Merge pull request #5563 from MrPetovan/bug/5470-fix-various-notices

Fix various notices

src/Core/Session.php

@@ -45,9 +45,24 @@ class Session
 		return isset($_SESSION[$name]);
 	}
 
-	public static function get($name)
+	/**
+	 * Retrieves a key from the session super global or the defaults if the key is missing or the value is falsy.
+	 * 
+	 * Handle the case where session_start() hasn't been called and the super global isn't available.
+	 *
+	 * @param string $name
+	 * @param mixed $defaults
+	 * @return mixed
+	 */
+	public static function get($name, $defaults = null)
 	{
-		return defaults($_SESSION, $name, null);
+		if (isset($_SESSION)) {
+			$return = defaults($_SESSION, $name, $defaults);
+		} else {
+			$return = $defaults;
+		}
+
+		return $return;
 	}
 
 	public static function set($name, $value)