_component_data_iter I think doesn't use sorted_robust?

[emma58]

This is still related to #567, but now I'm confused. On master (after #1842), now the pprint statement in the following code works, but the writer still throws the TypeError because it cannot sort the tuples in m.ick:

from pyomo.environ import *

m = ConcreteModel()
m.ick = Set(initialize=[(1, 'str1'), ('str2', 'str3')], ordered=True,
            within=Any)
m.v = Var(m.ick, within=Binary)
m.obj = Objective(expr=m.v[1, 'str1'])
m.cons = Constraint(expr=m.v[1,'str1'] >= m.v['str2', 'str3'])

m.pprint() # this is okay
SolverFactory('gurobi').solve(m, tee=True) # this throws the error below

Traceback (most recent call last):
  File "sorting_stuff.py", line 11, in <module>
    SolverFactory('gurobi').solve(m, tee=True)
  File "/home/esjohn/src/pyomo/pyomo/opt/base/solvers.py", line 574, in solve
    self._presolve(*args, **kwds)
  File "/home/esjohn/src/pyomo/pyomo/solvers/plugins/solvers/GUROBI.py", line 230, in _presolve
    ILMLicensedSystemCallSolver._presolve(self, *args, **kwds)
  File "/home/esjohn/src/pyomo/pyomo/opt/solver/shellcmd.py", line 200, in _presolve
    OptSolver._presolve(self, *args, **kwds)
  File "/home/esjohn/src/pyomo/pyomo/opt/base/solvers.py", line 674, in _presolve
    **kwds)
  File "/home/esjohn/src/pyomo/pyomo/opt/base/solvers.py", line 740, in _convert_problem
    **kwds)
  File "/home/esjohn/src/pyomo/pyomo/opt/base/convert.py", line 100, in convert_problem
    problem_files, symbol_map = converter.apply(*tmp, **tmpkw)
  File "/home/esjohn/src/pyomo/pyomo/solvers/plugins/converter/model.py", line 82, in apply
    io_options=io_options)
  File "/home/esjohn/src/pyomo/pyomo/core/base/block.py", line 1812, in write
    io_options)
  File "/home/esjohn/src/pyomo/pyomo/repn/plugins/cpxlp.py", line 172, in __call__
    include_all_variable_bounds=include_all_variable_bounds)
  File "/home/esjohn/src/pyomo/pyomo/repn/plugins/cpxlp.py", line 451, in _print_model_LP
    Var, sort=sortOrder) )
  File "/home/esjohn/src/pyomo/pyomo/core/base/block.py", line 1435, in component_data_objects
    sort=sort):
  File "/home/esjohn/src/pyomo/pyomo/core/base/block.py", line 1361, in _component_data_iter
    _items = sorted(_items, key=itemgetter(0))
TypeError: '<' not supported between instances of 'str' and 'int'

Should _component_data_iter be using sorted_robust?

[michaelbynum]

I think the LP writer can now be switched to not sort by default since sets are now ordered by default?

[michaelbynum]

Although it probably still makes sense to fix Block._component_data_iter

[emma58]

Yeah, this also means you can't call m.component_data_objects(Var, sort=SortComponents.deterministic) which is a thing that several transformations need to do, at least.