Logging is too chatty at WARN level

[nikita2206]

Describe the bug
We're currently getting a WARN-level log line when one of the Maven modules doesn't have a tests directory.

The code responsible for this:

fmt-maven-plugin/src/main/java/com/spotify/fmt/AbstractFMT.java

Lines 104 to 108 in 1cf19c0

	if (testSourceDirectory.exists() && !skipTestSourceDirectory) {
	directoriesToFormat.add(testSourceDirectory);
	} else {
	handleMissingDirectory("Test source", testSourceDirectory);
	}

fmt-maven-plugin/src/main/java/com/spotify/fmt/AbstractFMT.java

Lines 184 to 198 in 1cf19c0

	private void handleMissingDirectory(String directoryDisplayName, File directory)
	throws MojoFailureException {
	if (failOnUnknownFolder) {
	String message =
	directoryDisplayName
	+ " directory '"
	+ directory
	+ "' does not exist, failing build (failOnUnknownFolder is true).";
	getLog().error(message);
	throw new MojoFailureException(message);
	} else {
	getLog()
	.warn(directoryDisplayName + " directory '" + directory + "' does not exist, ignoring.");
	}
	}

It looks like it will WARN you of a missing directory even if you explicitly excluded that directory from being checked (even if it does in fact exist).

To me it feels like this is the kind of information that deserves to be logged but at a INFO level, otherwise it leads to 'warning fatigue' because most of the time this isn't something that people will act on and it's also not possible to disable.

[rschuerer-realnetworks]

And even worse: When using skipTestSourceDirectory=true, the plugin shows the same warning about a missing directory.

If skipTestSourceDirectory or skipSourceDirectory are set explicitly, then no message should be shown at all about a missing directory.