Merge pull request #3581 from Autodesk/gamaj/LOOKDEVX-2254/modernize_…

…ufe_ae_template

LOOKDEVX-2254 - Enable "Implicit Namespace Packages" feature

lib/mayaUsd/resources/ae/CMakeLists.txt

@@ -2,8 +2,15 @@
 # install
 # ---------------------------------------------------------------------------------------------
 
-# We need an empty __init__.py file in each subfolder so it is considered a python module.
+# In Python 2 we need an __init__.py file in the ufe_ae folder to declare it as a module.
+# In Python 3 we must not use an __init__.py file in that folder to enable the "Implicit Namespace
+# Packages" feature as defined in Python PEP 420, which allows other plugins to also be able to
+# declare an ufe_ae module that would be merged with this one. See https://peps.python.org/pep-0420/
+# for details.
+if (NOT BUILD_WITH_PYTHON_3)
 install(FILES __init__.py DESTINATION ${CMAKE_INSTALL_PREFIX}/lib/python/ufe_ae)
+endif()
+# We need an empty __init__.py file in each subfolder so it is considered a python module.
 install(FILES __init__.py DESTINATION ${CMAKE_INSTALL_PREFIX}/lib/python/ufe_ae/usd)
 install(FILES ae_utils.py DESTINATION ${CMAKE_INSTALL_PREFIX}/lib/python/ufe_ae/usd)
 install(FILES __init__.py DESTINATION ${CMAKE_INSTALL_PREFIX}/lib/python/ufe_ae/usd/nodes)