changed from os.umask to os.chmod (#206)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: jahrules

docs/changelog.rst

@@ -1,5 +1,9 @@
 Changelog
 =========
+v3.10.2 (2023-03-22)
+--------------------
+- Bug fix for using filelock with threaded programs causing undesired file permissions - by :user:`jahrules`.
+
 v3.10.1 (2023-03-22)
 --------------------
 - Handle pickle for :class:`filelock.Timeout` :pr:`203` - by :user:`TheMatt2`.

src/filelock/_api.py

@@ -179,11 +179,7 @@ def acquire(
                 with self._thread_lock:
                     if not self.is_locked:
                         _LOGGER.debug("Attempting to acquire lock %s on %s", lock_id, lock_filename)
-                        previous_umask = os.umask(0)
-                        try:
-                            self._acquire()
-                        finally:
-                            os.umask(previous_umask)  # reset umask to initial value
+                        self._acquire()
                 if self.is_locked:
                     _LOGGER.debug("Lock %s acquired on %s", lock_id, lock_filename)
                     break

src/filelock/_unix.py

@@ -32,7 +32,8 @@ class UnixFileLock(BaseFileLock):
 
         def _acquire(self) -> None:
             open_flags = os.O_RDWR | os.O_CREAT | os.O_TRUNC
-            fd = os.open(self._lock_file, open_flags, self._mode)
+            fd = os.open(self._lock_file, open_flags)
+            os.chmod(fd, self._mode)
             try:
                 fcntl.flock(fd, fcntl.LOCK_EX | fcntl.LOCK_NB)
             except OSError:

tests/test_filelock.py

@@ -440,7 +440,10 @@ def test_lock_mode_soft(tmp_path: Path) -> None:
     assert lock.is_locked
 
     mode = filemode(os.stat(lock_path).st_mode)
-    assert mode == "-rw-rw-rw-"
+    if sys.platform == "win32":
+        assert mode == "-rw-rw-rw-"
+    else:
+        assert mode == "-rw-r--r--"
 
     lock.release()