Merge branch '6.1.x'

spring-expression/src/main/java/org/springframework/expression/spel/ast/CompoundExpression.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -24,7 +24,6 @@
 import org.springframework.expression.spel.CodeFlow;
 import org.springframework.expression.spel.ExpressionState;
 import org.springframework.expression.spel.SpelEvaluationException;
-import org.springframework.expression.spel.SpelNode;
 
 /**
  * Represents a DOT separated expression sequence, such as
@@ -120,14 +119,13 @@ public String toStringAST() {
 		for (int i = 0; i < getChildCount(); i++) {
 			sb.append(getChild(i).toStringAST());
 			if (i < getChildCount() - 1) {
-				SpelNode nextChild = getChild(i + 1);
+				SpelNodeImpl nextChild = this.children[i + 1];
+				if (nextChild.isNullSafe()) {
+					sb.append("?.");
+				}
 				// Don't append a '.' if the next child is an Indexer.
 				// For example, we want 'myVar[0]' instead of 'myVar.[0]'.
-				if (!(nextChild instanceof Indexer)) {
-					if ((nextChild instanceof MethodReference methodRef && methodRef.isNullSafe()) ||
-						(nextChild instanceof PropertyOrFieldReference pofRef && pofRef.isNullSafe())) {
-						sb.append('?');
-					}
+				else if (!(nextChild instanceof Indexer)) {
 					sb.append('.');
 				}
 			}

spring-expression/src/main/java/org/springframework/expression/spel/ast/MethodReference.java

@@ -77,6 +77,7 @@ public MethodReference(boolean nullSafe, String methodName, int startPos, int en
 	 * Does this node represent a null-safe method reference?
 	 * @since 6.0.13
 	 */
+	@Override
 	public final boolean isNullSafe() {
 		return this.nullSafe;
 	}

spring-expression/src/main/java/org/springframework/expression/spel/ast/PropertyOrFieldReference.java

@@ -76,6 +76,7 @@ public PropertyOrFieldReference(boolean nullSafe, String propertyOrFieldName, in
 	/**
 	 * Does this node represent a null-safe property or field reference?
 	 */
+	@Override
 	public boolean isNullSafe() {
 		return this.nullSafe;
 	}
@@ -181,7 +182,7 @@ private TypedValue readProperty(TypedValue contextObject, EvaluationContext eval
 			throws EvaluationException {
 
 		Object targetObject = contextObject.getValue();
-		if (targetObject == null && this.nullSafe) {
+		if (targetObject == null && isNullSafe()) {
 			return TypedValue.NULL;
 		}
 
@@ -233,7 +234,7 @@ private void writeProperty(
 			TypedValue contextObject, EvaluationContext evalContext, String name, @Nullable Object newValue)
 			throws EvaluationException {
 
-		if (contextObject.getValue() == null && this.nullSafe) {
+		if (contextObject.getValue() == null && isNullSafe()) {
 			return;
 		}
 		if (contextObject.getValue() == null) {
@@ -353,7 +354,7 @@ public void generateCode(MethodVisitor mv, CodeFlow cf) {
 		}
 
 		Label skipIfNull = null;
-		if (this.nullSafe) {
+		if (isNullSafe()) {
 			mv.visitInsn(DUP);
 			skipIfNull = new Label();
 			Label continueLabel = new Label();
@@ -381,7 +382,7 @@ void setExitTypeDescriptor(String descriptor) {
 		// If this property or field access would return a primitive - and yet
 		// it is also marked null safe - then the exit type descriptor must be
 		// promoted to the box type to allow a null value to be passed on
-		if (this.nullSafe && CodeFlow.isPrimitive(descriptor)) {
+		if (isNullSafe() && CodeFlow.isPrimitive(descriptor)) {
 			this.originalPrimitiveExitTypeDescriptor = descriptor;
 			this.exitTypeDescriptor = CodeFlow.toBoxedDescriptor(descriptor);
 		}

spring-expression/src/main/java/org/springframework/expression/spel/ast/SpelNodeImpl.java

@@ -181,6 +181,16 @@ public int getEndPosition() {
 		return this.endPos;
 	}
 
+	/**
+	 * Determine if this node is the target of a null-safe navigation operation.
+	 * <p>The default implementation returns {@code false}.
+	 * @return {@code true} if this node is the target of a null-safe operation
+	 * @since 6.1.6
+	 */
+	public boolean isNullSafe() {
+		return false;
+	}
+
 	/**
 	 * Check whether a node can be compiled to bytecode. The reasoning in each node may
 	 * be different but will typically involve checking whether the exit type descriptor