[commands] Make `commands.Greedy` a `typing.Generic`

discord/ext/commands/converter.py

@@ -26,7 +26,7 @@ from __future__ import annotations
 
 import re
 import inspect
-from typing import TYPE_CHECKING, Generic, Protocol, TypeVar, Union, runtime_checkable
+from typing import TYPE_CHECKING, List, Protocol, TypeVar, Tuple, Union, runtime_checkable
 
 import discord
 from .errors import *
@@ -70,11 +70,12 @@ def _get_from_guilds(bot, getter, argument):
 
 
 _utils_get = discord.utils.get
-T = TypeVar('T', covariant=True)
+T = TypeVar('T')
+T_co = TypeVar('T_co', covariant=True)
 
 
 @runtime_checkable
-class Converter(Protocol[T]):
+class Converter(Protocol[T_co]):
     """The base class of custom converters that require the :class:`.Context`
     to be passed to be useful.
 
@@ -85,7 +86,7 @@ class Converter(Protocol[T]):
     method to do its conversion logic. This method must be a :ref:`coroutine <coroutine>`.
     """
 
-    async def convert(self, ctx: Context, argument: str) -> T:
+    async def convert(self, ctx: Context, argument: str) -> T_co:
         """|coro|
 
         The method to override to do conversion logic.
@@ -110,7 +111,8 @@ class Converter(Protocol[T]):
         """
         raise NotImplementedError('Derived classes need to implement this.')
 
-class IDConverter(Converter[T]):
+
+class IDConverter(Converter[T_co]):
     def __init__(self):
         self._id_regex = re.compile(r'([0-9]{15,20})$')
         super().__init__()
@@ -118,6 +120,7 @@ class IDConverter(Converter[T]):
     def _get_id_match(self, argument):
         return self._id_regex.match(argument)
 
+
 class MemberConverter(IDConverter[discord.Member]):
     """Converts to a :class:`~discord.Member`.
 
@@ -204,6 +207,7 @@ class MemberConverter(IDConverter[discord.Member]):
 
         return result
 
+
 class UserConverter(IDConverter[discord.User]):
     """Converts to a :class:`~discord.User`.
 
@@ -223,6 +227,7 @@ class UserConverter(IDConverter[discord.User]):
         This converter now lazily fetches users from the HTTP APIs if an ID is passed
         and it's not available in cache.
     """
+
     async def convert(self, ctx: Context, argument: str) -> discord.User:
         match = self._get_id_match(argument) or re.match(r'<@!?([0-9]+)>$', argument)
         result = None
@@ -263,6 +268,7 @@ class UserConverter(IDConverter[discord.User]):
 
         return result
 
+
 class PartialMessageConverter(Converter[discord.PartialMessage]):
     """Converts to a :class:`discord.PartialMessage`.
 
@@ -274,6 +280,7 @@ class PartialMessageConverter(Converter[discord.PartialMessage]):
     2. By message ID (The message is assumed to be in the context channel.)
     3. By message URL
     """
+
     @staticmethod
     def _get_id_matches(argument):
         id_regex = re.compile(r'(?:(?P<channel_id>[0-9]{15,20})-)?(?P<message_id>[0-9]{15,20})$')
@@ -285,8 +292,8 @@ class PartialMessageConverter(Converter[discord.PartialMessage]):
         match = id_regex.match(argument) or link_regex.match(argument)
         if not match:
             raise MessageNotFound(argument)
-        channel_id = match.group("channel_id")
-        return int(match.group("message_id")), int(channel_id) if channel_id else None
+        channel_id = match.group('channel_id')
+        return int(match.group('message_id')), int(channel_id) if channel_id else None
 
     async def convert(self, ctx: Context, argument: str) -> discord.PartialMessage:
         message_id, channel_id = self._get_id_matches(argument)
@@ -295,6 +302,7 @@ class PartialMessageConverter(Converter[discord.PartialMessage]):
             raise ChannelNotFound(channel_id)
         return discord.PartialMessage(channel=channel, id=message_id)
 
+
 class MessageConverter(IDConverter[discord.Message]):
     """Converts to a :class:`discord.Message`.
 
