fix. delete_cookite can't delete alreday set Cookie

Author: nyufeng

system/HTTP/Response.php

@@ -986,6 +986,7 @@ public function deleteCookie(string $name = '', string $domain = '', string $pat
 
 		$name = $prefix . $name;
 
+		$cookieHasFlag = false;
 		foreach ($this->cookies as &$cookie)
 		{
 			if ($cookie['name'] === $name)
@@ -1000,11 +1001,16 @@ public function deleteCookie(string $name = '', string $domain = '', string $pat
 				}
 				$cookie['value']   = '';
 				$cookie['expires'] = '';
-
+				$cookieHasFlag     = true;
 				break;
 			}
 		}
 
+		if (! $cookieHasFlag)
+		{
+			$this->setCookie($name, '', '', $domain, $path, $prefix);
+		}
+
 		return $this;
 	}
 

tests/system/Helpers/CookieHelperTest.php

@@ -104,4 +104,13 @@ public function testGetCookie()
 		$this->assertEquals(5, get_cookie('TEST'));
 	}
 
+	public function testDeleteCookieAfterLastSet()
+	{
+		delete_cookie($this->name);
+
+		$cookie = $this->response->getCookie($this->name);
+		// The cookie is set to be cleared when the request is sent....
+		$this->assertEquals('', $cookie['value']);
+	}
+
 }