Hello, I have a "compile" task that contains the following code:

source = fileTree("$projectDir").matching {
    include("$javaSourceDirName/**/*.java")
    excludedJavaFiles.forEach { exclude(it) }
}

This results in many errors such as:

Cannot infer source root(s) for source `file 'C:\...\Blabla.java'`. Supported types are `File` (directories only), `DirectoryTree` and `SourceDirectorySet`.

This seems to disable incremental compilation. How can I fix this code snippet?

I doubt you can. The error says you must set directories but you try to set files. But you might be at an XY-problem. Take a step back. What is your use-case, what do you try to achieve?

I have a directory (

$projectDir

) which contains Java source files (in nested directories). I also have a list of excluded Java files. I want to set the source of this "compile" task to the Java source files minus the excluded Java files.

That's the Y problem, what is the X problem?

Well my goal is to compile a bunch of Java files whilst excluding some specific files.

But why? You are still at the Y, tell us the X please.