Fix defaultUrlParams for 4.x.

src/Controller/Component/CommonComponent.php

@@ -156,11 +156,10 @@ class CommonComponent extends Component {
 	 * @return array URL params
 	 */
 	public static function defaultUrlParams() {
-		$defaults = ['plugin' => false];
-		$prefixes = (array)Configure::read('Routing.prefixes');
-		if ($prefixes) {
-			$defaults['prefix'] = false;
-		}
+		$defaults = [
+			'plugin' => false,
+			'prefix' => false,
+		];
 
 		return $defaults;
 	}

tests/TestCase/Controller/Component/CommonComponentTest.php

@@ -217,14 +217,6 @@ class CommonComponentTest extends TestCase {
 	 * @return void
 	 */
 	public function testDefaultUrlParams() {
-		Configure::write('Routing.prefixes', ['Admin', 'Tests']);
-		$result = CommonComponent::defaultUrlParams();
-		$expected = [
-			'plugin' => false,
-			'prefix' => false,
-		];
-		$this->assertEquals($expected, $result);
-		Configure::write('Routing.prefixes', 'Admin');
 		$result = CommonComponent::defaultUrlParams();
 		$expected = [
 			'plugin' => false,