updates

Backend/venv/lib/python3.12/site-packages/joblib/_multiprocessing_helpers.py

@@ -0,0 +1,51 @@
+"""Helper module to factorize the conditional multiprocessing import logic
+
+We use a distinct module to simplify import statements and avoid introducing
+circular dependencies (for instance for the assert_spawning name).
+"""
+
+import os
+import warnings
+
+# Obtain possible configuration from the environment, assuming 1 (on)
+# by default, upon 0 set to None. Should instructively fail if some non
+# 0/1 value is set.
+mp = int(os.environ.get("JOBLIB_MULTIPROCESSING", 1)) or None
+if mp:
+    try:
+        import _multiprocessing  # noqa
+        import multiprocessing as mp
+    except ImportError:
+        mp = None
+
+# 2nd stage: validate that locking is available on the system and
+#            issue a warning if not
+if mp is not None:
+    try:
+        # try to create a named semaphore using SemLock to make sure they are
+        # available on this platform. We use the low level object
+        # _multiprocessing.SemLock to avoid spawning a resource tracker on
+        # Unix system or changing the default backend.
+        import tempfile
+        from _multiprocessing import SemLock
+
+        _rand = tempfile._RandomNameSequence()
+        for i in range(100):
+            try:
+                name = "/joblib-{}-{}".format(os.getpid(), next(_rand))
+                _sem = SemLock(0, 0, 1, name=name, unlink=True)
+                del _sem  # cleanup
+                break
+            except FileExistsError as e:  # pragma: no cover
+                if i >= 99:
+                    raise FileExistsError("cannot find name for semaphore") from e
+    except (FileExistsError, AttributeError, ImportError, OSError) as e:
+        mp = None
+        warnings.warn("%s.  joblib will operate in serial mode" % (e,))
+
+
+# 3rd stage: backward compat for the assert_spawning helper
+if mp is not None:
+    from multiprocessing.context import assert_spawning
+else:
+    assert_spawning = None