SimpleFileLanguage always null due to DummyExchange

I'm trying to use the File component to move all *.txt files from the 'source' to the 'target' directory.

        public void configure() throws Exception {
            from("file://source?fileName=%24%7Bfile%3Aonlyname.noext%7D.txt")
                .to("log://org.apache.camel.howto?showAll=true")
                .to("file://target");
        }

I'm configuring the fileName as ${file:onlyname.noext}.txt.

https://github.com/apache/camel/blob/camel-2.25.x/camel-core/src/main/java/org/apache/camel/language/simple/SimpleLanguage.java#L85

However, not any file names match ever because the ${file:onlyname.noext} is always null because it's trying to obtain the file name from the exchange which is completely empty.

It seems to me that you should not create a DummyExchange:
https://github.com/apache/camel/blob/camel-2.25.x/camel-core/src/main/java/org/apache/camel/component/file/GenericFileConsumer.java#L701

Please find a demo project attached.