@@ -309,6 +317,7 @@ class MessageConverter(IDConverter[discord.Message]):
     .. versionchanged:: 1.5
          Raise :exc:`.ChannelNotFound`, :exc:`.MessageNotFound` or :exc:`.ChannelNotReadable` instead of generic :exc:`.BadArgument`
     """
+
     async def convert(self, ctx: Context, argument: str) -> discord.Message:
         message_id, channel_id = PartialMessageConverter._get_id_matches(argument)
         message = ctx.bot._connection._get_message(message_id)
@@ -324,6 +333,7 @@ class MessageConverter(IDConverter[discord.Message]):
         except discord.Forbidden:
             raise ChannelNotReadable(channel)
 
+
 class TextChannelConverter(IDConverter[discord.TextChannel]):
     """Converts to a :class:`~discord.TextChannel`.
 
@@ -339,6 +349,7 @@ class TextChannelConverter(IDConverter[discord.TextChannel]):
     .. versionchanged:: 1.5
          Raise :exc:`.ChannelNotFound` instead of generic :exc:`.BadArgument`
     """
+
     async def convert(self, ctx: Context, argument: str) -> discord.TextChannel:
         bot = ctx.bot
 
@@ -351,8 +362,10 @@ class TextChannelConverter(IDConverter[discord.TextChannel]):
             if guild:
                 result = discord.utils.get(guild.text_channels, name=argument)
             else:
+
                 def check(c):
                     return isinstance(c, discord.TextChannel) and c.name == argument
+
                 result = discord.utils.find(check, bot.get_all_channels())
         else:
             channel_id = int(match.group(1))
@@ -366,6 +379,7 @@ class TextChannelConverter(IDConverter[discord.TextChannel]):
 
         return result
 
+
 class VoiceChannelConverter(IDConverter[discord.VoiceChannel]):
     """Converts to a :class:`~discord.VoiceChannel`.
 
@@ -381,6 +395,7 @@ class VoiceChannelConverter(IDConverter[discord.VoiceChannel]):
     .. versionchanged:: 1.5
          Raise :exc:`.ChannelNotFound` instead of generic :exc:`.BadArgument`
     """
+
     async def convert(self, ctx: Context, argument: str) -> discord.VoiceChannel:
         bot = ctx.bot
         match = self._get_id_match(argument) or re.match(r'<#([0-9]+)>$', argument)
@@ -392,8 +407,10 @@ class VoiceChannelConverter(IDConverter[discord.VoiceChannel]):
             if guild:
                 result = discord.utils.get(guild.voice_channels, name=argument)
             else:
+
                 def check(c):
                     return isinstance(c, discord.VoiceChannel) and c.name == argument
+
                 result = discord.utils.find(check, bot.get_all_channels())
         else:
             channel_id = int(match.group(1))
@@ -407,6 +424,7 @@ class VoiceChannelConverter(IDConverter[discord.VoiceChannel]):
 
         return result
 
+
 class StageChannelConverter(IDConverter[discord.StageChannel]):
     """Converts to a :class:`~discord.StageChannel`.
 
@@ -421,6 +439,7 @@ class StageChannelConverter(IDConverter[discord.StageChannel]):
     2. Lookup by mention.
     3. Lookup by name
     """
+
     async def convert(self, ctx: Context, argument: str) -> discord.StageChannel:
         bot = ctx.bot
         match = self._get_id_match(argument) or re.match(r'<#([0-9]+)>$', argument)
@@ -432,8 +451,10 @@ class StageChannelConverter(IDConverter[discord.StageChannel]):
             if guild:
                 result = discord.utils.get(guild.stage_channels, name=argument)
             else:
+
                 def check(c):
                     return isinstance(c, discord.StageChannel) and c.name == argument
+
                 result = discord.utils.find(check, bot.get_all_channels())
         else:
             channel_id = int(match.group(1))
@@ -447,6 +468,7 @@ class StageChannelConverter(IDConverter[discord.StageChannel]):
 
         return result
 
+
 class CategoryChannelConverter(IDConverter[discord.CategoryChannel]):
     """Converts to a :class:`~discord.CategoryChannel`.
 
