[GitHub] [rocketmq] Wushiyii opened a new pull request, #4447: [ISSUE #4349] fix negative index when index reach Integer.MAX_VALUE

[GitBox <gi...@apache.org>]

Wushiyii opened a new pull request, #4447:
URL: https://github.com/apache/rocketmq/pull/4447

   ## What is the purpose of the change
   See https://github.com/apache/rocketmq/issues/4349
   
   In ThreadLocalIndex.java, when the random index increase to Integer.MAX_VALUE(2147483647), the next increment value is Integer.MIN_VALUE(-2147483648). And the code `Math.abs(index)` will also return the same negatice value Integer.MIN_VALUE(-2147483648)
   
   ```java
       /**
        * Returns the absolute value of an {@code int} value.
        * If the argument is not negative, the argument is returned.
        * If the argument is negative, the negation of the argument is returned.
        *
        * <p>Note that if the argument is equal to the value of
        * {@link Integer#MIN_VALUE}, the most negative representable
        * {@code int} value, the result is that same value, which is
        * negative.
        *
        * @param   a   the argument whose absolute value is to be determined
        * @return  the absolute value of the argument.
        */
       public static int abs(int a) {
           return (a < 0) ? -a : a;
       }
   ```
   
   ## Brief changelog
   [ISSUE #4349] Fix negative ThreadLocalIndex
   


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[GitHub] [rocketmq] duhenglucky merged pull request #4447: [ISSUE #4349] fix negative index when index reach Integer.MAX_VALUE

[GitBox <gi...@apache.org>]

duhenglucky merged PR #4447:
URL: https://github.com/apache/rocketmq/pull/4447


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[GitHub] [rocketmq] nxllxn commented on a diff in pull request #4447: [ISSUE #4349] fix negative index when index reach Integer.MAX_VALUE

[GitBox <gi...@apache.org>]

nxllxn commented on code in PR #4447:
URL: https://github.com/apache/rocketmq/pull/4447#discussion_r1004658293


##########
client/src/main/java/org/apache/rocketmq/client/common/ThreadLocalIndex.java:
##########
@@ -31,7 +32,7 @@ public int incrementAndGet() {
         }
 
         this.threadLocalIndex.set(++index);
-        return Math.abs(index);
+        return Math.abs(index & POSITIVE_MASK);

Review Comment:
   Awesome bit operation, but it seems that the Math.abs isn't needed anymore. correct me if I am wrong!



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