Null check as switch case

[Jenson3210]

What's changed?

Cutting up the task at hand in multiple smaller PR's for better insights, risk assessment...

• NullCheckAsSwitchCase

What's your motivation?

• Pattern Matching for switch in Java 21 / JEP 411 #306

Anything in particular you'd like reviewers to focus on?

Anyone you would like to review specifically?

Have you considered any alternatives or workarounds?

Any additional context

Checklist

• I've added unit tests to cover both positive and negative cases
• I've read and applied the recipe conventions and best practices
• I've used the IntelliJ IDEA auto-formatter on affected files

[Jenson3210]

@timtebeek would you want any further review? Or can I go ahead and do the necessary to merge (adapt the declarative yaml, do the nullcheck only in 1 PR...)

[timtebeek]

Great work here so far; explored a bit and added more tests and a couple fixes as seen in the diff cfd7189...dcadb16

In the last commit I show we're not consistent with how we handle throws depending on if it's in a block; would we want to make that consistent by allowing J.Throw in the if seen here?

rewrite-migrate-java/src/main/java/org/openrewrite/java/migrate/lang/NullCheck.java

Lines 66 to 73 in 3a9a928

	public boolean couldModifyNullCheckedValue() {
	Statement statement = whenNull();
	if (statement instanceof J.Block || statement instanceof Expression) {
	return couldModifyNullCheckedValue(statement, nullCheckedParameter);
	}
	// Cautious by default
	return true;
	}

[Jenson3210]

Added the Throws to the if statement.

IntelliJ says only Block, expression or throws is possible so we should be good to go now!

[timtebeek]

Nice work!