Bind mount doesn't allow to trash files and directories

Recently I hitted a wrong behavior that (I think) could be improved.

Im using xfce 4.16 and thunar 4.16.10 on gentoo.

Preparation

On your system, as root, create one directory like this :

# mkdir /home/foo

Always as root, chown this directory to your regular user :

# chown user:user /home/foo

You should have something like this :

$ ls -ld /home/foo
drwxr-xr-x 2 user user 4096 15 janv. 20:22 /home/foo

With your regular user, in your ~, create this directory :

$ mkdir ~/foo

As root, bind those two directories :

# mount -o bind /home/foo /home/user/foo

Now, with your regular user, create two files in this directory :

$ cd ~/foo
$ touch empty1 empty2

Run thunar with your regular user like this :

$ thunar /home/foo

In thunar, right click on empty2 file, send it to trash. It works.

Run thunar with your regular user like this :

$ thunar ~/foo

In thunar, right click on empty1 file, send it to trash. It does not work.

You cannot send files to trash from bind mounted directories.

Years ago, a bug was opened on kernel bugzilla⁽¹⁾. The answer was :

Your best bet is to file a bug against your desktop environment vendor and ask to implement EXDEV:copy+unlink fallback.

Thank you.