[Nhibernate-commit] SF.net SVN: nhibernate:[5414] trunk/nhibernate/src/NHibernate

[<ric...@us...>]

Revision: 5414
          http://nhibernate.svn.sourceforge.net/nhibernate/?rev=5414&view=rev
Author:   ricbrown
Date:     2011-03-02 22:20:24 +0000 (Wed, 02 Mar 2011)

Log Message:
-----------
Fix NH-2400 (Linq query fail when using contains from an empty Collection)

Modified Paths:
--------------
    trunk/nhibernate/src/NHibernate/Linq/Visitors/ExpressionKeyVisitor.cs
    trunk/nhibernate/src/NHibernate/Linq/Visitors/ResultOperatorProcessors/ProcessContains.cs
    trunk/nhibernate/src/NHibernate.Test/Linq/WhereTests.cs

Modified: trunk/nhibernate/src/NHibernate/Linq/Visitors/ExpressionKeyVisitor.cs
===================================================================
--- trunk/nhibernate/src/NHibernate/Linq/Visitors/ExpressionKeyVisitor.cs	2011-03-02 05:35:53 UTC (rev 5413)
+++ trunk/nhibernate/src/NHibernate/Linq/Visitors/ExpressionKeyVisitor.cs	2011-03-02 22:20:24 UTC (rev 5414)
@@ -1,5 +1,5 @@
+using System.Collections;
 using System.Collections.Generic;
-using System.Collections.ObjectModel;
 using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
@@ -82,6 +82,8 @@
 				// Nulls generate different query plans.  X = variable generates a different query depending on if variable is null or not.
 				if (param.Value == null)
 					_string.Append("NULL");
+				if (param.Value is ICollection && ((ICollection)param.Value).Count == 0)
+					_string.Append("EmptyList");
 				else
 					_string.Append(param.Name);
 			}

Modified: trunk/nhibernate/src/NHibernate/Linq/Visitors/ResultOperatorProcessors/ProcessContains.cs
===================================================================
--- trunk/nhibernate/src/NHibernate/Linq/Visitors/ResultOperatorProcessors/ProcessContains.cs	2011-03-02 05:35:53 UTC (rev 5413)
+++ trunk/nhibernate/src/NHibernate/Linq/Visitors/ResultOperatorProcessors/ProcessContains.cs	2011-03-02 22:20:24 UTC (rev 5414)
@@ -1,4 +1,5 @@
-using System.Linq;
+using System.Collections;
+using System.Linq;
 using NHibernate.Hql.Ast;
 using Remotion.Data.Linq.Clauses.ResultOperators;
 
@@ -18,7 +19,15 @@
             if (source is HqlParameter)
             {
                 // This is an "in" style statement
-                tree.SetRoot(tree.TreeBuilder.In(itemExpression, source));
+                if (IsEmptyList((HqlParameter)source, queryModelVisitor.VisitorParameters))
+                {
+                    // if the list is empty the expression will always be false, so generate "1 = 0"
+                    tree.SetRoot(tree.TreeBuilder.Equality(tree.TreeBuilder.Constant(1), tree.TreeBuilder.Constant(0)));
+                }
+                else
+                {
+                    tree.SetRoot(tree.TreeBuilder.In(itemExpression, source));
+                }
             }
             else
             {
@@ -39,5 +48,12 @@
         {
             return node.NodesPreOrder.Single(n => n is HqlRange).Children.Single(n => n is HqlAlias) as HqlAlias;
         }
+
+        private static bool IsEmptyList(HqlParameter source, VisitorParameters parameters)
+        {
+            var parameterName = source.NodesPreOrder.Single(n => n is HqlIdent).AstNode.Text;
+            var parameterValue = parameters.ConstantToParameterMap.Single(p => p.Value.Name == parameterName).Key.Value;
+            return ((ICollection)parameterValue).Count == 0;
+        }
     }
 }
\ No newline at end of file

Modified: trunk/nhibernate/src/NHibernate.Test/Linq/WhereTests.cs
===================================================================
--- trunk/nhibernate/src/NHibernate.Test/Linq/WhereTests.cs	2011-03-02 05:35:53 UTC (rev 5413)
+++ trunk/nhibernate/src/NHibernate.Test/Linq/WhereTests.cs	2011-03-02 22:20:24 UTC (rev 5414)
@@ -327,6 +327,18 @@
 		}
 
 		[Test]
+		public void UsersWithEmptyList_NH2400()
+		{
+			var names = new List<string>();
+
+			var query = (from user in db.Users
+						where names.Contains(user.Name)
+						select user).ToList();
+
+			Assert.That(query.Count, Is.EqualTo(0));
+		}
+
+		[Test]
 		public void WhenTheSourceOfConstantIsICollectionThenNoThrows()
 		{
 			ICollection<string> names = new List<string> {"ayende", "rahien"};


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