fix JSONPath#extract, for issue #2585

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

@@ -477,9 +477,7 @@ public void accept(JSONReader jsonReader, JSONPath.Context context) {
         for (int i = 0; jsonReader.ch != EOI; ++i) {
             if (jsonReader.ch == ']') {
                 jsonReader.next();
-                if (i == 0) {
-                    context.eval = true;
-                }
+                context.eval = true;
                 break;
             }
 

core/src/test/java/com/alibaba/fastjson2/issues_2500/Issue2585.java

@@ -0,0 +1,53 @@
+package com.alibaba.fastjson2.issues_2500;
+
+import com.alibaba.fastjson2.JSONPath;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class Issue2585 {
+    @Test
+    public void testMutant1() {
+        String str1 = "{\"data\": [1]}";
+        String str2 = "{\n" +
+                "  \"code\": \"1003\", \n" +
+                "  \"data\": [1], \n" +
+                "  \"message\": \"code: 1003,以【你好】开头的句子的长度不符合要求, 长度限制：3~500，实际长度：2\"\n" +
+                "}\n";
+        Object obj1 = JSONPath.eval(
+                str1, "$.data[0][0]");
+        Object obj2 = JSONPath.eval(
+                str2, "$.data[0][0]");
+        assertEquals(obj1, obj2);
+    }
+
+    @Test
+    public void testMutant2() {
+        String str1 = "{\"data\": [1,2]}";
+        String str2 = "{\n" +
+                "  \"code\": \"1003\", \n" +
+                "  \"data\": [1,2], \n" +
+                "  \"message\": \"code: 1003,以【你好】开头的句子的长度不符合要求, 长度限制：3~500，实际长度：2\"\n" +
+                "}\n";
+        System.out.println(str1);
+        System.out.println(str2);
+        assertEquals(
+                JSONPath.eval(str1, "$.data[0][0]"),
+                JSONPath.eval(str2, "$.data[0][0]"));
+    }
+
+    @Test
+    public void testMutant3() {
+        String str1 = "{\"data\": [{\"id\":\"1\"}]}";
+        String str2 = "{\n" +
+                "  \"code\": \"1003\", \n" +
+                "  \"data\": [{\"id\":\"1\"}], \n" +
+                "  \"message\": \"code: 1003,以【你好】开头的句子的长度不符合要求, 长度限制：3~500，实际长度：2\"\n" +
+                "}\n";
+        System.out.println(str1);
+        System.out.println(str2);
+        assertEquals(
+                JSONPath.eval(str1, "$.data[0][0]"),
+                JSONPath.eval(str2, "$.data[0][0]"));
+    }
+}