Feature Request

Note that Proton installation and game installation can be in different libraries in different drives (different mount points). Plain relative path might not handle this correctly.

What is your case for "base path changes"? Automount-generated paths or something?

able to reproduce the issue you're seeing with mainline Proton

In the mentioned and linked code i can see the lines responsible for the issue. Dont't you think that the behaviour described is the currently intended behaviour?

What is your case for "base path changes"? Automount-generated paths or something?

Yes, for example. To clarify the mentioned

for example in different environments or after reboots, a disk mount path may change

In my case, i am using different distros using a shared disk for storing games. So the mount path changes because one mounts it under /run/media, the other under /media.
So while you are right, it makes sense to have immutable paths and a clean solution in that case would be to ensure that, that's sadly not possible/adviseable/good practise here.

Note that Proton installation and game installation can be in different libraries in different drives (different mount points). Plain relative path might not handle this correctly.

Not quite sure about this, could you give me an example? In my case, a working workaround, was to replace the softlink at
/run/media/username/disk_name/Heroic/prefix/pfx/drive_c/users/steamuser/Documents
from
/run/media/username/disk_name/Heroic/prefix/pfx/drive_c/users/steamuser/My Documents
to
./My Documents
(as far as i remember)

This is a reasonable request, but I'd like to pin down exactly what's happening here.

For the Documents symlink you mention, we should be updating it automatically if it is run with a new path, see this chunk from the proton script:

    def migrate_user_paths(self):
        #move winxp-style paths to vista+ paths. we can't do this in
        #upgrade_pfx because Steam may drop cloud files here at any time.
        for (old, new, link) in \
                [
                    ("drive_c/users/steamuser/Local Settings/Application Data",
                        self.prefix_dir + "drive_c/users/steamuser/AppData/Local",
                        "../AppData/Local"),
                    ("drive_c/users/steamuser/Application Data",
                        self.prefix_dir + "drive_c/users/steamuser/AppData/Roaming",
                        "./AppData/Roaming"),
                    ("drive_c/users/steamuser/My Documents",
                        self.prefix_dir + "drive_c/users/steamuser/Documents",
                        "./Documents"),
                ]:

            #running unofficial Proton/Wine builds against a Proton prefix could
            #create an infinite symlink loop. detect this and clean it up.
            if os.path.lexists(new) and os.path.islink(new) and os.readlink(new).endswith(old):
                os.remove(new)

            old = self.prefix_dir + old

            if os.path.lexists(old) and not os.path.islink(old):
                merge_user_dir(src=old, dst=new)
                os.rename(old, old + " BACKUP")
            if not os.path.lexists(old):
                makedirs(os.path.dirname(old))
                os.symlink(src=link, dst=old)
>>>         elif os.path.islink(old) and not (os.readlink(old) == link):
>>>             os.remove(old)
>>>             os.symlink(src=link, dst=old)

Can you look into why the symlink isn't being recreated with the correct path after your prefix path has changed?

@aeikum I'm sorry, but i cannot reproduce my own issue now. After switching the different Proton versions and deleting the soft links the issue disappeared and links are created as they should. Sorry for wasting your time, if the problem arises again i will reopen.

No problem, always happy to field well-written bug reports like this. If you do figure out repro steps, let us know.