@@ -462,6 +484,7 @@ class CategoryChannelConverter(IDConverter[discord.CategoryChannel]):
     .. versionchanged:: 1.5
          Raise :exc:`.ChannelNotFound` instead of generic :exc:`.BadArgument`
     """
+
     async def convert(self, ctx: Context, argument: str) -> discord.CategoryChannel:
         bot = ctx.bot
 
@@ -474,8 +497,10 @@ class CategoryChannelConverter(IDConverter[discord.CategoryChannel]):
             if guild:
                 result = discord.utils.get(guild.categories, name=argument)
             else:
+
                 def check(c):
                     return isinstance(c, discord.CategoryChannel) and c.name == argument
+
                 result = discord.utils.find(check, bot.get_all_channels())
         else:
             channel_id = int(match.group(1))
@@ -489,6 +514,7 @@ class CategoryChannelConverter(IDConverter[discord.CategoryChannel]):
 
         return result
 
+
 class StoreChannelConverter(IDConverter[discord.StoreChannel]):
     """Converts to a :class:`~discord.StoreChannel`.
 
@@ -515,8 +541,10 @@ class StoreChannelConverter(IDConverter[discord.StoreChannel]):
             if guild:
                 result = discord.utils.get(guild.channels, name=argument)
             else:
+
                 def check(c):
                     return isinstance(c, discord.StoreChannel) and c.name == argument
+
                 result = discord.utils.find(check, bot.get_all_channels())
         else:
             channel_id = int(match.group(1))
@@ -530,6 +558,7 @@ class StoreChannelConverter(IDConverter[discord.StoreChannel]):
 
         return result
 
+
 class ColourConverter(Converter[discord.Colour]):
     """Converts to a :class:`~discord.Colour`.
 
@@ -612,8 +641,10 @@ class ColourConverter(Converter[discord.Colour]):
             raise BadColourArgument(arg)
         return method()
 
+
 ColorConverter = ColourConverter
 
+
 class RoleConverter(IDConverter[discord.Role]):
     """Converts to a :class:`~discord.Role`.
 
@@ -629,6 +660,7 @@ class RoleConverter(IDConverter[discord.Role]):
     .. versionchanged:: 1.5
          Raise :exc:`.RoleNotFound` instead of generic :exc:`.BadArgument`
     """
+
     async def convert(self, ctx: Context, argument: str) -> discord.Role:
         guild = ctx.guild
         if not guild:
@@ -644,11 +676,14 @@ class RoleConverter(IDConverter[discord.Role]):
             raise RoleNotFound(argument)
         return result
 
+
 class GameConverter(Converter[discord.Game]):
     """Converts to :class:`~discord.Game`."""
+
     async def convert(self, ctx: Context, argument: str) -> discord.Game:
         return discord.Game(name=argument)
 
+
 class InviteConverter(Converter[discord.Invite]):
     """Converts to a :class:`~discord.Invite`.
 
@@ -657,6 +692,7 @@ class InviteConverter(Converter[discord.Invite]):
     .. versionchanged:: 1.5
          Raise :exc:`.BadInviteArgument` instead of generic :exc:`.BadArgument`
     """
+
     async def convert(self, ctx: Context, argument: str) -> discord.Invite:
         try:
             invite = await ctx.bot.fetch_invite(argument)
@@ -664,6 +700,7 @@ class InviteConverter(Converter[discord.Invite]):
         except Exception as exc:
             raise BadInviteArgument() from exc
 
+
 class GuildConverter(IDConverter[discord.Guild]):
     """Converts to a :class:`~discord.Guild`.
 
@@ -690,6 +727,7 @@ class GuildConverter(IDConverter[discord.Guild]):
                 raise GuildNotFound(argument)
         return result
 
+
 class EmojiConverter(IDConverter[discord.Emoji]):
     """Converts to a :class:`~discord.Emoji`.
 
@@ -705,6 +743,7 @@ class EmojiConverter(IDConverter[discord.Emoji]):
     .. versionchanged:: 1.5
          Raise :exc:`.EmojiNotFound` instead of generic :exc:`.BadArgument`
     """
+
     async def convert(self, ctx: Context, argument: str) -> discord.Emoji:
         match = self._get_id_match(argument) or re.match(r'<a?:[a-zA-Z0-9\_]+:([0-9]+)>$', argument)
         result = None
@@ -733,6 +772,7 @@ class EmojiConverter(IDConverter[discord.Emoji]):
 
         return result
 
+
 class PartialEmojiConverter(Converter[discord.PartialEmoji]):
     """Converts to a :class:`~discord.PartialEmoji`.
 
