From 775004f934bfe620b68f0e79151ae14ba5c9e9b5 Mon Sep 17 00:00:00 2001
From: Go1c <1c@live.cn>
Date: Tue, 14 Apr 2026 17:02:24 +0800
Subject: [PATCH] fix: delay watcher unignore to prevent echo push-back loop
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When the CLI receives a sync event from the server and writes/deletes
a file locally, the watchdog inotify event is queued by the kernel and
delivered asynchronously. By the time the observer thread processes it,
unignore_file had already been called, causing the watcher to treat the
server-written file as a local change and push it back — creating an
echo loop confirmed in logs (NoteSyncModify received → NoteModify sent
back → server pushes again).

Fix: add asyncio.sleep(0.6) before unignore_file in all server→client
file operation handlers (write, delete, rename, chunked download) in
both NoteSync and FileSync. This keeps the file ignored until the
watchdog debounce window (0.5s) has expired.
---
 fns_cli/file_sync.py | 7 ++++++-
 fns_cli/note_sync.py | 3 +++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/fns_cli/file_sync.py b/fns_cli/file_sync.py
index a7cee47..93e5500 100644
--- a/fns_cli/file_sync.py
+++ b/fns_cli/file_sync.py
@@ -2,6 +2,7 @@
 
 from __future__ import annotations
 
+import asyncio
 import logging
 import os
 import uuid
@@ -203,6 +204,7 @@ async def _on_sync_update(self, msg: WSMessage) -> None:
         except Exception:
             log.exception("Failed to write file %s", rel_path)
         finally:
+            await asyncio.sleep(0.6)
             self.engine.unignore_file(rel_path)
 
         self._received_modify += 1
@@ -232,6 +234,7 @@ async def _on_sync_delete(self, msg: WSMessage) -> None:
         except Exception:
             log.exception("Failed to delete file %s", rel_path)
         finally:
+            await asyncio.sleep(0.6)
             self.engine.unignore_file(rel_path)
 
         self._received_delete += 1
@@ -256,6 +259,7 @@ async def _on_sync_rename(self, msg: WSMessage) -> None:
         except Exception:
             log.exception("Failed to rename file %s → %s", old_path, new_path)
         finally:
+            await asyncio.sleep(0.6)
             self.engine.unignore_file(old_path)
             self.engine.unignore_file(new_path)
 
@@ -315,8 +319,9 @@ async def _finalize_download(self, session_id: str, session: _DownloadSession) -
         except Exception:
             log.exception("Failed to write downloaded file %s", rel_path)
         finally:
-            self.engine.unignore_file(rel_path)
             self._download_sessions.pop(session_id, None)
+            await asyncio.sleep(0.6)
+            self.engine.unignore_file(rel_path)
 
     async def _on_sync_end(self, msg: WSMessage) -> None:
         data = _extract_inner(msg.data)
diff --git a/fns_cli/note_sync.py b/fns_cli/note_sync.py
index 6a63f8a..83cc2d5 100644
--- a/fns_cli/note_sync.py
+++ b/fns_cli/note_sync.py
@@ -2,6 +2,7 @@
 
 from __future__ import annotations
 
+import asyncio
 import logging
 import os
 import uuid
@@ -147,6 +148,7 @@ async def _on_sync_modify(self, msg: WSMessage) -> None:
         except Exception:
             log.exception("Failed to write %s", rel_path)
         finally:
+            await asyncio.sleep(0.6)
             self.engine.unignore_file(rel_path)
 
         self._received_modify += 1
@@ -167,6 +169,7 @@ async def _on_sync_delete(self, msg: WSMessage) -> None:
         except Exception:
             log.exception("Failed to delete %s", rel_path)
         finally:
+            await asyncio.sleep(0.6)
             self.engine.unignore_file(rel_path)
 
         self._received_delete += 1