Unable to serialize value problem with Magento 2.2.6

Question

Please teach in order to solve the problem.

cd /vagrant
sudo php bin/magento setup:upgrade
sudo php bin/magento setup:di:compile
sudo php bin/magento setup:static-content:deploy
sudo php bin/magento setup:static-content:deploy ja_JP
sudo php bin/magento cache:flush;
sudo php bin/magento cache:clean
sudo php bin/magento indexer:reindex
sudo find var generated vendor pub/static pub/media app/etc -type f -exec chmod g+w {} +
sudo find var generated vendor pub/static pub/media app/etc -type d -exec chmod g+ws {} +
sudo chown -R :www-data .
sudo chmod u+x bin/magento

1 exception(s): Exception #0 (InvalidArgumentException): Unable to serialize value.

Exception #0 (InvalidArgumentException): Unable to serialize value.
#0 /vagrant/vendor/magento/framework/App/PageCache/Kernel.php(153):

Magento\Framework\Serialize\Serializer\Json->serialize(Array) #1 /vagrant/vendor/magento/module-page-cache/Model/Controller/Result/BuiltinPlugin.php(96): Magento\Framework\App\PageCache\Kernel->process(Object(Magento\Framework\App\Response\Http\Interceptor)) #2 /vagrant/vendor/magento/framework/Interception/Interceptor.php(146): Magento\PageCache\Model\Controller\Result\BuiltinPlugin->afterRenderResult(Object(Magento\Framework\View\Result\Page\Interceptor), Object(Magento\Framework\View\Result\Page\Interceptor), Object(Magento\Framework\App\Response\Http\Interceptor)) #3 /vagrant/vendor/magento/framework/Interception/Interceptor.php(153): Magento\Framework\View\Result\Page\Interceptor->Magento\Framework\Interception{closure}(Object(Magento\Framework\App\Response\Http\Interceptor)) #4 /vagrant/generated/code/Magento/Framework/View/Result/Page/Interceptor.php(26): Magento\Framework\View\Result\Page\Interceptor->___callPlugins('renderResult', Array, Array) #5 /vagrant/vendor/magento/framework/App/Http.php(139): Magento\Framework\View\Result\Page\Interceptor->renderResult(Object(Magento\Framework\App\Response\Http\Interceptor)) #6 /vagrant/vendor/magento/framework/App/Bootstrap.php(257): Magento\Framework\App\Http->launch() #7 /vagrant/pub/index.php(37): Magento\Framework\App\Bootstrap->run(Object(Magento\Framework\App\Http\Interceptor)) #8 {main}

• fmsthird: post code that is getting the error
• Philipp Sander: have you cleared the caches?
• mr.hironobu: Yes, I deleted the cache.
• Emipro Technologies Pvt. Ltd.: Please follow @Ronak Rathod's answer. It will solve your problem.
• mr.hironobu: I followed Ronak Rathod's answer, but the problem is not solved. We still need help.

Answer 1

The problem is in /vendor/magento/framework/Serialize/Serializer/Json.php there is a function unserialize($string)

There is a workaround - you can check if string is serialized and then use serialize($string). Change unserialize to:

public function unserialize($string)
{
 /* Workaround: serialize first if is serialized */
 if($this->is_serialized($string))
 {
 $string = $this->serialize($string);
 }
 $result = json_decode($string, true);
 if (json_last_error() !== JSON_ERROR_NONE) {
 throw new \InvalidArgumentException('Unable to unserialize value.');
 }
 return $result;
}

and add function to check if string is serialized:

function is_serialized($value, &$result = null)
{
 // Bit of a give away this one
 if (!is_string($value))
 {
 return false;
 }
 // Serialized false, return true. unserialize() returns false on an
 // invalid string or it could return false if the string is serialized
 // false, eliminate that possibility.
 if ($value === 'b:0;')
 {
 $result = false;
 return true;
 }
 $length = strlen($value);
 $end = '';
 switch ($value[0])
 {
 case 's':
 if ($value[$length - 2] !== '"')
 {
 return false;
 }
 case 'b':
 case 'i':
 case 'd':
 // This looks odd but it is quicker than isset()ing
 $end .= ';';
 case 'a':
 case 'O':
 $end .= '}';
 if ($value[1] !== ':')
 {
 return false;
 }
 switch ($value[2])
 {
 case 0:
 case 1:
 case 2:
 case 3:
 case 4:
 case 5:
 case 6:
 case 7:
 case 8:
 case 9:
 break;
 default:
 return false;
 }
 case 'N':
 $end .= ';';
 if ($value[$length - 1] !== $end[0])
 {
 return false;
 }
 break;
 default:
 return false;
 }
 if (($result = @unserialize($value)) === false)
 {
 $result = null;
 return false;
 }
 return true;
}

• zekia: error is throwed in serialize() function, not unserialize(), so your code has no effect

Answer 2

Please remove var cache as sudo rm -rf var/cache var/page_cache. It works for me.

Answer 3

Please add more description when submiting a Question , when this error showed up and for what reason ?

Possible solutions:

• Clear redis cache :

  redis-cli flushall

• Permissions issue , need to set the umask :

Follow this link

Check this link for more info link

• mr.hironobu: Could you tell me the command by example?
• Ylgen Guxholli: What command do you want to know?
• mr.hironobu: Move to the root directory and run "echo 077 > magento_umask"?
• Ylgen Guxholli: Better run this command : " echo 022 > magento_umask "
• mr.hironobu: I confirmed that "echo 022> magento_umask" file was created and the setting was written. I logged in to the administrator screen and confirmed the front end, but the problem was not solved.