Multiple driver errors caused by invalid return type of `driverRead()`

[ShockedPlot7560]

Configuration

• PhpFastCache version: 9.0.2
• PhpFastCache API version: 4.0.0
• PHP version: 8.0.13
• Operating system: Ubuntu

Describe the bug

I don't really know the nature of the bug, but it seems to come from the File driver Phpfastcache\Drivers\Files\Driver::driverRead()

To Reproduce Code to reproduce the issue:

/** @var ExtendedCacheItemPoolInterface */
$cacheManager = $this->container->get(CacheManager::class);
$cacheString = "SimplyString";
$cacheItem = $cacheManager->getItem($cacheString);

Driver used : files

Stacktrace

TypeError: Phpfastcache\Drivers\Files\Driver::driverRead(): Return value must be of type ?array, bool returned in /var/www/html/vendor/phpfastcache/phpfastcache/lib/Phpfastcache/Drivers/Files/Driver.php:74
Stack trace:
#0 /var/www/html/vendor/phpfastcache/phpfastcache/lib/Phpfastcache/Core/Pool/CacheItemPoolTrait.php(132): Phpfastcache\Drivers\Files\Driver->driverRead(Object(Phpfastcache\Drivers\Files\Item))
#1 /var/www/html/src/core/middleware/MaintenanceMiddleware.php(32): Phpfastcache\Drivers\Files\Driver->getItem('MaintenanceAuto...')
...
#7 {main}

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[aemla]

I have the same issue with Memcached driver.

• PhpFastCache version: 9.1.0
• PHP version: 8.0.17
  • Operating system: Ubuntu

PHP Fatal error:  Uncaught TypeError: Phpfastcache\Drivers\Memcached\Driver::driverRead(): Return value must be of type ?array, string returned in /public_html/vendor/phpfastcache/phpfastcache/lib/Phpfastcache/Drivers/Memcached/Driver.php:154
Stack trace:
#0 /public_html/vendor/phpfastcache/phpfastcache/lib/Phpfastcache/Core/Pool/CacheItemPoolTrait.php(132): Phpfastcache\Drivers\Memcached\Driver->driverRead()
#1 /public_html/controller/Controller.php(61): Phpfastcache\Drivers\Memcached\Driver->getItem()
...
#4 {main}
  thrown in /public_html/vendor/phpfastcache/phpfastcache/lib/Phpfastcache/Drivers/Memcached/Driver.php on line 154

[Geolim4]

This behavior is very surprising as all tests would have been broken if such behavior would happens.

Did you decorated Phpfastcache services or something ?

If you see in /tests lot of call to getItem are made, especially with Files driver.

(See ReadWriteOperations.test.php)

[Geolim4]

Can you please post your full code implementation below ?

Because this is the very first time report me this kind of issue that should be impossible to produce, especially with LOT of tests calling getItem().

[Geolim4]

I have the same issue with Memcached driver.

* **PhpFastCache version:** 9.1.0

* **PHP version:** 8.0.17

* **Operating system:** Ubuntu

PHP Fatal error:  Uncaught TypeError: Phpfastcache\Drivers\Memcached\Driver::driverRead(): Return value must be of type ?array, string returned in /public_html/vendor/phpfastcache/phpfastcache/lib/Phpfastcache/Drivers/Memcached/Driver.php:154
Stack trace:
#0 /public_html/vendor/phpfastcache/phpfastcache/lib/Phpfastcache/Core/Pool/CacheItemPoolTrait.php(132): Phpfastcache\Drivers\Memcached\Driver->driverRead()
#1 /public_html/controller/Controller.php(61): Phpfastcache\Drivers\Memcached\Driver->getItem()
...
#4 {main}
  thrown in /public_html/vendor/phpfastcache/phpfastcache/lib/Phpfastcache/Drivers/Memcached/Driver.php on line 154

Can't reproduce it neither, I'm gonna need more information with your full code implementation. For confidentiality you can send me sensible code at contact at geolim4.com

[ShockedPlot7560]

