fix(backup): preserve service action metadata in raw_data

src/telegram_backup.py

@@ -8,6 +8,7 @@
 import logging
 import os
 import random
+import re
 from datetime import UTC, datetime
 
 from telethon import TelegramClient
@@ -289,6 +290,17 @@ async def iter_messages_with_flood_retry(client, entity, *, min_id=0, **kwargs):
             await asyncio.sleep(sleep_duration)
 
 
+def _service_action_type(action: object) -> str:
+    """Normalize a Telethon MessageAction class name to snake_case.
+
+    Examples: MessageActionTopicCreate -> "topic_create",
+    MessageActionTopicEdit -> "topic_edit",
+    MessageActionChatEditTitle -> "chat_edit_title".
+    """
+    name = type(action).__name__.removeprefix("MessageAction")
+    return re.sub(r"(?<!^)(?=[A-Z])", "_", name).lower()
+
+
 class TelegramBackup:
     """Main class for managing Telegram backups."""
 
@@ -1412,6 +1424,19 @@ async def _process_message(self, message: Message, chat_id: int) -> dict:
             "is_pinned": 1 if getattr(message, "pinned", False) else 0,
         }
 
+        # Preserve service-action metadata (e.g. forum topic creations and
+        # renames) so historical backfills keep parity with the listener's
+        # raw_data convention (service_type / action_type, since v6.0.0).
+        # Without this, service events are stored without their payload and
+        # the information is irrecoverable once the history is archived.
+        action = getattr(message, "action", None)
+        if action is not None:
+            message_data["raw_data"]["service_type"] = "service"
+            message_data["raw_data"]["action_type"] = _service_action_type(action)
+            action_title = getattr(action, "title", None)
+            if action_title is not None:
+                message_data["raw_data"]["new_title"] = self._text_with_entities_to_string(action_title)
+
         # Capture grouped_id for album detection (multiple photos/videos sent together)
         if message.grouped_id:
             message_data["raw_data"]["grouped_id"] = str(message.grouped_id)

tests/test_telegram_backup.py

@@ -12,6 +12,8 @@
 from telethon.tl.types import (
     Channel,
     Chat,
+    MessageActionTopicCreate,
+    MessageActionTopicEdit,
     MessageMediaContact,
     MessageMediaDocument,
     MessageMediaGeo,
@@ -366,6 +368,9 @@ def _make_message(self, msg_id, reply_to=None):
         # topic-skip guard in _backup_dialog doesn't accidentally filter
         # every message via MagicMock truthiness.
         msg.reply_to = reply_to
+        # Explicitly None so the service-action capture in _process_message
+        # is not triggered by MagicMock truthiness.
+        msg.action = None
         return msg
 
     def test_checkpoint_after_every_batch(self):
@@ -1164,6 +1169,9 @@ def _make_message(self, msg_id, text="hello", sender_id=42):
         msg.media = None
         msg.reactions = None
         msg.post_author = None
+        # Explicitly None so the service-action capture in _process_message
+        # is not triggered by MagicMock truthiness.
+        msg.action = None
         return msg
 
     def test_basic_text_message(self):
@@ -1215,6 +1223,49 @@ def test_post_author_stored(self):
         result = self._run(self.backup._process_message(msg, 100))
         self.assertEqual(result["raw_data"]["post_author"], "Editor Name")
 
+    def test_topic_create_action_stored_in_raw_data(self):
+        """Topic-create service action stores service metadata in raw_data."""
+        msg = self._make_message(8, text=None)
+        msg.action = MessageActionTopicCreate(title="Synthetic Topic", icon_color=0)
+        result = self._run(self.backup._process_message(msg, 100))
+        self.assertEqual(result["raw_data"]["service_type"], "service")
+        self.assertEqual(result["raw_data"]["action_type"], "topic_create")
+        self.assertEqual(result["raw_data"]["new_title"], "Synthetic Topic")
+        # Topic creations are linkable: the topic id equals the service
+        # message id (forum_topics.id == messages.id).
+        self.assertEqual(result["id"], 8)
+
+    def test_topic_edit_action_stores_new_title(self):
+        """Topic rename stores the new title and stays linkable by topic id."""
+        msg = self._make_message(9, text=None)
+        msg.action = MessageActionTopicEdit(title="Renamed Topic")
+        msg.reply_to = MagicMock()
+        msg.reply_to.forum_topic = True
+        msg.reply_to.reply_to_top_id = 8
+        result = self._run(self.backup._process_message(msg, 100))
+        self.assertEqual(result["raw_data"]["service_type"], "service")
+        self.assertEqual(result["raw_data"]["action_type"], "topic_edit")
+        self.assertEqual(result["raw_data"]["new_title"], "Renamed Topic")
+        # Topic edits are linkable through reply_to_top_id.
+        self.assertEqual(result["reply_to_top_id"], 8)
+
+    def test_topic_edit_without_title_has_no_new_title(self):
+        """Topic edits that do not rename (e.g. close) store no new_title."""
+        msg = self._make_message(10, text=None)
+        msg.action = MessageActionTopicEdit(closed=True)
+        result = self._run(self.backup._process_message(msg, 100))
+        self.assertEqual(result["raw_data"]["service_type"], "service")
+        self.assertEqual(result["raw_data"]["action_type"], "topic_edit")
+        self.assertNotIn("new_title", result["raw_data"])
+
+    def test_regular_message_has_no_service_metadata(self):
+        """Regular messages carry no service metadata in raw_data."""
+        msg = self._make_message(11)
+        result = self._run(self.backup._process_message(msg, 100))
+        self.assertNotIn("service_type", result["raw_data"])
+        self.assertNotIn("action_type", result["raw_data"])
+        self.assertNotIn("new_title", result["raw_data"])
+
     def test_none_text_becomes_empty_string(self):
         """Message with None text stores empty string."""
         msg = self._make_message(7, text=None)

tests/test_telegram_backup_extended.py

@@ -62,6 +62,9 @@ def _make_message(msg_id, *, reply_to=None, text="hello", media=None):
     msg.media = media
     msg.reactions = None
     msg.post_author = None
+    # Explicitly None so the service-action capture in _process_message
+    # is not triggered by MagicMock truthiness.
+    msg.action = None
     return msg