[GitHub] [flink] wangyang0918 commented on a change in pull request #12357: [FLINK-17958][core] Fix MathUtils#divideRoundUp bug for handling zero or negative values.

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

wangyang0918 commented on a change in pull request #12357:
URL: https://github.com/apache/flink/pull/12357#discussion_r431025047



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File path: flink-core/src/main/java/org/apache/flink/util/MathUtils.java
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@@ -209,12 +209,18 @@ public static long flipSignBit(long in) {
 
 	/**
 	 * Divide and rounding up to integer.
-	 * E.g., divideRoundUp(3, 2) returns 2.
+	 * E.g., divideRoundUp(3, 2) returns 2, divideRoundUp(0, 3) returns 0.
+	 * Note that this method does not support negative values.
 	 * @param dividend value to be divided by the divisor
 	 * @param divisor value by which the dividend is to be divided
 	 * @return the quotient rounding up to integer
 	 */
 	public static int divideRoundUp(int dividend, int divisor) {
+		Preconditions.checkArgument(dividend >= 0, "Negative dividend is not supported.");
+		Preconditions.checkArgument(divisor > 0, "Negative or zero divisor is not supported.");
+		if (dividend == 0) {

Review comment:
       nit: Could be done in one line.
   `return dividend == 0 ? 0 : (dividend - 1) / divisor + 1`




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