Hello, The error also seems very strange to me and never happens in local but only in production.
I will detail below the architecture likely to make a bug and will take the simplest case which brings me this error :

Before anything, I use the PHP-DI container for dependency injection that I build like this:

$buildeur = new ContainerBuilder();
$buildeur->addDefinitions($pathToConfigFile);
$buildeur->enableCompilation(__ROOT_FOLDER . "/tmp");
$container = $buildeur->build();

The configuration file is of type:

<?php

use DI\Container;
use Phpfastcache\CacheManager;
use Phpfastcache\Config\ConfigurationOption;

require __ROOT_FOLDER . "/vendor/autoload.php";

return [
    CacheManager::class => function (Container $container) {
        $instance = $container->get("ENV") === "dev" ? "Devnull" : "files";
        CacheManager::setDefaultConfig(new ConfigurationOption([
            "path" => $container->get("tmp.path")
        ]));
        return CacheManager::getInstance($instance);
    }
];

After that, so the compilation of the container has been defined, and phpfastcache and DI share the same tmp/ directory.
A case that I have a problem with is going to be below. Or, the code that seems to be problematic anyway, a very trivial value retrieval and saving code.

//I have simplified the operation and removed the portions of code that are not necessary and do not interfere
$pdo = $container->get(PDO::class);
/** @var ExtendedCacheItemPoolInterface */
$cacheManager = $container->get(CacheManager::class);
$cacheString = "Maintenance";
$cacheItem = $cacheManager->getItem($cacheString);
if ($config["maintenance"] !== true && $pdo !== null) {
    $cacheItem->set(false)->expiresAfter(3600 * 24);
    $cacheManager->save($cacheItem);
} else {
    if($pdo === null){
        if($cacheItem->get() === false || $cacheItem->get() === null){
            // send notification to discord
        }
        if(!$cacheItem->isHit()){
            $cacheItem->set(true)->expiresAfter(3600 * 24);
        }
        $cacheManager->save($cacheItem);
    }
}

[Geolim4]

I think you are facing race condition issue with Files driver. Try to enable the option preventCacheSlams (only for Files driver), see Wiki.

Also I suggest you a better approach with the CacheManager.

Instead of calling:

        CacheManager::setDefaultConfig(new ConfigurationOption([
            "path" => $container->get("tmp.path")
        ]));

Try to do:

        return CacheManager::getInstance($instance, [
            'path' => $container->get("tmp.path"),
            'preventCacheSlams' => true,
                ]);
                // OR

Also try a more performant driver like Redis if you can, this will be more appropriated for heavy cache usage.

[ShockedPlot7560]

I'll try your answer, however regarding the Redis driver, it takes, I guess a lot of memory space?

[Geolim4]

Not at all, redis is one of the lightweight memory backend I know. It is popular because of its efficiency and few ressources needed 😁

But first try to enable the option I suggested above.

[ShockedPlot7560]

Update after testing in production (where it crashes). The error is always launched having set the configuration as requested. I will try to switch to the Redis driver to see if it still happens or not.

[Geolim4]

How many request per second do you have ?

Can you invit me to talk on discord maybe ? :)

[ShockedPlot7560]

This can go up I think to 10/15 requests per second at most. They are then limited by the capacity of my proxy and the traffic.

Of course, here is my discord: ShockedPlot7560 # 9999

[Geolim4]

Added you, so we can discuss more clearly about your issue !

[Geolim4]

I have the same issue with Memcached driver.

