Joda Recipe NullpointerException when visting Java Records

[christopherfischer]

What version of OpenRewrite are you using?

I am using

• Java 21
• Maven CLI 3.9.6
• rewrite-migrate-java-2.31.0

How are you running OpenRewrite?

I am using the Maven CLI , and my project is a multi module project.
mvn -U org.openrewrite.maven:rewrite-maven-plugin:run -Drewrite.recipeArtifactCoordinates=org.openrewrite.recipe:rewrite-migrate-java:RELEASE -Drewrite.activeRecipes=org.openrewrite.java.migrate.joda.JodaTimeRecipe -Drewrite.exportDatatables=true

What is the full stack trace of any errors you encountered?

java.lang.NullPointerException: Cannot read field "variables" because "x0" is null
[ERROR]   org.openrewrite.java.migrate.joda.ScopeAwareVisitor$VariablesInScope.access$000(ScopeAwareVisitor.java:86)
[ERROR]   org.openrewrite.java.migrate.joda.ScopeAwareVisitor.preVisit(ScopeAwareVisitor.java:46)
[ERROR]   org.openrewrite.java.migrate.joda.ScopeAwareVisitor.preVisit(ScopeAwareVisitor.java:31)
[ERROR]   org.openrewrite.TreeVisitor.visit(TreeVisitor.java:247)
[ERROR]   org.openrewrite.TreeVisitor.visitAndCast(TreeVisitor.java:320)
[ERROR]   org.openrewrite.java.JavaVisitor.visitRightPadded(JavaVisitor.java:1367)
[ERROR]   org.openrewrite.java.JavaVisitor.lambda$visitVariableDeclarations$27(JavaVisitor.java:961)
[ERROR]   org.openrewrite.internal.ListUtils.map(ListUtils.java:243)
[ERROR]   org.openrewrite.internal.ListUtils.map(ListUtils.java:265)
[ERROR]   org.openrewrite.java.JavaVisitor.visitVariableDeclarations(JavaVisitor.java:961)
[ERROR]   org.openrewrite.java.tree.J$VariableDeclarations.acceptJava(J.java:5812)
[ERROR]   org.openrewrite.java.tree.J.accept(J.java:59)
[ERROR]   org.openrewrite.TreeVisitor.visit(TreeVisitor.java:250)
[ERROR]   org.openrewrite.TreeVisitor.visitAndCast(TreeVisitor.java:320)
[ERROR]   org.openrewrite.java.JavaVisitor.visitRightPadded(JavaVisitor.java:1367)
[ERROR]   org.openrewrite.java.JavaVisitor.lambda$visitContainer$35(JavaVisitor.java:1417)

Are you interested in contributing a fix to OpenRewrite?

[timtebeek]

Thanks for the report! This one is a bit puzzling, given that it's reporting an error on line 86 here:

rewrite-migrate-java/src/main/java/org/openrewrite/java/migrate/joda/ScopeAwareVisitor.java

Lines 85 to 94 in 2f005af

	@Value
	public static class VariablesInScope {
	Cursor scope;
	Set<J.VariableDeclarations.NamedVariable> variables;
	public VariablesInScope(Cursor scope) {
	this.scope = scope;
	this.variables = new HashSet<>();
	}
	}

Any clue @amishra-u ?

[christopherfischer]

It looks like scopes.peek() is null

rewrite-migrate-java/src/main/java/org/openrewrite/java/migrate/joda/ScopeAwareVisitor.java

Line 46 in 2f005af

scopes.peek().variables.add(variable);

[amishra-u]

We need to update the preVisit method in ScopeAwareVisitor to handle Record. As with Records, classes can have variable as parameter (not sure the right term)

    public J preVisit(J j, ExecutionContext ctx) {
        if (j instanceof J.Class) {
            scopes.push(new VariablesInScope(getCursor()));
        }
        if (j instanceof J.Block) {
            scopes.push(new VariablesInScope(getCursor()));
        }
        if (j instanceof J.MethodDeclaration) {
            scopes.push(new VariablesInScope(getCursor()));
        }
        if (j instanceof J.VariableDeclarations.NamedVariable) {
            assert !scopes.isEmpty();
            NamedVariable variable = (NamedVariable) j;
            scopes.peek().variables.add(variable);
        }
        return super.preVisit(j, ctx);
    }