[5.1] Fixed support for PHP 7.1 (#14549)

* Test on PHP 7.1

* Fixed cache incrementing on php 7.1

* Skipped the legacy encrypter test on PHP 7.1+

.travis.yml

@@ -5,6 +5,7 @@ php:
   - 5.5
   - 5.6
   - 7.0
+  - 7.1
   - hhvm
 
 env:

src/Illuminate/Cache/ArrayStore.php

@@ -48,7 +48,7 @@ public function put($key, $value, $minutes)
      */
     public function increment($key, $value = 1)
     {
-        $this->storage[$key] = $this->storage[$key] + $value;
+        $this->storage[$key] = ((int) $this->storage[$key]) + $value;
 
         return $this->storage[$key];
     }

src/Illuminate/Cache/DatabaseStore.php

@@ -159,7 +159,7 @@ protected function incrementOrDecrement($key, $value, Closure $callback)
             }
 
             $current = $this->encrypter->decrypt($cache->value);
-            $new = $callback($current, $value);
+            $new = $callback((int) $current, $value);
 
             if (! is_numeric($current)) {
                 return false;

tests/Encryption/EncrypterTest.php

@@ -86,6 +86,10 @@ public function testOpenSslEncrypterCanDecryptMcryptedData()
             $this->markTestSkipped('Mcrypt module not installed');
         }
 
+        if (version_compare(PHP_VERSION, '7.1') > 0) {
+            $this->markTestSkipped('Not compatable with PHP 7.1+');
+        }
+
         $key = Str::random(32);
         $encrypter = new Illuminate\Encryption\McryptEncrypter($key);
         $encrypted = $encrypter->encrypt('foo');