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subprocess_env

subprocess_env

Environment-construction helpers for spawned terok child processes.

Centralises the PYTHONPATH shim that every subprocess.run / Popen of sys.executable must use, so adding a new spawn site doesn't silently regress Franz Pöschel's Nix-wrapped-Python fix (terok-ai/terok#717).

child_process_env(overrides=None)

Build the environment for a spawned terok child process.

Threads the parent's sys.path through as PYTHONPATH so the child can import terok regardless of how the parent was launched. Under Nix, sys.executable is a wrapper script that rewrites the env on startup — but spawning it directly via subprocess / create_subprocess_exec bypasses that wrapper, leaving the child unable to find the terok package. This shim restores it (Franz Pöschel's fix in #717).

overrides are applied on top of the parent env; PYTHONPATH always wins so a stray ambient value can't shadow the parent's real import path.

Source code in src/terok/lib/util/subprocess_env.py 
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def child_process_env(overrides: dict[str, str] | None = None) -> dict[str, str]:
    """Build the environment for a spawned ``terok`` child process.

    Threads the parent's ``sys.path`` through as ``PYTHONPATH`` so the
    child can import ``terok`` regardless of how the parent was
    launched.  Under Nix, ``sys.executable`` is a wrapper script that
    rewrites the env on startup — but spawning it directly via
    ``subprocess`` / ``create_subprocess_exec`` bypasses that wrapper,
    leaving the child unable to find the ``terok`` package.  This shim
    restores it (Franz Pöschel's fix in #717).

    *overrides* are applied on top of the parent env; ``PYTHONPATH``
    always wins so a stray ambient value can't shadow the parent's
    real import path.
    """
    return {**os.environ, **(overrides or {}), "PYTHONPATH": os.pathsep.join(sys.path)}