Prevent ghost-pings in docs get command

Won't delete the invoking message when the giving symbol is invalid if the message contains user/role mentions. If it has mentions, allows deletions of error message through reactions.

1 files changed, 25 insertions, 5 deletions

diff --git a/bot/exts/info/doc/_cog.py b/bot/exts/info/doc/_cog.py
index c54a3ee1c..b83c3c47e 100644
--- a/bot/exts/info/doc/_cog.py
+++ b/bot/exts/info/doc/_cog.py
@@ -10,6 +10,7 @@ from types import SimpleNamespace
 from typing import Dict, NamedTuple, Optional, Tuple, Union
 
 import aiohttp
+import asyncio
 import discord
 from discord.ext import commands
 
@@ -34,6 +35,7 @@ FORCE_PREFIX_GROUPS = (
     "pdbcommand",
     "2to3fixer",
 )
+DELETE_ERROR_MESSAGE_REACTION = '\u274c'  # :x:
 NOT_FOUND_DELETE_DELAY = RedirectOutput.delete_delay
 # Delay to wait before trying to reach a rescheduled inventory again, in minutes
 FETCH_RESCHEDULE_DELAY = SimpleNamespace(first=2, repeated=5)
@@ -340,11 +342,29 @@ class DocCog(commands.Cog):
 
             if doc_embed is None:
                 error_message = await send_denial(ctx, "No documentation found for the requested symbol.")
-                await wait_for_deletion(error_message, (ctx.author.id,), timeout=NOT_FOUND_DELETE_DELAY)
-                with suppress(discord.NotFound):
-                    await ctx.message.delete()
-                with suppress(discord.NotFound):
-                    await error_message.delete()
+
+                if ctx.message.mentions or ctx.message.role_mentions:
+                    await error_message.add_reaction(DELETE_ERROR_MESSAGE_REACTION)
+
+                    try:
+                        await self.bot.wait_for(
+                            'reaction_add',
+                            check=lambda reaction, user: reaction.message == error_message and user == ctx.author and str(reaction) == DELETE_ERROR_MESSAGE_REACTION,
+                            timeout=NOT_FOUND_DELETE_DELAY
+                        )
+
+                        with suppress(discord.HTTPException):
+                            await error_message.delete()
+
+                    except asyncio.TimeoutError:
+                        await error_message.clear_reaction(DELETE_ERROR_MESSAGE_REACTION)
+
+                else:
+                    await wait_for_deletion(error_message, (ctx.author.id,), timeout=NOT_FOUND_DELETE_DELAY)
+                    with suppress(discord.NotFound):
+                        await ctx.message.delete()
+                    with suppress(discord.NotFound):
+                        await error_message.delete()
             else:
                 msg = await ctx.send(embed=doc_embed)
                 await wait_for_deletion(msg, (ctx.author.id,))