Executing GraalPython unconditionally creates __pycache__ if file name "sitecustomize.py" exists

[oroppas]

$ touch sitecustomize.py
$ graalpython
Python 3.8.5 (Fri Apr 30 13:16:00 JST 2021)
[Graal, GraalVM CE, Java 11.0.10] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> quit()

Tracing by graalpython -v,

...
# code object from /home/ryuta/tmp/sitecustomize.py
# created '/home/ryuta/tmp/__pycache__/sitecustomize.graalpython-38.pyc'
import 'sitecustomize' # <importlib._bootstrap_external.SourceFileLoader object at 0xda59018>
import 'site' # <importlib._bootstrap_external.SourceFileLoader object at 0x607cc131>
Python 3.8.5 (Fri Apr 30 13:16:00 JST 2021)
[Graal, GraalVM CE, Java 11.0.10] on linux
Type "help", "copyright", "credits" or "license" for more information.
# /home/ryuta/packages/graalvm/graal/graal/sdk/mxbuild/linux-amd64/GRAALVM_845C45B806_JAVA11/graalvm-845c45b806-java11-21.2.0-dev/languages/python/lib-python/3/__pycache__/rlcompleter.graalpython-38.pyc matches /home/ryuta/packages/graalvm/graal/graal/sdk/mxbuild/linux-amd64/GRAALVM_845C45B806_JAVA11/graalvm-845c45b806-java11-21.2.0-dev/languages/python/lib-python/3/rlcompleter.py
# code object from '/home/ryuta/packages/graalvm/graal/graal/sdk/mxbuild/linux-amd64/GRAALVM_845C45B806_JAVA11/graalvm-845c45b806-java11-21.2.0-dev/languages/python/lib-python/3/__pycache__/rlcompleter.graalpython-38.pyc'
import 'rlcompleter' # <importlib._bootstrap_external.SourceFileLoader object at 0x145a36cc>

[oroppas]

It seems that GraalPython simply executes sitecustomize.py even when invoking interactive mode.

$ cat sitecustomize.py
print('\nsitecustomize\n')

$ graalpython

sitecustomize

Python 3.8.5 (Thu May 06 10:31:17 JST 2021)
[Graal, GraalVM CE, Java 11.0.11] on linux
Type "help", "copyright", "credits" or "license" for more information.

Is this the expected behavior?

[msimacek]

I can reproduce that too and I believe it's not expected. We don't have any special handling for sitecustomize, we're simply using CPython's site module, so I think the problem could be in the way we initialize the path. I'll take a look.