NH-3334 - 'collection is not associated with any session' upon refreshing objects from QueryOver<>().Future<>()

[nhibernate-bot]

Fabrizio Gennari created an issue — 28th November 2012, 17:35:17:

This program

namespace NhibernateExperiments
{
    using System.Collections.Generic;
    using System.Reflection;

    using log4net.Config;

    using NHibernate;
    using NHibernate.Cfg;

    public class Program
    {
        public static void Main(string[] args)
        {
            BasicConfigurator.Configure();
            Configuration configuration = new Configuration().SetProperties(new Dictionary<string, string>
            {
                {Environment.ConnectionDriver, "NHibernate.Driver.SQLite20Driver"},
                {Environment.ConnectionString, "Data Source=h:\\testdb;Version=3"},
                {Environment.Dialect, "NHibernate.Dialect.SQLiteDialect"},
                {Environment.QuerySubstitutions, "true=1;false=0"},
                {Environment.ShowSql, "true"},
            }).AddAssembly(Assembly.GetExecutingAssembly());
            ISessionFactory buildSessionFactory = configuration.BuildSessionFactory();
            ISession session = buildSessionFactory.OpenSession();
            IEnumerable<CarDealer> carDealers = session.QueryOver<CarDealer>().Future();
            foreach (CarDealer carDealer in carDealers)
            {
                session.Refresh(carDealer);
            }
        }
    }
}

is causing a HibernateException "collection is not associated with any session".
Mapping file

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"
                   assembly="nhibernateExperiments"
                   namespace="NhibernateExperiments">

  <class name="CarDealer" lazy="false">
    <id name="id" column="id" access="field">
      <generator class="native"/>
    </id>
    <property name="Name" />
    <set name="models" table="ModelInStock" lazy="false" access="field">
      <key column="dealerid"/>
      <many-to-many class="CarModel" column="modelid"/>
    </set>
  </class>

  <class name="CarModel" lazy="false">
    <id name="id" column="id" access="field">
      <generator class="native"/>
    </id>
    <property name="Name" />
    <property name="Year" />
    <set name="dealers" table="ModelInStock" lazy="false" access="field">
      <key column="modelid"/>
      <many-to-many class="CarDealer" column="dealerid"/>
    </set>
  </class>

</hibernate-mapping>

Objects

namespace NhibernateExperiments
{
    using System.Collections.Generic;
    using Iesi.Collections.Generic;

    public class CarModel
    {
        private readonly Iesi.Collections.Generic.ISet<CarDealer> dealers = new HashedSet<CarDealer>();

        private int id;

        public CarModel(string name, int year)
        {
            Year = year;
            Name = name;
        }

        private CarModel()
        {
        }

        public string Name { get; private set; }

        public int Year{ get; private set; }
    }

    public class CarDealer
    {
        private readonly Iesi.Collections.Generic.ISet<CarModel> models;

        private int id;

        public CarDealer(string name)
        {
            this.Name = name;
            this.models = new HashedSet<CarModel>();
        }

        private CarDealer()
        {
        }

        public string Name { get; private set; }

        public IEnumerable<CarModel> Models
        {
            get
            {
                return this.models;
            }
        }

        public void AddModel(CarModel model)
        {
            this.models.Add(model);
        }
    }
}

DB schema

CREATE TABLE CarDealer (
id integer primary key autoincrement,
Name varchar(50)
)
CREATE TABLE CarModel (
id integer primary key autoincrement,
Name varchar(50),
Year int
)
CREATE TABLE ModelInStock (
modelid integer,
dealerid integer,
foreign key (dealerid) references CarDealer(id),
foreign key (modelid) references CarModel(id)
)

---

Fabrizio Gennari added a comment — 28th November 2012, 17:37:16:

Sorry, type should be "bug", not "patch"

---

Fabrizio Gennari added a comment — 29th November 2012, 10:57:42:

Workaround is to change the foreach loop

        foreach (CarDealer carDealer in carDealers)
        {
            IPersistentCollection collection = carDealer.Models as IPersistentCollection;
            if (collection != null)
            {
                collection.ForceInitialization();
            }

            session.Refresh(carDealer);
        }