ConfigFormBase produces an error when saving empty number value from the form to a numeric schema item: This value should be of the correct primitive type

The validation error appears in the core/lib/Drupal/Core/Validation/Plugin/Validation/Constraint/PrimitiveTypeConstraintValidator.php file when it uses the function filter_var() having the empty string ('') in the$value:

    if ($typed_data instanceof IntegerInterface && filter_var($value, FILTER_VALIDATE_INT) === FALSE) {
      $valid = FALSE;
    }

So, seems the easiest solution is to cast the value to the "int" type (and the same - for float), something like this:

    if ($typed_data instanceof IntegerInterface && filter_var((int) $value, FILTER_VALIDATE_INT) === FALSE) {
      $valid = FALSE;
    }

I prepared a MR https://git.drupalcode.org/project/drupal/-/merge_requests/11998 with this fix, which resolves the issue. But not sure that this is the correct fix, and seems we should cover this with tests, so marking the issue as "Needs Review" to get the feedback.

Thanks for reporting and getting an MR already. Appears to have a pipeline failure.

Also can we get a test case showing the problem as a next step.

Thanks

I created a separate MR https://git.drupalcode.org/project/drupal/-/merge_requests/11998 representing the issue and the failing test.
And updated the MR to fix the issue and make the same test pass.
Please review.

smustgrave → closed merge request !12013

Removing tests tag after running test-only feature https://git.drupalcode.org/issue/drupal-3522116/-/jobs/5129880

Change seems straight forward and didn't break existing tests so don't think have to worry about breaking other stuff.

LGTM

I have only read the title here and tagging for a title update.

The title should be a description of what is being fixed or improved. The title is used as the git commit message so it should be meaningful and concise. See List of issue fields → .

I updated the issue title, please check if the name suits the rules now.

Attach a static patch file with those changes, to make it possible to use in composer until 🐛 GitLab Merge Requests Unable to Generate Incremental Patch Files Active is resolved.

Title has been updated

How is that casted back to a numeric then? Do we need to use int|string everywhere?
I'm not sure this is the way forward. I'd prefer it to be nullable than allowing a string.