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eangulo

Fatal error when delete content of "caches" table

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Hello everyone,

Usually in many CMS database tables prefixed or suffixed with "cache" can be manually cleared without a problem because the system will populate them on the "next page request". Actually in Processwire I am expecting this behaviour:

[On PW 3.x]

  1. Manually clear table "caches" in database
  2. Go to "client" side (not in the admin panel)
  3. All references to my "/site/modules" in my template files does not work : wire("modules")->get(""), $modules->get("") and modules()->get("")
    1. PHP error:  Fatal error: Uncaught TypeError: Return value...
    2. My _init.php file are not able to find the references to my /site/modules/
  4.  The client side not working because this PHP fatal error.

If I go to the admin panel "Admin -> Modules" and I trigger the action "Check for New Modules" in the top-right corner in the page, it populates the caches table with the required information and them the client side works.

It is normal? Or I am doing something wrong ?

A solution could be to manually call the script that the button "Check for New Modules" calls, but I want to know if  I am doing something wrong here.

Thank you in advance guys ! 

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Always do backups before manually changing something in the DB.

I never touched the caches DB-table. I only delete assets/cache/ stuff from the file-system if I need to (rarely). Perhaps delete those file-caches too and it will then try to re-create all DB-caches? 

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Hi @dragan,

Yes that's a very good advice, I always do this kind of manipulation in a local environnement.

Maybe I'm comparing to much Processwire with others CMS/CMF. Maybe the "caches" table that contains the system registry entries should never be cleared manually.

(caches table system registry)

  • Modules.info
  • Modules.site/modules/ (This is the one causing the Fatal PHP error, after "caches" table is manually cleared and the system is not generating it automatically)
  • Modules.wire/modules/
  • ... and so on

If @ryan design it that way, I understand :).

But I think it would be nice, if the rebuild caches table's content script can generate the content for this one too "Modules.site/modules/".

Thank you,

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I agree that it should sort this out itself, but just so you know, a Modules > Refresh is the correct way to fix this.

As for clearing caches in general, take a look at: https://github.com/somatonic/ClearCacheAdmin - much more elegant than just deleting that table.

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Thank you @adrian for this module and I fully agree with you that this is a much better way to do it, but I was looking for an explanation for this behaviour to explain it to my team.

Thank you guys,

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Just now, eangulo said:

but I was looking for an explanation for this behaviour to explain it to my team.

I think it's an oversight that should be fixed - I think you should post a Github issue for Ryan to think about. He may not agree but I think that is the best way forward.

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