TYPO3 Core

I think this is still reproducible on version 12 (not tried 11 nor 13); I basically followed the guides here

- https://docs.typo3.org/c/typo3/cms-form/main/en-us/I/Concepts/Configuration/Index.html
- https://docs.typo3.org/c/typo3/cms-form/main/en-us/I/Concepts/FormFileStorages/Index.html

In detail

Prerequisites¶

- TYPO3 12.4.19
- a sitepackage EXT:my_site_package

Steps¶

1. I started creating a form inside the Form module (I used the default "Contact Form" example) and saved it as
public/fileadmin/form_definitions/simpleFormTest.form.yaml

2. I added the file EXT:my_site_package/Configuration/Form/CustomFormSetup.yaml

persistenceManager:
  allowedExtensionPaths:
    10: EXT:my_site_package/Resources/Private/Forms/

3. I edited EXT:my_site_package/ext_localconf.php by adding:

call_user_func(function () {
     \TYPO3\CMS\Core\Utility\ExtensionManagementUtility::addTypoScriptSetup(
         trim('
             module.tx_form {
                 settings {
                     yamlConfigurations {
                         100 = EXT:my_site_package/Configuration/Form/CustomFormSetup.yaml
                     }
                 }
             }
         ')
     );
});

4. I added to my TypoScript template:

plugin.tx_form {
    settings {
        yamlConfigurations {
            100 = EXT:my_site_package/Configuration/Form/CustomFormSetup.yaml
        }
    }
}

5. I moved the file public/fileadmin/form_definitions/simpleFormTest.form.yaml to EXT:my_site_package/Resources/Private/Forms/simpleFormTest.form.yaml

6. Cleared all cache with Install Tool

Results¶

The module Form shows the form definition "simpleFormTest" with the path EXT:my_site_package/Resources/Private/Forms/simpleFormTest.form.yaml

7. I added a form plugin CE inside a page, choosing the only form definition available
8. I went back to the Form module and the reference has been taken into account

9. I clicked on the "kebab menu" of the definition > choosed "show references for this form" from the dropdown

Results¶

- an empty Error message shows up on the bottom right corner (there is just the "Error" title)
- the Log module shows the entry:

Core: Exception handler (WEB): Uncaught TYPO3 Exception: #1633777536: Tried to access a private resource file "EXT:my_site_package/Resources/Private/Forms/simpleFormTest.form.yaml" from fallback compatibility storage. This storage only handles public files. | TYPO3\CMS\Core\Resource\Exception\ResourceDoesNotExistException thrown in file /var/www/html/vendor/typo3/cms-core/Classes/Resource/ResourceFactory.php in line 312. Requested URL: https://typo3.12.it.ddev.site/typo3/module/web/FormFormbuilder/FormManager/references?token=--AnonymizedToken--&formPersistenceIdentifier=EXT:my_site_package/Resources/Private/Forms/simpleFormTest.form.yaml