Correct input generation for postgres numeric types.

Numeric types in postgres are treated like decimals, except they can
have no length, precision or scale components defined.

IE does not accept 1.00000 as a valid step attribute so we'll default to
any when we encounter decimal types with no length.

Refs #7497

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

@@ -353,6 +353,7 @@ class ValidateUser extends CakeTestModel {
 		'email' => array('type' => 'string', 'null' => '', 'default' => '', 'length' => '255'),
 		'balance' => array('type' => 'float', 'null' => false, 'length' => '5,2'),
 		'cost_decimal' => array('type' => 'decimal', 'null' => false, 'length' => '6,3'),
+		'null_decimal' => array('type' => 'decimal', 'null' => false, 'length' => null),
 		'ratio' => array('type' => 'decimal', 'null' => false, 'length' => '10,6'),
 		'population' => array('type' => 'decimal', 'null' => false, 'length' => '15,0'),
 		'created' => array('type' => 'date', 'null' => '1', 'default' => '', 'length' => ''),
@@ -2045,6 +2046,17 @@ public function testInput() {
 		);
 		$this->assertTags($result, $expected);
 
+		$result = $this->Form->input('ValidateUser.null_decimal');
+		$expected = array(
+			'div' => array('class'),
+			'label' => array('for'),
+			'Null Decimal',
+			'/label',
+			'input' => array('name', 'type' => 'number', 'step' => 'any', 'id'),
+			'/div',
+		);
+		$this->assertTags($result, $expected);
+
 		$result = $this->Form->input('ValidateUser.ratio');
 		$expected = array(
 			'div' => array('class'),

lib/Cake/View/Helper/FormHelper.php

@@ -1209,10 +1209,10 @@ protected function _magicOptions($options) {
 			if ($options['type'] === 'number' &&
 				!isset($options['step'])
 			) {
-				if ($type === 'decimal') {
+				if ($type === 'decimal' && isset($fieldDef['length'])) {
 					$decimalPlaces = substr($fieldDef['length'], strpos($fieldDef['length'], ',') + 1);
 					$options['step'] = sprintf('%.' . $decimalPlaces . 'F', pow(10, -1 * $decimalPlaces));
-				} elseif ($type === 'float') {
+				} elseif ($type === 'float' || $type === 'decimal') {
 					$options['step'] = 'any';
 				}
 			}