Fix bound method autocomplete callbacks not working

This also adds some regression tests

discord/app_commands/commands.py

@@ -233,8 +233,9 @@ def _validate_auto_complete_callback(
     binding = getattr(callback, '__self__', None)
     if binding is not None:
         callback = callback.__func__
-
+        requires_binding = True
-    requires_binding = (binding is None and is_inside_class(callback)) or skip_binding
+    else:
+        requires_binding = is_inside_class(callback) or skip_binding
 
     callback.requires_binding = requires_binding
     callback.binding = binding

tests/test_app_commands_autocomplete.py

@@ -0,0 +1,130 @@
+"""
+The MIT License (MIT)
+
+Copyright (c) 2015-present Rapptz
+
+Permission is hereby granted, free of charge, to any person obtaining a
+copy of this software and associated documentation files (the "Software"),
+to deal in the Software without restriction, including without limitation
+the rights to use, copy, modify, merge, publish, distribute, sublicense,
+and/or sell copies of the Software, and to permit persons to whom the
+Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
+"""
+
+from __future__ import annotations
+from typing import List
+
+import discord
+import pytest
+from discord import app_commands
+from discord.utils import MISSING
+
+
+async def free_function_autocomplete(interaction: discord.Interaction, current: str) -> List[app_commands.Choice[str]]:
+    return []
+
+
+async def invalid_free_function(self, interaction: discord.Interaction, current: str) -> List[app_commands.Choice[str]]:
+    return []
+
+
+class X(app_commands.Transformer):
+    @classmethod
+    async def autocomplete(cls, interaction: discord.Interaction, current: str) -> List[app_commands.Choice[str]]:
+        return []
+
+
+class ClassBased:
+    async def autocomplete(self, interaction: discord.Interaction, current: str) -> List[app_commands.Choice[str]]:
+        return []
+
+    async def invalid(self, interaction: discord.Interaction, current: str, bad: int) -> List[app_commands.Choice[str]]:
+        return []
+
+
+lookup = ClassBased()
+bound_autocomplete = lookup.autocomplete
+invalid_bound_autocomplete = lookup.invalid
+
+
+def test_free_function_autocomplete():
+    @app_commands.command()
+    @app_commands.autocomplete(name=free_function_autocomplete)
+    async def cmd(interaction: discord.Interaction, name: str):
+        ...
+
+    param = cmd._params['name']
+    assert param.autocomplete is not MISSING
+    assert param.autocomplete.binding is None  # type: ignore
+    assert not param.autocomplete.requires_binding  # type: ignore
+
+
+def test_invalid_free_function_autocomplete():
+    with pytest.raises(TypeError):
+
+        @app_commands.command()
+        @app_commands.autocomplete(name=invalid_free_function)
+        async def cmd(interaction: discord.Interaction, name: str):
+            ...
+
+
+def test_transformer_autocomplete():
+    @app_commands.command()
+    async def cmd(interaction: discord.Interaction, param: app_commands.Transform[str, X]):
+        ...
+
+    param = cmd._params['param']
+    assert param.autocomplete is not MISSING
+    assert param.autocomplete.binding is X  # type: ignore
+    assert param.autocomplete.requires_binding  # type: ignore
+
+
+def test_bound_function_autocomplete():
+    @app_commands.command()
+    @app_commands.autocomplete(name=bound_autocomplete)
+    async def cmd(interaction: discord.Interaction, name: str):
+        ...
+
+    param = cmd._params['name']
+    assert param.autocomplete is not MISSING
+    assert param.autocomplete.binding is lookup  # type: ignore
+    assert param.autocomplete.requires_binding  # type: ignore
+
+
+def test_invalid_bound_function_autocomplete():
+    with pytest.raises(TypeError):
+
+        @app_commands.command()
+        @app_commands.autocomplete(name=invalid_bound_autocomplete)  # type: ignore
+        async def cmd(interaction: discord.Interaction, name: str):
+            ...
+
+
+def test_group_function_autocomplete():
+    class MyGroup(app_commands.Group):
+        @app_commands.command()
+        async def foo(self, interaction: discord.Interaction, name: str):
+            ...
+
+        @foo.autocomplete('name')
+        async def autocomplete(self, interaction: discord.Interaction, current: str) -> List[app_commands.Choice[str]]:
+            return []
+
+    g = MyGroup()
+    param = g.foo._params['name']
+
+    assert param.autocomplete is not MISSING
+    # Note: The binding is filled later when actually invoked
+    assert param.autocomplete.binding is None  # type: ignore
+    assert param.autocomplete.requires_binding  # type: ignore

tests/test_app_commands_invoke.py

@@ -104,9 +104,7 @@ class MockTree(discord.app_commands.CommandTree):
         self.last_exception = None
         return await super().call(interaction)
 
-    async def on_error(
+    async def on_error(self, interaction: discord.Interaction, error: discord.app_commands.AppCommandError) -> None:
-        self, interaction: discord.Interaction, error: discord.app_commands.AppCommandError
-    ) -> None:
         self.last_exception = error