JPQL: attribute inside CASE WHEN fails in queries without an identification variable

[renatsaf]

EclipseLink 5.0.1 (5.0.1.v202606291238) and master, H2 2.3.230, JDK 21.

An attribute referenced without an identification variable inside a CASE WHEN condition fails in a query that does not declare an identification variable (implicit this, as generated for Jakarta Data queries):

@Entity
public class Todo {
    @Id
    private Long id;
    private String title;
}

Query	Result
SELECT this FROM Todo WHERE CASE WHEN id = 1 THEN 'x' ELSE 'y' END = 'x'	JPQLException: 'id' cannot be resolved to a type
DELETE FROM Todo WHERE CASE WHEN id = 1 THEN 'x' ELSE 'y' END = 'x'	JPQLException: 'id' cannot be resolved to a type
UPDATE Todo SET title = CASE WHEN id = 1 THEN 'x' ELSE 'y' END	NullPointerException

The same queries work with this.id, or with an identification variable (FROM Todo t ... CASE WHEN t.id = 1). id outside CASE (WHERE id = 1) works as well.

UPDATE stack trace:

java.lang.NullPointerException: Cannot invoke "org.eclipse.persistence.descriptors.ClassDescriptor.getJavaClass()" because "descriptor" is null
    at org.eclipse.persistence.internal.jpa.jpql.ExpressionBuilderVisitor.visit(ExpressionBuilderVisitor.java:1081)
    at org.eclipse.persistence.jpa.jpql.parser.EntityTypeLiteral.accept(EntityTypeLiteral.java:42)
    at org.eclipse.persistence.internal.jpa.jpql.ExpressionBuilderVisitor$ComparisonExpressionVisitor.visit(ExpressionBuilderVisitor.java:2339)
    at org.eclipse.persistence.jpa.jpql.parser.AnonymousExpressionVisitor.visit(AnonymousExpressionVisitor.java:173)
    at org.eclipse.persistence.jpa.jpql.parser.EntityTypeLiteral.accept(EntityTypeLiteral.java:42)
    at org.eclipse.persistence.internal.jpa.jpql.ExpressionBuilderVisitor.visit(ExpressionBuilderVisitor.java:737)
    at org.eclipse.persistence.jpa.jpql.parser.ComparisonExpression.accept(ComparisonExpression.java:71)
    at org.eclipse.persistence.internal.jpa.jpql.ExpressionBuilderVisitor$WhenClauseExpressionVisitor.visit(ExpressionBuilderVisitor.java:2852)
    at org.eclipse.persistence.jpa.jpql.parser.WhenClause.accept(WhenClause.java:84)
    at org.eclipse.persistence.internal.jpa.jpql.ExpressionBuilderVisitor.visit(ExpressionBuilderVisitor.java:580)
    at org.eclipse.persistence.jpa.jpql.parser.CaseExpression.accept(CaseExpression.java:105)
    at org.eclipse.persistence.internal.jpa.jpql.ExpressionBuilderVisitor.buildExpression(ExpressionBuilderVisitor.java:285)

Inside the WHEN condition the bare id is parsed as an EntityTypeLiteral (an entity type name) rather than as an attribute, so it is not qualified with the implicit this: validation of the SELECT and DELETE queries reports it as an unknown type, and the UPDATE query passes validation and fails in ExpressionBuilderVisitor.visit(EntityTypeLiteral), where no descriptor exists for id.