From bd0ba745dd016e923853575ffff45e4eed8fa482 Mon Sep 17 00:00:00 2001
From: 04cb <0x04cb@gmail.com>
Date: Tue, 12 May 2026 08:38:11 +0800
Subject: [PATCH] fix(wecom): preserve real filename from SDK when payload
 omits name (#3737)

---
 nanobot/channels/wecom.py            |  9 +++++----
 tests/channels/test_wecom_channel.py | 20 ++++++++++++++++++++
 2 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/nanobot/channels/wecom.py b/nanobot/channels/wecom.py
index 2dd9f8856..8fd360526 100644
--- a/nanobot/channels/wecom.py
+++ b/nanobot/channels/wecom.py
@@ -292,17 +292,18 @@ class WecomChannel(BaseChannel):
                 file_info = body.get("file", {})
                 file_url = file_info.get("url", "")
                 aes_key = file_info.get("aeskey", "")
-                file_name = file_info.get("name", "unknown")
+                file_name = file_info.get("name") or None
 
                 if file_url and aes_key:
                     file_path = await self._download_and_save_media(file_url, aes_key, "file", file_name)
                     if file_path:
-                        content_parts.append(f"[file: {file_name}]")
+                        display_name = os.path.basename(file_path)
+                        content_parts.append(f"[file: {display_name}]")
                         media_paths.append(file_path)
                     else:
-                        content_parts.append(f"[file: {file_name}: download failed]")
+                        content_parts.append(f"[file: {file_name or 'unknown'}: download failed]")
                 else:
-                    content_parts.append(f"[file: {file_name}: download failed]")
+                    content_parts.append(f"[file: {file_name or 'unknown'}: download failed]")
 
             elif msg_type == "mixed":
                 # Mixed content contains multiple message items
diff --git a/tests/channels/test_wecom_channel.py b/tests/channels/test_wecom_channel.py
index 7cb61ab82..cc0bbf29f 100644
--- a/tests/channels/test_wecom_channel.py
+++ b/tests/channels/test_wecom_channel.py
@@ -552,6 +552,26 @@ async def test_process_file_message() -> None:
             os.unlink(p)
 
 
+@pytest.mark.asyncio
+async def test_process_file_message_uses_sdk_filename_when_name_missing(tmp_path: Path) -> None:
+    """Without `file.name`, fall back to SDK fname instead of saving as 'unknown' (#3737)."""
+    channel = WecomChannel(WecomConfig(bot_id="b", secret="s", allow_from=["user1"]), MessageBus())
+    client = _FakeWeComClient()
+    client.download_file.return_value = (b"%PDF-1.4 fake", "real_name.pdf")
+    channel._client = client
+
+    with patch("nanobot.channels.wecom.get_media_dir", return_value=tmp_path):
+        frame = _FakeFrame(body={
+            "msgid": "msg_file_2", "chatid": "chat1", "from": {"userid": "user1"},
+            "file": {"url": "https://example.com/x", "aeskey": "key456"},
+        })
+        await channel._process_message(frame, "file")
+
+    msg = await channel.bus.consume_inbound()
+    assert msg.media == [str(tmp_path / "real_name.pdf")]
+    assert "[file: real_name.pdf]" in msg.content
+
+
 @pytest.mark.asyncio
 async def test_process_voice_message() -> None:
     """Voice message: transcribed text is included in content."""