@@ -741,6 +781,7 @@ class PartialEmojiConverter(Converter[discord.PartialEmoji]):
     .. versionchanged:: 1.5
          Raise :exc:`.PartialEmojiConversionFailure` instead of generic :exc:`.BadArgument`
     """
+
     async def convert(self, ctx: Context, argument: str) -> discord.PartialEmoji:
         match = re.match(r'<(a?):([a-zA-Z0-9\_]+):([0-9]+)>$', argument)
 
@@ -749,11 +790,13 @@ class PartialEmojiConverter(Converter[discord.PartialEmoji]):
             emoji_name = match.group(2)
             emoji_id = int(match.group(3))
 
-            return discord.PartialEmoji.with_state(ctx.bot._connection, animated=emoji_animated, name=emoji_name,
-                                                   id=emoji_id)
+            return discord.PartialEmoji.with_state(
+                ctx.bot._connection, animated=emoji_animated, name=emoji_name, id=emoji_id
+            )
 
         raise PartialEmojiConversionFailure(argument)
 
+
 class clean_content(Converter[str]):
     """Converts the argument to mention scrubbed version of
     said content.
@@ -773,6 +816,7 @@ class clean_content(Converter[str]):
 
         .. versionadded:: 1.7
     """
+
     def __init__(self, *, fix_channel_mentions=False, use_nicknames=True, escape_markdown=False, remove_markdown=False):
         self.fix_channel_mentions = fix_channel_mentions
         self.use_nicknames = use_nicknames
@@ -784,6 +828,7 @@ class clean_content(Converter[str]):
         transformations = {}
 
         if self.fix_channel_mentions and ctx.guild:
+
             def resolve_channel(id, *, _get=ctx.guild.get_channel):
                 ch = _get(id)
                 return f'<#{id}>', ('#' + ch.name if ch else '#deleted-channel')
@@ -791,15 +836,18 @@ class clean_content(Converter[str]):
             transformations.update(resolve_channel(channel) for channel in message.raw_channel_mentions)
 
         if self.use_nicknames and ctx.guild:
+
             def resolve_member(id, *, _get=ctx.guild.get_member):
                 m = _get(id)
                 return '@' + m.display_name if m else '@deleted-user'
+
         else:
+
             def resolve_member(id, *, _get=ctx.bot.get_user):
                 m = _get(id)
                 return '@' + m.name if m else '@deleted-user'
 
-
+        # fmt: off
         transformations.update(
             (f'<@{member_id}>', resolve_member(member_id))
             for member_id in message.raw_mentions
@@ -809,8 +857,10 @@ class clean_content(Converter[str]):
             (f'<@!{member_id}>', resolve_member(member_id))
             for member_id in message.raw_mentions
         )
+        # fmt: on
 
         if ctx.guild:
+
             def resolve_role(_id, *, _find=ctx.guild.get_role):
                 r = _find(_id)
                 return '@' + r.name if r else '@deleted-role'
@@ -818,7 +868,7 @@ class clean_content(Converter[str]):
             transformations.update(
                 (f'<@&{role_id}>', resolve_role(role_id))
                 for role_id in message.raw_role_mentions
-            )
+            )  # fmt: off
 
         def repl(obj):
             return transformations.get(obj.group(0), '')
@@ -834,28 +884,51 @@ class clean_content(Converter[str]):
         # Completely ensure no mentions escape:
         return discord.utils.escape_mentions(result)
 
-class _Greedy:
+
+class Greedy(List[T]):
+    r"""A special converter that greedily consumes arguments until it can't.
+    As a consequence of this behaviour, most input errors are silently discarded,
+    since it is used as an indicator of when to stop parsing.
+
+    When a parser error is met the greedy converter stops converting, undoes the
+    internal string parsing routine, and continues parsing regularly.
+
+    For example, in the following code:
+
+    .. code-block:: python3
+
+        @commands.command()
+        async def test(ctx, numbers: Greedy[int], reason: str):
+            await ctx.send("numbers: {}, reason: {}".format(numbers, reason))
+
+    An invocation of ``[p]test 1 2 3 4 5 6 hello`` would pass ``numbers`` with
+    ``[1, 2, 3, 4, 5, 6]`` and ``reason`` with ``hello``\.
+
+    For more information, check :ref:`ext_commands_special_converters`.
+    """
+
     __slots__ = ('converter',)
 
