Fix up precision loss for defined smaller scale.

Author: dereuromark

src/Decimal.php

@@ -871,8 +871,12 @@ protected function fromScientific(string $value, ?int $scale): void
     protected function setScale(?int $scale, bool $strict): void
     {
         $calculatedScale = strlen($this->fractionalPart);
-        if ($strict && $scale && $calculatedScale > $scale) {
-            throw new InvalidArgumentException('Loss of precision detected. Detected scale `' . $calculatedScale . '` > `' . $scale . '` as defined.');
+        if ($scale && $calculatedScale > $scale) {
+            if ($strict) {
+                throw new InvalidArgumentException('Loss of precision detected. Detected scale `' . $calculatedScale . '` > `' . $scale . '` as defined.');
+            }
+
+            $this->fractionalPart = substr($this->fractionalPart, 0, $scale);
         }
 
         $this->scale = $scale ?? $calculatedScale;

tests/DecimalTest.php

@@ -1031,6 +1031,18 @@ public function testDebugInfo(): void
         $this->assertEquals($expected, $result);
     }
 
+    /**
+     * @return void
+     */
+    public function testPrecisionLoss(): void
+    {
+        $a = Decimal::create('0.123456789', 10);
+        $this->assertSame('0.123456789', (string)$a);
+
+        $b = Decimal::create((string)$a, 8);
+        $this->assertSame('0.12345678', (string)$b);
+    }
+
     /**
      * @return void
      */