sane-sync-music: prune directories left empty by sync

pkgs/additional/sane-scripts/src/sane-sync-music

@@ -280,6 +280,7 @@ class Sync:
         in_files = { p.relative_to(self.in_dir) for p in Path(self.in_dir).rglob("*") if not p.is_dir() }
         logger.info(f'found {len(in_files)} files in source')
 
+        # create a map from source path to dest path
         in_out_map = ((in_f, self.target_name(in_f)) for in_f in in_files)
         in_out_map = dict((in_f, out_f) for (in_f, out_f) in in_out_map if out_f is not None)
         logger.info(f'recognized {len(in_files)} source files as media')
@@ -323,7 +324,11 @@ class Sync:
         '''
         for f in files:
             logger.info(f'removing {f}')
-            self.encoder.remove(Path(self.out_dir) / f)
+            f = Path(self.out_dir) / f
+            self.encoder.remove(f)
+            # if the directory is empty after removing this file, then remove the directory (and possibly prune its parents too)
+            if not os.listdir(f.parent):
+                os.removedirs(f.parent)
 
     def copy_one(self, src_name: Path, dest_name: Path) -> None:
         '''