This is the companion setting to canUpload, letting you control whether existing files from the asset store can be referenced. It's particularly useful when using UploadField on the front-end.
The entire framework repo (with the exception of system-generated files) has been amended to respect the 120c line-length limit. This is in preparation for the enforcement of this rule with PHP_CodeSniffer.
UploadField was relying entirely on the File::get_class_for_file_extension to
select a class, so it could only create File or Image objects. This
would break the relationships based on derived objects. Also make it
respect the FileField::relationAutoSetting.
DataObject::get_one returns false if not found, so better check for
object. Also, the directory would not be cleaned, so on the subsequent
run the files could end up having suffixes.
missed this one
