JvmLocalCache should force state evaluation of any LazyForwardingEquality to give it a chance to null-out its initializing lambda.

Addresses #1194 (comment)

Author: nedtwigg

lib/src/main/java/com/diffplug/spotless/LazyForwardingEquality.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016 DiffPlug
+ * Copyright 2016-2022 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -111,4 +111,9 @@ static byte[] toBytes(Serializable obj) {
 		}
 		return byteOutput.toByteArray();
 	}
+
+	/** Ensures that the lazy state has been evaluated. */
+	public static void unlazy(LazyForwardingEquality<?> in) {
+		in.state();
+	}
 }

plugin-gradle/src/main/java/com/diffplug/gradle/spotless/JvmLocalCache.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2021 DiffPlug
+ * Copyright 2021-2022 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -26,6 +26,7 @@
 import org.gradle.api.Task;
 
 import com.diffplug.spotless.FileSignature;
+import com.diffplug.spotless.LazyForwardingEquality;
 
 class JvmLocalCache {
 	private static GradleException cacheIsStale() {
@@ -53,6 +54,11 @@ static class LiveCacheKeyImpl<T> implements LiveCache<T>, Serializable {
 
 		@Override
 		public void set(T value) {
+			if (value instanceof LazyForwardingEquality) {
+				// whenever we cache an instance of LazyForwardingEquality, we want to make sure that we give it
+				// a chance to null-out its initialization lambda (see https://github.com/diffplug/spotless/issues/1194#issuecomment-1120744842)
+				LazyForwardingEquality.unlazy((LazyForwardingEquality<?>) value);
+			}
 			daemonState.put(internalKey, value);
 		}