPath implements \IteratorAggregate, PropertyPathInterface
                     }
 
                     return;
+                } else {
+                    $adderRemoverError = ', nor could adders and removers be found based on the ';
+                    if (null === $singular) {
+                        $adderRemoverError .= 'guessed singulars: '.implode(', ', $singulars).' (provide a singular by suffixing the property path with "|{singular}" to override the guesser)';
+                    } else {
+                        $adderRemoverError .= 'passed singular: '.$singular;
+                    }
                 }
             }
 
@@ -503,7 +518,7 @@ class PropertyPath implements \IteratorAggregate, PropertyPathInterface
                 // needed to support \stdClass instances
                 $objectOrArray->$property = $value;
             } else {
-                throw new InvalidPropertyException(sprintf('Neither element "%s" nor method "%s()" exists in class "%s"', $property, $setter, $reflClass->name));
+                throw new InvalidPropertyException(sprintf('Neither element "%s" nor method "%s()" exists in class "%s"%s', $property, $setter, $reflClass->name, $adderRemoverError));
             }
         } else {
             throw new InvalidPropertyException(sprintf('Cannot write property "%s" in an array. Maybe you should write the property path as "[%s]" instead?', $property, $property));
@@ -532,37 +547,8 @@ class PropertyPath implements \IteratorAggregate, PropertyPathInterface
      *
      * @throws InvalidPropertyException      If the property does not exist.
      */
-    private function findAdderAndRemover(\ReflectionClass $reflClass, $singular)
+    private function findAdderAndRemover(\ReflectionClass $reflClass, array $singulars)
     {
-        if (null !== $singular) {
-            $addMethod = 'add' . $this->camelize($singular);
-            $removeMethod = 'remove' . $this->camelize($singular);
-
-            if (!$this->isAccessible($reflClass, $addMethod, 1)) {
-                throw new InvalidPropertyException(sprintf(
-                    'The public method "%s" with exactly one required parameter was not found on class %s',
-                    $addMethod,
-                    $reflClass->name
-                ));
-            }
-
-            if (!$this->isAccessible($reflClass, $removeMethod, 1)) {
-                throw new InvalidPropertyException(sprintf(
-                    'The public method "%s" with exactly one required parameter was not found on class %s',
-                    $removeMethod,
-                    $reflClass->name
-                ));
-            }
-
-            return array($addMethod, $removeMethod);
-        }
-
-        // The plural form is the last element of the property path
-        $plural = $this->camelize($this->elements[$this->length - 1]);
-
-        // Any of the two methods is required, but not yet known
-        $singulars = (array) FormUtil::singularify($plural);
-
         foreach ($singulars as $singular) {
             $addMethod = 'add' . $singular;
             $removeMethod = 'remove' . $singular;