When using io.helidon.config.Config and doing get of a non existent property, Exception message is missing the key

[cyrilgeorge-oracle]

Environment Details

• Helidon Version: 4.1.3
• Helidon MP
• JDK version: 23
• OS: Windows

---

Problem Description

@HelidonTest
class MyTest {
    @Inject
    Config config;

    @Test
    void printConfig(WebTarget t) {
        System.out.println(config.get("not.a.valid.property").asString().get());
    }
}

Above test throws below exception
io.helidon.config.MissingValueException: Requested value for configuration key '' is not present in the configuration.
where key is empty

The behaviour is mainly due to the asString() method invocation io.helidon.config.mp.SeConfig#as(java.lang.Class<T>) which in turn calls ConfigValues.empty() where key is set to empty string

Expected behavior

Test should throw exception io.helidon.config.MissingValueException: Requested value for configuration key 'not.a.valid.property' is not present in the configuration.