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Revise null-safe index operator support in SpEL 

See gh-29847
This commit is contained in:
Sam Brannen 2024-02-21 17:28:50 +01:00
parent 9f4d46fe33
commit 4d433174eb
3 changed files with 98 additions and 31 deletions
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40
spring-expression/src/main/java/org/springframework/expression/spel/ast/Indexer.java
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@ -68,6 +68,8 @@ public class Indexer extends SpelNodeImpl {
private enum IndexedType {ARRAY, LIST, MAP, STRING, OBJECT}
private final boolean nullSafe;
@Nullable
private IndexedType indexedType;
@ -103,11 +105,24 @@ public class Indexer extends SpelNodeImpl {
private PropertyAccessor cachedWriteAccessor;
private final boolean nullSafe;
/**
* Create an {@code Indexer} with the given start position, end position, and
* index expression.
* @see #Indexer(boolean, int, int, SpelNodeImpl)
* @deprecated as of Spring Framework 6.2, in favor of {@link #Indexer(boolean, int, int, SpelNodeImpl)}
*/
@Deprecated(since = "6.2", forRemoval = true)
public Indexer(int startPos, int endPos, SpelNodeImpl indexExpression) {
this(false, startPos, endPos, indexExpression);
}
public Indexer(boolean nullSafe, int startPos, int endPos, SpelNodeImpl expr) {
super(startPos, endPos, expr);
/**
* Create an {@code Indexer} with the given null-safe flag, start position,
* end position, and index expression.
* @since 6.2
*/
public Indexer(boolean nullSafe, int startPos, int endPos, SpelNodeImpl indexExpression) {
super(startPos, endPos, indexExpression);
this.nullSafe = nullSafe;
}
@ -136,6 +151,15 @@ public class Indexer extends SpelNodeImpl {
protected ValueRef getValueRef(ExpressionState state) throws EvaluationException {
TypedValue context = state.getActiveContextObject();
Object target = context.getValue();
if (target == null) {
if (this.nullSafe) {
return ValueRef.NullValueRef.INSTANCE;
}
// Raise a proper exception in case of a null target
throw new SpelEvaluationException(getStartPosition(), SpelMessage.CANNOT_INDEX_INTO_NULL_VALUE);
}
TypeDescriptor targetDescriptor = context.getTypeDescriptor();
TypedValue indexValue;
Object index;
@ -159,14 +183,6 @@ public class Indexer extends SpelNodeImpl {
}
}
// Raise a proper exception in case of a null target
if (target == null) {
if (this.nullSafe) {
return ValueRef.NullValueRef.INSTANCE;
}
throw new SpelEvaluationException(getStartPosition(), SpelMessage.CANNOT_INDEX_INTO_NULL_VALUE);
}
// At this point, we need a TypeDescriptor for a non-null target object
Assert.state(targetDescriptor != null, "No type descriptor");

3
spring-expression/src/main/java/org/springframework/expression/spel/standard/InternalSpelExpressionParser.java
View File

@ -538,8 +538,7 @@ class InternalSpelExpressionParser extends TemplateAwareExpressionParser {
else if (maybeEatBeanReference()) {
return pop();
}
else if (maybeEatProjection(false) || maybeEatSelection(false) ||
maybeEatIndexer(false)) {
else if (maybeEatProjection(false) || maybeEatSelection(false) || maybeEatIndexer(false)) {
return pop();
}
else if (maybeEatInlineListOrMap()) {

86
spring-expression/src/test/java/org/springframework/expression/spel/IndexingTests.java
View File

@ -26,7 +26,9 @@ import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.junit.jupiter.api.Nested;
import org.junit.jupiter.api.Test;
import org.springframework.expression.EvaluationContext;
@ -35,6 +37,7 @@ import org.springframework.expression.PropertyAccessor;
import org.springframework.expression.TypedValue;
import org.springframework.expression.spel.standard.SpelExpressionParser;
import org.springframework.expression.spel.support.StandardEvaluationContext;
import org.springframework.expression.spel.testresources.Person;
import static org.assertj.core.api.Assertions.assertThat;
import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
@ -376,18 +379,74 @@ class IndexingTests {
assertThat(expression.getValue(this, String.class)).isEqualTo("apple");
}
@Test
void nullSafeIndex() {
ContextWithNullCollections testContext = new ContextWithNullCollections();
StandardEvaluationContext context = new StandardEvaluationContext(testContext);
Expression expr = new SpelExpressionParser().parseRaw("nullList?.[4]");
assertThat(expr.getValue(context)).isNull();
@Nested
class NullSafeIndexTests { // gh-29847
expr = new SpelExpressionParser().parseRaw("nullArray?.[4]");
assertThat(expr.getValue(context)).isNull();
private final RootContextWithIndexedProperties rootContext = new RootContextWithIndexedProperties();
private final StandardEvaluationContext context = new StandardEvaluationContext(rootContext);
private final SpelExpressionParser parser = new SpelExpressionParser();
private Expression expression;
@Test
void nullSafeIndexIntoArray() {
expression = parser.parseExpression("array?.[0]");
assertThat(expression.getValue(context)).isNull();
rootContext.array = new int[] {42};
assertThat(expression.getValue(context)).isEqualTo(42);
}
@Test
void nullSafeIndexIntoList() {
expression = parser.parseExpression("list?.[0]");
assertThat(expression.getValue(context)).isNull();
rootContext.list = List.of(42);
assertThat(expression.getValue(context)).isEqualTo(42);
}
@Test
void nullSafeIndexIntoSet() {
expression = parser.parseExpression("set?.[0]");
assertThat(expression.getValue(context)).isNull();
rootContext.set = Set.of(42);
assertThat(expression.getValue(context)).isEqualTo(42);
}
@Test
void nullSafeIndexIntoString() {
expression = parser.parseExpression("string?.[0]");
assertThat(expression.getValue(context)).isNull();
rootContext.string = "XYZ";
assertThat(expression.getValue(context)).isEqualTo("X");
}
@Test
void nullSafeIndexIntoMap() {
expression = parser.parseExpression("map?.['enigma']");
assertThat(expression.getValue(context)).isNull();
rootContext.map = Map.of("enigma", 42);
assertThat(expression.getValue(context)).isEqualTo(42);
}
@Test
void nullSafeIndexIntoObject() {
expression = parser.parseExpression("person?.['name']");
assertThat(expression.getValue(context)).isNull();
rootContext.person = new Person("Jane");
assertThat(expression.getValue(context)).isEqualTo("Jane");
}
static class RootContextWithIndexedProperties {
public int[] array;
public List<Integer> list;
public Set<Integer> set;
public String string;
public Map<String, Integer> map;
public Person person;
}
expr = new SpelExpressionParser().parseRaw("nullMap:?.[4]");
assertThat(expr.getValue(context)).isNull();
}
@ -450,11 +509,4 @@ class IndexingTests {
}
static class ContextWithNullCollections {
public List nullList = null;
public String[] nullArray = null;
public Map nullMap = null;
}
}