From dfc8d4762bbecc421c175bf8dfadc7316818cf42 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=27=C3=A9lectron=20rare?=
 <108685187+electron-rare@users.noreply.github.com>
Date: Sun, 21 Jun 2026 09:31:42 +0200
Subject: [PATCH] fix(tower): lock transfers history writes
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Add _history_lock to serialize history load→extend→write in
transfers_end(), preventing lost-update races on transfers.json if a
second writer is added later. Fix file handle leak in
_transfers_history_load() with context manager.
---
 tower/lisael_content.py | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/tower/lisael_content.py b/tower/lisael_content.py
index 703a0b9..e0d781b 100644
--- a/tower/lisael_content.py
+++ b/tower/lisael_content.py
@@ -412,6 +412,9 @@ def push_file(ip, name, subdir="podcasts"):
 _busy = set()
 _busy_lock = threading.Lock()
 
+# ---- transfers journal lock ----
+_history_lock = threading.Lock()
+
 def push_batch(ip, delta):
     ok = 0
     for f in delta:
@@ -494,7 +497,8 @@ def transfers_active():
 def _transfers_history_load():
     if os.path.exists(TRANSFERS_JSON):
         try:
-            return json.load(open(TRANSFERS_JSON, encoding="utf-8"))
+            with open(TRANSFERS_JSON, encoding="utf-8") as fh:
+                return json.load(fh)
         except Exception:
             pass
     return []
@@ -510,7 +514,8 @@ def transfers_end():
         done = [{k: v for k, v in f.items() if k != "_t0"}
                 for f in _active["files"] if f["status"] in ("done", "failed")]
         _active = None
-    hist = _transfers_history_load()
-    hist.extend(done)
-    hist = hist[-TRANSFERS_MAX:]
-    _atomic_write_json(TRANSFERS_JSON, hist)
+    with _history_lock:
+        hist = _transfers_history_load()
+        hist.extend(done)
+        hist = hist[-TRANSFERS_MAX:]
+        _atomic_write_json(TRANSFERS_JSON, hist)