From f4f2cf3ca5cddd8ee6e8bc7e1b8650f4bc24356d Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Fri, 9 Jan 2026 09:24:29 +0530
Subject: [PATCH] Fix re-deleting the same book format not updating mtime of
 the formats fir in caltrash

---
 src/calibre/db/backend.py |  4 ++--
 src/calibre/db/utils.py   | 11 +++++++++++
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/src/calibre/db/backend.py b/src/calibre/db/backend.py
index 3da1a65754..884d86fe08 100644
--- a/src/calibre/db/backend.py
+++ b/src/calibre/db/backend.py
@@ -49,6 +49,7 @@ from calibre.db.tables import (
     SizeTable,
     UUIDTable,
 )
+from calibre.db.utils import atomic_write
 from calibre.ebooks.metadata import author_to_author_sort, title_sort
 from calibre.library.field_metadata import FieldMetadata
 from calibre.ptempfile import PersistentTemporaryFile, TemporaryFile
@@ -2284,8 +2285,7 @@ class DB:
         for path in format_abspaths:
             ext = path.rpartition('.')[-1].lower()
             fmap[path] = os.path.join(dest, ext)
-        with open(os.path.join(dest, 'metadata.json'), 'wb') as f:
-            f.write(json.dumps(metadata).encode('utf-8'))
+        atomic_write(os.path.join(dest, 'metadata.json'), json.dumps(metadata).encode('utf-8'))
         copy_files(fmap, delete_source=True)
 
     def get_metadata_for_trash_book(self, book_id, read_annotations=True):
diff --git a/src/calibre/db/utils.py b/src/calibre/db/utils.py
index d6a49f0110..45d9ab637b 100644
--- a/src/calibre/db/utils.py
+++ b/src/calibre/db/utils.py
@@ -9,6 +9,7 @@ import os
 import re
 import shutil
 import sys
+import tempfile
 from collections import OrderedDict, namedtuple
 from contextlib import suppress
 from locale import localeconv
@@ -16,10 +17,20 @@ from threading import Lock
 
 from calibre import as_unicode, prints
 from calibre.constants import cache_dir, get_windows_number_formats, iswindows, preferred_encoding
+from calibre.utils.filenames import make_long_path_useable
 from calibre.utils.icu import lower as icu_lower
 from calibre.utils.localization import canonicalize_lang, ngettext
 
 
+def atomic_write(path: str, data: str | bytes) -> None:
+    mode = 'w' if isinstance(data, str) else 'wb'
+    dpath = make_long_path_useable(os.path.dirname(path))
+    os.makedirs(dpath, exist_ok=True)
+    with tempfile.NamedTemporaryFile(mode, delete=False, dir=dpath) as f:
+        f.write(data)
+    os.replace(make_long_path_useable(f.name), make_long_path_useable(path))
+
+
 def force_to_bool(val):
     if isinstance(val, (bytes, str)):
         if isinstance(val, bytes):