Add root alias support for commands

5 files changed, 73 insertions, 2 deletions

diff --git a/bot/__init__.py b/bot/__init__.py
index bdb18666..c8550537 100644
--- a/bot/__init__.py
+++ b/bot/__init__.py
@@ -2,10 +2,13 @@ import asyncio
 import logging
 import logging.handlers
 import os
+from functools import partial, partialmethod
 from pathlib import Path
 
 import arrow
+from discord.ext import commands
 
+from bot.command import Command
 from bot.constants import Client
 
 
@@ -70,3 +73,9 @@ logging.getLogger().info('Logging initialization complete')
 # On Windows, the selector event loop is required for aiodns.
 if os.name == "nt":
     asyncio.set_event_loop_policy(asyncio.WindowsSelectorEventLoopPolicy())
+
+
+# Monkey-patch discord.py decorators to use the Command subclass which supports root aliases.
+# Must be patched before any cogs are added.
+commands.command = partial(commands.command, cls=Command)
+commands.GroupMixin.command = partialmethod(commands.GroupMixin.command, cls=Command)
diff --git a/bot/bot.py b/bot/bot.py
index 97b09243..f51139bb 100644
--- a/bot/bot.py
+++ b/bot/bot.py
@@ -64,6 +64,26 @@ class Bot(commands.Bot):
         super().add_cog(cog)
         log.info(f"Cog loaded: {cog.qualified_name}")
 
+    def add_command(self, command: commands.Command) -> None:
+        """Add `command` as normal and then add its root aliases to the bot."""
+        super().add_command(command)
+        self._add_root_aliases(command)
+
+    def remove_command(self, name: str) -> Optional[commands.Command]:
+        """
+        Remove a command/alias as normal and then remove its root aliases from the bot.
+
+        Individual root aliases cannot be removed by this function.
+        To remove them, either remove the entire command or manually edit `bot.all_commands`.
+        """
+        command = super().remove_command(name)
+        if command is None:
+            # Even if it's a root alias, there's no way to get the Bot instance to remove the alias.
+            return
+
+        self._remove_root_aliases(command)
+        return command
+
     async def on_command_error(self, context: commands.Context, exception: DiscordException) -> None:
         """Check command errors for UserInputError and reset the cooldown if thrown."""
         if isinstance(exception, commands.UserInputError):
@@ -124,6 +144,27 @@ class Bot(commands.Bot):
         """
         await self._guild_available.wait()
 
+    def _add_root_aliases(self, command: commands.Command) -> None:
+        """Recursively add root aliases for `command` and any of its subcommands."""
+        if isinstance(command, commands.Group):
+            for subcommand in command.commands:
+                self._add_root_aliases(subcommand)
+
+        for alias in getattr(command, "root_aliases", ()):
+            if alias in self.all_commands:
+                raise commands.CommandRegistrationError(alias, alias_conflict=True)
+
+            self.all_commands[alias] = command
+
+    def _remove_root_aliases(self, command: commands.Command) -> None:
+        """Recursively remove root aliases for `command` and any of its subcommands."""
+        if isinstance(command, commands.Group):
+            for subcommand in command.commands:
+                self._remove_root_aliases(subcommand)
+
+        for alias in getattr(command, "root_aliases", ()):
+            self.all_commands.pop(alias, None)
+
 
 _allowed_roles = [discord.Object(id_) for id_ in constants.MODERATION_ROLES]
 
diff --git a/bot/command.py b/bot/command.py
new file mode 100644
index 00000000..0fb900f7
--- /dev/null
+++ b/bot/command.py
@@ -0,0 +1,18 @@
+from discord.ext import commands
+
+
+class Command(commands.Command):
+    """
+    A `discord.ext.commands.Command` subclass which supports root aliases.
+
+    A `root_aliases` keyword argument is added, which is a sequence of alias names that will act as
+    top-level commands rather than being aliases of the command's group. It's stored as an attribute
+    also named `root_aliases`.
+    """
+
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.root_aliases = kwargs.get("root_aliases", [])
+
+        if not isinstance(self.root_aliases, (list, tuple)):
+            raise TypeError("Root aliases of a command must be a list or a tuple of strings.")
diff --git a/bot/exts/evergreen/help.py b/bot/exts/evergreen/help.py
index 91147243..f557e42e 100644
--- a/bot/exts/evergreen/help.py
+++ b/bot/exts/evergreen/help.py
@@ -289,7 +289,9 @@ class HelpSession:
             parent = self.query.full_parent_name + ' ' if self.query.parent else ''
             paginator.add_line(f'**```{prefix}{parent}{signature}```**')
 
-            aliases = ', '.join(f'`{a}`' for a in self.query.aliases)
+            aliases = [f"`{alias}`" if not parent else f"`{parent} {alias}`" for alias in self.query.aliases]
+            aliases += [f"`{alias}`" for alias in getattr(self.query, "root_aliases", ())]
+            aliases = ", ".join(sorted(aliases))
             if aliases:
                 paginator.add_line(f'**Can also use:** {aliases}\n')
 
diff --git a/bot/exts/evergreen/pfp_modify.py b/bot/exts/evergreen/pfp_modify.py
index 4245432e..a3f7e3f8 100644
--- a/bot/exts/evergreen/pfp_modify.py
+++ b/bot/exts/evergreen/pfp_modify.py
@@ -139,12 +139,13 @@ class PfpModify(commands.Cog):
         await ctx.send(file=file, embed=embed)
 
     @commands.max_concurrency(1, commands.BucketType.guild, wait=True)
+    @commands.group()
     async def pfp_modify(self, ctx: commands.Context) -> None:
         """Groups all of the pfp modifing commands to allow a single concurrency limit."""
         if not ctx.invoked_subcommand:
             await ctx.send_help(ctx.command)
 
-    @pfp_modify.command(name="8bitify")
+    @pfp_modify.command(name="8bitify", root_aliases=("8bitify",))
     async def eightbit_command(self, ctx: commands.Context) -> None:
         """Pixelates your avatar and changes the palette to an 8bit one."""
         async with ctx.typing():