[9.x] Add decimal validation rule (#45356)

* Add `decimal` validation rule

* formatting

Co-authored-by: Taylor Otwell <[email protected]>

Author: RaazPuspa

src/Illuminate/Validation/Concerns/ValidatesAttributes.php

@@ -554,6 +554,32 @@ public function validateDateEquals($attribute, $value, $parameters)
         return $this->compareDates($attribute, $value, $parameters, '=');
     }
 
+    /**
+     * Validate that an attribute has a given number of decimal places.
+     *
+     * @param  string  $attribute
+     * @param  mixed  $value
+     * @param  array<int, int|string>  $parameters
+     * @return bool
+     */
+    public function validateDecimal($attribute, $value, $parameters)
+    {
+        if (!$this->validateNumeric($attribute, $value)) {
+            return false;
+        }
+
+        $this->requireParameterCount(1, $parameters, 'decimal');
+
+        $matches = [];
+
+        preg_match('/^\d*.(\d*)$/', $value, $matches);
+
+        $decimals = strlen(end($matches));
+
+        return $decimals >= $parameters[0] &&
+               (! isset($parameters[1]) || $decimals <= $parameters[1]);
+    }
+
     /**
      * Validate that an attribute is different from another attribute.
      *

tests/Validation/ValidationValidatorTest.php

@@ -2448,6 +2448,43 @@ public function testValidateInteger()
         $this->assertTrue($v->passes());
     }
 
+    public function testValidateDecimal()
+    {
+        $trans = $this->getIlluminateArrayTranslator();
+        $v = new Validator($trans, ['foo' => 'asdad'], ['foo' => 'Decimal:2,3']);
+        $this->assertFalse($v->passes());
+
+        $v = new Validator($trans, ['foo' => '1.2345'], ['foo' => 'Decimal:2,3']);
+        $this->assertFalse($v->passes());
+
+        $v = new Validator($trans, ['foo' => '1.234'], ['foo' => 'Decimal:2,3']);
+        $this->assertTrue($v->passes());
+
+        $v = new Validator($trans, ['foo' => '1.23'], ['foo' => 'Decimal:2,3']);
+        $this->assertTrue($v->passes());
+
+        $v = new Validator($trans, ['foo' => '1.2'], ['foo' => 'Decimal:2,3']);
+        $this->assertFalse($v->passes());
+
+        $v = new Validator($trans, ['foo' => '1.234'], ['foo' => 'Decimal:2']);
+        $this->assertTrue($v->passes());
+
+        $v = new Validator($trans, ['foo' => '1.23'], ['foo' => 'Decimal:2']);
+        $this->assertTrue($v->passes());
+
+        $v = new Validator($trans, ['foo' => '1.2'], ['foo' => 'Decimal:2']);
+        $this->assertFalse($v->passes());
+
+        $v = new Validator($trans, ['foo' => '1'], ['foo' => 'Decimal:0,1']);
+        $this->assertTrue($v->passes());
+
+        $v = new Validator($trans, ['foo' => '1.2'], ['foo' => 'Decimal:0,1']);
+        $this->assertTrue($v->passes());
+
+        $v = new Validator($trans, ['foo' => '1.23'], ['foo' => 'Decimal:0,1']);
+        $this->assertFalse($v->passes());
+    }
+
     public function testValidateInt()
     {
         $trans = $this->getIlluminateArrayTranslator();