Merge pull request #2517 from python-discord/thread_filter

Thread filter

6 files changed, 64 insertions, 37 deletions

diff --git a/bot/exts/filtering/_filter_context.py b/bot/exts/filtering/_filter_context.py
index 0794a48e4..9d8bbba9a 100644
--- a/bot/exts/filtering/_filter_context.py
+++ b/bot/exts/filtering/_filter_context.py
@@ -21,6 +21,7 @@ class Event(Enum):
     MESSAGE = auto()
     MESSAGE_EDIT = auto()
     NICKNAME = auto()
+    THREAD_NAME = auto()
     SNEKBOX = auto()
 
 
diff --git a/bot/exts/filtering/_filter_lists/token.py b/bot/exts/filtering/_filter_lists/token.py
index 0c591ac3b..5bb21cfc5 100644
--- a/bot/exts/filtering/_filter_lists/token.py
+++ b/bot/exts/filtering/_filter_lists/token.py
@@ -32,7 +32,9 @@ class TokensList(FilterList[TokenFilter]):
 
     def __init__(self, filtering_cog: Filtering):
         super().__init__()
-        filtering_cog.subscribe(self, Event.MESSAGE, Event.MESSAGE_EDIT, Event.NICKNAME, Event.SNEKBOX)
+        filtering_cog.subscribe(
+            self, Event.MESSAGE, Event.MESSAGE_EDIT, Event.NICKNAME, Event.THREAD_NAME, Event.SNEKBOX
+        )
 
     def get_filter_type(self, content: str) -> type[Filter]:
         """Get a subclass of filter matching the filter list and the filter's content."""
diff --git a/bot/exts/filtering/_settings_types/actions/remove_context.py b/bot/exts/filtering/_settings_types/actions/remove_context.py
index 5ec2613f4..dc01426d8 100644
--- a/bot/exts/filtering/_settings_types/actions/remove_context.py
+++ b/bot/exts/filtering/_settings_types/actions/remove_context.py
@@ -1,7 +1,7 @@
 from collections import defaultdict
 from typing import ClassVar
 
-from discord import Message
+from discord import Message, Thread
 from discord.errors import HTTPException
 from pydis_core.utils import scheduling
 from pydis_core.utils.logging import get_logger
@@ -52,6 +52,8 @@ class RemoveContext(ActionEntry):
             await self._handle_messages(ctx)
         elif ctx.event == Event.NICKNAME:
             await self._handle_nickname(ctx)
+        elif ctx.event == Event.THREAD_NAME:
+            await self._handle_thread(ctx)
 
     @staticmethod
     async def _handle_messages(ctx: FilterContext) -> None:
@@ -106,7 +108,18 @@ class RemoveContext(ActionEntry):
             return
 
         await command(FakeContext(ctx.message, alerts_channel, command), ctx.author, None, reason=SUPERSTAR_REASON)
-        ctx.action_descriptions.append("superstar")
+        ctx.action_descriptions.append("superstarred")
+
+    @staticmethod
+    async def _handle_thread(ctx: FilterContext) -> None:
+        """Delete the context thread."""
+        if isinstance(ctx.channel, Thread):
+            try:
+                await ctx.channel.delete()
+            except HTTPException:
+                ctx.action_descriptions.append("failed to delete thread")
+            else:
+                ctx.action_descriptions.append("deleted thread")
 
     def union(self, other: Self) -> Self:
         """Combines two actions of the same type. Each type of action is executed once per filter."""
diff --git a/bot/exts/filtering/filtering.py b/bot/exts/filtering/filtering.py
index 392428bb0..82006c9db 100644
--- a/bot/exts/filtering/filtering.py
+++ b/bot/exts/filtering/filtering.py
@@ -12,7 +12,7 @@ from typing import Literal, Optional, get_type_hints
 import arrow
 import discord
 from async_rediscache import RedisCache
-from discord import Colour, Embed, HTTPException, Message, MessageType
+from discord import Colour, Embed, HTTPException, Message, MessageType, Thread
 from discord.ext import commands, tasks
 from discord.ext.commands import BadArgument, Cog, Context, command, has_any_role
 from pydis_core.site_api import ResponseCodeError
@@ -206,6 +206,11 @@ class Filtering(Cog):
         """Filter the contents of a sent message."""
         if msg.author.bot or msg.webhook_id or msg.type == MessageType.auto_moderation_action:
             return
+        if msg.type == MessageType.channel_name_change and isinstance(msg.channel, Thread):
+            ctx = FilterContext.from_message(Event.THREAD_NAME, msg)
+            await self._check_bad_name(ctx)
+            return
+
         self.message_cache.append(msg)
 
