Pyomo Compatibility with Python 3.11-CodePudding

Is there a known compatibility issue with pyomo and python 3.11?

Just trying out the latest/greatest python release and importing pyomo is failing with pyomo v 6.4.2:

Python 3.11.0 (v3.11.0:deaf509e8f, Oct 24 2022, 14:43:23) [Clang 13.0.0 (clang-1300.0.29.30)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> from pyomo.environ import *
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/pyomo/environ/__init__.py", line 79, in <module>
    _import_packages()
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/pyomo/environ/__init__.py", line 61, in _import_packages
    _do_import(pname)
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/pyomo/environ/__init__.py", line 16, in _do_import
    importlib.import_module(pkg_name)
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/pyomo/core/__init__.py", line 43, in <module>
    from pyomo.core import expr, util, kernel
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/pyomo/core/util.py", line 21, in <module>
    from pyomo.core.base.var import Var
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/pyomo/core/base/__init__.py", line 34, in <module>
    from pyomo.core.base.label import (CuidLabeler,
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/pyomo/core/base/label.py", line 19, in <module>
    from pyomo.core.base.componentuid import ComponentUID
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/pyomo/core/base/componentuid.py", line 25, in <module>
    from pyomo.core.base.reference import Reference
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/pyomo/core/base/reference.py", line 17, in <module>
    from pyomo.core.base.set import SetOf, OrderedSetOf, _SetDataBase
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/pyomo/core/base/set.py", line 4208, in <module>
    DeclareGlobalSet(_AnySet(
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/pyomo/core/base/set.py", line 4199, in DeclareGlobalSet
    _set.__class__.__setstate__(_set, obj.__getstate__())
                                      ^^^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/pyomo/core/base/component.py", line 787, in __getstate__
    state = _base.__getstate__()
            ^^^^^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/pyomo/core/base/indexed_component.py", line 316, in __getstate__
    state = super(IndexedComponent, self).__getstate__()
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/pyomo/core/base/component.py", line 471, in __getstate__
    state[key] = val
    ~~~~~^^^^^
TypeError: 'tuple' object does not support item assignment
>>>

Pyomo Version check:

~ % pip3 show pyomo
Name: Pyomo
Version: 6.4.2
Summary: Pyomo: Python Optimization Modeling Objects
Home-page: http://pyomo.org
Author: 
Author-email: 
License: BSD
Location: /Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages
Requires: ply
Required-by: 
~ %

CodePudding user response：

Pyomo 6.4.2 isn't compatible with python 3.11. It does some stuff with pickle and the __getstate__/__setstate__ functions. However, Python 3.11 introduced a default implementation for these functions that does not match Pyomo's expectations. So the whole thing falls over.

This this note on the new default implementation for __getstate__.

In the v6.4.2 code base you can see it does a check to see if __getstate__ is implemented or not. https://github.com/Pyomo/pyomo/blob/6.4.2/pyomo/core/base/component.py#L467

In the main branch, this code has recently been changed. And there is a recent commit saying that the code is now 3.11 compatible. So just hang tight, and wait for the new version to be release.

Or if you really cannot wait and just want to experiment, then install the development version of 6.4.3 with git:

eg.

pip install git https://github.com/Pyomo/pyomo.git@main

NB. Obviously, you'll need git installed to be able to do this. And do not use this to install pyomo for production code. This is code that is under development and has not yet been released.