From cd80d501f9eb12d9aca3e65f742041b142ee659f Mon Sep 17 00:00:00 2001
From: Damian Mooyman <damian@silverstripe.com>
Date: Tue, 2 Aug 2016 18:07:31 +1200
Subject: [PATCH] BUG Fix unset config options returning isset() = true Fixes
 #4791

---
 core/Config.php           | 11 +++++++++++
 tests/core/ConfigTest.php | 19 ++++++++++++++++---
 2 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/core/Config.php b/core/Config.php
index 31662b645..a3198714d 100644
--- a/core/Config.php
+++ b/core/Config.php
@@ -881,6 +881,7 @@ class Config_ForClass {
 
 	/**
 	 * @param string $name
+	 * @return mixed
 	 */
 	public function __get($name) {
 		return Config::inst()->get($this->class, $name);
@@ -894,6 +895,16 @@ class Config_ForClass {
 		return Config::inst()->update($this->class, $name, $val);
 	}
 
+	/**
+	 * @param string $name
+	 * @return bool
+	 */
+	public function __isset($name)
+	{
+		$val = $this->__get($name);
+		return isset($val);
+	}
+
 	/**
 	 * @param string $name
 	 * @param int $sourceOptions
diff --git a/tests/core/ConfigTest.php b/tests/core/ConfigTest.php
index bbfe3b1a3..cd3ad70ff 100644
--- a/tests/core/ConfigTest.php
+++ b/tests/core/ConfigTest.php
@@ -82,15 +82,15 @@ class ConfigTest_TestNest extends Object implements TestOnly {
 }
 
 class ConfigTest extends SapphireTest {
-	
+
 	protected $depSettings = null;
-	
+
 	public function setUp() {
 		parent::setUp();
 		$this->depSettings = Deprecation::dump_settings();
 		Deprecation::set_enabled(false);
 	}
-	
+
 	public function tearDown() {
 		Deprecation::restore_settings($this->depSettings);
 		parent::tearDown();
@@ -262,6 +262,19 @@ class ConfigTest extends SapphireTest {
 		$this->assertEquals(Object::static_lookup('ConfigTest_DefinesFooDoesntExtendObject', 'bar'), null);
 	}
 
+	public function testForClass() {
+		$config = ConfigTest_DefinesFoo::config();
+		// Set values
+		$this->assertTrue(isset($config->foo), 'foo is set');
+		$this->assertFalse(empty($config->foo), 'foo is not empty');
+		$this->assertEquals(1, $config->foo, 'foo is 1');
+		
+		// Unset values
+		$this->assertFalse(isset($config->bar), 'bar is not set');
+		$this->assertTrue(empty($config->bar), 'bar is empty');
+		$this->assertEquals(null, $config->bar, 'bar is accessible but empty');
+	}
+
 	public function testFragmentOrder() {
 		$this->markTestIncomplete();
 	}