         ctx = FilterContext.from_message(Event.MESSAGE, msg, None, self.message_cache)
@@ -218,7 +223,7 @@ class Filtering(Cog):
 
         nick_ctx = FilterContext.from_message(Event.NICKNAME, msg)
         nick_ctx.content = msg.author.display_name
-        await self._check_bad_name(nick_ctx)
+        await self._check_bad_display_name(nick_ctx)
 
         await self._maybe_schedule_msg_delete(ctx, result_actions)
         self._increment_stats(triggers)
@@ -252,6 +257,12 @@ class Filtering(Cog):
         ctx = FilterContext(Event.NICKNAME, member, None, member.display_name, None)
         await self._check_bad_name(ctx)
 
+    @Cog.listener()
+    async def on_thread_create(self, thread: Thread) -> None:
+        """Check for bad words in new thread names."""
+        ctx = FilterContext(Event.THREAD_NAME, thread.owner, thread, thread.name, None)
+        await self._check_bad_name(ctx)
+
     async def filter_snekbox_output(
         self, stdout: str, files: list[FileAttachment], msg: Message
     ) -> tuple[bool, set[str]]:
@@ -966,11 +977,17 @@ class Filtering(Cog):
         return False
 
     @lock_arg("filtering.check_bad_name", "ctx", attrgetter("author.id"))
-    async def _check_bad_name(self, ctx: FilterContext) -> None:
+    async def _check_bad_display_name(self, ctx: FilterContext) -> None:
         """Check filter triggers in the passed context - a member's display name."""
         if await self._recently_alerted_name(ctx.author):
             return
+        new_ctx = await self._check_bad_name(ctx)
+        if new_ctx.send_alert:
+            # Update time when alert sent
+            await self.name_alerts.set(ctx.author.id, arrow.utcnow().timestamp())
 
+    async def _check_bad_name(self, ctx: FilterContext) -> FilterContext:
+        """Check filter triggers for some given name (thread name, a member's display name)."""
         name = ctx.content
         normalised_name = unicodedata.normalize("NFKC", name)
         cleaned_normalised_name = "".join([c for c in normalised_name if not unicodedata.combining(c)])
@@ -981,13 +998,13 @@ class Filtering(Cog):
 
         new_ctx = ctx.replace(content=" ".join(names_to_check))
         result_actions, list_messages, triggers = await self._resolve_action(new_ctx)
+        new_ctx = new_ctx.replace(content=ctx.content)  # Alert with the original content.
         if result_actions:
-            await result_actions.action(ctx)
-        if ctx.send_alert:
-            await self._send_alert(ctx, list_messages)  # `ctx` has the original content.
-            # Update time when alert sent
-            await self.name_alerts.set(ctx.author.id, arrow.utcnow().timestamp())
+            await result_actions.action(new_ctx)
+        if new_ctx.send_alert:
+            await self._send_alert(new_ctx, list_messages)
         self._increment_stats(triggers)
+        return new_ctx
 
     async def _resolve_list_type_and_name(
         self, ctx: Context, list_type: ListType | None = None, list_name: str | None = None, *, exclude: str = ""
diff --git a/bot/exts/help_channels/_channel.py b/bot/exts/help_channels/_channel.py
index b1a319145..774e9178e 100644
--- a/bot/exts/help_channels/_channel.py
+++ b/bot/exts/help_channels/_channel.py
@@ -142,11 +142,15 @@ async def help_post_opened(opened_post: discord.Thread, *, reopen: bool = False)
     try:
         await opened_post.starter_message.pin()
     except (discord.HTTPException, AttributeError) as e:
-        # Suppress if the message was not found, most likely deleted
+        # Suppress if the message or post were not found, most likely deleted
         # The message being deleted could be surfaced as an AttributeError on .starter_message,
         # or as an exception from the Discord API, depending on timing and cache status.
-        if isinstance(e, discord.HTTPException) and e.code != 10008:
-            raise e
+        # The post being deleting would happen if it had a bad name that would cause the filtering system to delete it.
+        if isinstance(e, discord.HTTPException):
+            if e.code == 10003:  # Post not found.
+                return
+            elif e.code != 10008:  # 10008 - Starter message not found.
+                raise e
 
     await send_opened_post_message(opened_post)
 
