[9.x] Fix decimal cast, again

composer.json

@@ -18,6 +18,7 @@
         "php": "^8.0.2",
         "ext-mbstring": "*",
         "ext-openssl": "*",
+        "brick/math": "^0.10.2",
         "doctrine/inflector": "^2.0",
         "dragonmantank/cron-expression": "^3.3.2",
         "egulias/email-validator": "^3.2.1",

src/Illuminate/Database/Eloquent/Concerns/HasAttributes.php

@@ -3,6 +3,9 @@
 namespace Illuminate\Database\Eloquent\Concerns;
 
 use BackedEnum;
+use Brick\Math\BigDecimal;
+use Brick\Math\Exception\MathException as BrickMathException;
+use Brick\Math\RoundingMode;
 use Carbon\CarbonImmutable;
 use Carbon\CarbonInterface;
 use DateTimeImmutable;
@@ -23,6 +26,7 @@
 use Illuminate\Support\Arr;
 use Illuminate\Support\Carbon;
 use Illuminate\Support\Collection as BaseCollection;
+use Illuminate\Support\Exceptions\MathException;
 use Illuminate\Support\Facades\Crypt;
 use Illuminate\Support\Facades\Date;
 use Illuminate\Support\Str;
@@ -31,8 +35,6 @@
 use ReflectionClass;
 use ReflectionMethod;
 use ReflectionNamedType;
-use RuntimeException;
-use TypeError;
 
 trait HasAttributes
 {
@@ -1322,21 +1324,11 @@ public function fromFloat($value)
      */
     protected function asDecimal($value, $decimals)
     {
-        if (extension_loaded('bcmath')) {
-            return bcadd($value, 0, $decimals);
-        }
-
-        if (! is_numeric($value)) {
-            throw new TypeError('$value must be numeric.');
-        }
-
-        if (is_string($value) && Str::contains($value, 'e', true)) {
-            throw new RuntimeException('The "decimal" model cast is unable to handle string based floats with exponents.');
+        try {
+            return (string) BigDecimal::of($value)->toScale($decimals, RoundingMode::HALF_UP);
+        } catch (BrickMathException $e) {
+            throw new MathException('Unable to cast value to a decimal.', previous: $e);
         }
-
-        [$int, $fraction] = explode('.', $value) + [1 => ''];
-
-        return Str::of($int)->padLeft('1', '0').'.'.Str::of($fraction)->limit($decimals, '')->padRight($decimals, '0');
     }
 
     /**

src/Illuminate/Support/Exceptions/MathException.php

@@ -0,0 +1,10 @@
+<?php
+
+namespace Illuminate\Support\Exceptions;
+
+use RuntimeException;
+
+class MathException extends RuntimeException
+{
+    //
+}

tests/Integration/Database/EloquentModelDecimalCastingTest.php

@@ -2,12 +2,12 @@
 
 namespace Illuminate\Tests\Integration\Database\EloquentModelDecimalCastingTest;
 
+use Brick\Math\Exception\NumberFormatException;
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Exceptions\MathException;
 use Illuminate\Support\Facades\Schema;
 use Illuminate\Tests\Integration\Database\DatabaseTestCase;
-use TypeError;
-use ValueError;
 
 class EloquentModelDecimalCastingTest extends DatabaseTestCase
 {
@@ -33,28 +33,9 @@ public function testItHandlesExponent()
 
         $model->amount = 0.123456789e3;
         $this->assertSame('123.45678900000000000000', $model->amount);
-    }
-
-    public function testItThrowsWhenPassingExponentAsString()
-    {
-        $model = new class extends Model
-        {
-            public $timestamps = false;
-
-            protected $casts = [
-                'amount' => 'decimal:20',
-            ];
-        };
-        $model->amount = '0.1e3';
-
-        if (extension_loaded('bcmath')) {
-            $this->expectException(ValueError::class);
-        } else {
-            $this->expectException(RuntimeException::class);
-            $this->expectExceptionMessage('The "decimal" model cast is unable to handle string based floats with exponents.'); // when bcmath is not available
-        }
 
