[Validator] Add a Length::$allowEmptyString option to reject empty strings

which defaults to `true` in 4.4 but will trigger a deprecation if not set explicitly
in order to make the default `false` in 5.0.

Author: ogizanagi

CHANGELOG.md

@@ -8,6 +8,7 @@ CHANGELOG
  * added the `compared_value_path` parameter in violations when using any 
    comparison constraint with the `propertyPath` option.
  * added support for checking an array of types in `TypeValidator`
+ * added a new `allowEmptyString` option to the `Length` constraint to allow rejecting empty strings when `min` is set, by setting it to `false`.
 
 4.3.0
 -----

Constraints/Length.php

@@ -41,6 +41,7 @@ class Length extends Constraint
     public $min;
     public $charset = 'UTF-8';
     public $normalizer;
+    public $allowEmptyString;
 
     public function __construct($options = null)
     {
@@ -56,6 +57,13 @@ public function __construct($options = null)
 
         parent::__construct($options);
 
+        if (null === $this->allowEmptyString) {
+            $this->allowEmptyString = true;
+            if (null !== $this->min) {
+                @trigger_error(sprintf('Using the "%s" constraint with the "min" option without setting the "allowEmptyString" one is deprecated and defaults to true. In 5.0, it will become optional and default to false.', self::class), E_USER_DEPRECATED);
+            }
+        }
+
         if (null === $this->min && null === $this->max) {
             throw new MissingOptionsException(sprintf('Either option "min" or "max" must be given for constraint %s', __CLASS__), ['min', 'max']);
         }

Constraints/LengthValidator.php

@@ -30,7 +30,7 @@ public function validate($value, Constraint $constraint)
             throw new UnexpectedTypeException($constraint, __NAMESPACE__.'\Length');
         }
 
-        if (null === $value || '' === $value) {
+        if (null === $value || ('' === $value && $constraint->allowEmptyString)) {
             return;
         }
 

Tests/Constraints/LengthTest.php

@@ -21,7 +21,7 @@ class LengthTest extends TestCase
 {
     public function testNormalizerCanBeSet()
     {
-        $length = new Length(['min' => 0, 'max' => 10, 'normalizer' => 'trim']);
+        $length = new Length(['min' => 0, 'max' => 10, 'normalizer' => 'trim', 'allowEmptyString' => false]);
 
         $this->assertEquals('trim', $length->normalizer);
     }
@@ -32,7 +32,7 @@ public function testNormalizerCanBeSet()
      */
     public function testInvalidNormalizerThrowsException()
     {
-        new Length(['min' => 0, 'max' => 10, 'normalizer' => 'Unknown Callable']);
+        new Length(['min' => 0, 'max' => 10, 'normalizer' => 'Unknown Callable', 'allowEmptyString' => false]);
     }
 
     /**
@@ -41,6 +41,6 @@ public function testInvalidNormalizerThrowsException()
      */
     public function testInvalidNormalizerObjectThrowsException()
     {
-        new Length(['min' => 0, 'max' => 10, 'normalizer' => new \stdClass()]);
+        new Length(['min' => 0, 'max' => 10, 'normalizer' => new \stdClass(), 'allowEmptyString' => false]);
     }
 }

Tests/Constraints/LengthValidatorTest.php

@@ -22,26 +22,47 @@ protected function createValidator()
         return new LengthValidator();
     }
 
-    public function testNullIsValid()
+    public function testLegacyNullIsValid()
     {
-        $this->validator->validate(null, new Length(6));
+        $this->validator->validate(null, new Length(['value' => 6, 'allowEmptyString' => false]));
 
         $this->assertNoViolation();
     }
 
-    public function testEmptyStringIsValid()
+    /**
+     * @group legacy
+     * @expectedDeprecation Using the "Symfony\Component\Validator\Constraints\Length" constraint with the "min" option without setting the "allowEmptyString" one is deprecated and defaults to true. In 5.0, it will become optional and default to false.
+     */
+    public function testLegacyEmptyStringIsValid()
     {
         $this->validator->validate('', new Length(6));
 
         $this->assertNoViolation();
     }
 
+    public function testEmptyStringIsInvalid()
+    {
+        $this->validator->validate('', new Length([
+            'value' => $limit = 6,
+            'allowEmptyString' => false,
+            'exactMessage' => 'myMessage',
+        ]));
+
+        $this->buildViolation('myMessage')
+            ->setParameter('{{ value }}', '""')
+            ->setParameter('{{ limit }}', $limit)
+            ->setInvalidValue('')
+            ->setPlural($limit)
+            ->setCode(Length::TOO_SHORT_ERROR)
+            ->assertRaised();
+    }
+
     /**
      * @expectedException \Symfony\Component\Validator\Exception\UnexpectedValueException
      */
     public function testExpectsStringCompatibleType()
     {
-        $this->validator->validate(new \stdClass(), new Length(5));
+        $this->validator->validate(new \stdClass(), new Length(['value' => 5, 'allowEmptyString' => false]));
     }
 
     public function getThreeOrLessCharacters()
@@ -109,7 +130,7 @@ public function getThreeCharactersWithWhitespaces()
      */
     public function testValidValuesMin($value)
     {
-        $constraint = new Length(['min' => 5]);
+        $constraint = new Length(['min' => 5, 'allowEmptyString' => false]);
         $this->validator->validate($value, $constraint);
 
