gracefully handle invalid regexes

nomen/notifications.py

@@ -5,6 +5,7 @@ from typing import Union
 
 from disnake import Embed, Member, Thread, User
 from disnake.abc import GuildChannel
+from disnake.errors import Forbidden
 from disnake.ext.commands import Cog, group, guild_only
 
 from .utils import can_view, confirm, test_keyword
@@ -64,10 +65,16 @@ async def handle_notification(db_updates, ctx, message, keyword, user_id, use_em
             icon_url=message.author.display_avatar,
         )
 
+        try:
             await member.send(header, embed=embed)
+        except Forbidden:
+            log.warning("Cannot send messages to this user")
     else:
         log.debug("Sending plain message")
+        try:
             await member.send("\n".join((header, indent(message.content, "> ", lambda line: True).strip(), footer)))
+        except Forbidden:
+            log.warning("Cannot send messages to this user")
 
     log.debug("Sent")
 

nomen/settings.py

@@ -148,6 +148,10 @@ You may want to `{ctx.clean_prefix}nomen export` first"""
         You will not trigger anyone else's notifications, and you will not receive any notifications
         """
 
+        if await ctx.bot.get_setting(ctx.author.id, "disabled"):
+            await ctx.send("You are already opted-out")
+            return
+
         log.debug(f"Opting-out: {ctx.author} ({ctx.author.id})")
 
         await ctx.send(
@@ -163,6 +167,10 @@ You may want to `{ctx.clean_prefix}nomen export` first"""
         Opt-in to Nomen processing your messages
         """
 
+        if not await ctx.bot.get_setting(ctx.author.id, "disabled"):
+            await ctx.send("You are already opted-in")
+            return
+
         log.debug(f"Opting-in: {ctx.author} ({ctx.author.id})")
 
         await ctx.send(

nomen/utils.py

@@ -4,6 +4,7 @@ from itertools import chain
 
 import re2 as re
 from disnake import ChannelType
+from disnake.ext.commands import BadArgument
 
 log = logging.getLogger("nomen.utils")
 
@@ -87,9 +88,14 @@ def compile_keyword(keyword, regex):
     if not regex:
         keyword = re.escape(keyword)
 
+    try:
         reg = re.compile(rf"(?i)\b{keyword}\b")
         regex_cache[(keyword, regex)] = reg
         return reg
+    except re._re2.Error:
+        raise BadArgument(
+            "Invalid regex. Nomen only supports regexes that [re2](<https://github.com/google/re2>) can parse."
+        )
 
 
 def contains(string, keyword, regex):