* **PhpFastCache version:** 9.1.0

* **PHP version:** 8.0.17

* **Operating system:** Ubuntu

PHP Fatal error:  Uncaught TypeError: Phpfastcache\Drivers\Memcached\Driver::driverRead(): Return value must be of type ?array, string returned in /public_html/vendor/phpfastcache/phpfastcache/lib/Phpfastcache/Drivers/Memcached/Driver.php:154
Stack trace:
#0 /public_html/vendor/phpfastcache/phpfastcache/lib/Phpfastcache/Core/Pool/CacheItemPoolTrait.php(132): Phpfastcache\Drivers\Memcached\Driver->driverRead()
#1 /public_html/controller/Controller.php(61): Phpfastcache\Drivers\Memcached\Driver->getItem()
...
#4 {main}
  thrown in /public_html/vendor/phpfastcache/phpfastcache/lib/Phpfastcache/Drivers/Memcached/Driver.php on line 154

I need more information @aemla. What is the string returned exactly ? Can you dump me the content of that string please ? Because unlike @ShockedPlot7560 I can't reproduce your issue.

[aemla]

I have the same issue with Memcached driver.

* **PhpFastCache version:** 9.1.0

* **PHP version:** 8.0.17

* **Operating system:** Ubuntu

PHP Fatal error:  Uncaught TypeError: Phpfastcache\Drivers\Memcached\Driver::driverRead(): Return value must be of type ?array, string returned in /public_html/vendor/phpfastcache/phpfastcache/lib/Phpfastcache/Drivers/Memcached/Driver.php:154
Stack trace:
#0 /public_html/vendor/phpfastcache/phpfastcache/lib/Phpfastcache/Core/Pool/CacheItemPoolTrait.php(132): Phpfastcache\Drivers\Memcached\Driver->driverRead()
#1 /public_html/controller/Controller.php(61): Phpfastcache\Drivers\Memcached\Driver->getItem()
...
#4 {main}
  thrown in /public_html/vendor/phpfastcache/phpfastcache/lib/Phpfastcache/Drivers/Memcached/Driver.php on line 154

I need more information @aemla. What is the string returned exactly ? Can you dump me the content of that string please ? Because unlike @ShockedPlot7560 I can't reproduce your issue.

It can be reproduced by running it in a loop. I wrote a little example, it doesn't make any sense, but it throws the same error. 😁 In my original code, I am getting data from a database. I am getting this error only with the Memcached driver. Files driver works fine.

Dump of that string: string(0) ""

    function test()
    {
        $array = [
            ['userId' => 1, 'data' => 'test'],
            ['userId' => 2, 'data' => 'test'],
            ['userId' => 3, 'data' => 'test'],
            ['userId' => 4, 'data' => 'test'],
            ['userId' => 5, 'data' => 'test'],
            ['userId' => 6, 'data' => 'test'],
            ['userId' => 7, 'data' => 'test'],
            ['userId' => 8, 'data' => 'test'],
            ['userId' => 9, 'data' => 'test'],
            ['userId' => 10, 'data' => 'test'],
            ['userId' => 11, 'data' => 'test'],
            ['userId' => 12, 'data' => 'test'],
            ['userId' => 13, 'data' => 'test'],
            ['userId' => 14, 'data' => 'test'],
            ['userId' => 15, 'data' => 'test'],
            ['userId' => 16, 'data' => 'test'],
            ['userId' => 17, 'data' => 'test'],
            ['userId' => 18, 'data' => 'test'],
            ['userId' => 19, 'data' => 'test'],
            ['userId' => 20, 'data' => 'test'],
            ['userId' => 21, 'data' => 'test'],
            ['userId' => 22, 'data' => 'test'],
        ];

        $cache = CacheManager::getInstance('Memcached');

        // The error only occurs when writing to the cache, so let's clear it before running the loop.
        $cache->clear();

        foreach ($array as $row) {
            $this->getFromCache($cache, $row['userId'], $row['data']);
        }
    }

    function getFromCache(ExtendedCacheItemPoolInterface $cache, $userId, $data)
    {
        $cachedString = $cache->getItem('dataById=' . $userId);
        if (!$cachedString->isHit()) {
            $cachedString->set($data)->expiresAfter(300);
            $cache->save($cachedString);

            return $cachedString->get();
        } else {
            return $cachedString->get();
        }
    }

[Geolim4]

I ran your code sample:

And I have no error at all, so I can't reproduce your bug :/

[Geolim4]

What version of php-memcached version are you using ? Do you run multiple concurrent process ?

