Merge PR #2520: fix(telegram): split oversized final streamed replies

fix(telegram): split oversized final streamed replies

nanobot/channels/telegram.py

@@ -558,8 +558,10 @@ class TelegramChannel(BaseChannel):
                     await self._remove_reaction(chat_id, int(reply_to_message_id))
                 except ValueError:
                     pass
+            chunks = split_message(buf.text, TELEGRAM_MAX_MESSAGE_LEN)
+            primary_text = chunks[0] if chunks else buf.text
             try:
-                html = _markdown_to_telegram_html(buf.text)
+                html = _markdown_to_telegram_html(primary_text)
                 await self._call_with_retry(
                     self._app.bot.edit_message_text,
                     chat_id=int_chat_id, message_id=buf.message_id,
@@ -575,15 +577,18 @@ class TelegramChannel(BaseChannel):
                     await self._call_with_retry(
                         self._app.bot.edit_message_text,
                         chat_id=int_chat_id, message_id=buf.message_id,
-                        text=buf.text,
+                        text=primary_text,
                     )
                 except Exception as e2:
                     if self._is_not_modified_error(e2):
                         logger.debug("Final stream plain edit already applied for {}", chat_id)
-                        self._stream_bufs.pop(chat_id, None)
+                    else:
-                        return
+                        logger.warning("Final stream edit failed: {}", e2)
-                    logger.warning("Final stream edit failed: {}", e2)
+                        raise  # Let ChannelManager handle retry
-                    raise  # Let ChannelManager handle retry
+            # If final content exceeds Telegram limit, keep the first chunk in
+            # the edited stream message and send the rest as follow-up messages.
+            for extra_chunk in chunks[1:]:
+                await self._send_text(int_chat_id, extra_chunk)
             self._stream_bufs.pop(chat_id, None)
             return
 

tests/channels/test_telegram_channel.py

@@ -385,6 +385,32 @@ async def test_send_delta_stream_end_treats_not_modified_as_success() -> None:
     assert "123" not in channel._stream_bufs
 
 
+@pytest.mark.asyncio
+async def test_send_delta_stream_end_splits_oversized_reply() -> None:
+    """Final streamed reply exceeding Telegram limit is split into chunks."""
+    from nanobot.channels.telegram import TELEGRAM_MAX_MESSAGE_LEN
+
+    channel = TelegramChannel(
+        TelegramConfig(enabled=True, token="123:abc", allow_from=["*"]),
+        MessageBus(),
+    )
+    channel._app = _FakeApp(lambda: None)
+    channel._app.bot.edit_message_text = AsyncMock()
+    channel._app.bot.send_message = AsyncMock(return_value=SimpleNamespace(message_id=99))
+
+    oversized = "x" * (TELEGRAM_MAX_MESSAGE_LEN + 500)
+    channel._stream_bufs["123"] = _StreamBuf(text=oversized, message_id=7, last_edit=0.0)
+
+    await channel.send_delta("123", "", {"_stream_end": True})
+
+    channel._app.bot.edit_message_text.assert_called_once()
+    edit_text = channel._app.bot.edit_message_text.call_args.kwargs.get("text", "")
+    assert len(edit_text) <= TELEGRAM_MAX_MESSAGE_LEN
+
+    channel._app.bot.send_message.assert_called_once()
+    assert "123" not in channel._stream_bufs
+
+
 @pytest.mark.asyncio
 async def test_send_delta_new_stream_id_replaces_stale_buffer() -> None:
     channel = TelegramChannel(