SPR-6059 Avoiding NPE for unary-not and ternary operators. If the value is null instead of a valid boolean or Boolean, it will now trigger an EvaluationException.

org.springframework.expression/src/main/java/org/springframework/expression/spel/ast/OperatorNot.java

@@ -16,6 +16,7 @@
 
 package org.springframework.expression.spel.ast;
 
+import org.springframework.core.convert.TypeDescriptor;
 import org.springframework.expression.EvaluationException;
 import org.springframework.expression.spel.ExpressionState;
 import org.springframework.expression.spel.SpelEvaluationException;
@@ -36,7 +37,7 @@ public class OperatorNot extends SpelNodeImpl { // Not is a unary operator so do
 	@Override
 	public BooleanTypedValue getValueInternal(ExpressionState state) throws EvaluationException {
 		try {
-			boolean value = (Boolean)state.convertValue(children[0].getValueInternal(state), BOOLEAN_TYPE_DESCRIPTOR);
+			boolean value = (Boolean) state.convertValue(children[0].getValueInternal(state), TypeDescriptor.valueOf(boolean.class));
 			return BooleanTypedValue.forValue(!value);
 		}
 		catch (SpelEvaluationException see) {

org.springframework.expression/src/main/java/org/springframework/expression/spel/ast/Ternary.java

@@ -19,6 +19,8 @@ package org.springframework.expression.spel.ast;
 import org.springframework.expression.EvaluationException;
 import org.springframework.expression.TypedValue;
 import org.springframework.expression.spel.ExpressionState;
+import org.springframework.expression.spel.SpelEvaluationException;
+import org.springframework.expression.spel.SpelMessage;
 
 /**
  * Represents a ternary expression, for example: "someCheck()?true:false".
@@ -43,6 +45,10 @@ public class Ternary extends SpelNodeImpl {
 	@Override
 	public TypedValue getValueInternal(ExpressionState state) throws EvaluationException {
 		Boolean value = children[0].getValue(state, Boolean.class);
+		if (value == null) {
+			throw new SpelEvaluationException(getChild(0).getStartPosition(),
+					SpelMessage.TYPE_CONVERSION_ERROR, "null", "boolean");
+		}
 		if (value.booleanValue()) {
 			return children[1].getValueInternal(state);
 		} else {

org.springframework.expression/src/test/java/org/springframework/expression/spel/EvaluationTests.java

@@ -36,6 +36,8 @@ import org.springframework.expression.spel.support.StandardTypeLocator;
  * Tests the evaluation of real expressions in a real context.
  * 
  * @author Andy Clement
+ * @author Mark Fisher
+ * @since 3.0
  */
 public class EvaluationTests extends ExpressionTestCase {
 
@@ -296,6 +298,16 @@ public class EvaluationTests extends ExpressionTestCase {
 		evaluate("!true", "false", Boolean.class);
 	}
 
+	@Test
+	public void testUnaryNot02() {
+		evaluate("!false", "true", Boolean.class);
+	}
+
+	@Test(expected = EvaluationException.class)
+	public void testUnaryNotWithNullValue() {
+		parser.parseExpression("!null").getValue();
+	}
+
 	// assignment
 	@Test
 	public void testAssignmentToVariables01() {
@@ -307,7 +319,6 @@ public class EvaluationTests extends ExpressionTestCase {
 		evaluate("2>4?1:2",2,Integer.class);
 	}
 
-	
 	@Test
 	public void testTernaryOperator02() {
 		evaluate("'abc'=='abc'?1:2",1,Integer.class);
@@ -332,6 +343,11 @@ public class EvaluationTests extends ExpressionTestCase {
 		evaluate("2>4?(3>2?true:false):(5<3?true:false)",false,Boolean.class);
 	}
 
+	@Test(expected = EvaluationException.class)
+	public void testTernaryOperatorWithNullValue() {
+		parser.parseExpression("null ? 0 : 1").getValue();
+	}
+
 	@Test
 	public void testIndexer03() {
 		evaluate("'christian'[8]", "n", String.class);