Remove the `spotlessDiagnose` task from the gradle plugin

[nedtwigg]

Some formatters have idempotency bugs. Spotless has a padded cell feature which can fix them.

A long time ago, this feature was off by default. A user would get an error related to idempotency, they could run spotlessDiagnose to understand it, and then they might turn on the padded cell feature.

In 3.29.0 released May 2020 we made padded cell mandatory, so idempotency problems are always silently fixed.

The maven plugin has never had a "diagnose" task. Probably no one would notice if we removed it from the Gradle plugin also.

Here is the code:

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

Lines 34 to 77 in 88c83de

	@UntrackedTask(because = "undeclared inputs/outputs")
	public class SpotlessDiagnoseTask extends DefaultTask {
	SpotlessTask source;
	@Internal
	public SpotlessTask getSource() {
	return source;
	}
	@TaskAction
	@SuppressFBWarnings("NP_NULL_ON_SOME_PATH_FROM_RETURN_VALUE")
	public void performAction() throws IOException {
	Path srcRoot = getProject().getProjectDir().toPath();
	Path diagnoseRoot = getProject().getLayout().getBuildDirectory().getAsFile().get()
	.toPath().resolve("spotless-diagnose-" + source.formatName());
	getProject().delete(diagnoseRoot.toFile());
	try (Formatter formatter = source.buildFormatter()) {
	for (File file : source.target) {
	getLogger().debug("Running padded cell check on " + file);
	PaddedCell padded = PaddedCell.check(formatter, file);
	if (!padded.misbehaved()) {
	getLogger().debug(" well-behaved.");
	} else {
	// the file is misbehaved, so we'll write all its steps to DIAGNOSE_DIR
	Path relative = srcRoot.relativize(file.toPath());
	Path diagnoseFile = diagnoseRoot.resolve(relative);
	for (int i = 0; i < padded.steps().size(); i++) {
	Path path = Path.of(diagnoseFile + "." + padded.type().name().toLowerCase(Locale.ROOT) + i);
	Files.createDirectories(path.getParent());
	String version = padded.steps().get(i);
	Files.write(path, version.getBytes(formatter.getEncoding()));
	}
	// dump the type of the misbehavior to console
	getLogger().lifecycle(" " + relative + " " + padded.userMessage());
	}
	}
	}
	if (Files.exists(diagnoseRoot)) {
	getLogger().lifecycle("Some formatters are misbehaving, you can see details at " + diagnoseRoot);
	} else {
	getLogger().lifecycle("All formatters are well behaved for all files.");
	}
	}
	}

And here is info on some tech debt that it has accumulated. Probably better to just delete it than fix it. Anybody object?

• Use Task Providers for task initialization #2719 (comment)

[jbduncan]

Probably better to just delete it than fix it. Anybody object?

Fine by me, but admittedly I've never used the feature before nor am I a power user nowadays, so I'll let others chime in. :)