QByteArray::toDouble() behavior changed on whitespaces only string

On Qt 5.9 a string with only white-spaces (eg. '  ') passed to QByteArray::toDouble() will produce a failed convertion with the ok flag set to false.

But since at least Qt 5.12, the ok flag is now true.

While with QString::toDouble(), it remained false until now.

Tested on Qt 5.12, 5.15, 6.2, 6.8.

The attached program allows to the issue.

Qt 5.9 output:

QByteArray: "   " val: 0 ok: false
QByteArray: " " val: 0 ok: false
QByteArray: "" val: 0 ok: false
QString: "   " val: 0 ok: false
QString: " " val: 0 ok: false
QString: "" val: 0 ok: false 

Qt 5.12 and later output:

QByteArray: "   " val: 0 ok: true
QByteArray: " " val: 0 ok: true
QByteArray: "" val: 0 ok: false
QString: "   " val: 0 ok: false
QString: " " val: 0 ok: false
QString: "" val: 0 ok: false 

This seems like an old bug but I have not found any other issue on this or a documentation about this change.