symfony
diff --git a/‎src/Symfony/Component/Uid/Tests/UuidTest.php
Copy file name to clipboardExpand all lines: src/Symfony/Component/Uid/Tests/UuidTest.php
+19Lines changed: 19 additions & 0 deletions b/‎src/Symfony/Component/Uid/Tests/UuidTest.php
Copy file name to clipboardExpand all lines: src/Symfony/Component/Uid/Tests/UuidTest.php
+19Lines changed: 19 additions & 0 deletions
diff --git a/‎src/Symfony/Component/Uid/Uuid.php
Copy file name to clipboardExpand all lines: src/Symfony/Component/Uid/Uuid.php
+9-1Lines changed: 9 additions & 1 deletion b/‎src/Symfony/Component/Uid/Uuid.php
Copy file name to clipboardExpand all lines: src/Symfony/Component/Uid/Uuid.php
+9-1Lines changed: 9 additions & 1 deletion
@@ -170,6 +170,25 @@ public function testIsValid()
         $this->assertTrue(UuidV4::isValid(self::A_UUID_V4));
     }
 
+    public function testIsValidWithNilUuid()
+    {
+        $this->assertTrue(Uuid::isValid('00000000-0000-0000-0000-000000000000'));
+        $this->assertTrue(NilUuid::isValid('00000000-0000-0000-0000-000000000000'));
+
+        $this->assertFalse(UuidV1::isValid('00000000-0000-0000-0000-000000000000'));
+        $this->assertFalse(UuidV4::isValid('00000000-0000-0000-0000-000000000000'));
+    }
+
+    public function testIsValidWithMaxUuid()
+    {
+        $this->assertTrue(Uuid::isValid('ffffffff-ffff-ffff-ffff-ffffffffffff'));
+        $this->assertTrue(Uuid::isValid('FFFFFFFF-FFFF-FFFF-FFFF-FFFFFFFFFFFF'));
+        $this->assertTrue(Uuid::isValid('fFFFFFFF-ffff-FFFF-FFFF-FFFFffFFFFFF'));
+
+        $this->assertFalse(UuidV5::isValid('ffffffff-ffff-ffff-ffff-ffffffffffff'));
+        $this->assertFalse(UuidV6::isValid('ffffffff-ffff-ffff-ffff-ffffffffffff'));
+    }
+
     public function testEquals()
     {
         $uuid1 = new UuidV1(self::A_UUID_V1);
 
@@ -58,7 +58,7 @@ public static function fromString(string $uuid): parent
             $uuid = substr_replace($uuid, '-', 18, 0);
             $uuid = substr_replace($uuid, '-', 23, 0);
         } elseif (26 === \strlen($uuid) && Ulid::isValid($uuid)) {
-            $ulid = new Ulid('00000000000000000000000000');
+            $ulid = new NilUlid();
             $ulid->uid = strtoupper($uuid);
             $uuid = $ulid->toRfc4122();
         }
@@ -117,6 +117,14 @@ final public static function v6(): UuidV6
 
     public static function isValid(string $uuid): bool
     {
+        if (self::NIL === $uuid && \in_array(static::class, [__CLASS__, NilUuid::class], true)) {
+            return true;
+        }
+
+        if (__CLASS__ === static::class && 'ffffffff-ffff-ffff-ffff-ffffffffffff' === strtr($uuid, 'F', 'f')) {
+            return true;
+        }
+
         if (!preg_match('{^[0-9a-f]{8}(?:-[0-9a-f]{4}){2}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$}Di', $uuid)) {
             return false;
         }