System-installed Python dir is used for installing dependencies

[sybrenstuvel]

Hey folks,

In short: the wrong installation directory is used when installing the Python dependencies.

This is what my terminal shows when trying to enable BlenderCam 1.0.21 on Blender 4.1.1 / Windows 10 64-bit:

Read prefs: "C:\Users\Sybren\AppData\Roaming\Blender Foundation\Blender\4.1\config\userpref.blend"
addon_utils.disable: cam not loaded
Modules Installed (cam) from 'D:\\syncthing\\lasercutting\\software\\blendercam-1.0.21.zip' into 'C:\\Users\\Sybren\\AppData\\Roaming\\Blender Foundation\\Blender\\4.1\\scripts\\addons'
Defaulting to user installation because normal site-packages is not writeable
Looking in links: c:\Users\Sybren\AppData\Local\Temp\tmp2kc59_9g
Requirement already satisfied: setuptools in c:\program files\blender foundation\blender 4.1\4.1\python\lib\site-packages (63.2.0)
Requirement already satisfied: pip in c:\program files\blender foundation\blender 4.1\4.1\python\lib\site-packages (23.2.1)
Defaulting to user installation because normal site-packages is not writeable
Requirement already satisfied: pip in c:\program files\blender foundation\blender 4.1\4.1\python\lib\site-packages (23.2.1)
Collecting pip
  Obtaining dependency information for pip from https://files.pythonhosted.org/packages/8a/6a/19e9fe04fca059ccf770861c7d5721ab4c2aebc539889e97c7977528a53b/pip-24.0-py3-none-any.whl.metadata
  Using cached pip-24.0-py3-none-any.whl.metadata (3.6 kB)
Using cached pip-24.0-py3-none-any.whl (2.1 MB)
Installing collected packages: pip
  WARNING: The scripts pip.exe, pip3.11.exe and pip3.exe are installed in 'C:\Users\Sybren\AppData\Roaming\Python\Python311\Scripts' which is not on PATH.
  Consider adding this directory to PATH or, if you prefer to suppress this warning, use --no-warn-script-location.
Successfully installed pip-24.0

[notice] A new release of pip is available: 23.2.1 -> 24.0
[notice] To update, run: C:\Program Files\Blender Foundation\Blender 4.1\4.1\python\bin\python.exe -m pip install --upgrade pip
Defaulting to user installation because normal site-packages is not writeable
Collecting shapely
  Downloading shapely-2.0.4-cp311-cp311-win_amd64.whl.metadata (7.2 kB)
Collecting Equation
  Downloading Equation-1.2.01.zip (25 kB)
  Installing build dependencies ... done
  Getting requirements to build wheel ... done
  Installing backend dependencies ... done
  Preparing metadata (pyproject.toml) ... done
Collecting opencamlib
  Downloading opencamlib-2023.1.11-cp311-cp311-win_amd64.whl.metadata (47 kB)
     ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 47.8/47.8 kB 2.3 MB/s eta 0:00:00
Requirement already satisfied: numpy<3,>=1.14 in c:\program files\blender foundation\blender 4.1\4.1\python\lib\site-packages (from shapely) (1.24.3)
Downloading shapely-2.0.4-cp311-cp311-win_amd64.whl (1.4 MB)
   ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 1.4/1.4 MB 8.3 MB/s eta 0:00:00
Downloading opencamlib-2023.1.11-cp311-cp311-win_amd64.whl (272 kB)
   ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 272.5/272.5 kB 8.5 MB/s eta 0:00:00
Building wheels for collected packages: Equation
  Building wheel for Equation (pyproject.toml) ... done
  Created wheel for Equation: filename=Equation-1.2.1-py3-none-any.whl size=16262 sha256=a7328e17a97109466639575cfbe7a1f5ff24e8cc5cfb0d611c7fb60919b58dfb
  Stored in directory: c:\users\sybren\appdata\local\pip\cache\wheels\6d\6e\9a\5957d601b8310909854d888d13636e0603c1eff517ff95fc59
Successfully built Equation
Installing collected packages: Equation, shapely, opencamlib
Successfully installed Equation-1.2.1 opencamlib-2023.1.11 shapely-2.0.4
Traceback (most recent call last):
  File "C:\Program Files\Blender Foundation\Blender 4.1\4.1\scripts\modules\addon_utils.py", line 376, in enable
    mod = importlib.import_module(module_name)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Blender Foundation\Blender 4.1\4.1\python\Lib\importlib\__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<frozen importlib._bootstrap>", line 1204, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1176, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1147, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 690, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 940, in exec_module
  File "<frozen importlib._bootstrap>", line 241, in _call_with_frames_removed
  File "C:\Users\Sybren\AppData\Roaming\Blender Foundation\Blender\4.1\scripts\addons\cam\__init__.py", line 42, in <module>
    from .cam_operation import camOperation
  File "C:\Users\Sybren\AppData\Roaming\Blender Foundation\Blender\4.1\scripts\addons\cam\cam_operation.py", line 9, in <module>
    from shapely import geometry as sgeometry
ModuleNotFoundError: No module named 'shapely'

