From c83aabf1bc247f29c6b0f5c24fc31f0aadce75aa Mon Sep 17 00:00:00 2001
From: NetDwarf <NetDwarf@users.noreply.github.com>
Date: Wed, 20 Sep 2023 16:55:14 +0200
Subject: [PATCH] Fix WhereClause.IsIn with empty List

---
 DOLDatabase/WhereClause.cs        |  9 +++++----
 Tests/UnitTests/UT_WhereClause.cs | 13 +++++++++++--
 2 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/DOLDatabase/WhereClause.cs b/DOLDatabase/WhereClause.cs
index f0b422b944..6fee427070 100644
--- a/DOLDatabase/WhereClause.cs
+++ b/DOLDatabase/WhereClause.cs
@@ -81,7 +81,7 @@ public virtual QueryParameter[] Parameters
             }
         }
 
-        internal abstract List<TextAtom> IntermediateRepresentation { get; }
+        internal abstract IEnumerable<TextAtom> IntermediateRepresentation { get; }
 
         public virtual WhereClause And(WhereClause rightExpression)
             => rightExpression.Equals(Empty) ? this : new ChainingExpression(this, "AND", rightExpression);
@@ -134,13 +134,14 @@ internal FilterExpression(string columnName, string op, object val)
             this.val = val;
         }
 
-        internal override List<TextAtom> IntermediateRepresentation
+        internal override IEnumerable<TextAtom> IntermediateRepresentation
         {
             get
             {
-                if (val is IEnumerable<object> valueCollection && valueCollection.Any())
+                if (val is IEnumerable<object> valueCollection)
                 {
                     var result = new List<TextAtom>() { new TextAtom(columnName), new TextAtom(op), new TextAtom("(") };
+                    if(!valueCollection.Any()) return result.Append(new TextAtom(")"));
                     result.Add(new ValueAtom(valueCollection.ElementAt(0)));
                     foreach(var element in valueCollection.Skip(1))
                     {
@@ -208,7 +209,7 @@ internal ChainingExpression(WhereClause left, string chainingOperator, WhereClau
             this.chainingOperator = chainingOperator;
         }
 
-        internal override List<TextAtom> IntermediateRepresentation
+        internal override IEnumerable<TextAtom> IntermediateRepresentation
         {
             get
             {
diff --git a/Tests/UnitTests/UT_WhereClause.cs b/Tests/UnitTests/UT_WhereClause.cs
index f5f3151d5b..44aebc8aad 100644
--- a/Tests/UnitTests/UT_WhereClause.cs
+++ b/Tests/UnitTests/UT_WhereClause.cs
@@ -59,7 +59,7 @@ public void ParameterizedText_FooIsEqualToOneAndBarIsEqualToOne_WhereFooEqualAtA
         [Test]
         public void ParameterizedText_FooIsInOneAndTwo_FooIsInAtACommaAtB()
         {
-            var expr = DB.Column("foo").IsIn(new [] { 1, 2 });
+            var expr = DB.Column("foo").IsIn(new[] { 1, 2 });
             var placeHolder1 = expr.Parameters[0].Item1;
             var placeHolder2 = expr.Parameters[1].Item1;
             var actual = expr.ParameterizedText;
@@ -70,7 +70,7 @@ public void ParameterizedText_FooIsInOneAndTwo_FooIsInAtACommaAtB()
         [Test]
         public void ParameterizedText_FooIsInAandB_FooIsInAtACommaAtB()
         {
-            var expr = DB.Column("foo").IsIn(new [] { "a", "b" });
+            var expr = DB.Column("foo").IsIn(new[] { "a", "b" });
             var placeHolder1 = expr.Parameters[0].Item1;
             var placeHolder2 = expr.Parameters[1].Item1;
             var actual = expr.ParameterizedText;
@@ -78,6 +78,15 @@ public void ParameterizedText_FooIsInAandB_FooIsInAtACommaAtB()
             Assert.AreEqual(expected, actual);
         }
 
+        [Test]
+        public void ParameterizedText_FooIsInEmptyArray_FooInEmptyParenthesis()
+        {
+            var expr = DB.Column("foo").IsIn(Array.Empty<object>());
+            var actual = expr.ParameterizedText;
+            var expected = $"WHERE foo IN ( )";
+            Assert.AreEqual(expected, actual);
+        }
+
         [Test]
         public void Parameters_Expression1AndExpression2_ConcatenationOfBothParameters()
         {