-    def __init__(self, *, converter=None):
+    def __init__(self, *, converter: T):
         self.converter = converter
 
-    def __getitem__(self, params):
+    def __class_getitem__(cls, params: Union[Tuple[T], T]) -> Greedy[T]:
         if not isinstance(params, tuple):
             params = (params,)
         if len(params) != 1:
             raise TypeError('Greedy[...] only takes a single argument')
         converter = params[0]
 
-        if not (callable(converter) or isinstance(converter, Converter) or hasattr(converter, '__origin__')):
+        origin = getattr(converter, '__origin__', None)
+        args = getattr(converter, '__args__', ())
+
+        if not (callable(converter) or isinstance(converter, Converter) or origin is not None):
             raise TypeError('Greedy[...] expects a type or a Converter instance.')
 
-        if converter is str or converter is type(None) or converter is _Greedy:
+        if converter in (str, type(None)) or origin is Greedy:
             raise TypeError(f'Greedy[{converter.__name__}] is invalid.')
 
-        if getattr(converter, '__origin__', None) is Union and type(None) in converter.__args__:
+        if origin is Union and type(None) in args:
             raise TypeError(f'Greedy[{converter!r}] is invalid.')
 
-        return self.__class__(converter=converter)
-
-Greedy = _Greedy()
+        return cls(converter=converter)

discord/ext/commands/core.py

@@ -560,7 +560,7 @@ class Command(_BaseCommand):
 
         # The greedy converter is simple -- it keeps going until it fails in which case,
         # it undos the view ready for the next parameter to use instead
-        if type(converter) is converters._Greedy:
+        if isinstance(converter, converters.Greedy):
             if param.kind == param.POSITIONAL_OR_KEYWORD or param.kind == param.POSITIONAL_ONLY:
                 return await self._transform_greedy_pos(ctx, param, required, converter.converter)
             elif param.kind == param.VAR_POSITIONAL:
@@ -1042,7 +1042,7 @@ class Command(_BaseCommand):
 
         result = []
         for name, param in params.items():
-            greedy = isinstance(param.annotation, converters._Greedy)
+            greedy = isinstance(param.annotation, converters.Greedy)
             optional = False  # postpone evaluation of if it's an optional argument
 
             # for typing.Literal[...], typing.Optional[typing.Literal[...]], and Greedy[typing.Literal[...]], the
@@ -1059,7 +1059,6 @@ class Command(_BaseCommand):
             if origin is typing.Literal:
                 name = '|'.join(f'"{v}"' if isinstance(v, str) else str(v)
                                 for v in self._flattened_typing_literal_args(annotation))
-
             if param.default is not param.empty:
                 # We don't want None or '' to trigger the [name=value] case and instead it should
                 # do [name] since [name=None] or [name=] are not exactly useful for the user.

docs/ext/commands/api.rst

@@ -323,27 +323,7 @@ Converters
 .. autoclass:: discord.ext.commands.clean_content
     :members:
 
-.. data:: ext.commands.Greedy
-
-    A special converter that greedily consumes arguments until it can't.
-    As a consequence of this behaviour, most input errors are silently discarded,
-    since it is used as an indicator of when to stop parsing.
-
-    When a parser error is met the greedy converter stops converting, undoes the
-    internal string parsing routine, and continues parsing regularly.
-
-    For example, in the following code:
-
-    .. code-block:: python3
-
-        @commands.command()
-        async def test(ctx, numbers: Greedy[int], reason: str):
-            await ctx.send(f"numbers: {numbers}, reason: {reason}")
-
-    An invocation of ``[p]test 1 2 3 4 5 6 hello`` would pass ``numbers`` with
-    ``[1, 2, 3, 4, 5, 6]`` and ``reason`` with ``hello``\.
-
-    For more information, check :ref:`ext_commands_special_converters`.
+.. autoclass:: ext.commands.Greedy()
 
 .. _ext_commands_api_errors: