Config.Builder ignores explicit ordering of systemProperties() and environmentVariables()

[pfmackin]

Helidon Version: 1.2.1

Helidon MP

JDK version: 1.8.0_211

OS: MacOS 10.13.6

Problem Description:
Config.Builder ignores explicit ordering of systemProperties() and environmentVariables().
When systemProperties() is before environmentVariables(), the env vars still take precedence.

Note: The Helidon Javadoc documents that the ordering of sources establishes precedence. See Config.Buider at https://helidon.io/docs/latest/apidocs/index.html?overview-summary.html

Steps to reproduce:

1. Create a a project using MP archetype to test this.

2. Change app.greeting to appGreeting in GreetingProvider.java and META-INF/microprofile-config.properties.

3. Change Main.java as follows:

   static Server startServer() {

    return Server.builder()
        .config(Config.builder()
            .sources(
                systemProperties(),
                environmentVariables(),
                classpath("META-INF/microprofile-config.properties"))
            .build())
        .build()
        .start();
   

4. Build and run the application as follows:
   export appGreeting=HelloFromEnvironment
   mvn package -DskipTests=true
   java -DappGreeting="HelloFromJavaProperty" -jar target/helidon-quickstart-mp.jar

5. Test the app

curl http://localhost:8080/greet
{"message":"HelloFromEnvironment World!"}