Remove solve.patch_pyomo()

This code previously patched Pyomo to remove a quadratic dependency
on the number of variables around Pyomo 5.4. This dependency was
fixed in [Pyomo 6.4.1](Pyomo/pyomo#2351) but
testing indicates that Pyomo 6.0.0+ don't go down that path when
using our typical solvers (cplex, gurobi, cplexamp, appsi_highs,
glpk, cbc). This patch has also caused problems for some users
with new versions of Pyomo that install without source code. So we
are removing the patch now.

switch_model/solve.py

@@ -167,10 +167,6 @@ def main(args=None, return_model=False, return_instance=False):
         # the current module (to register define_arguments callback)
         modules = get_module_list(args)
 
-        # Patch pyomo if needed, to allow reconstruction of expressions.
-        # This must be done before the model is constructed.
-        patch_pyomo()
-
         # Define the model
         model = create_model(modules, args=args, logger=logger)
         # Add any suffixes specified on the command line (usually only iis)
@@ -391,82 +387,6 @@ def reload_prior_solution_from_pickle(instance, pickle_file):
     return instance
 
 
-patched_pyomo = False
-
-
-def patch_pyomo():
-    # patch Pyomo if needed
-    global patched_pyomo
-    if patched_pyomo:
-        return
-    patched_pyomo = True
-
-    # Pyomo 5.1.1 (and maybe others) is very slow to load prior solutions
-    # because it does a full-component search for each component name as it
-    # assigns the data. This ends up taking longer than solving the model. So we
-    # micro- patch pyomo.core.base.PyomoModel.ModelSolutions.add_solution to use
-    # Pyomo's built-in caching system for component names.
-    # TODO: create a pull request for Pyomo to do this
-    # NOTE: space inside the long quotes is significant; must match the Pyomo code
-    old_code = """
-                    for obj in instance.component_data_objects(Var):
-                        cache[obj.name] = obj
-                    for obj in instance.component_data_objects(Objective, active=True):
-                        cache[obj.name] = obj
-                    for obj in instance.component_data_objects(Constraint, active=True):
-                        cache[obj.name] = obj"""
-    new_code = """
-                    # use buffer to avoid full search of component for data object
-                    # which introduces a delay that is quadratic in model size
-                    buf=dict()
-                    for obj in instance.component_data_objects(Var):
-                        cache[obj.getname(fully_qualified=True, name_buffer=buf)] = obj
-                    for obj in instance.component_data_objects(Objective, active=True):
-                        cache[obj.getname(fully_qualified=True, name_buffer=buf)] = obj
-                    for obj in instance.component_data_objects(Constraint, active=True):
-                        cache[obj.getname(fully_qualified=True, name_buffer=buf)] = obj"""
-
-    from pyomo.core.base.PyomoModel import ModelSolutions
-
-    add_solution_code = inspect.getsource(ModelSolutions.add_solution)
-    if old_code in add_solution_code:
-        # create and inject a new version of the method
-        add_solution_code = add_solution_code.replace(old_code, new_code)
-        replace_method(ModelSolutions, "add_solution", add_solution_code)
-    elif pyomo.version.version_info[:2] >= (5, 0):
-        # We don't allow later versions of Pyomo than we've tested with, so
-        # this should only show up during testing when preparing to release a
-        # new version.
-        print(
-            "NOTE: The patch to pyomo.core.base.PyomoModel.ModelSolutions.add_solution "
-            "has been deactivated because the Pyomo source code has changed. "
-            f"Check whether this patch is still needed and edit {__file__} "
-            "accordingly."
-        )
-
-
-def replace_method(class_ref, method_name, new_source_code):
-    """
-    Replace specified class method with a compiled version of new_source_code.
-    """
-    orig_method = getattr(class_ref, method_name)
-    # compile code into a function
-    workspace = dict()
-    exec(textwrap.dedent(new_source_code), workspace)
-    new_method = workspace[method_name]
-    # create a new function with the same body, but using the old method's namespace
-    new_func = types.FunctionType(
-        new_method.__code__,
-        orig_method.__globals__,
-        orig_method.__name__,
-        orig_method.__defaults__,
-        orig_method.__closure__,
-    )
-    # note: this normal function will be automatically converted to an unbound
-    # method when it is assigned as an attribute of a class
-    setattr(class_ref, method_name, new_func)
-
-
 def reload_prior_solution_from_csvs(instance):
     """
     Assign values to all model variables from <variable>.csv files saved after