[Validator][Choice] Fix callback option if not array or iterable returned

Author: symfonyaml

src/Symfony/Component/Validator/Constraints/ChoiceValidator.php

@@ -55,6 +55,12 @@ public function validate($value, Constraint $constraint)
                 throw new ConstraintDefinitionException('The Choice constraint expects a valid callback.');
             }
             $choices = $choices();
+            if ($choices instanceof \Traversable) {
+                $choices = iterator_to_array($choices);
+            }
+            if (!is_array($choices)) {
+                throw new ConstraintDefinitionException(sprintf('The Choice constraint callback "%s" expects to return an iterable, got "%s".', trim($this->formatValue($constraint->callback), '"'), get_debug_type($choices)));
+            }
         } else {
             $choices = $constraint->choices;
         }

src/Symfony/Component/Validator/Tests/Constraints/ChoiceValidatorTest.php

@@ -39,6 +39,18 @@ public function objectMethodCallback()
         return ['foo', 'bar'];
     }
 
+    public static function staticCallbackTraversable()
+    {
+        yield 1;
+        yield 2;
+        yield 3;
+    }
+
+    public static function staticCallbackInvalid()
+    {
+        return null;
+    }
+
     public function testExpectArrayIfMultipleIsTrue()
     {
         $this->expectException(UnexpectedValueException::class);
@@ -134,6 +146,31 @@ public function testValidChoiceCallbackContextMethod()
         $this->assertNoViolation();
     }
 
+    public function testInvalidChoiceCallbackContextMethod()
+    {
+        $this->expectException(ConstraintDefinitionException::class);
+        $this->expectExceptionMessage('The Choice constraint callback "staticCallbackInvalid" expects to return an iterable, got "null".');
+
+        // search $this for "staticCallbackInvalid"
+        $this->setObject($this);
+
+        $constraint = new Choice(['callback' => 'staticCallbackInvalid']);
+
+        $this->validator->validate('bar', $constraint);
+    }
+
+    public function testValidChoiceCallbackContextMethodTraversable()
+    {
+        // search $this for "staticCallbackTraversable"
+        $this->setObject($this);
+
+        $constraint = new Choice(['callback' => 'staticCallbackTraversable']);
+
+        $this->validator->validate(2, $constraint);
+
+        $this->assertNoViolation();
+    }
+
     public function testValidChoiceCallbackContextObjectMethod()
     {
         // search $this for "objectMethodCallback"