typing: add type hints to `i18n._msgcache`

Since 10db46e128d4, pytype stopped inferring that the key is bytes.

mercurial/i18n.py

@@ -1,123 +1,126 b''
 # i18n.py - internationalization support for mercurial
 #
 # Copyright 2005, 2006 Olivia Mackall <[e-mail]>
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 
 import gettext as gettextmod
 import locale
 import os
 import sys
 
 from typing import (
+    Dict,
     List,
 )
 
 from .utils import resourceutil
 from . import (
     encoding,
     pycompat,
 )
 
 # modelled after templater.templatepath:
 if getattr(sys, 'frozen', None) is not None:
     module = pycompat.sysexecutable
 else:
     module = pycompat.fsencode(__file__)
 
 _languages = None
 if (
     pycompat.iswindows
     and b'LANGUAGE' not in encoding.environ
     and b'LC_ALL' not in encoding.environ
     and b'LC_MESSAGES' not in encoding.environ
     and b'LANG' not in encoding.environ
 ):
     # Try to detect UI language by "User Interface Language Management" API
     # if no locale variables are set. Note that locale.getdefaultlocale()
     # uses GetLocaleInfo(), which may be different from UI language.
     # (See http://msdn.microsoft.com/en-us/library/dd374098(v=VS.85).aspx )
     try:
         import ctypes
 
         # pytype: disable=module-attr
         langid = ctypes.windll.kernel32.GetUserDefaultUILanguage()
         # pytype: enable=module-attr
 
         _languages = [locale.windows_locale[langid]]
     except (ImportError, AttributeError, KeyError):
         # ctypes not found or unknown langid
         pass
 
 
 datapath = pycompat.fsdecode(resourceutil.datapath)
 localedir = os.path.join(datapath, 'locale')
 t = gettextmod.translation('hg', localedir, _languages, fallback=True)
 try:
     _ugettext = t.ugettext  # pytype: disable=attribute-error
 except AttributeError:
     _ugettext = t.gettext
 
 
-_msgcache = {}  # encoding: {message: translation}
+_msgcache: Dict[
+    bytes, Dict[bytes, bytes]
+] = {}  # encoding: {message: translation}
 
 
 def gettext(message: bytes) -> bytes:
     """Translate message.
 
     The message is looked up in the catalog to get a Unicode string,
     which is encoded in the local encoding before being returned.
 
     Important: message is restricted to characters in the encoding
     given by sys.getdefaultencoding() which is most likely 'ascii'.
     """
     # If message is None, t.ugettext will return u'None' as the
     # translation whereas our callers expect us to return None.
     if message is None or not _ugettext:
         return message
 
     cache = _msgcache.setdefault(encoding.encoding, {})
     if message not in cache:
         if type(message) is str:
             # goofy unicode docstrings in test
             paragraphs: List[str] = message.split(u'\n\n')
         else:
             # should be ascii, but we have unicode docstrings in test, which
             # are converted to utf-8 bytes on Python 3.
             paragraphs = [p.decode("utf-8") for p in message.split(b'\n\n')]
         # Be careful not to translate the empty string -- it holds the
         # meta data of the .po file.
         u = u'\n\n'.join([p and _ugettext(p) or u'' for p in paragraphs])
         try:
             # encoding.tolocal cannot be used since it will first try to
             # decode the Unicode string. Calling u.decode(enc) really
             # means u.encode(sys.getdefaultencoding()).decode(enc). Since
             # the Python encoding defaults to 'ascii', this fails if the
             # translated string use non-ASCII characters.
             encodingstr = pycompat.sysstr(encoding.encoding)
             cache[message] = u.encode(encodingstr, "replace")
         except LookupError:
             # An unknown encoding results in a LookupError.
             cache[message] = message
     return cache[message]
 
 
 def _plain():
     if (
         b'HGPLAIN' not in encoding.environ
         and b'HGPLAINEXCEPT' not in encoding.environ
     ):
         return False
     exceptions = encoding.environ.get(b'HGPLAINEXCEPT', b'').strip().split(b',')
     return b'i18n' not in exceptions
 
 
 if _plain():
 
     def _(message: bytes) -> bytes:
         return message
 
 else:
     _ = gettext