[maven-4.0.x] ImmutableCollections.ROProperties loses Properties defaults chain

[elharo]

ImmutableCollections.ROProperties loses Properties defaults chain

Found in: maven-4.0.x branch
File: api/maven-api-xml/src/main/java/org/apache/maven/api/xml/ImmutableCollections.java (lines ~168-176)
Severity: Medium

Description

ROProperties constructor calls super() (equivalent to Properties()) instead of preserving the parent defaults chain:

private ROProperties(Properties props) {
    super();      // calls Properties() which sets defaults=null
    if (props != null) {
        for (Map.Entry<Object, Object> e : props.entrySet()) {
            super.put(e.getKey(), e.getValue());
        }
    }
}

java.util.Properties has a defaults field that stores fallback properties. By calling super() instead of super(props != null ? props.defaults : null), the defaults chain is discarded. If props was created as new Properties(defaultsProps) where defaultsProps had key "foo"="bar", after wrapping in ROProperties, getProperty("foo") would return null instead of "bar".