fix create error for empty EnumSet and EnumMap for issue #2423

alibaba · Apr 12, 2024 · 5612e15 · 5612e15
1 parent deedf37
commit 5612e15
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Showing 3 changed files with 56 additions and 2 deletions.
diff --git a/core/src/main/java/com/alibaba/fastjson2/reader/ObjectReaderImplList.java b/core/src/main/java/com/alibaba/fastjson2/reader/ObjectReaderImplList.java
@@ -95,7 +95,15 @@ public static ObjectReader of(Type type, Class listClass, long features) {
             instanceClass = HashSet.class;
         } else if (listClass == EnumSet.class) {
             instanceClass = HashSet.class;
-            builder = (o) -> EnumSet.copyOf((Collection) o);
+            Type finalItemType = itemType;
+            builder = (o) -> {
+                Collection collection = (Collection) o;
+                if (collection.isEmpty() && finalItemType instanceof Class) {
+                    return EnumSet.noneOf((Class) finalItemType);
+                } else {
+                    return EnumSet.copyOf(collection);
+                }
+            };
         } else if (listClass == NavigableSet.class || listClass == SortedSet.class) {
             instanceClass = TreeSet.class;
         } else if (listClass == CLASS_SINGLETON) {
@@ -473,7 +481,14 @@ public Object readJSONBObject(JSONReader jsonReader, Type fieldType, Object fiel
         } else if (listType != null && EnumSet.class.isAssignableFrom(listType)) {
             // maybe listType is java.util.RegularEnumSet or java.util.JumboEnumSet
             list = new HashSet();
-            builder = (o) -> EnumSet.copyOf((Collection) o);
+            builder = (o) -> {
+                Collection collection = (Collection) o;
+                if (collection.isEmpty() && itemType instanceof Class) {
+                    return EnumSet.noneOf((Class) itemType);
+                } else {
+                    return EnumSet.copyOf(collection);
+                }
+            };
         } else if (listType != null && listType != this.listType) {
             try {
                 list = (Collection) listType.newInstance();

diff --git a/core/src/main/java/com/alibaba/fastjson2/reader/ObjectReaderImplMapTyped.java b/core/src/main/java/com/alibaba/fastjson2/reader/ObjectReaderImplMapTyped.java
@@ -304,6 +304,8 @@ public Object readObject(JSONReader jsonReader, Type fieldType, Object fieldName
             } else {
                 object = new HashMap<>();
             }
+        } else if (instanceType == EnumMap.class && keyType instanceof Class) {
+            object = new EnumMap((Class) keyType);
         } else {
             object = (Map) createInstance(contextFeatures);
         }

diff --git a/core/src/test/java/com/alibaba/fastjson2/issues_2400/Issue2423.java b/core/src/test/java/com/alibaba/fastjson2/issues_2400/Issue2423.java
@@ -0,0 +1,37 @@
+package com.alibaba.fastjson2.issues_2400;
+
+import com.alibaba.fastjson.JSON;
+import lombok.Data;
+import org.junit.jupiter.api.Test;
+
+import java.util.EnumMap;
+import java.util.EnumSet;
+import java.util.concurrent.TimeUnit;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+public class Issue2423 {
+    @Test
+    void test() {
+        Bean bean = new Bean();
+
+        String jsonStr = com.alibaba.fastjson.JSON.toJSONString(bean);
+        Bean object = JSON.parseObject(jsonStr, Bean.class);
+        assertTrue(object.getSet().isEmpty());
+        assertTrue(object.getMap().isEmpty());
+        assertEquals(bean, object);
+
+        jsonStr = com.alibaba.fastjson2.JSON.toJSONString(bean);
+        object = com.alibaba.fastjson2.JSON.parseObject(jsonStr, Bean.class);
+        assertTrue(object.getSet().isEmpty());
+        assertTrue(object.getMap().isEmpty());
+        assertEquals(bean, object);
+    }
+
+    @Data
+    static class Bean {
+        private EnumSet<TimeUnit> set = EnumSet.noneOf(TimeUnit.class);
+        private EnumMap<TimeUnit, Integer> map = new EnumMap<>(TimeUnit.class);
+    }
+}