toggleOffOn breaks the configuration cache hack

[breskeby]

We validate the cache ability of our elasticsearch build once on a regular basis. Testing updating spotless gradle plugin to 7.0.0BETA3(and 4) the cachabiltiy of one of the spotlessJava tasks within our build-tool-internal subproject is not cacheable due to stepsInternalEquality is reported to be different. I don't understand what causes this to be honest. it must be something special with the subproject. the only configuration there is using onOffToggle that we do not do in other places.

spotless {
  java {
    toggleOffOn()
  }
}

Find attached a screenshot of our develocity check:

[nedtwigg]

That spotless block wouldn't do anything, there must be some other configuration blocks hiding somewhere else...

[breskeby]

It must be the spotless block. I had added a workaround by excluding the file in question instead of using a toggle and that fixes the problem:

spotless {
  java {

    // workaround for https://github.com/diffplug/spotless/issues/2317
    //toggleOffOn()
    target project.fileTree("src/main/java") {
      include '**/*.java'
      exclude '**/DockerBase.java'
    }
  }
}

[nedtwigg]

Ah, here is the problem, thanks for reporting it so clearly. FenceStep is the code that implements toggleOffOn. It stores a list of the steps that must be "toggled-on"

spotless/lib/src/main/java/com/diffplug/spotless/generic/FenceStep.java

Lines 140 to 145 in 3638f8f

	@SuppressFBWarnings("SE_TRANSIENT_FIELD_NOT_RESTORED")
	private static abstract class BaseStep implements Serializable, FormatterStep {
	final String name;
	private static final long serialVersionUID = -2301848328356559915L;
	final Pattern regex;
	final List<FormatterStep> steps;

It implements full roundtripping, but it does not implement the crazy equality hack that we did in

• Fix remote build cache #2298

This is fixable, but pretty tricky to fix. It will probably still be broken in 7.0.0 when it comes out of beta.