The temp directory is not prepared in Drupal\Core\File\FileSystem::saveData

This issue is being reviewed by the kind folks in Slack, #needs-review-queue-initiative. We are working to keep the size of Needs Review queue [2700+ issues] to around 400 (1 month or less), following Review a patch or merge request → as a guide.

As a bug this will need a test case showing the issue.

liam morland → made their first commit to this issue’s fork.

I have rebased this on 11.x. The merge request needs to be updated to target 11.x. @DieterHolvoet can you do this?

How would a test for this be done?

I changed the target branch.