Problem when providing pair of pickup and delivery indices

Start with node-or-tools/test/vrp.js, reproduce the failure using the shown pickups, deliveries, routeLocks, and time windows, and trace the VRP.Solve entry point into the binding. Compare the failing case with the same example without pickup and delivery indices. Done means the example returns a valid route order without reporting "Unable to find a solution".

Hey,

There is this issue where providing a pair of pickup and delivery indices would lead to this error message: Unable to find a solution

Expected Behavior

It should return a valid route order based on cost array.

Current Behavior

Returns Unable to find a solution

Steps to Reproduce

1. Copy node-or-tools/test/vrp.js file content to a new file
2. Remove all assertions
3. Add a pair of pickup and delivery indices in searchOpts.

   pickups: [4, 7],
   deliveries: [7, 10]

Context (Environment)

I have a pair of pickup and delivery indices and I want to visit one or more stops before visiting others.

This is my code snippet. You could see that if we remove the pickup and delivery indices, the code will work but after adding aforementioned indices, it returns Unable to find a solution

module.exports = () => {
  const ortools = require('node_or_tools')
  var locations = [
    [0, 0], [0, 1], [0, 2], [0, 3],
    [1, 0], [1, 1], [1, 2], [1, 3],
    [2, 0], [2, 1], [2, 2], [2, 3],
    [3, 0], [3, 1], [3, 2], [3, 3]]

  var depot = 0

  function manhattanDistance(lhs, rhs) {
    return Math.abs(lhs[0] - rhs[0]) + Math.abs(lhs[1] - rhs[1])
  }

  var costMatrix = new Array(locations.length)

  for (var from = 0; from < locations.length; ++from) {
    costMatrix[from] = new Array(locations.length)

    for (var to = 0; to < locations.length; ++to) {
      costMatrix[from][to] = manhattanDistance(locations[from], locations[to])
    }
  }

  var dayStarts = Hours(0)
  var dayEnds = Hours(3)


  var seed = 2147483650

  function ParkMillerRNG(seed) {
    var modulus = 2147483647
    var multiplier = 48271
    var increment = 0
    var state = seed

    return function() {
      state = (multiplier * state + increment) % modulus
      return state / modulus
    }
  }

  var rand = ParkMillerRNG(seed)


  function Seconds(v) {
    return v
  }

  function Minutes(v) {
    return Seconds(v * 60)
  }

  function Hours(v) {
    return Minutes(v * 60)
  }


  var durationMatrix = new Array(locations.length)

  for (var from = 0; from < locations.length; ++from) {
    durationMatrix[from] = new Array(locations.length)

    for (var to = 0; to < locations.length; ++to) {
      var serviceTime = Minutes(3)
      var travelTime = Minutes(costMatrix[from][to])

      durationMatrix[from][to] = serviceTime + travelTime
    }
  }


  var timeWindows = new Array(locations.length)

  for (var at = 0; at < locations.length; ++at) {
    if (at === depot) {
      timeWindows[at] = [dayStarts, dayEnds]
      continue
    }

    var earliest = dayStarts
    var latest = dayEnds - Hours(1)

    var start = rand() * (latest - earliest) + earliest
    var stop = rand() * (latest - start) + start

    timeWindows[at] = [start, stop]
  }


  var demandMatrix = new Array(locations.length)

  for (var from = 0; from < locations.length; ++from) {
    demandMatrix[from] = new Array(locations.length)

    for (var to = 0; to < locations.length; ++to) {
      if (from === depot)
        demandMatrix[from][to] = 0
      else
        demandMatrix[from][to] = 1
    }
  }


  var solverOpts = {
    numNodes: locations.length,
    costs: costMatrix,
    durations: durationMatrix,
    timeWindows: timeWindows,
    demands: demandMatrix
  }

  var VRP = new ortools.VRP(solverOpts)

  var numVehicles = 10
  var timeHorizon = dayEnds - dayStarts
  var vehicleCapacity = 10

// Dummy lock to let vehicle 0 go to location 2 and 3 first - to test route locks
  var routeLocks = new Array(numVehicles)

  for (var vehicle = 0; vehicle < numVehicles; ++vehicle) {
    if (vehicle === 0)
      routeLocks[vehicle] = [2, 3]
    else
      routeLocks[vehicle] = []
  }

  var searchOpts = {
    computeTimeLimit: 1000,
    numVehicles: numVehicles,
    depotNode: depot,
    timeHorizon: timeHorizon,
    vehicleCapacity: vehicleCapacity,
    routeLocks: routeLocks,
    pickups: [4, 7],
    deliveries: [7, 10]
  }

  VRP.Solve(searchOpts, function(err, solution) {


    console.log('**********************')
    console.log(err,solution)
    console.log('**********************')
    function used(v) {
      return v.length == 0 ? 0 : 1
    }

    function addition(l, r) {
      return l + r
    }

    var numVehiclesUsed = solution.routes.map(used).reduce(addition, 0)


    function checkRoute(v) {
      var depotInRoute = v.find(function(u) {
        return u == depot
      })
    }

    function checkTimeWindows(v) {
      v.forEach(function(u) {
      })
    }

    solution.routes.forEach(checkRoute)
    solution.times.forEach(checkTimeWindows)

  })

}