Allow skipping targets based on text they contain

[oldergod]

Follow-up of #1738

Add an field to FormatExtension (Gradle) to accept lists of text which if detected will get a Formatter to skip a file as a whole and will not apply anything.
I didn't touch the maven plugin.

[oldergod]

I didn't add it as a step because every steps would then be repeating the same logic. I thought it best to filter files before thinking of computing them or not.

[nedtwigg]

The approach you took is a bit faster, but it has some downsides

• more code (we already have a mechanism for skipping based on content, now we have two mechanisms)
• functionality spread (formatter was as simple as possible to operate the FormatterStep, now it has one more mechanism that it needs to have)

This is a useful feature to have, but I think it is better to implement it using FormatterStep.filterByContentPattern. Making the fast part of a program a little faster doesn't matter very much.

[oldergod]

Thank you for the feedback. I removed most of the code and left the API in the Gradle extension + the tests.
I don't see how to use FilterByContentPatternFormatterStep so I took it out. This one is opting-in based on a pattern, and I would wanna do the reverse. I don't know how to do that from the existing class.
If this was sorted out, I would probably then, when setting the task, wrap all steps with a filtering one.
Let me know if you have better ideas on how to reuse FilterByContentPatternFormatterStep

[nedtwigg]

I would

• add a field boolean formatIfMatches to

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

  Lines 25 to 29 in d245b60

  	final class FilterByContentPatternFormatterStep extends DelegateFormatterStep {
  	final Pattern contentPattern;
  	FilterByContentPatternFormatterStep(FormatterStep delegateStep, String contentPattern) {
  	super(delegateStep);

• then change this to if (matcher.find() == formatIfMatches)

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

  Lines 25 to 29 in d245b60

  	final class FilterByContentPatternFormatterStep extends DelegateFormatterStep {
  	final Pattern contentPattern;
  	FilterByContentPatternFormatterStep(FormatterStep delegateStep, String contentPattern) {
  	super(delegateStep);

• Now you can add a boolean to this method

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

  Lines 56 to 58 in d245b60

  	public default FormatterStep filterByContentPattern(String contentPattern) {
  	return new FilterByContentPatternFormatterStep(this, contentPattern);
  	}

Now, in FormatExtension, save the excludeContent, and apply it to each step at the end with steps.replaceAll

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

Lines 883 to 892 in d245b60

	List<FormatterStep> steps;
	if (togglePair != null) {
	steps = new ArrayList<>(this.steps.size() + 2);
	steps.add(togglePair.in());
	steps.addAll(this.steps);
	steps.add(togglePair.out());
	} else {
	steps = this.steps;
	}
	task.setSteps(steps);

[oldergod]

Updated the code @nedtwigg with passing tests.

[oldergod]

The logic might be executed twice across computeLineEndings and compute but they're both public so to guarantee skipIfContentContains are respected, I added it to both.

[nedtwigg]

Formatter should not change, use FormatterStep.filterByContentPattern.

[oldergod]

I can update this one directly if you don't mind having an API change.

[nedtwigg]

Because I'm not able to push to this PR, I opened a new PR (#1755) where I added a few more commits. Thanks for a great PR, it will be merged shortly.

[oldergod]

Thank you

[nedtwigg]

Released in plugin-gradle 6.20.0.