-        $model->amount;
+        $model->amount = '0.123456789e3';
+        $this->assertSame('123.45678900000000000000', $model->amount);
     }
 
     public function testItHandlesIntegersWithUnderscores()
@@ -72,7 +53,7 @@ public function testItHandlesIntegersWithUnderscores()
         $this->assertSame('1234.50', $model->amount);
     }
 
-    public function testItThrowsOnNonNumericValues()
+    public function testItWrapsThrownExceptions()
     {
         $model = new class extends Model
         {
@@ -84,13 +65,14 @@ public function testItThrowsOnNonNumericValues()
         };
         $model->amount = 'foo';
 
-        if (extension_loaded('bcmath')) {
-            $this->expectException(ValueError::class);
-        } else {
-            $this->expectException(TypeError::class);
+        try {
+            $model->amount;
+            $this->fail();
+        } catch (MathException $e) {
+            $this->assertSame('Unable to cast value to a decimal.', $e->getMessage());
+            $this->assertInstanceOf(NumberFormatException::class, $e->getPrevious());
+            $this->assertSame('The given value "foo" does not represent a valid number.', $e->getPrevious()->getMessage());
         }
-
-        $model->amount;
     }
 
     public function testItHandlesMissingIntegers()
@@ -129,6 +111,21 @@ public function testItHandlesLargeNumbers()
         $this->assertSame('89898989898989898989.00000000000000000000', $model->amount);
     }
 
+    public function testItRounds()
+    {
+        $model = new class extends Model
+        {
+            public $timestamps = false;
+
+            protected $casts = [
+                'amount' => 'decimal:2',
+            ];
+        };
+
+        $model->amount = '0.8989898989';
+        $this->assertSame('0.90', $model->amount);
+    }
+
     public function testItTrimsLongValues()
     {
         $model = new class extends Model
@@ -141,7 +138,7 @@ public function testItTrimsLongValues()
         };
 
         $model->amount = '0.89898989898989898989898989898989898989898989';
-        $this->assertSame('0.89898989898989898989', $model->amount);
+        $this->assertSame('0.89898989898989898990', $model->amount);
     }
 
     public function testItDoesntRoundNumbers()
@@ -156,7 +153,7 @@ public function testItDoesntRoundNumbers()
         };
 
         $model->amount = '0.99';
-        $this->assertSame('0.9', $model->amount);
+        $this->assertSame('1.0', $model->amount);
     }
 
     public function testDecimalsAreCastable()
@@ -180,6 +177,46 @@ public function testDecimalsAreCastable()
         $user->decimal_field_4 = '1234.1234';
         $this->assertTrue($user->isDirty());
     }
+
+    public function testRoundingDirection()
+    {
+        $model = new class extends Model
+        {
+            protected $casts = [
+                'amount' => 'decimal:2',
+            ];
+        };
+
+        $model->amount = '0.999';
+        $this->assertSame('1.00', $model->amount);
+
+        $model->amount = '-0.999';
+        $this->assertSame('-1.00', $model->amount);
+
+        $model->amount = '0.554';
+        $this->assertSame('0.55', $model->amount);
+
+        $model->amount = '-0.554';
+        $this->assertSame('-0.55', $model->amount);
+
+        $model->amount = '0.555';
+        $this->assertSame('0.56', $model->amount);
+
+        $model->amount = '-0.555';
+        $this->assertSame('-0.56', $model->amount);
+
+        $model->amount = '0.005';
+        $this->assertSame('0.01', $model->amount);
+
+        $model->amount = '-0.005';
+        $this->assertSame('-0.01', $model->amount);
+
+        $model->amount = '0.8989898989';
+        $this->assertSame('0.90', $model->amount);
+
+        $model->amount = '-0.8989898989';
+        $this->assertSame('-0.90', $model->amount);
+    }
 }
 
 class TestModel1 extends Model