mount: make up volname if not given (macOS), fixes #7690

macFUSE supports a volname mount option to give what
finder displays on desktop / in directory list.

if the user did not specify it, we make something up,
because otherwise it would be "macFUSE Volume 0 (Python)".

src/borg/fuse.py

@@ -40,6 +40,7 @@ def async_wrapper(fn):
 from .item import Item
 from .lrucache import LRUCache
 from .platform import uid2user, gid2group
+from .platformflags import is_darwin
 from .remote import RemoteRepository
 
 
@@ -522,6 +523,13 @@ def pop_option(options, key, present, not_present, wanted_type, int_base=0):
         options = ['fsname=borgfs', 'ro', 'default_permissions']
         if mount_options:
             options.extend(mount_options.split(','))
+        if is_darwin:
+            # macFUSE supports a volname mount option to give what finder displays on desktop / in directory list.
+            volname = pop_option(options, 'volname', '', '', str)
+            # if the user did not specify it, we make something up,
+            # because otherwise it would be "macFUSE Volume 0 (Python)", #7690.
+            volname = volname or f"{os.path.basename(mountpoint)} (borgfs)"
+            options.append(f"volname={volname}")
         ignore_permissions = pop_option(options, 'ignore_permissions', True, False, bool)
         if ignore_permissions:
             # in case users have a use-case that requires NOT giving "default_permissions",