Only expand '~' at the start of config paths

Every '~' in inputs and backup_dir was replaced with '~user', so
paths like 'notes~' or '~otheruser' did not match. Expand only a
leading '~' or '~/'.

simple_backup/simple_backup.py

@@ -697,6 +697,15 @@ def _parse_arguments() -> argparse.Namespace:
     return args
 
 
+def _expand_home(path: str, user: str) -> str:
+    """Expand a leading '~' to the home directory of user (other '~' are left as they are)"""
+
+    if path == '~' or path.startswith('~/'):
+        path = f'~{user}{path[1:]}'
+
+    return os.path.expanduser(path)
+
+
 def _expand_inputs(inputs, user: Optional[str] = None):
     expanded_inputs = []
 
@@ -705,11 +714,11 @@ def _expand_inputs(inputs, user: Optional[str] = None):
             continue
 
         if user is not None:
-            i_ex = glob(os.path.expanduser(i.replace('~', f'~{user}')))
+            i_ex = glob(_expand_home(i, user))
         else:
             i_ex = glob(i)
 
-            if '~' in i:
+            if i.startswith('~'):
                 logger.warning('Cannot expand \'~\'. No user specified')
 
         if len(i_ex) == 0:
@@ -762,8 +771,8 @@ def _read_config(config_file, user: Optional[str] = None):
     output = config.get(section, 'backup_dir')
 
     if user is not None:
-        output = os.path.expanduser(output.replace('~', f'~{user}'))
+        output = _expand_home(output, user)
-    elif user is None and '~' in output:
+    elif user is None and output.startswith('~'):
         logger.warning('Cannot expand \'~\', no user specified')
 
     config_args['output'] = output