emacs remove macOS Tags when resave the file

Question

I found emacs cannot save the macOS tag when the file changed and save from buffer

I create a empty file with macOS tag

and use emacs to open it and write something

use C-x C-s to save and the tags in Finder disappeared

How could I have a method to reserve these tags when I resave it?

Answer 1

I don't know how the tags are implemented but if they are associated to the inode and not to the name you can try to set the variable backup-by-copying to t.

When emacs creates a backup normally renames the old file and create a new one with the new content (see the documentation), when backup-by-copying is t it copies the old file to create a backup and writes the new content in the old one.