Undefined class constant 'Monolog\Utils::DEFAULT_JSON_FLAGS'

Can anyone understand what is going on?

I searched for users in the backoffice, and suddenly I got a 500 with the following:

Fatal error: Uncaught Error: Undefined class constant ‘Monolog\Utils::DEFAULT_JSON_FLAGS’ in /customers/5/a/c/MYDOMAIN.se/httpd.www/vendor/monolog/monolog/src/Monolog/Handler/AbstractHandler.php:194 Stack trace: #0 /customers/5/a/c/MYDOMAIN.se/httpd.www/vendor/monolog/monolog/src/Monolog/Handler/AbstractHandler.php(113): Monolog\Handler\AbstractHandler->getDefaultFormatter() #1 /customers/5/a/c/MYDOMAIN.se/httpd.www/vendor/monolog/monolog/src/Monolog/Handler/AbstractProcessingHandler.php(37): Monolog\Handler\AbstractHandler->getFormatter() #2 /customers/5/a/c/MYDOMAIN.se/httpd.www/vendor/monolog/monolog/src/Monolog/Logger.php(344): Monolog\Handler\AbstractProcessingHandler->handle(Array) #3 /customers/5/a/c/MYDOMAIN.se/httpd.www/vendor/monolog/monolog/src/Monolog/Logger.php(470): Monolog\Logger->addRecord(500, ‘Undefined class…’, Array) #4 /customers/5/a/c/MYDOMAIN.se/httpd.www/system/src/Grav/Common/Errors/Errors.php(73): Monolog\Logger->addCritical(‘Undefined class…’) #5 /customers/5/a/c/MYDOMAIN.se/httpd.www/vendor/filp/w in /customers/5/a/c/MYDOMAIN.se/httpd.www/vendor/monolog/monolog/src/Monolog/Handler/AbstractHandler.php on line 194 Fatal error: Uncaught Error: Undefined class constant ‘Monolog\Utils::DEFAULT_JSON_FLAGS’ in /customers/5/a/c/MYDOMAIN.se/httpd.www/vendor/monolog/monolog/src/Monolog/Handler/AbstractHandler.php:194 Stack trace: #0 /customers/5/a/c/MYDOMAIN.se/httpd.www/vendor/monolog/monolog/src/Monolog/Handler/AbstractHandler.php(113): Monolog\Handler\AbstractHandler->getDefaultFormatter() #1 /customers/5/a/c/MYDOMAIN.se/httpd.www/vendor/monolog/monolog/src/Monolog/Handler/AbstractProcessingHandler.php(37): Monolog\Handler\AbstractHandler->getFormatter() #2 /customers/5/a/c/MYDOMAIN.se/httpd.www/vendor/monolog/monolog/src/Monolog/Logger.php(344): Monolog\Handler\AbstractProcessingHandler->handle(Array) #3 /customers/5/a/c/MYDOMAIN.se/httpd.www/vendor/monolog/monolog/src/Monolog/Logger.php(470): Monolog\Logger->addRecord(500, ‘Uncaught Error:…’, Array) #4 /customers/5/a/c/MYDOMAIN.se/httpd.www/system/src/Grav/Common/Errors/Errors.php(73): Monolog\Logger->addCritical(‘Uncaught Error:…’) #5 /customers/5/a/c/MYDOMAIN.se/httpd.www/vendor/filp/w in /customers/5/a/c/MYDOMAIN.se/httpd.www/vendor/monolog/monolog/src/Monolog/Handler/AbstractHandler.php on line 194

Hi @gravtedde
Have you recently updated grav or php at all ?

Can you let us know what version of Grav your running and what your current plugins running are and what version. Just grab a screenshot of your plugins directory.

First thing it may be good to do a full cache clean , if using the admin interface then use the ALL dropdown from the admin dashboard or use the command line

bin/grav clear-cache

Is it only when you search ?,
Do you see a list of users ?

Possibility of the user->accounts->admin.yaml is hitting an error

You can do the check with the command line

bin/grav yamllinter 

Are there any errors displayed there ?

Monolog is a found under the grav\vendor\monolog\ so its 3rd party library, which is used to do the logging of errors , so might not be the “problem” as something might be tripping it out before it gets time to log it properly.

Can you create a clean install and copy your user directory across to the new install and see if the problem is still there ?

With it being a 3rd party module, you could run

 bin/grav composer -u

to ensure all your vendors folder is up to date

You do have an existing site running

Is that correct, maybe there is something in the existing site interfering , maybe try and install to a sub directory as it look like you are doing this on a live server.

Make a directory called grav and then install a fresh copy there and access via your domain
mydomain.se/grav and see if works.

There isn’t much info to go on. Come back if you can give us more info and the results of a clean install to a sub directory.

**** After a bit of googling afterwards, the only thing I could find which relates to a similar person having an issue, is where the translator plugin is being used. This screenshot of your plugins folder might reveal more ***

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I upgraded core grav just before this hit. So something is related to that.

Thank you for your advice!

I will install a fresh one in a subdirectory and try that path first.

No Problem.
If you need to roll back to a previous version, presuming you upgraded to 7.15, use this link to go back to 7.14

https://github.com/getgrav/grav/tree/7.14

Please see the below post by pamtabbu

There was a few issues with on the 7.15 upgrade but a lot have been resolved with the current unreleased develop build and this can be found here.

GitHub - getgrav/grav: Modern, Crazy Fast, Ridiculously Easy and Amazingly Powerful Flat-File CMS

Please see the below post by pamtabbu

Let us know either way how things go :slight_smile:

Please note:
As advised by the Grav team, do not download releases from Github. The installation docs have been updated to reflect this.

Instead use the following format to download pre-packaged zips:
https://getgrav.org/download/TYPE/PACKAGE/VERSION

Where TYPE can be:

  • core
  • plugins
  • themes

PACKAGE:

  • grav
  • grav-admin
  • grav-update
  • name of plugin or theme

VERSION:

  • E.g. 1.7.14
1 Like