fix unsupported operation error when field is Collections.EMPTY_LIST,…

… for issue #2691 and issue #1835
alibaba · Jun 23, 2024 · 8f8acb4 · 8f8acb4
1 parent 5b1e892
commit 8f8acb4
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diff --git a/core/src/main/java/com/alibaba/fastjson2/reader/ObjectReaderCreatorASM.java b/core/src/main/java/com/alibaba/fastjson2/reader/ObjectReaderCreatorASM.java
@@ -3743,7 +3743,15 @@ private int genReadFieldValueList(
                 mw.visitInsn(Opcodes.DUP);
                 mw.visitTypeInsn(Opcodes.CHECKCAST, TYPE_FIELD_CLASS);
                 mw.visitVarInsn(Opcodes.ASTORE, LIST);
-                mw.visitJumpInsn(IFNONNULL, listInitEnd_);
+                Label listNull_ =  new Label();
+                mw.visitJumpInsn(Opcodes.IFNULL, listNull_);
+
+                mw.visitVarInsn(Opcodes.ALOAD, LIST);
+                mw.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/Object", "getClass", "()Ljava/lang/Class;", false);
+                mw.visitFieldInsn(Opcodes.GETSTATIC, "java/util/Collections", "EMPTY_LIST", "Ljava/util/List;");
+                mw.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/Object", "getClass", "()Ljava/lang/Class;", false);
+                mw.visitJumpInsn(Opcodes.IF_ACMPNE, listInitEnd_);
+                mw.visitLabel(listNull_);
             }
 
             mw.visitTypeInsn(Opcodes.NEW, LIST_TYPE);

diff --git a/core/src/test/java/com/alibaba/fastjson2/issues_2600/Issue2691.java b/core/src/test/java/com/alibaba/fastjson2/issues_2600/Issue2691.java
@@ -0,0 +1,107 @@
+package com.alibaba.fastjson2.issues_2600;
+
+import com.alibaba.fastjson2.JSONB;
+import com.alibaba.fastjson2.JSONReader;
+import com.alibaba.fastjson2.JSONWriter;
+import lombok.EqualsAndHashCode;
+import lombok.Getter;
+import lombok.Setter;
+import lombok.experimental.Accessors;
+import org.junit.jupiter.api.Test;
+
+import java.util.*;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+
+public class Issue2691 {
+    @Test
+    void testUnmodifiableList() {
+        UnmodifiableList list = new UnmodifiableList();
+        ArrayList<String> strings = new ArrayList<>();
+        strings.add("1");
+        list.setList(strings);
+        writeReade(list);
+    }
+
+    @Test
+    void testUnmodifiableMap() {
+        UnmodifiableMap map = new UnmodifiableMap();
+        Map<String, String> stringMap = new HashMap<>();
+        stringMap.put("1", "1");
+        map.setMap(stringMap);
+        writeReade(map);
+    }
+
+    @Test
+    void testUnmodifiableSet() {
+        UnmodifiableSet set = new UnmodifiableSet();
+        Set<String> stringSet = new HashSet<>();
+        stringSet.add("1");
+        set.setSet(stringSet);
+        writeReade(set);
+    }
+
+    void writeReade(Object value) {
+        byte[] bytes = JSONB.toBytes(
+                value,
+                JSONWriter.Feature.WriteClassName,
+                JSONWriter.Feature.FieldBased,
+                JSONWriter.Feature.NotWriteHashMapArrayListClassName
+        );
+
+        Object result = JSONB.parseObject(
+                bytes,
+                value.getClass(),
+                JSONReader.Feature.FieldBased);
+        assertNotNull(result);
+        assertEquals(result, value);
+    }
+
+    @Test
+    public void test() {
+        Page<String> page = new Page<>();
+        List<String> data = new ArrayList<>();
+        data.add(null);
+        data.add("abc");
+        data.add(null);
+        page.setData(data);
+        byte[] bytes = JSONB.toBytes(page);
+        Page<String> page1 = JSONB.parseObject(bytes, Page.class);
+        assertNotNull(page1);
+        assertEquals(3, page1.data.size());
+        assertEquals("abc", page1.data.get(1));
+    }
+
+    @Getter
+    @Setter
+    @EqualsAndHashCode
+    @Accessors(chain = true)
+    private static class UnmodifiableList {
+        private List<String> list = Collections.emptyList();
+    }
+
+    @Getter
+    @Setter
+    @EqualsAndHashCode
+    @Accessors(chain = true)
+    private static class UnmodifiableSet {
+        private Set<String> set = Collections.emptySet();
+    }
+
+    @Getter
+    @Setter
+    @EqualsAndHashCode
+    @Accessors(chain = true)
+    private static class UnmodifiableMap {
+        private Map<String, String> map = Collections.emptyMap();
+    }
+
+    public static class Page<T> {
+        public List<T> data = Collections.emptyList();
+
+        public void setData(List<T> items) {
+            this.data = items;
+        }
+    }
+}