TYPO3 Core

Yes all caches were cleared, including opcode cache, even typo3temp-folder was cleared.

Do you by chance have some kind of a mixed state, like a load-balancing cluster with nodes that are not synched?
-> No there is no mixed state or sth. like this active.

I reproduced it in 4 installations.

Curious thing about the extension form:
By deactivating the extension "form" the bug is gone.
Even if i don't have any form created by the form extension on my site, the bug shows up.
The extension form just has to be installed and active.
After deactivating the form extension, it seems like that the bug is gone.

How are the affected installations set up? Classic installation or composer-based?

All of our affected installations are composer based. After updating to 8.7.17 the frontend and backend show the error "Core: Exception handler (WEB): Uncaught TYPO3 Exception: Undefined class constant ‘SIGNAL_PreFileCreate’".

Entering the install tool is possible but trying to delete the cache also triggers "Core: Exception handler (WEB): Uncaught TYPO3 Exception: Undefined class constant ‘SIGNAL_PreFileCreate’".

When checking the extensions in the install tool the install tool does show "forms" as unsupported extension and offers to uninstall the extension. When trying to uninstall the extension the exception shows up again. After manually editing the PackageStates.php removing the "forms" extension, the error is gone. If you need more feedback you can also drop me a message on the slack channel.

We experienced this issue on two instances, both classic setup.

I did the same: EXT:form manually removed from PackageStates.php. Then opened Extension Manager, made sure EXT:form is disabled (in both instances, we don't use forms).
A few days later, I re-enabled EXT:form via the Extension Manager (just as a test) and this seem to work, too.

• PHP version being used
• Is PHP opcache enabled or disabled?
• Is the installation based on Composer or using a classic tar.gz/zip package (typo3_src directory)
  • When using Composer, paste the require part for all typo3/cms and/or typo3/cms-* packages in your root composer.json file
• Does the file in typo3/sysext/core/Classes/Resource/ResourceStorageInterface.php contain the according SIGNAL_PreFileCreate constant in the TYPO3 source directory (either in typo3_src-* or vendor/typo3/cms/)?

The current assumption is, that after having updated the source files (either by using tar.gz/zip packages or Composer packages) the PHP opcache is not up-to-date. In order to clear PHP opcache, it's is possible to

• either gracefully restart the webserver (for mod_php and fcgid/fpm)
• or use a tool like http://gordalina.github.io/cachetool/ to purge caches - e.g. php cachetool.phar opcache:reset

Please also report back, in case the error does not exist on your side anymore.

Thanks in advance for your support!

PHP version used: PHP 7.0.30-0+deb9u1 (however, at the time of the TYPO3 update it could also be 7.0.27-0+deb9u1).
PHP opcache is enabled.
Installation uses classic setup.

# grep -n "PreFileCreate" typo3/sysext/core/Classes/Resource/ResourceStorageInterface.php

25:    const SIGNAL_PreFileCreate = 'preFileCreate';

I can't be 100% sure, but I doubt that the web server has been restarted (or the PHP opcache cleared forcibly) as part of our TYPO3 update process.

PHP Version: PHP 7.1.14
PHP opcache: enabled
Installation: classic setup

Does the file in typo3/sysext/core/Classes/Resource/ResourceStorageInterface.php contain the according SIGNAL_PreFileCreate constant?
Yes it does at line 25: const SIGNAL_PreFileCreate = 'preFileCreate';

We didn't restart our webserver or used a tool for purging caches.