Fix BigInteger::gcdAll() returning negative value when using a single operand

Author: BenMorel

CHANGELOG.md

@@ -10,6 +10,10 @@ All notable changes to this project will be documented in this file.
 - New method: `BigInteger::lcmAll()`
 - New method: `BigRational::toRepeatingDecimalString()`
 
+🐛 **Bug fixes**
+
+- `BigInteger::gcdAll()` / `gcdMultiple()` could return a negative result when used with a single negative number
+
 ## [0.14.2](https://github.com/brick/math/releases/tag/0.14.2) - 2026-01-30
 
 🗑️ **Deprecations**

src/BigInteger.php

@@ -354,7 +354,7 @@ public static function ten(): BigInteger
      */
     public static function gcdAll(BigNumber|int|float|string $a, BigNumber|int|float|string ...$n): BigInteger
     {
-        $result = BigInteger::of($a);
+        $result = BigInteger::of($a)->abs();
 
         foreach ($n as $next) {
             $result = $result->gcd(BigInteger::of($next));

tests/BigIntegerTest.php

@@ -393,17 +393,17 @@ public function testTen(): void
     }
 
     #[DataProvider('providerGcdAll')]
-    public function testGcdAll(array $values, string $expectedGCD): void
+    public function testGcdAll(array $values, string|int $expectedGCD): void
     {
-        self::assertSame($expectedGCD, (string) BigInteger::gcdAll(...$values));
-        self::assertSame($expectedGCD, (string) BigInteger::gcdMultiple(...$values));
+        self::assertBigIntegerEquals((string) $expectedGCD, BigInteger::gcdAll(...$values));
+        self::assertBigIntegerEquals((string) $expectedGCD, BigInteger::gcdMultiple(...$values));
     }
 
     public static function providerGcdAll(): Generator
     {
         // 1 value
-        foreach (['-2', '-1', '0', '1', '2'] as $value) {
-            yield [[$value], $value];
+        foreach ([-4, -3, -2, -1, 0, 1, 2, 3, 4] as $value) {
+            yield [[$value], abs($value)];
         }
 
         // 2 values
@@ -417,6 +417,9 @@ public static function providerGcdAll(): Generator
         yield [['2', '4', '-7'], '1'];
         yield [['2', '4', '-8'], '2'];
         yield [['28', '56', '77777'], '7'];
+        yield [['-28', '56', '77777'], '7'];
+        yield [['-28', '-56', '77777'], '7'];
+        yield [['-28', '-56', '-77777'], '7'];
         yield [['28', '56', '77778'], '2'];
         yield [['28', '56', '77782'], '2'];
         yield [['28', '56', '77783'], '1'];