[GROOVY-11488] STC: NPE for not-instanceof examination

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.0.22, 4.0.23
• Fix Version/s: 3.0.23, 4.0.24
• Labels: NullPointerException

Language

groovy

• Assignee: Eric Milles
• Reporter: Eric Milles
• Created: 01/Oct/24 15:50
• Updated: 4 days ago 11:41
• Resolved: 01/Oct/24 20:23

Description

Consider the following:

@groovy.transform.TypeChecked test(what) {
  if (false) {
    return "false"
  } else if (what !instanceof Object[]) {
    return "!array"
  }
}

NOTE: The actual code is more complex, but this was enough to trigger the exception.

The visitClosingBlock method of StaticTypeCheckingVisitor is throwing a NullPointerException due to the !instanceof expression. This is not a problem for Groovy 5 as it has implemented more complete handling of instanceof and !instanceof.

java.lang.NullPointerException: Cannot invoke "java.util.Map.forEach(java.util.function.BiConsumer)" because "this.typeCheckingContext.ifElseForWhileAssignmentTracker" is null
	at org.codehaus.groovy.transform.stc.StaticTypeCheckingVisitor.popAssignmentTracking(StaticTypeCheckingVisitor.java:4394)
	at org.codehaus.groovy.transform.stc.StaticTypeCheckingVisitor.visitClosingBlock(StaticTypeCheckingVisitor.java:4268)
	at org.codehaus.groovy.transform.stc.StaticTypeCheckingVisitor.visitBlockStatement(StaticTypeCheckingVisitor.java:4258)
	at org.codehaus.groovy.ast.stmt.BlockStatement.visit(BlockStatement.java:69)
	at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitClassCodeContainer(ClassCodeVisitorSupport.java:165)
	at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitConstructorOrMethod(ClassCodeVisitorSupport.java:138)
	at org.codehaus.groovy.transform.stc.StaticTypeCheckingVisitor.visitConstructorOrMethod(StaticTypeCheckingVisitor.java:2388)
	at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitMethod(ClassCodeVisitorSupport.java:133)
	at org.codehaus.groovy.transform.stc.StaticTypeCheckingVisitor.startMethodInference(StaticTypeCheckingVisitor.java:2887)
	at org.codehaus.groovy.transform.stc.StaticTypeCheckingVisitor.visitMethod(StaticTypeCheckingVisitor.java:2855)
	at org.codehaus.groovy.transform.StaticTypesTransformation.visit(StaticTypesTransformation.java:70)
	at org.codehaus.groovy.transform.ASTTransformationVisitor.visitClass(ASTTransformationVisitor.java:189)
	at org.codehaus.groovy.transform.ASTTransformationVisitor.lambda$2(ASTTransformationVisitor.java:284)
	at org.codehaus.groovy.control.CompilationUnit$IPrimaryClassNodeOperation.doPhaseOperation(CompilationUnit.java:1040)
	... 24 more