src/Ext/freecad/utils.py

# SPDX-License-Identifier: LGPL-2.1-or-later

# ***************************************************************************
# *                                                                         *
# *   Copyright (c) 2022-2023 FreeCAD Project Association                   *
# *   Copyright (c) 2018 Gaël Écorchard <galou_breizh@yahoo.fr>             *
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# *   This file is part of FreeCAD.                                         *
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import os
import platform
import shutil

import FreeCAD


def get_python_exe() -> str:
    """Find Python. In preference order
    A) The value of the BaseApp/Preferences/PythonConsole/PathToPythonExecutable user preference
    B) The executable located in the same bin directory as FreeCAD and called "python3"
    C) The executable located in the same bin directory as FreeCAD and called "python"
    D) The result of a shutil search for your system's "python3" executable
    E) The result of a shutil search for your system's "python" executable"""
    prefs = FreeCAD.ParamGet("User parameter:BaseApp/Preferences/PythonConsole")
    python_exe = prefs.GetString("PathToPythonExecutable", "")
    fc_dir = FreeCAD.getHomePath()
    if not python_exe or not os.path.exists(python_exe):
        python_exe = os.path.join(fc_dir, "bin", "python3")
        if "Windows" in platform.system():
            python_exe += ".exe"

    if not python_exe or not os.path.exists(python_exe):
        python_exe = os.path.join(fc_dir, "bin", "python")
        if "Windows" in platform.system():
            python_exe += ".exe"

    if not python_exe or not os.path.exists(python_exe):
        python_exe = shutil.which("python3")

    if not python_exe or not os.path.exists(python_exe):
        python_exe = shutil.which("python")

    if not python_exe or not os.path.exists(python_exe):
        return ""

    python_exe = python_exe.replace("/", os.path.sep)
    return python_exe