Add on_app_command_completion event

Fix #8126

discord/app_commands/tree.py

@@ -1189,6 +1189,8 @@ class CommandTree(Generic[ClientT]):
             if ctx_menu.on_error is not None:
                 await ctx_menu.on_error(interaction, e)
             await self.on_error(interaction, e)
+        else:
+            self.client.dispatch('app_command_completion', interaction, ctx_menu)
 
     async def interaction_check(self, interaction: Interaction, /) -> bool:
         """|coro|
@@ -1237,3 +1239,5 @@ class CommandTree(Generic[ClientT]):
         except AppCommandError as e:
             await command._invoke_error_handlers(interaction, e)
             await self.on_error(interaction, e)
+        else:
+            self.client.dispatch('app_command_completion', interaction, command)

docs/api.rst

@@ -215,6 +215,18 @@ App Commands
     :param payload: The raw event payload data.
     :type payload: :class:`RawAppCommandPermissionsUpdateEvent`
 
+.. function:: on_app_command_completion(interaction, command)
+
+    Called when a :class:`app_commands.Command` or :class:`app_commands.ContextMenu` has
+    successfully completed without error.
+
+    .. versionadded:: 2.0
+
+    :param interaction: The interaction of the command.
+    :type interaction: :class:`Interaction`
+    :param command: The command that completed successfully
+    :type command: Union[:class:`app_commands.Command`, :class:`app_commands.ContextMenu`]
+
 AutoMod
 ~~~~~~~~