Merge branch '3.4' into 4.2

* 3.4:
  Fix expired lock not cleaned
  [HttpFoundation] Fix SA/phpdoc JsonResponse
  SimpleCacheAdapter fails to cache any item if a namespace is used
  validate composite constraints in all groups
  [Serializer] Handle true and false appropriately in CSV encoder
  Fix binary operation `+`, `-` or `*` on string
  [VarDumper] fix dumping objects that implement __debugInfo()
  [Routing] fix absolute url generation when scheme is not known

Author: nicolas-grekas

Constraints/IssnValidator.php

@@ -121,7 +121,7 @@ public function validate($value, Constraint $constraint)
 
         for ($i = 0; $i < 7; ++$i) {
             // Multiply the first digit by 8, the second by 7, etc.
-            $checkSum += (8 - $i) * $canonical[$i];
+            $checkSum += (8 - $i) * (int) $canonical[$i];
         }
 
         if (0 !== $checkSum % 11) {

Constraints/LuhnValidator.php

@@ -84,7 +84,7 @@ public function validate($value, Constraint $constraint)
         //         ^     ^     ^     ^     ^
         //    =    1+8 + 4  +  6  +  1+6 + 2
         for ($i = $length - 2; $i >= 0; $i -= 2) {
-            $checkSum += array_sum(str_split($value[$i] * 2));
+            $checkSum += array_sum(str_split((int) $value[$i] * 2));
         }
 
         if (0 === $checkSum || 0 !== $checkSum % 10) {