Fix alias join on join

Fixes #1928

Author: fredericDelaporte

src/NHibernate.Test/Async/NHSpecificTest/GH1928/Fixture.cs

@@ -0,0 +1,72 @@
+//------------------------------------------------------------------------------
+// <auto-generated>
+//     This code was generated by AsyncGenerator.
+//
+//     Changes to this file may cause incorrect behavior and will be lost if
+//     the code is regenerated.
+// </auto-generated>
+//------------------------------------------------------------------------------
+
+
+using NHibernate.Criterion;
+using NUnit.Framework;
+
+namespace NHibernate.Test.NHSpecificTest.GH1928
+{
+	using System.Threading.Tasks;
+	[TestFixture]
+	public class FixtureAsync : BugTestCase
+	{
+		protected override void OnSetUp()
+		{
+			using (var session = OpenSession())
+			using (var transaction = session.BeginTransaction())
+			{
+				var ez = new EntityZ { Name = "Bob" };
+				session.Save(ez);
+				var ey = new EntityY { Z = ez };
+				session.Save(ey);
+				var ex = new EntityX { Y = ey };
+				session.Save(ex);
+
+				ez = new EntityZ { Name = "Sally" };
+				session.Save(ez);
+				ey = new EntityY { Z = ez };
+				session.Save(ey);
+				ex = new EntityX { Y = ey };
+				session.Save(ex);
+
+				transaction.Commit();
+			}
+		}
+
+		protected override void OnTearDown()
+		{
+			using (var session = OpenSession())
+			using (var transaction = session.BeginTransaction())
+			{
+				session.CreateQuery("delete from System.Object").ExecuteUpdate();
+
+				transaction.Commit();
+			}
+		}
+
+		[Test]
+		public async Task JoinAliasOnJoinAsync()
+		{
+			using (var session = OpenSession())
+			using (session.BeginTransaction())
+			{
+				EntityZ aliasZ = null;
+				var result = await (session
+					.QueryOver<EntityX>()
+					.Inner.JoinQueryOver(x => x.Y)
+					.Inner.JoinAlias(y => y.Z, () => aliasZ)
+					.Select(Projections.Entity(() => aliasZ))
+					.ListAsync<EntityZ>());
+
+				Assert.That(result, Has.Count.EqualTo(2));
+			}
+		}
+	}
+}

src/NHibernate.Test/NHSpecificTest/GH1928/Entity.cs

@@ -0,0 +1,22 @@
+using System;
+
+namespace NHibernate.Test.NHSpecificTest.GH1928
+{
+	class EntityX
+	{
+		public virtual Guid Id { get; set; }
+		public virtual EntityY Y { get; set; }
+	}
+
+	class EntityY
+	{
+		public virtual Guid Id { get; set; }
+		public virtual EntityZ Z { get; set; }
+	}
+
+	class EntityZ
+	{
+		public virtual Guid Id { get; set; }
+		public virtual string Name { get; set; }
+	}
+}

src/NHibernate.Test/NHSpecificTest/GH1928/Fixture.cs

@@ -0,0 +1,61 @@
+using NHibernate.Criterion;
+using NUnit.Framework;
+
+namespace NHibernate.Test.NHSpecificTest.GH1928
+{
+	[TestFixture]
+	public class Fixture : BugTestCase
+	{
+		protected override void OnSetUp()
+		{
+			using (var session = OpenSession())
+			using (var transaction = session.BeginTransaction())
+			{
+				var ez = new EntityZ { Name = "Bob" };
+				session.Save(ez);
+				var ey = new EntityY { Z = ez };
+				session.Save(ey);
+				var ex = new EntityX { Y = ey };
+				session.Save(ex);
+
+				ez = new EntityZ { Name = "Sally" };
+				session.Save(ez);
+				ey = new EntityY { Z = ez };
+				session.Save(ey);
+				ex = new EntityX { Y = ey };
+				session.Save(ex);
+
+				transaction.Commit();
+			}
+		}
+
+		protected override void OnTearDown()
+		{
+			using (var session = OpenSession())
+			using (var transaction = session.BeginTransaction())
+			{
+				session.CreateQuery("delete from System.Object").ExecuteUpdate();
+
+				transaction.Commit();
+			}
+		}
+
+		[Test]
+		public void JoinAliasOnJoin()
+		{
+			using (var session = OpenSession())
+			using (session.BeginTransaction())
+			{
+				EntityZ aliasZ = null;
+				var result = session
+					.QueryOver<EntityX>()
+					.Inner.JoinQueryOver(x => x.Y)
+					.Inner.JoinAlias(y => y.Z, () => aliasZ)
+					.Select(Projections.Entity(() => aliasZ))
+					.List<EntityZ>();
+
+				Assert.That(result, Has.Count.EqualTo(2));
+			}
+		}
+	}
+}

src/NHibernate.Test/NHSpecificTest/GH1928/Mappings.hbm.xml

@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" assembly="NHibernate.Test"
+                   namespace="NHibernate.Test.NHSpecificTest.GH1928">
+
+  <class name="EntityX">
+    <id name="Id" generator="guid.comb"/>
+    <many-to-one name="Y"/>
+  </class>
+
+  <class name="EntityY">
+    <id name="Id" generator="guid.comb"/>
+    <many-to-one name="Z"/>
+  </class>
+
+  <class name="EntityZ">
+    <id name="Id" generator="guid.comb"/>
+    <property name="Name"/>
+  </class>
+
+</hibernate-mapping>

src/NHibernate/Loader/Criteria/CriteriaQueryTranslator.cs

@@ -418,15 +418,16 @@ private void CreateAssociationPathCriteriaMap()
 			foreach (var crit in rootCriteria.IterateSubcriteria())
 			{
 				var wholeAssociationPath = GetWholeAssociationPath(crit, out var parentAlias);
-				if (parentAlias != null)
+				if (parentAlias == null)
+					parentAlias = rootCriteria.Alias;
+
+				if (!associationAliasToChildrenAliasesMap.TryGetValue(parentAlias, out var children))
 				{
-					if (!associationAliasToChildrenAliasesMap.TryGetValue(parentAlias, out var children))
-					{
-						children = new HashSet<string>();
-						associationAliasToChildrenAliasesMap.Add(parentAlias, children);
-					}
-					children.Add(crit.Alias);
+					children = new HashSet<string>();
+					associationAliasToChildrenAliasesMap.Add(parentAlias, children);
 				}
+				children.Add(crit.Alias);
+
 				var key = new AliasKey(crit.Alias, wholeAssociationPath);
 				try
 				{