QFile::copy is unable to copy locked file on MacOS

Steps to reproduce:

lock a file by right-clicking file and selecting 'Get Info' and then check the 'Locked' checkbox under the General tab.

execute code

QFile from(path_to_the_locked_file);
// use a USB drive to reproduce the issue
// don't know why but it works fine if the target is not external
from.copy(path_to_the_external_device);

expected behavior: - destination file is created with the same permissions as source file and content is copied.

actual behavior: error "Cannot create blabla for output" and destination file does not exist

the erroneous code is in the qfile.cpp QFile::copy method search for 

if (!d->engine()>cloneTo(out.d_func()>engine())) {

engine cloneTo tries to surprise surprise clone the file but out at this moment is TEMPORARY. So temporary file becomes LOCKED as well as source file because during clone metadata (including permissions) are copied. After this if statement there is

if (!error && !out.rename(newName)) {

Obviously, rename fails because the temporary out file is locked.

Possible solution:

implement cloneDataOnlyTo and cloneMetadataOnlyTo functions in the engine class that copies data and metadata only correspondingly. Replace 

if (!d->engine()>cloneTo(out.d_func()>engine())) {

onto

if (!d->engine()>cloneDataOnlyTo(out.d_func()>engine())) {

Replace 

if (!error && !out.rename(newName)) {

 onto

if (!error && !(out.rename(newName) && d->engine()>cloneMetadataOnlyTo(out.d_func()>engine())) {