fix compilation error and make field private

Author: kwin

plugin-maven/src/main/java/com/diffplug/spotless/maven/AbstractSpotlessMojo.java

@@ -90,7 +90,7 @@ public abstract class AbstractSpotlessMojo extends AbstractMojo {
 	private ResourceManager resourceManager;
 
 	@Component
-	protected BuildContext buildContext;
+	private BuildContext buildContext;
 
 	@Parameter(defaultValue = "${mojoExecution.goal}", required = true, readonly = true)
 	private String goal;

plugin-maven/src/main/java/com/diffplug/spotless/maven/incremental/UpToDateChecker.java

@@ -49,7 +49,7 @@ public void setUpToDate(Path file) {
 
 			@Override
 			public boolean isUpToDate(Path file) {
-				if (buildContext.hasDelta(file)) {
+				if (buildContext.hasDelta(file.toFile())) {
 					return delegate.isUpToDate(file);
 				}
 				return true;