If Jflex input is defined as the output of another task, Jflex generation fails

[stalb]

Problem description

If Jflex input is defined as the output of another task, this will not be taken into account by Jflex tasks.

An example can be found in stalb/JFlex_Example2:

plugins {
    id "org.xbib.gradle.plugin.jflex" version "1.7.0"
}

repositories {
    mavenCentral()
}

def copyJflex = tasks.register("copyJflex", Copy) {
    from 'src/main/custom/'
    into "${project.buildDir}/generated/sources/custom/jflex/"
}

sourceSets {
    main {
        jflex {
            srcDir copyJflex
        }
    }
}

The main Jflex SourceDirectorySet should contains copyJflex output, however this is not the case.

In fact the generateJflex task doesn't consider copyJflex as a dependency, so running generateJflex won't trigger copyJflex task and will produce nothing.

Expected behavior

• The generateJflex task should depend on the copyJflex task.
• Running the generateJflex task should trigger the copyJflex task and its output processed by Jflex.