As you can see, it picks up my system-installed Python 3.11's pip, and installs the dependencies neatly in C:\Users\Sybren\AppData\Roaming\Python\Python311\site-packages\shapely, which is not on Blender's search path:

PYTHON INTERACTIVE CONSOLE 3.11.7 (main, Feb  5 2024, 18:45:06) [MSC v.1928 64 bit (AMD64)]

Builtin Modules:       bpy, bpy.data, bpy.ops, bpy.props, bpy.types, bpy.context, bpy.utils, bgl, gpu, blf, mathutils
Convenience Imports:   from mathutils import *; from math import *
Convenience Variables: C = bpy.context, D = bpy.data

>>> import sys
>>> print('\n'.join(sys.path))
C:\Users\Sybren\AppData\Roaming\Blender Foundation\Blender\4.1\scripts\startup
C:\Program Files\Blender Foundation\Blender 4.1\4.1\scripts\startup
C:\Users\Sybren\AppData\Roaming\Blender Foundation\Blender\4.1\scripts\addons\flamenco\wheels\python_dateutil-2.8.2-py2.py3-none-any.whl
C:\Users\Sybren\AppData\Roaming\Blender Foundation\Blender\4.1\scripts\addons\flamenco\wheels\six-1.16.0-py2.py3-none-any.whl
C:\Program Files\Blender Foundation\Blender 4.1\4.1\scripts\modules
C:\Program Files\Blender Foundation\Blender 4.1\python311.zip
C:\Program Files\Blender Foundation\Blender 4.1\4.1\python\DLLs
C:\Program Files\Blender Foundation\Blender 4.1\4.1\python\Lib
C:\Program Files\Blender Foundation\Blender 4.1
C:\Program Files\Blender Foundation\Blender 4.1\4.1\python
C:\Program Files\Blender Foundation\Blender 4.1\4.1\python\Lib\site-packages
C:\Program Files\Blender Foundation\Blender 4.1\4.1\scripts\freestyle\modules
C:\Program Files\Blender Foundation\Blender 4.1\4.1\scripts\addons\modules
C:\Users\Sybren\AppData\Roaming\Blender Foundation\Blender\4.1\scripts\addons\modules
C:\Program Files\Blender Foundation\Blender 4.1\4.1\scripts\startup\bl_ui
C:\Program Files\Blender Foundation\Blender 4.1\4.1\scripts\addons
C:\Users\Sybren\AppData\Roaming\Blender Foundation\Blender\4.1\scripts\addons
C:\Program Files\Blender Foundation\Blender 4.1\4.1\scripts\addons_contrib

Workaround

As a workaround, I moved the dependencies into C:\Users\Sybren\AppData\Roaming\Blender Foundation\Blender\4.1\scripts\addons\modules and restarted Blender. Then enabling the add-on works fine.