Define a Command subclass with root alias support

A subclass is used because cogs make copies of Command objects. They do
this to allow multiple instances of a cog to be used. If the Command
class doesn't inherently support the `root_aliases` kwarg, it won't end
up being copied when a command gets copied.

`Command.__original_kwargs__` could be updated to include the new kwarg.
However, updating it and adding the attribute to the command wouldn't be
as elegant as passing a `Command` subclass as a `cls` attribute to the
`commands.command` decorator. This is because the former requires
copying the entire code of the decorator to add the two lines into the
nested function (it's a decorator with args, hence the nested function).

1 files changed, 15 insertions, 0 deletions

diff --git a/bot/command.py b/bot/command.py
new file mode 100644
index 000000000..92e61d97e
--- /dev/null
+++ b/bot/command.py
@@ -0,0 +1,15 @@
+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", [])