bug #20122 [Validator] Reset constraint options (ro0NL)

This PR was merged into the 2.7 branch.

Discussion
----------

[Validator] Reset constraint options

| Q             | A
| ------------- | ---
| Branch?       | 2.7
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #20106
| License       | MIT
| Doc PR        | reference to the documentation PR, if any

I think it's good to reset the internal pointer of the options array if we depend on `key($options)`. I've added tests to clarify we intentionally check for the first key.

The current behavior actually differs for hhvm/php7 - https://3v4l.org/e6r6E

Commits
-------

4c6ddd4 reset constraint options

src/Symfony/Component/Validator/Constraint.php

@@ -129,6 +129,9 @@ abstract class Constraint
             unset($options['value']);
         }
 
+        if (is_array($options)) {
+            reset($options);
+        }
         if (is_array($options) && count($options) > 0 && is_string(key($options))) {
             foreach ($options as $option => $value) {
                 if (array_key_exists($option, $knownOptions)) {

src/Symfony/Component/Validator/Tests/ConstraintTest.php

@@ -206,4 +206,35 @@ class ConstraintTest extends \PHPUnit_Framework_TestCase
     {
         Constraint::getErrorName(1);
     }
+
+    public function testOptionsAsDefaultOption()
+    {
+        $constraint = new ConstraintA($options = array('value1'));
+
+        $this->assertEquals($options, $constraint->property2);
+
+        $constraint = new ConstraintA($options = array('value1', 'property1' => 'value2'));
+
+        $this->assertEquals($options, $constraint->property2);
+    }
+
+    /**
+     * @expectedException \Symfony\Component\Validator\Exception\InvalidOptionsException
+     * @expectedExceptionMessage The options "0", "5" do not exist
+     */
+    public function testInvalidOptions()
+    {
+        new ConstraintA(array('property2' => 'foo', 'bar', 5 => 'baz'));
+    }
+
+    public function testOptionsWithInvalidInternalPointer()
+    {
+        $options = array('property1' => 'foo');
+        next($options);
+        next($options);
+
+        $constraint = new ConstraintA($options);
+
+        $this->assertEquals('foo', $constraint->property1);
+    }
 }