bug fix for JSONPath.set if parent is null

core/src/main/java/com/alibaba/fastjson2/JSONPath.java

@@ -3156,6 +3156,34 @@ public void set(Object root, Object value) {
  }
 
  segment.eval(context);
+ if (context.value == null && nextSegment != null) {
+ if (value == null) {
+ return;
+ }
+
+ Object parentObject;
+ if (i == 0) {
+ parentObject = root;
+ } else {
+ parentObject = context.parent.value;
+ }
+
+ Object emptyValue;
+ if (nextSegment instanceof IndexSegment) {
+ emptyValue = new JSONArray();
+ } else if (nextSegment instanceof NameSegment) {
+ emptyValue = new JSONObject();
+ } else {
+ return;
+ }
+ context.value = emptyValue;
+
+ if (parentObject instanceof Map && segment instanceof NameSegment) {
+ ((Map) parentObject).put(((NameSegment) segment).name, emptyValue);
+ } else if (parentObject instanceof List && segment instanceof IndexSegment) {
+ ((List) parentObject).set(((IndexSegment) segment).index, emptyValue);
+ }
+ }
  }
  context = new Context(this, context, segments.get(0), null, 0L);
  context.root = root;

core/src/test/java/com/alibaba/fastjson2/issues/Issue424.java

@@ -0,0 +1,16 @@
+package com.alibaba.fastjson2.issues;
+
+import com.alibaba.fastjson2.JSONObject;
+import com.alibaba.fastjson2.JSONPath;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class Issue424 {
+ @Test
+ public void test() {
+ JSONObject jsonObject = new JSONObject();
+ JSONPath.set(jsonObject, "a[0].b", 1);
+ assertEquals("{\"a\":[{\"b\":1}]}", jsonObject.toString());
+ }
+}