         $this->assertNoViolation();
@@ -131,7 +152,7 @@ public function testValidValuesMax($value)
      */
     public function testValidValuesExact($value)
     {
-        $constraint = new Length(4);
+        $constraint = new Length(['value' => 4, 'allowEmptyString' => false]);
         $this->validator->validate($value, $constraint);
 
         $this->assertNoViolation();
@@ -142,7 +163,7 @@ public function testValidValuesExact($value)
      */
     public function testValidNormalizedValues($value)
     {
-        $constraint = new Length(['min' => 3, 'max' => 3, 'normalizer' => 'trim']);
+        $constraint = new Length(['min' => 3, 'max' => 3, 'normalizer' => 'trim', 'allowEmptyString' => false]);
         $this->validator->validate($value, $constraint);
 
         $this->assertNoViolation();
@@ -156,6 +177,7 @@ public function testInvalidValuesMin($value)
         $constraint = new Length([
             'min' => 4,
             'minMessage' => 'myMessage',
+            'allowEmptyString' => false,
         ]);
 
         $this->validator->validate($value, $constraint);
@@ -199,6 +221,7 @@ public function testInvalidValuesExactLessThanFour($value)
             'min' => 4,
             'max' => 4,
             'exactMessage' => 'myMessage',
+            'allowEmptyString' => false,
         ]);
 
         $this->validator->validate($value, $constraint);
@@ -221,6 +244,7 @@ public function testInvalidValuesExactMoreThanFour($value)
             'min' => 4,
             'max' => 4,
             'exactMessage' => 'myMessage',
+            'allowEmptyString' => false,
         ]);
 
         $this->validator->validate($value, $constraint);
@@ -244,6 +268,7 @@ public function testOneCharset($value, $charset, $isValid)
             'max' => 1,
             'charset' => $charset,
             'charsetMessage' => 'myMessage',
+            'allowEmptyString' => false,
         ]);
 
         $this->validator->validate($value, $constraint);
@@ -262,15 +287,15 @@ public function testOneCharset($value, $charset, $isValid)
 
     public function testConstraintDefaultOption()
     {
-        $constraint = new Length(5);
+        $constraint = new Length(['value' => 5, 'allowEmptyString' => false]);
 
         $this->assertEquals(5, $constraint->min);
         $this->assertEquals(5, $constraint->max);
     }
 
     public function testConstraintAnnotationDefaultOption()
     {
-        $constraint = new Length(['value' => 5, 'exactMessage' => 'message']);
+        $constraint = new Length(['value' => 5, 'exactMessage' => 'message', 'allowEmptyString' => false]);
 
         $this->assertEquals(5, $constraint->min);
         $this->assertEquals(5, $constraint->max);

Tests/Validator/RecursiveValidatorTest.php

@@ -103,7 +103,7 @@ public function testRelationBetweenChildAAndChildB()
     public function testCollectionConstraintValidateAllGroupsForNestedConstraints()
     {
         $this->metadata->addPropertyConstraint('data', new Collection(['fields' => [
-            'one' => [new NotBlank(['groups' => 'one']), new Length(['min' => 2, 'groups' => 'two'])],
+            'one' => [new NotBlank(['groups' => 'one']), new Length(['min' => 2, 'groups' => 'two', 'allowEmptyString' => false])],
             'two' => [new NotBlank(['groups' => 'two'])],
         ]]));
 
@@ -121,16 +121,17 @@ public function testAllConstraintValidateAllGroupsForNestedConstraints()
     {
         $this->metadata->addPropertyConstraint('data', new All(['constraints' => [
             new NotBlank(['groups' => 'one']),
-            new Length(['min' => 2, 'groups' => 'two']),
+            new Length(['min' => 2, 'groups' => 'two', 'allowEmptyString' => false]),
         ]]));
 
         $entity = new Entity();
         $entity->data = ['one' => 't', 'two' => ''];
 
         $violations = $this->validator->validate($entity, null, ['one', 'two']);
 
-        $this->assertCount(2, $violations);
+        $this->assertCount(3, $violations);
         $this->assertInstanceOf(NotBlank::class, $violations->get(0)->getConstraint());
         $this->assertInstanceOf(Length::class, $violations->get(1)->getConstraint());
+        $this->assertInstanceOf(Length::class, $violations->get(2)->getConstraint());
     }
 }