@@ -178,7 +182,11 @@ async def help_post_deleted(deleted_post_event: discord.RawThreadDeleteEvent) ->
     _stats.report_post_count()
     cached_post = deleted_post_event.thread
     if cached_post and not cached_post.archived:
-        # If the post is in the bot's cache, and it was not archived before deleting, report a complete session.
+        # If the post is in the bot's cache, and it was not archived before deleting,
+        # report a complete session and remove the cooldown.
+        poster = cached_post.owner
+        cooldown_role = cached_post.guild.get_role(constants.Roles.help_cooldown)
+        await members.handle_role_change(poster, poster.remove_roles, cooldown_role)
         await _stats.report_complete_session(cached_post, _stats.ClosingReason.DELETED)
 
 
@@ -218,6 +226,12 @@ async def maybe_archive_idle_post(post: discord.Thread, scheduler: scheduling.Sc
     If `has_task` is True and rescheduling is required, the extant task to make the post
     dormant will first be cancelled.
     """
+    try:
+        await post.guild.fetch_channel(post.id)
+    except discord.HTTPException:
+        log.trace(f"Not closing missing post #{post} ({post.id}).")
+        return
+
     if post.locked:
         log.trace(f"Not closing already closed post #{post} ({post.id}).")
         return
diff --git a/bot/exts/help_channels/_cog.py b/bot/exts/help_channels/_cog.py
index 6c8478a3f..dd6dee9ee 100644
--- a/bot/exts/help_channels/_cog.py
+++ b/bot/exts/help_channels/_cog.py
@@ -1,7 +1,5 @@
 """Contains the Cog that receives discord.py events and defers most actions to other files in the module."""
 
-import typing as t
-
 import discord
 from discord.ext import commands
 from pydis_core.utils import scheduling
@@ -13,9 +11,6 @@ from bot.log import get_logger
 
 log = get_logger(__name__)
 
-if t.TYPE_CHECKING:
-    from bot.exts.filtering.filtering import Filtering
-
 
 class HelpForum(commands.Cog):
     """
@@ -62,18 +57,6 @@ class HelpForum(commands.Cog):
             self.bot.stats.incr("help.dormant_invoke.staff")
         return has_role
 
-    async def post_with_disallowed_title_check(self, post: discord.Thread) -> None:
-        """Check if the given post has a bad word, alerting moderators if it does."""
-        filter_cog: Filtering | None = self.bot.get_cog("Filtering")
-        if filter_cog and (match := filter_cog.get_name_match(post.name)):
-            mod_alerts = self.bot.get_channel(constants.Channels.mod_alerts)
-            await mod_alerts.send(
-                f"<@&{constants.Roles.moderators}>\n"
-                f"<@{post.owner_id}> ({post.owner_id}) opened the post {post.mention} ({post.id}), "
-                "which triggered the token filter with its name!\n"
-                f"**Match:** {match.group()}"
-            )
-
     @commands.group(name="help-forum", aliases=("hf",))
     async def help_forum_group(self,  ctx: commands.Context) -> None:
         """A group of commands that help manage our help forum system."""
@@ -133,7 +116,7 @@ class HelpForum(commands.Cog):
 
     @commands.Cog.listener("on_message")
     async def new_post_listener(self, message: discord.Message) -> None:
-        """Defer application of new post logic for posts the help forum to the _channel helper."""
+        """Defer application of new post logic for posts in the help forum to the _channel helper."""
         if not isinstance(message.channel, discord.Thread):
             return
         thread = message.channel
@@ -145,7 +128,6 @@ class HelpForum(commands.Cog):
         if thread.parent_id != self.help_forum_channel.id:
             return
 
-        # await self.post_with_disallowed_title_check(thread)  TODO bring this back with the new filtering system
         await _channel.help_post_opened(thread)
 
         delay = min(constants.HelpChannels.deleted_idle_minutes, constants.HelpChannels.idle_minutes) * 60
@@ -162,12 +144,10 @@ class HelpForum(commands.Cog):
             return
         if not before.archived and after.archived:
             await _channel.help_post_archived(after)
-        if before.name != after.name:
-            await self.post_with_disallowed_title_check(after)
 
     @commands.Cog.listener()
     async def on_raw_thread_delete(self, deleted_thread_event: discord.RawThreadDeleteEvent) -> None:
-        """Defer application of new post logic for posts the help forum to the _channel helper."""
+        """Defer application of deleted post logic for posts in the help forum to the _channel helper."""
         if deleted_thread_event.parent_id == self.help_forum_channel.id:
             await _channel.help_post_deleted(deleted_thread_event)