Description
Summary
I'm not actually sure that this really is a bug because the use case is ridiculous, but at least for the sake of documentation, Gurobi has a 255 character limit on tokens. With symbolic_solver_labels set to True we will happily violate this limit.
(Please don't ask me how I know. :P)
Steps to reproduce the issue
In the following script, the first solve is fine because we make sane names. The second solve gives a Gurobi error, recorded below.
from pyomo.environ import *
m = ConcreteModel()
m.s = Set(initialize=["apologies",
"This_is_a_name_with_more_than_255_characters_which_I_agree_is_a_totally_ridiculous_thing_to_do_so_why_did_I_do_it_you_might_ask_but_naturally_I_would_dodge_the_question_so_you_will_have_to_imagine_the_reason_which_honestly_should_be_way_more_fun_than_knowing_the_unfortunate_reality"])
m.x = Var(m.s, bounds=(0, 10))
m.obj = Objective(expr=sum(m.x[i] for i in m.s), sense=maximize)
SolverFactory('gurobi').solve(m, tee=True)
# uh oh
SolverFactory('gurobi').solve(m, symbolic_solver_labels=True, tee=True)
Yields the output:
Read LP format model from file /tmp/tmpagj3adcl.pyomo.lp
Reading time = 0.00 seconds
x1: 1 rows, 3 columns, 1 nonzeros
Gurobi Optimizer version 12.0.0 build v12.0.0rc1 (linux64 - "CentOS Linux 7 (Core)")
CPU model: 13th Gen Intel(R) Core(TM) i7-1365U, instruction set [SSE2|AVX|AVX2]
Thread count: 4 physical cores, 4 logical processors, using up to 4 threads
Optimize a model with 1 rows, 3 columns and 1 nonzeros
Model fingerprint: 0x08b875f2
Coefficient statistics:
Matrix range [1e+00, 1e+00]
Objective range [1e+00, 1e+00]
Bounds range [1e+00, 1e+01]
RHS range [1e+00, 1e+00]
Presolve removed 1 rows and 3 columns
Presolve time: 0.00s
Presolve: All rows and columns removed
Iteration Objective Primal Inf. Dual Inf. Time
0 2.0000000e+01 0.000000e+00 0.000000e+00 0s
Solved in 0 iterations and 0.00 seconds (0.00 work units)
Optimal objective 2.000000000e+01
Error reading LP format file /tmp/tmp7mef0crh.pyomo.lp at line 5
Token contains more than 255 characters
Neighboring tokens: " max obj: +1 x(apologies) +1 x(This_is_a_name_with_more_than_255_characters_which_I_agree_is_a_totally_ridiculous_thing_to_do_so_why_did_I_do_it_you_might_ask_but_naturally_I_would_dodge_the_question_so_you_will_have_to_imagine_the_reason_which_honestly_should_be_way_more_fun_than_kno "
Traceback (most recent call last):
File "/home/esjohn/src/capsiid/capsiid-interdiction/nihba/ha.py", line 13, in <module>
SolverFactory('gurobi').solve(m, symbolic_solver_labels=True, tee=True)
File "/home/esjohn/src/pyomo/pyomo/opt/base/solvers.py", line 610, in solve
_status = self._apply_solver()
^^^^^^^^^^^^^^^^^^^^
File "/home/esjohn/src/pyomo/pyomo/solvers/plugins/solvers/GUROBI.py", line 689, in _apply_solver
self._soln = GUROBI_RUN.gurobi_run(
^^^^^^^^^^^^^^^^^^^^^^
File "/home/esjohn/src/pyomo/pyomo/solvers/plugins/solvers/GUROBI_RUN.py", line 66, in gurobi_run
model = read(model_file)
^^^^^^^^^^^^^^^^
File "src/gurobipy/gurobi.pxi", line 336, in gurobipy._core.read
File "src/gurobipy/gurobi.pxi", line 121, in gurobipy._core.gurobi.read
gurobipy._exception.GurobiError: Unable to read file
Information on your system
Pyomo version: main
Python version: 3.11
Operating system: linux
How Pyomo was installed (PyPI, conda, source): source
Solver (if applicable): Gurobi
Additional information
For the LP interface the error message is clear and it's easy enough to fix on the user side that this probably doesn't matter. But I thought I might note it because it is a bit more opaque in a direct interface (though the Gurobi error in that case too at least cites the problem, though it does not give the name that is causing it.)