Implement nested field validators.

This adds support for nested field validators. To better support
model-less forms and the elasticsearch ODM, we will need to validate
nested fields. This set of changes is the smallest change I could make
that implements the basic requirements.

Refs #6496

src/Validation/Validator.php

@@ -17,6 +17,7 @@
 use ArrayAccess;
 use Cake\Validation\RulesProvider;
 use Cake\Validation\ValidationSet;
+use Cake\Utility\Hash;
 use Countable;
 use IteratorAggregate;
 
@@ -97,25 +98,27 @@ public function errors(array $data, $newRecord = true)
             $requiredMessage = __d('cake', 'This field is required');
             $emptyMessage = __d('cake', 'This field cannot be left empty');
         }
+        $flat = Hash::flatten($data);
 
         foreach ($this->_fields as $name => $field) {
-            $keyPresent = array_key_exists($name, $data);
+            $isPath = strpos($name, '.') !== false;
+            $keyPresent = array_key_exists($name, $isPath ? $flat : $data);
 
             if (!$keyPresent && !$this->_checkPresence($field, $newRecord)) {
                 $errors[$name]['_required'] = isset($this->_presenceMessages[$name])
                     ? $this->_presenceMessages[$name]
                     : $requiredMessage;
                 continue;
             }
-
             if (!$keyPresent) {
                 continue;
             }
+            $value = $isPath ? $flat[$name] : $data[$name];
 
             $providers = $this->_providers;
             $context = compact('data', 'newRecord', 'field', 'providers');
             $canBeEmpty = $this->_canBeEmpty($field, $context);
-            $isEmpty = $this->_fieldIsEmpty($data[$name]);
+            $isEmpty = $this->_fieldIsEmpty($value);
 
             if (!$canBeEmpty && $isEmpty) {
                 $errors[$name]['_empty'] = isset($this->_allowEmptyMessages[$name])
@@ -128,7 +131,7 @@ public function errors(array $data, $newRecord = true)
                 continue;
             }
 
-            $result = $this->_processRules($name, $field, $data, $newRecord);
+            $result = $this->_processRules($name, $value, $field, $data, $newRecord);
             if ($result) {
                 $errors[$name] = $result;
             }
@@ -547,13 +550,13 @@ protected function _fieldIsEmpty($data)
      *
      * @param string $field The name of the field that is being processed
      * @param ValidationSet $rules the list of rules for a field
+     * @param mixed $value The field value.
      * @param array $data the full data passed to the validator
      * @param bool $newRecord whether is it a new record or an existing one
      * @return array
      */
-    protected function _processRules($field, ValidationSet $rules, $data, $newRecord)
+    protected function _processRules($field, $value, ValidationSet $rules, $data, $newRecord)
     {
-        $value = $data[$field];
         $errors = [];
         // Loading default provider in case there is none
         $this->provider('default');

tests/TestCase/Validation/ValidatorTest.php

@@ -46,6 +46,31 @@ public function testAddingRulesToField()
         $this->assertCount(2, $validator);
     }
 
+    /**
+     * Testing you can add nested field rules
+     *
+     * @return void
+     */
+    public function testAddingNestedRulesToField()
+    {
+        $validator = new Validator;
+        $validator->add('user.username', 'not-blank', ['rule' => 'notBlank']);
+        $this->assertCount(0, $validator->field('user'));
+
+        $set = $validator->field('user.username');
+        $this->assertInstanceOf('Cake\Validation\ValidationSet', $set);
+        $this->assertCount(1, $set);
+
+        $validator->add('user.username', 'letters', ['rule' => 'alphanumeric']);
+        $this->assertCount(2, $set);
+
+        $validator->remove('user.username', 'letters');
+        $this->assertCount(1, $set);
+
+        $validator->requirePresence('user.twitter');
+        $this->assertTrue($validator->field('user.twitter')->isPresenceRequired());
+    }
+
     /**
      * Tests that calling field will create a default validation set for it
      *
@@ -163,6 +188,33 @@ public function testErrorsWithPresenceRequired()
         $this->assertEmpty($validator->errors(['foo' => 'bar']));
     }
 
+    /**
+     * Test that errors() can work with nested data.
+     *
+     * @return void
+     */
+    public function testErrorsWithNestedFields()
+    {
+        $validator = new Validator;
+        $validator->add('user.username', 'letter', ['rule' => 'alphanumeric']);
+        $validator->add('comments.0.comment', 'letter', ['rule' => 'alphanumeric']);
+
+        $data = [
+            'user' => [
+                'username' => 'is wrong'
+            ],
+            'comments' => [
+                ['comment' => 'is wrong']
+            ]
+        ];
+        $errors = $validator->errors($data);
+        $expected = [
+            'user.username' => ['letter' => 'The provided value is invalid'],
+            'comments.0.comment' => ['letter' => 'The provided value is invalid']
+        ];
+        $this->assertEquals($expected, $errors);
+    }
+
     /**
      * Tests custom error messages generated when a field presence is required
      *