component_data_objects returns the values of immutable Params

[emma58]

Summary

Calling component_data_objects returns the values of immutable Params. This is scary since that means that it can return things that don't have a ctype. I think it should only return the ParamDatas for mutable Params.

Steps to reproduce the issue

from pyomo.environ import *

m = ConcreteModel()

m.p = Param([1, 2, 3, 4], initialize={1: 1, 2: 1}, mutable=False, default=0)

for thing in m.component_data_objects(active=True, descend_into=True):
    print(thing)

outputs:

p_index
1
1
0
0

Information on your system

Pyomo version: main branch
Python version:
Operating system:
How Pyomo was installed (PyPI, conda, source):
Solver (if applicable):