HHH-17253 - Fix for StackOverflowError in static metamodel generator

Signed-off-by: Jan Schatteman <jschatte@redhat.com>
hibernate · Dec 19, 2023 · f8bfb85 · f8bfb85
1 parent fc43836
commit f8bfb85
Showing 1 changed file with 18 additions and 9 deletions.
diff --git a/tooling/metamodel-generator/src/main/java/org/hibernate/jpamodelgen/util/TypeUtils.java b/tooling/metamodel-generator/src/main/java/org/hibernate/jpamodelgen/util/TypeUtils.java
@@ -7,6 +7,7 @@
 package org.hibernate.jpamodelgen.util;
 
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -121,7 +122,7 @@ protected TypeMirror defaultAction(TypeMirror e, Void aVoid) {
 	}
 
 	public static String extractClosestRealTypeAsString(TypeMirror type, Context context) {
-		final TypeMirror mirror = extractClosestRealType( type, context );
+		final TypeMirror mirror = extractClosestRealType( type, context, new HashSet<>() );
 		return mirror == null ? "?" : mirror.toString();
 	}
 
@@ -133,22 +134,30 @@ public static String extractClosestRealTypeAsString(TypeMirror type, Context con
 		return bound == null || (bound.getKind() == TypeKind.DECLARED && bound.toString().equals("java.lang.Object")) ? null : bound;
 	}
 
-	public static @Nullable TypeMirror extractClosestRealType(TypeMirror type, Context context) {
+	public static @Nullable TypeMirror extractClosestRealType(TypeMirror type, Context context, Set<TypeVariable> beingVisited) {
 		if ( type == null ) {
 			return null;
 		}
 		switch ( type.getKind() ) {
 			case TYPEVAR:
 				final TypeVariable typeVariable = (TypeVariable) type;
-				return context.getTypeUtils().getWildcardType(
-						upperBound( extractClosestRealType( typeVariable.getUpperBound(), context ) ),
-						lowerBound( extractClosestRealType( typeVariable.getLowerBound(), context ) )
-				);
+				if ( !beingVisited.add( typeVariable ) ) {
+					// A self-referential type variable has to be represented as plain wildcard `?`
+					return context.getTypeUtils().getWildcardType( null, null );
+				}
+				else {
+					final WildcardType wildcardType = context.getTypeUtils().getWildcardType(
+							upperBound( extractClosestRealType( typeVariable.getUpperBound(), context, beingVisited ) ),
+							lowerBound( extractClosestRealType( typeVariable.getLowerBound(), context, beingVisited ) )
+					);
+					beingVisited.remove( typeVariable );
+					return wildcardType;
+				}
 			case WILDCARD:
 				final WildcardType wildcardType = (WildcardType) type;
 				return context.getTypeUtils().getWildcardType(
-						extractClosestRealType( wildcardType.getExtendsBound(), context ),
-						extractClosestRealType( wildcardType.getSuperBound(), context )
+						extractClosestRealType( wildcardType.getExtendsBound(), context, beingVisited ),
+						extractClosestRealType( wildcardType.getSuperBound(), context, beingVisited )
 				);
 			case DECLARED:
 				final DeclaredType declaredType = (DeclaredType) type;
@@ -159,7 +168,7 @@ public static String extractClosestRealTypeAsString(TypeMirror type, Context con
 								.map( new Function<TypeMirror, TypeMirror>() {
 											@Override
 											public @Nullable TypeMirror apply(TypeMirror arg) {
-												return extractClosestRealType( arg, context );
+												return extractClosestRealType( arg, context, beingVisited );
 											}
 										} )
 								.toArray( TypeMirror[]::new )