From 7cd90cc4a273eb2a69ed6a7c3acea17c6c316e61 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fr=C3=A9d=C3=A9ric=20Delaporte?=
 <12201973+fredericdelaporte@users.noreply.github.com>
Date: Thu, 1 Feb 2024 15:32:26 +0100
Subject: [PATCH 1/3] Add a test case for #3465

---
 .../NHSpecificTest/GH3465/Entities.cs         | 20 +++++++++++++++++++
 .../NHSpecificTest/GH3465/Fixture.cs          | 20 +++++++++++++++++++
 .../NHSpecificTest/GH3465/Mappings.hbm.xml    | 18 +++++++++++++++++
 3 files changed, 58 insertions(+)
 create mode 100644 src/NHibernate.Test/NHSpecificTest/GH3465/Entities.cs
 create mode 100644 src/NHibernate.Test/NHSpecificTest/GH3465/Fixture.cs
 create mode 100644 src/NHibernate.Test/NHSpecificTest/GH3465/Mappings.hbm.xml

diff --git a/src/NHibernate.Test/NHSpecificTest/GH3465/Entities.cs b/src/NHibernate.Test/NHSpecificTest/GH3465/Entities.cs
new file mode 100644
index 00000000000..3a325ed9ba8
--- /dev/null
+++ b/src/NHibernate.Test/NHSpecificTest/GH3465/Entities.cs
@@ -0,0 +1,20 @@
+using System;
+using System.Collections.Generic;
+
+namespace NHibernate.Test.NHSpecificTest.GH3465
+{
+	class EntityA
+	{
+		public virtual Guid Id { get; set; }
+		public virtual ISet<EntityB> Children { get; set; }
+	}
+	class EntityB
+	{
+		public virtual Guid Id { get; set; }
+		public virtual EntityA Parent { get; set; }
+	}
+	class EntityC
+	{
+		public virtual Guid Id { get; set; }
+	}
+}
diff --git a/src/NHibernate.Test/NHSpecificTest/GH3465/Fixture.cs b/src/NHibernate.Test/NHSpecificTest/GH3465/Fixture.cs
new file mode 100644
index 00000000000..e51af1211d9
--- /dev/null
+++ b/src/NHibernate.Test/NHSpecificTest/GH3465/Fixture.cs
@@ -0,0 +1,20 @@
+using System.Linq;
+using NUnit.Framework;
+
+namespace NHibernate.Test.NHSpecificTest.GH3465
+{
+	[TestFixture]
+	public class Fixture : BugTestCase
+	{
+		[Test]
+		public void ThetaJoinSubQuery()
+		{
+			using (var session = OpenSession())
+			using (session.BeginTransaction())
+			{
+				var query = session.CreateQuery("select e.Id from EntityA e where exists (from e.Children b, EntityC c)");
+				Assert.DoesNotThrow(() => query.List());
+			}
+		}
+	}
+}
diff --git a/src/NHibernate.Test/NHSpecificTest/GH3465/Mappings.hbm.xml b/src/NHibernate.Test/NHSpecificTest/GH3465/Mappings.hbm.xml
new file mode 100644
index 00000000000..b89c139fa29
--- /dev/null
+++ b/src/NHibernate.Test/NHSpecificTest/GH3465/Mappings.hbm.xml
@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" assembly="NHibernate.Test"
+                   namespace="NHibernate.Test.NHSpecificTest.GH3465">
+  <class name="EntityA">
+    <id name="Id" generator="guid.comb" />
+    <set name="Children" cascade="all-delete-orphan" inverse="true">
+      <key column="EntityAId" />
+      <one-to-many class="EntityB" />
+    </set>
+  </class>
+  <class name="EntityB">
+    <id name="Id" generator="guid.comb" />
+    <many-to-one name="Parent" column="EntityAId" class="EntityA" not-null="true" />
+  </class>
+  <class name="EntityC">
+    <id name="Id" generator="guid.comb" />
+  </class>
+</hibernate-mapping>

From 3f02e7c7dd09f22bfc288982bd994ab8b44f5b06 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fr=C3=A9d=C3=A9ric=20Delaporte?=
 <12201973+fredericdelaporte@users.noreply.github.com>
Date: Thu, 1 Feb 2024 18:14:27 +0100
Subject: [PATCH 2/3] Do not append from element when already in from

Fix #3465
---
 src/NHibernate/Hql/Ast/ANTLR/Tree/FromElement.cs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/NHibernate/Hql/Ast/ANTLR/Tree/FromElement.cs b/src/NHibernate/Hql/Ast/ANTLR/Tree/FromElement.cs
index a22c13e84ff..ade63aaa929 100644
--- a/src/NHibernate/Hql/Ast/ANTLR/Tree/FromElement.cs
+++ b/src/NHibernate/Hql/Ast/ANTLR/Tree/FromElement.cs
@@ -716,7 +716,7 @@ public void SetOrigin(FromElement origin, bool manyToMany)
 					JoinSequence.SetUseThetaStyle(true);
 				}
 			}
-			else
+			else if (Walker.CurrentClauseType != HqlSqlWalker.FROM)
 			{
 				FromClause.AppendFromElement(this);
 			}

From 382095b1a689a52be0af87fcd5863c6cd00ee20e Mon Sep 17 00:00:00 2001
From: "github-actions[bot]" <github-actions[bot]@users.noreply.github.com>
Date: Thu, 1 Feb 2024 17:19:45 +0000
Subject: [PATCH 3/3] Generate async files

---
 .../Async/NHSpecificTest/GH3465/Fixture.cs    | 31 +++++++++++++++++++
 1 file changed, 31 insertions(+)
 create mode 100644 src/NHibernate.Test/Async/NHSpecificTest/GH3465/Fixture.cs

diff --git a/src/NHibernate.Test/Async/NHSpecificTest/GH3465/Fixture.cs b/src/NHibernate.Test/Async/NHSpecificTest/GH3465/Fixture.cs
new file mode 100644
index 00000000000..8d4b62bb325
--- /dev/null
+++ b/src/NHibernate.Test/Async/NHSpecificTest/GH3465/Fixture.cs
@@ -0,0 +1,31 @@
+//------------------------------------------------------------------------------
+// <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 System.Linq;
+using NUnit.Framework;
+
+namespace NHibernate.Test.NHSpecificTest.GH3465
+{
+	using System.Threading.Tasks;
+	[TestFixture]
+	public class FixtureAsync : BugTestCase
+	{
+		[Test]
+		public void ThetaJoinSubQueryAsync()
+		{
+			using (var session = OpenSession())
+			using (session.BeginTransaction())
+			{
+				var query = session.CreateQuery("select e.Id from EntityA e where exists (from e.Children b, EntityC c)");
+				Assert.DoesNotThrowAsync(() => query.ListAsync());
+			}
+		}
+	}
+}