(commons-numbers) branch master updated: NUMBERS-218: Fix representable minimum-value powers

[aherbert]

This is an automated email from the ASF dual-hosted git repository.

aherbert pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/commons-numbers.git


The following commit(s) were added to refs/heads/master by this push:
     new 8cfc04e8 NUMBERS-218: Fix representable minimum-value powers
8cfc04e8 is described below

commit 8cfc04e8719d00bde40b3faba19180cc92e20f9e
Author: AryanRG <aryanrgan...@gmail.com>
AuthorDate: Sun Oct 18 03:51:48 2026 +0530

    NUMBERS-218: Fix representable minimum-value powers
---
 .../org/apache/commons/numbers/core/ArithmeticUtils.java   |  4 ++--
 .../apache/commons/numbers/core/ArithmeticUtilsTest.java   | 14 ++++++++++++++
 src/changes/changes.xml                                    |  4 ++++
 3 files changed, 20 insertions(+), 2 deletions(-)

diff --git 
a/commons-numbers-core/src/main/java/org/apache/commons/numbers/core/ArithmeticUtils.java
 
b/commons-numbers-core/src/main/java/org/apache/commons/numbers/core/ArithmeticUtils.java
index 153b3202..b5d4ad70 100644
--- 
a/commons-numbers-core/src/main/java/org/apache/commons/numbers/core/ArithmeticUtils.java
+++ 
b/commons-numbers-core/src/main/java/org/apache/commons/numbers/core/ArithmeticUtils.java
@@ -294,7 +294,7 @@ public final class ArithmeticUtils {
             return (e & 1) == 0 ? 1 : -1;
         }
 
-        if (e >= 31) {
+        if (e > 31) {
             throw new ArithmeticException("integer overflow");
         }
 
@@ -354,7 +354,7 @@ public final class ArithmeticUtils {
             return (e & 1) == 0 ? 1L : -1L;
         }
 
-        if (e >= 63) {
+        if (e > 63) {
             throw new ArithmeticException("long overflow");
         }
 
diff --git 
a/commons-numbers-core/src/test/java/org/apache/commons/numbers/core/ArithmeticUtilsTest.java
 
b/commons-numbers-core/src/test/java/org/apache/commons/numbers/core/ArithmeticUtilsTest.java
index b77ae08f..057471d5 100644
--- 
a/commons-numbers-core/src/test/java/org/apache/commons/numbers/core/ArithmeticUtilsTest.java
+++ 
b/commons-numbers-core/src/test/java/org/apache/commons/numbers/core/ArithmeticUtilsTest.java
@@ -423,6 +423,20 @@ class ArithmeticUtilsTest {
         }
     }
 
+    @Test
+    void testPowMinValue() {
+        // (-2)^31 and (-2)^63 are exactly representable as the minimum value
+        Assertions.assertEquals(Integer.MIN_VALUE, ArithmeticUtils.pow(-2, 
31));
+        Assertions.assertEquals(Long.MIN_VALUE, ArithmeticUtils.pow(-2L, 63));
+        // Adjacent results overflow
+        Assertions.assertThrows(ArithmeticException.class, () -> 
ArithmeticUtils.pow(2, 31));
+        Assertions.assertThrows(ArithmeticException.class, () -> 
ArithmeticUtils.pow(-2, 32));
+        Assertions.assertThrows(ArithmeticException.class, () -> 
ArithmeticUtils.pow(3, 31));
+        Assertions.assertThrows(ArithmeticException.class, () -> 
ArithmeticUtils.pow(2L, 63));
+        Assertions.assertThrows(ArithmeticException.class, () -> 
ArithmeticUtils.pow(-2L, 64));
+        Assertions.assertThrows(ArithmeticException.class, () -> 
ArithmeticUtils.pow(3L, 63));
+    }
+
     @Test
     void testPowEdgeCases() {
         Assertions.assertEquals(0, ArithmeticUtils.pow(0, 2));
diff --git a/src/changes/changes.xml b/src/changes/changes.xml
index f30c55f8..704ab630 100644
--- a/src/changes/changes.xml
+++ b/src/changes/changes.xml
@@ -56,6 +56,10 @@ If the output is not quite correct, check for invisible 
trailing spaces!
     <release version="1.4" date="TBD" description="
 New features, updates and bug fixes.
 ">
+      <action type="fix" due-to="Aryan Ganjoo" issue="NUMBERS-218">
+        "ArithmeticUtils.pow": Return the representable minimum int and long 
values for
+        (-2)^31 and (-2)^63 instead of reporting overflow.
+      </action>
       <action dev="aherbert" type="update" due-to="Security scan, Alex 
Herbert" issue="NUMBERS-214">
         "GeneralizedContinuedFraction": Lower the defaut iterations to 
1_000_000. This
         introduces a behavioural change for slowly converging fractions that 
may now