[aemla]

This error occurs only in 9.x, it works fine in 8.x. I am using LSMCD https://github.com/litespeedtech/lsmcd could this be the reason why it sometimes returns an empty string?

[aemla]

This issue can be fixed by adding a check for an empty string.

    /**
     * @param ExtendedCacheItemInterface $item
     * @return null|array
     */
    protected function driverRead(ExtendedCacheItemInterface $item): ?array
    {
        $val = $this->instance->get($item->getKey());

        if ($val === false || $val === “”) {
            return null;
        }

        return $val;
    }

[Geolim4]

"it works fine in 8.x" ?

That's interesting. Did you tried in v8.1.x or previous one ?

[Geolim4]

I understand now, I typed driverRead with ?array as of v9.

[Geolim4]

Ok ok, that make sense now.

v8 was workin well because I previously made a weak validation: https://github.com/PHPSocialNetwork/phpfastcache/blob/894421d73b8aa1eb839553cfcb3201be13ecda90/lib/Phpfastcache/Core/Pool/CacheItemPoolTrait.php#L139

But as of v9 I introduced (very) strict types everywhere this one can be problematic under some circumstances.

[Geolim4]

Just out of curiosity tell me if replacing:

        if ($val === false) {
            return null;
        }

by

        if (empty($val) || !\is_array($val)) {
            return null;
        }

fixes your issue ?

[aemla]

Just out of curiosity tell me if replacing:

        if ($val === false) {
            return null;
        }

by

        if (empty($val) || !\is_array($val)) {
            return null;
        }

fixes your issue ?

Yes, now it works fine.

[Geolim4]

Roger that. I'll push a fix tonight and make a new release by the end of the week at late.

[GrandFelix]

Hi,

we are still getting the same error. We are using version 9.1.2 and php 8.1.

PHP Fatal error:  Uncaught TypeError: Phpfastcache\Drivers\Files\Driver::driverRead(): Return value must be of type ?array, bool returned in /var/www/prod/app/vendor8/phpfastcache/phpfastcache/lib/Phpfastcache/Drivers/Files/Driver.php:74
Stack trace:
#0 /var/www/prod/app/vendor8/phpfastcache/phpfastcache/lib/Phpfastcache/Core/Pool/CacheItemPoolTrait.php(143): Phpfastcache\Drivers\Files\Driver->driverRead()
#1 /var/www/prod/app/vendor8/phpfastcache/phpfastcache/lib/Phpfastcache/Core/Pool/CacheItemPoolTrait.php(106): Phpfastcache\Drivers\Files\Driver->getItem()
#2 /var/www/prod/app/vendor8/phpfastcache/phpfastcache/lib/Phpfastcache/Core/Pool/TaggableCacheItemPoolTrait.php(399): Phpfastcache\Drivers\Files\Driver->getItems()
#3 /var/www/prod/app/vendor8/phpfastcache/phpfastcache/lib/Phpfastcache/Core/Pool/CacheItemPoolTrait.php(386): Phpfastcache\Drivers\Files\Driver->driverWriteTags()
#4 /var/www/prod/app/library/App/Cache/Cache.php(76): Phpfastcache\Drivers\Files\Driver->save()

Any tip?

[Geolim4]

You seem to have concurrency issue as the file exists on disk but looks empty, very weird.

Did you tried to enable preventCacheSlams option ?

[GrandFelix]

will try and I report back.

[GrandFelix]

We have tried it and we still get the same error. I think the problem is in decode() function when calling unserialize() which one return false when it cant unserialize a string.

[Geolim4]

Then you have a serious problem of I/O with your disk this is is not supposed to happens unless the file are corrupted or partially written which is a sign of a failing disk. I have multiple tests with this driver on the CI including concurrent writes and I'm not encountering this kind of issue.

[GrandFelix]

The problem is that this happens on multiple different servers and I really doubt that all servers have disk issues 😕

[GrandFelix]

now we have tired to set setSecureFileManipulation() and it looks good.