bug fix for jsonpath set, for issue #3125

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

@@ -378,7 +378,7 @@ public void set(JSONPath.Context context, Object value) {
                 ObjectReader objectReader = provider.getObjectReader(item.getClass());
                 FieldReader fieldReader = objectReader.getFieldReader(nameHashCode);
                 if (fieldReader != null) {
-                    fieldReader.accept(item, null);
+                    fieldReader.accept(item, value);
                 }
             }
             return;

core/src/test/java/com/alibaba/fastjson2/issues_3100/Issue3125.java

@@ -0,0 +1,50 @@
+package com.alibaba.fastjson2.issues_3100;
+
+import com.alibaba.fastjson2.JSON;
+import com.alibaba.fastjson2.JSONPath;
+import lombok.Getter;
+import lombok.Setter;
+import lombok.ToString;
+import org.junit.jupiter.api.Test;
+
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class Issue3125 {
+    @Getter
+    @Setter
+    static class User {
+        private String name;
+        private List<NVString> additionalInfo;
+    }
+
+    @Getter
+    @Setter
+    @ToString
+    static class NVString {
+        String name;
+        String value;
+    }
+
+    public static final String str = "{\"name\":\"fastjson2\",\"additionalInfo\":[{\"name\":\"srv6-color\",\"value\":\"test\"},{\"name\":\"test2\",\"value\":\"3\"}]}";
+
+    public static String path = "$.additionalInfo[?(@.name=='srv6-color')].value";
+
+    @Test
+    public void test_fastjson2_case1() {
+        User user = JSON.parseObject(str, User.class);
+        JSONPath jsonPath = JSONPath.of("$.additionalInfo[?(@.name=='srv6-color')].value");
+        jsonPath.set(user, "modify");
+        assertEquals(user.getAdditionalInfo().get(0).getValue(), "modify");
+    }
+
+    @Test
+    public void test_fastjson_case1() {
+        User user = JSON.parseObject(str, User.class);
+        com.alibaba.fastjson.JSONPath.set(user, "$.additionalInfo[?(@.name=='srv6-color')].value", "modify");
+        JSONPath jsonPath = JSONPath.of("$.additionalInfo[?(@.name=='srv6-color')].value");
+        jsonPath.set(user, "modify");
+        assertEquals(user.getAdditionalInfo().get(0).getValue(), "modify");
+    }
+}