chore: remove deprecated function wrappers and fix bytes bug

Remove unused deprecated wrappers with no callers in the codebase:
- common.py: decode_string(), utf8_encoded()
- client.py: start_classic_mode(), stop_classic_mode(), is_classicmode()
- torrent.py: set_prioritize_first_last(), set_save_path()

Fix Python 2 bytes-formatting bug in client.py start_daemon() where
b'--config=%s' % config mixed bytes format strings with encoded paths.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: flound1129

deluge/common.py

@@ -31,7 +31,6 @@
 from urllib.parse import unquote_plus, urljoin
 from urllib.request import pathname2url
 
-from deluge.decorators import deprecated
 from deluge.error import InvalidPathError
 
 try:
@@ -1107,18 +1106,6 @@ def decode_bytes(byte_str, encoding='utf8'):
     return ''
 
 
-@deprecated
-def decode_string(byte_str, encoding='utf8'):
-    """Deprecated: Use decode_bytes"""
-    return decode_bytes(byte_str, encoding)
-
-
-@deprecated
-def utf8_encoded(str_, encoding='utf8'):
-    """Deprecated: Use encode or decode_bytes if needed"""
-    return decode_bytes(str_, encoding).encode('utf8')
-
-
 def utf8_encode_structure(data):
     """Recursively convert all unicode keys and values in a data structure to utf8.
 

deluge/core/torrent.py

@@ -27,7 +27,6 @@
 from deluge.common import decode_bytes
 from deluge.configmanager import ConfigManager, get_config_dir
 from deluge.core.authmanager import AUTH_LEVEL_ADMIN
-from deluge.decorators import deprecated
 from deluge.event import (
     TorrentFolderRenamedEvent,
     TorrentStateChangedEvent,
@@ -387,11 +386,6 @@ def set_max_download_speed(self, m_down_speed):
             value = int(m_down_speed * 1024)
         self.handle.set_download_limit(value)
 
-    @deprecated
-    def set_prioritize_first_last(self, prioritize):
-        """Deprecated: Use set_prioritize_first_last_pieces."""
-        self.set_prioritize_first_last_pieces(prioritize)
-
     def set_prioritize_first_last_pieces(self, prioritize):
         """Prioritize the first and last pieces in the torrent.
 
@@ -570,11 +564,6 @@ def set_file_priorities(self, file_priorities):
         if self.options['prioritize_first_last_pieces']:
             self.set_prioritize_first_last_pieces(True)
 
-    @deprecated
-    def set_save_path(self, download_location):
-        """Deprecated: Use set_download_location."""
-        self.set_download_location(download_location)
-
     def set_download_location(self, download_location):
         """The location for downloading torrent data."""
         self.options['download_location'] = download_location

deluge/ui/client.py

@@ -16,7 +16,6 @@
 
 from deluge import error
 from deluge.common import VersionSplit, get_localhost_auth, get_version
-from deluge.decorators import deprecated
 from deluge.transfer import DelugeTransferProtocol
 
 RPC_RESPONSE = 1
@@ -646,16 +645,6 @@ def stop_standalone(self):
         self._daemon_proxy = None
         self.__started_standalone = False
 
-    @deprecated
-    def start_classic_mode(self):
-        """Deprecated: Use start_standalone"""
-        self.start_standalone()
-
-    @deprecated
-    def stop_classic_mode(self):
-        """Deprecated: Use stop_standalone"""
-        self.stop_standalone()
-
     def start_daemon(self, port, config):
         """Starts a daemon process.
 
@@ -667,10 +656,8 @@ def start_daemon(self, port, config):
             bool: True is successfully started the daemon, False otherwise.
 
         """
-        # subprocess.popen does not work with unicode args (with non-ascii characters) on windows
-        config = config.encode(sys.getfilesystemencoding())
         try:
-            subprocess.Popen(['deluged', '--port=%s' % port, b'--config=%s' % config])
+            subprocess.Popen(['deluged', f'--port={port}', f'--config={config}'])
         except OSError as ex:
             from errno import ENOENT
 
@@ -714,11 +701,6 @@ def is_standalone(self):
         """
         return self.__started_standalone
 
-    @deprecated
-    def is_classicmode(self):
-        """Deprecated: Use is_standalone"""
-        self.is_standalone()
-
     def connected(self):
         """
         Check to see if connected to a daemon.