Omitted requireOneSlicingArgument if not set in listSize directive

src/HotChocolate/CostAnalysis/src/CostAnalysis/Types/ListSizeAttribute.cs

@@ -13,6 +13,7 @@ namespace HotChocolate.CostAnalysis.Types;
 public sealed class ListSizeAttribute : ObjectFieldDescriptorAttribute
 {
     private readonly int? _assumedSize;
+    private readonly bool? _requireOneSlicingArgument;
 
     /// <summary>
     /// The maximum length of the list returned by this field.
@@ -44,7 +45,11 @@ public int AssumedSize
     /// Whether to require a single slicing argument in the query. If that is not the case (i.e., if
     /// none or multiple slicing arguments are present), the static analysis will throw an error.
     /// </summary>
-    public bool RequireOneSlicingArgument { get; init; } = true;
+    public bool RequireOneSlicingArgument
+    {
+        get => _requireOneSlicingArgument ?? true;
+        init => _requireOneSlicingArgument = value;
+    }
 
     protected override void OnConfigure(
         IDescriptorContext context,
@@ -56,6 +61,6 @@ protected override void OnConfigure(
                 _assumedSize,
                 SlicingArguments?.ToImmutableArray(),
                 SizedFields?.ToImmutableArray(),
-                RequireOneSlicingArgument));
+                _requireOneSlicingArgument));
     }
 }

src/HotChocolate/CostAnalysis/src/CostAnalysis/Types/ListSizeDirective.cs

@@ -31,11 +31,7 @@ public ListSizeDirective(
         SlicingArguments = slicingArguments ?? ImmutableArray<string>.Empty;
         SizedFields = sizedFields ?? ImmutableArray<string>.Empty;
         SlicingArgumentDefaultValue = slicingArgumentDefaultValue;
-
-        // https://ibm.github.io/graphql-specs/cost-spec.html#sec-requireOneSlicingArgument
-        // Per default, requireOneSlicingArgument is enabled,
-        // and has to be explicitly disabled if not desired for a field.
-        RequireOneSlicingArgument = SlicingArguments is { Length: > 0 } && (requireOneSlicingArgument ?? true);
+        RequireOneSlicingArgument = requireOneSlicingArgument;
     }
 
     /// <summary>
@@ -86,5 +82,5 @@ public ListSizeDirective(
     /// <seealso href="https://ibm.github.io/graphql-specs/cost-spec.html#sec-requireOneSlicingArgument">
     /// Specification URL
     /// </seealso>
-    public bool RequireOneSlicingArgument { get; }
+    public bool? RequireOneSlicingArgument { get; }
 }

src/HotChocolate/CostAnalysis/src/CostAnalysis/Types/ListSizeDirectiveType.cs

@@ -170,7 +170,10 @@ private static DirectiveNode FormatValue(object value)
             arguments.Add(new ArgumentNode(SizedFields, directive.SizedFields.ToListValueNode()));
         }
 
-        arguments.Add(new ArgumentNode(RequireOneSlicingArgument, directive.RequireOneSlicingArgument));
+        if (directive.RequireOneSlicingArgument is not null)
+        {
+            arguments.Add(new ArgumentNode(RequireOneSlicingArgument, directive.RequireOneSlicingArgument.Value));
+        }
 
         return new DirectiveNode(_name, arguments.ToImmutableArray());
     }

src/HotChocolate/CostAnalysis/test/CostAnalysis.Tests/AttributeTests.cs

@@ -1,4 +1,6 @@
+using CookieCrumble;
 using HotChocolate.CostAnalysis.Types;
+using HotChocolate.Language.Utilities;
 using HotChocolate.Types;
 
 namespace HotChocolate.CostAnalysis;
@@ -112,6 +114,36 @@ public void ListSize_ObjectFieldAttribute_AppliesDirective()
         Assert.False(costDirective.RequireOneSlicingArgument);
     }
 
+    [Fact]
+    public void ListSize_ObjectFieldAttribute_AppliesRequireOneSlicingArgumentCorrectly()
+    {
+        // arrange & act
+        var query = CreateSchema().GetType<ObjectType>(OperationTypeNames.Query);
+
+        var listSizeDirective1Sdl = query.Fields["examplesAssumedSizeOnly"]
+            .Directives
+            .Single(d => d.Type.Name == "listSize")
+            .AsSyntaxNode()
+            .Print();
+
+        var listSizeDirective2Sdl = query.Fields["examplesRequireOneSlicingArgumentTrue"]
+            .Directives
+            .Single(d => d.Type.Name == "listSize")
+            .AsSyntaxNode()
+            .Print();
+
+        var listSizeDirective3Sdl = query.Fields["examplesRequireOneSlicingArgumentFalse"]
+            .Directives
+            .Single(d => d.Type.Name == "listSize")
+            .AsSyntaxNode()
+            .Print();
+
+        // assert
+        listSizeDirective1Sdl.MatchInlineSnapshot("@listSize(assumedSize: 10)");
+        listSizeDirective2Sdl.MatchInlineSnapshot("@listSize(requireOneSlicingArgument: true)");
+        listSizeDirective3Sdl.MatchInlineSnapshot("@listSize(requireOneSlicingArgument: false)");
+    }
+
     private static ISchema CreateSchema()
     {
         return SchemaBuilder.New()
@@ -128,6 +160,8 @@ private static ISchema CreateSchema()
     [QueryType]
     private static class Queries
     {
+        private static readonly List<Example> List = [new Example(ExampleEnum.Member)];
+
         [ListSize(
             AssumedSize = 10,
             SlicingArguments = ["first", "last"],
@@ -137,7 +171,28 @@ private static class Queries
         // ReSharper disable once UnusedMember.Local
         public static List<Example> GetExamples([Cost(8.0)] ExampleInput _)
         {
-            return [new Example(ExampleEnum.Member)];
+            return List;
+        }
+
+        [ListSize(AssumedSize = 10)]
+        // ReSharper disable once UnusedMember.Local
+        public static List<Example> GetExamplesAssumedSizeOnly()
+        {
+            return List;
+        }
+
+        [ListSize(RequireOneSlicingArgument = true)]
+        // ReSharper disable once UnusedMember.Local
+        public static List<Example> GetExamplesRequireOneSlicingArgumentTrue()
+        {
+            return List;
+        }
+
+        [ListSize(RequireOneSlicingArgument = false)]
+        // ReSharper disable once UnusedMember.Local
+        public static List<Example> GetExamplesRequireOneSlicingArgumentFalse()
+        {
+            return List;
         }
     }