Strange behavior in scheduling problems with activities parameters (UP)

[nicola-gigante]

Hi,

consider this example:

from unified_planning.shortcuts import *
import unified_planning.model.scheduling as sched

problem = sched.SchedulingProblem()

a = problem.add_activity('a', 10)

a.add_parameter('p', BoolType())

print(problem)

with OneshotPlanner(name='aries') as planner:
    solution = planner.solve(problem)
    print(solution)

It prints the following:

fluents = [
]

initial fluents default = [
]

initial values = [
]


BASE: {
  }

Activities:
  a(bool a.p) {
    duration = [10, 10]
  }
  
status: INTERNAL_ERROR
engine: aries
plan: None

Why does it give INTERNAL_ERROR?

If I comment the add_parameter() line, it works.

Best,
Nicola