fix: AttributeError when fetching a message from a PartialMessageable that has a thread

CHANGELOG.md

@@ -21,11 +21,13 @@ These changes are available on the `master` branch, but have not yet been releas
 
 ### Fixed
 
-- Fix `TypeError` when accessing `ApplicationCommand.guild_only` or
+- Fixed `TypeError` when accessing `ApplicationCommand.guild_only` or
   `SlashCommandGroup.guild_only` when `contexts` is `None`.
   ([#3320](https://github.com/Pycord-Development/pycord/pull/3320))
-- Fix `SyntaxWarning` about `return` in a `finally` block raised on Python 3.14+
+- Fixed `SyntaxWarning` about `return` in a `finally` block raised on Python 3.14+
   ([#3332](https://github.com/Pycord-Development/pycord/pull/3334))
+- Fixed `AttributeError` when fetching a message from a `PartialMessageable` object that
+  has a thread. ([#3309](https://github.com/Pycord-Development/pycord/pull/3309))
 - Fix `ScheduledEvent.subscriber_count` being incremented instead of decremented when a
   user leaves the event.
   ([#3387](https://github.com/Pycord-Development/pycord/pull/3387))

discord/message.py

@@ -1201,13 +1201,16 @@ def __init__(
         except KeyError:
             self._poll = None
 
-        self.thread: Thread | None
-        try:
-            self.thread = Thread(
-                guild=self.guild, state=self._state, data=data["thread"]
+        self.thread: Thread | None = None
+        if thread_data := data.get("thread"):
+            # When fetching from a PartialMessageable, we don't have a guild so we need to fallback here
+            guild = self.guild or state._get_guild(
+                utils._get_as_snowflake(thread_data, "guild_id")
             )
-        except KeyError:
-            self.thread = None
+            if guild is not None:
+                self.thread = guild.get_thread(int(thread_data["id"])) or Thread(
+                    guild=guild, state=self._state, data=thread_data
+                )
 
         self.call: MessageCall | None
         try:

discord/threads.py

@@ -208,7 +208,11 @@ def _from_data(self, data: ThreadPayload):
         ]
 
         # Here, we try to fill in potentially missing data
-        if thread := self.guild.get_thread(self.id) and data.pop("_invoke_flag", False):
+        if (
+            self.guild
+            and (thread := self.guild.get_thread(self.id))
+            and data.pop("_invoke_flag", False)
+        ):
             self.owner_id = thread.owner_id if self.owner_id is None else self.owner_id
             self.last_message_id = (
                 thread.last_message_id