Call to undefined function Doctrine\Common\Cache\apcu_fetch() about cache HOT 14 CLOSED

@Laurent3170 something like (pseudo-code):

public function __construct()
{
    if (! function_exists('apcu_set')) {
        throw new SomethingSomethingException('APCu is not installed: please install APCu before using the APCu cache');
    }
}

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Thanks for your answer but can you explain a little bit more what should be done?

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@Laurent3170 you should make sure that the mentioned extension is installed on your environment.

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Closing as invalid

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@Ocramius I can understand that you close this, as it seems not to be an issue directly related to the project, but it's linked with, as the apcu_fetch() is called by it.
So it can't work if the external library is not installed, and it may be indicated somewhere (maybe it is but I haven't found).
@lcobucci thanks, I will have a look at it, when I have time. For the time being I can only find information about php-pecl-apcu

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So it can't work if the external library is not installed, and it may be indicated somewhere (maybe it is but I haven't found).

Yes, feel free to send a patch that verifies if the APCu extension is installed at boot time, but it's not really needed out of the box.

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Euh... I do need to understand before how it works and how to implement it... If I was able to do so, maybe I will have not set this issue ;-)

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I am sorry to bother you but... I can't find how to install ext-apcu on Centos, I just can't find anything about ext-apcu.
On my dev (Ubuntu) I have php-apcu but no packages seems to exists for Centos...
Moreover, when I use the command php bin/console doctrine:cache:clear-metadata --env=prod; on my Centos prod server in a Symfony project, it works well, even if apcu_fetch() is not present in the above mentionned file and in another project, same server, it gives me the error.
I've looked around composer.json and they are the same.
I have installed pecl install apc but it doesn't solve the problem.

So... As I don't really understand differences between APC and APCu and neither OPCache, if you have "spare time" to give me a little bit of explanation, and/or where to search, it will be greatly appreciated! As when I move to production server, I always receive this, even when calling Console Command from crontab that don't call cache clearing.

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Argh... I have tried this but not looked at the error message.

pecl/apcu requires PHP (version >= 7.0.0-dev), installed version is 5.6.29
No valid packages found
install failed

So the problem is on my server... Thanks for your answer!

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So, the problem was on my server, it has been updated and then downgraded to php 5.6 without noticing me... But as clearing the cache doesn't work without apcu installed, I think it's better to prevent the user so I will try to work on a PR, as suggested, to do so. Just need to check a bit.

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Handled in #225

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