A simple problem breaks when adding objectives

[Esya]

Hello, using a build from master, all jobs fail with NO_REASON_FOUND when adding any objective - Here it is with minimize-cost then minimize-arrival-time, but I've also tried no objective at all. When I remove the objectives section entirely, I do get a solution. I'm not sure what the reason is here. Any idea ?

Problem

{
  "fleet": {
    "profiles": [{ "name": "car" }],
    "vehicles": [
      {
        "capacity": [100000],
        "costs": { "distance": 1, "fixed": 1, "time": 1 },
        "profile": { "matrix": "car", "scale": 1 },
        "shifts": [
          {
            "start": {
              "earliest": "2022-12-06T09:00:00.000+01:00",
              "location": { "lat": 48.59384, "lng": 1.5860837 }
            },
            "end": {
              "latest": "2022-12-06T18:00:00.000+01:00",
              "location": { "lat": 48.59384, "lng": 1.5860837 }
            }
          },
          {
            "start": {
              "earliest": "2022-12-07T09:00:00.000+01:00",
              "location": { "lat": 48.59384, "lng": 1.5860837 }
            },
            "end": {
              "latest": "2022-12-07T18:00:00.000+01:00",
              "location": { "lat": 48.59384, "lng": 1.5860837 }
            }
          }
        ],
        "typeId": "type_3",
        "vehicleIds": ["vehicle_3"]
      }
    ]
  },
  "plan": {
    "jobs": [
      {
        "id": "job_15",
        "services": [
          {
            "places": [
              {
                "duration": 3600,
                "location": { "lat": 48.9147, "lng": 2.29764 }
              }
            ]
          }
        ]
      },
      {
        "id": "job_16",
        "services": [
          {
            "places": [
              {
                "duration": 3600,
                "location": { "lat": 48.93144, "lng": 2.27157 }
              }
            ]
          }
        ]
      }
    ]
  },
  "objectives": [
    [{ "type": "minimize-cost" }],
    [{ "type": "minimize-arrival-time" }]
  ]
}

Cost matrix

{"travelTimes":[0,381,4629,363,0,4638,4597,4643,0],"distances":[0,3464,78071,3376,0,79686,79401,79295,0],"profile":"car"}

Output

{
  "statistic": {
    "cost": 0.0,
    "distance": 0,
    "duration": 0,
    "times": {
      "driving": 0,
      "serving": 0,
      "waiting": 0,
      "break": 0,
      "commuting": 0,
      "parking": 0
    }
  },
  "tours": [],
  "unassigned": [
    {
      "jobId": "job_16",
      "reasons": [
        {
          "code": "NO_REASON_FOUND",
          "description": "unknown"
        }
      ]
    },
    {
      "jobId": "job_15",
      "reasons": [
        {
          "code": "NO_REASON_FOUND",
          "description": "unknown"
        }
      ]
    }
  ]
}

[Esya]

After digging a bit deeper, it seems that if I add minimize-unassigned as the first objective it does not happen. Is this objective mandatory in my situation ?

[reinterpretcat]

Yes, it needs to be added. Otherwise you're telling the solver that you want to minimize cost at first and don't care about amount of unassigned jobs. Zero assigned and zero cost - it looks like a best solution.

Actually, it would be nice to add validation rule to prevent this, but it is not yet there

[Esya]

Ah - that makes sense now that you mention it. I'll close my comment then! Thanks a lot.