Add PyGrain support to ml_python

PiperOrigin-RevId: 702368911

CHANGELOG.md

@@ -9,6 +9,8 @@ Changelog follow https://keepachangelog.com/ format.
 ## [Unreleased]
 
 *   `epy`:
+    *   Add experimental util for ml_python + multi-process compatibility
+        for adhoc-imports (when using PyGrain).
     *   `epy.lazy_api_imports`: Make lazy importing thread safe.
 
 ## [1.11.0] - 2024-11-27

etils/epy/_multiprocess.py

@@ -0,0 +1,33 @@
+# Copyright 2024 The etils Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Multiprocessing utilities."""
+
+import atexit
+import os
+import sys
+
+
+def is_ipython_subprocess() -> bool:
+  """Check if we are in a sub-process launched from within a `ipython` terminal.
+
+  Returns:
+    `True` only if we are in ipython terminal (e.g. `ml_python`) and inside
+    a sub-process.
+  """
+  return False
+
+
+def register_adhoc_init() -> None:
+  """Registers a callback to activate adhoc imports in sub-processes."""