Fix boolean values in select widgets.

Boolean `false` should be treated like `0` when comparing option values.

Refs #8468

lib/Cake/Test/Case/View/Helper/FormHelperTest.php

@@ -4844,6 +4844,50 @@ public function testSelect() {
 		$this->assertTags($result, $expected);
 	}
 
+/**
+ * testSelect boolean method
+ *
+ * @return void
+ */
+	public function testSelectBoolean() {
+		$result = $this->Form->select(
+			'Model.field',
+			array(0 => 'No', 1 => 'Yes'),
+			array('value' => false, 'empty' => false)
+		);
+		$expected = array(
+			'select' => array('name' => 'data[Model][field]', 'id' => 'ModelField'),
+			array('option' => array('value' => '0', 'selected' => 'selected')),
+			'No',
+			'/option',
+			array('option' => array('value' => '1')),
+			'Yes',
+			'/option',
+			'/select'
+		);
+		$this->assertTags($result, $expected);
+
+		$result = $this->Form->select(
+			'Model.field',
+			array(0 => 'No', 1 => 'Yes', 2 => 'Yes again'),
+			array('value' => [false, 2], 'empty' => false)
+		);
+		$expected = array(
+			'select' => array('name' => 'data[Model][field]', 'id' => 'ModelField'),
+			array('option' => array('value' => '0', 'selected' => 'selected')),
+			'No',
+			'/option',
+			array('option' => array('value' => '1')),
+			'Yes',
+			'/option',
+			array('option' => array('value' => '2', 'selected' => 'selected')),
+			'Yes again',
+			'/option',
+			'/select'
+		);
+		$this->assertTags($result, $expected);
+	}
+
 /**
  * test that select() with optiongroups listens to the escape param.
  *

lib/Cake/View/Helper/FormHelper.php

@@ -2781,6 +2781,11 @@ protected function _selectOptions($elements = array(), $parents = array(), $show
 		$selectedIsEmpty = ($attributes['value'] === '' || $attributes['value'] === null);
 		$selectedIsArray = is_array($attributes['value']);
 
+		// Cast boolean false into an integer so string comparisons can work.
+		if ($attributes['value'] === false) {
+			$attributes['value'] = 0;
+		}
+
 		$this->_domIdSuffixes = array();
 		foreach ($elements as $name => $title) {
 			$htmlOptions = array();