[Fusion] Added support for merging @cost and @listSize directives

src/HotChocolate/Fusion-vnext/src/Fusion.Composition/Definitions/CostMutableDirectiveDefinition.cs

@@ -0,0 +1,34 @@
+using HotChocolate.Types;
+using HotChocolate.Types.Mutable;
+
+namespace HotChocolate.Fusion.Definitions;
+
+internal sealed class CostMutableDirectiveDefinition : MutableDirectiveDefinition
+{
+    public CostMutableDirectiveDefinition(MutableScalarTypeDefinition stringType)
+        : base(DirectiveNames.Cost.Name)
+    {
+        Arguments.Add(
+            new MutableInputFieldDefinition(
+                DirectiveNames.Cost.Arguments.Weight,
+                new NonNullType(stringType)));
+
+        Locations =
+            DirectiveLocation.ArgumentDefinition
+            | DirectiveLocation.Enum
+            | DirectiveLocation.FieldDefinition
+            | DirectiveLocation.InputFieldDefinition
+            | DirectiveLocation.Object
+            | DirectiveLocation.Scalar;
+    }
+
+    public static CostMutableDirectiveDefinition Create(ISchemaDefinition schema)
+    {
+        if (!schema.Types.TryGetType<MutableScalarTypeDefinition>(SpecScalarNames.String.Name, out var stringType))
+        {
+            stringType = BuiltIns.String.Create();
+        }
+
+        return new CostMutableDirectiveDefinition(stringType);
+    }
+}

src/HotChocolate/Fusion-vnext/src/Fusion.Composition/Definitions/FusionCostMutableDirectiveDefinition.cs

@@ -0,0 +1,43 @@
+using HotChocolate.Types;
+using HotChocolate.Types.Mutable;
+using static HotChocolate.Fusion.Properties.CompositionResources;
+using static HotChocolate.Fusion.WellKnownArgumentNames;
+using static HotChocolate.Fusion.WellKnownDirectiveNames;
+
+namespace HotChocolate.Fusion.Definitions;
+
+/// <summary>
+/// The <c>@fusion__cost</c> directive specifies cost metadata for each source schema.
+/// </summary>
+internal sealed class FusionCostMutableDirectiveDefinition : MutableDirectiveDefinition
+{
+    public FusionCostMutableDirectiveDefinition(
+        MutableEnumTypeDefinition schemaMutableEnumType,
+        MutableScalarTypeDefinition stringType)
+        : base(FusionCost)
+    {
+        Description = FusionCostMutableDirectiveDefinition_Description;
+
+        Arguments.Add(
+            new MutableInputFieldDefinition(Schema, new NonNullType(schemaMutableEnumType))
+            {
+                Description = FusionCostMutableDirectiveDefinition_Argument_Schema_Description
+            });
+
+        Arguments.Add(
+            new MutableInputFieldDefinition(Weight, new NonNullType(stringType))
+            {
+                Description = FusionCostMutableDirectiveDefinition_Argument_Weight_Description
+            });
+
+        IsRepeatable = true;
+
+        Locations =
+            DirectiveLocation.ArgumentDefinition
+            | DirectiveLocation.Enum
+            | DirectiveLocation.FieldDefinition
+            | DirectiveLocation.InputFieldDefinition
+            | DirectiveLocation.Object
+            | DirectiveLocation.Scalar;
+    }
+}

src/HotChocolate/Fusion-vnext/src/Fusion.Composition/Definitions/FusionListSizeMutableDirectiveDefinition.cs

@@ -0,0 +1,63 @@
+using HotChocolate.Types;
+using HotChocolate.Types.Mutable;
+using static HotChocolate.Fusion.Properties.CompositionResources;
+using static HotChocolate.Fusion.WellKnownArgumentNames;
+using static HotChocolate.Fusion.WellKnownDirectiveNames;
+
+namespace HotChocolate.Fusion.Definitions;
+
+/// <summary>
+/// The <c>@fusion__listSize</c> directive specifies list size metadata for each source schema.
+/// </summary>
+internal sealed class FusionListSizeMutableDirectiveDefinition : MutableDirectiveDefinition
+{
+    public FusionListSizeMutableDirectiveDefinition(
+        MutableEnumTypeDefinition schemaMutableEnumType,
+        MutableScalarTypeDefinition intType,
+        MutableScalarTypeDefinition stringType,
+        MutableScalarTypeDefinition booleanType)
+        : base(FusionListSize)
+    {
+        Description = FusionListSizeMutableDirectiveDefinition_Description;
+
+        Arguments.Add(
+            new MutableInputFieldDefinition(Schema, new NonNullType(schemaMutableEnumType))
+            {
+                Description = FusionListSizeMutableDirectiveDefinition_Argument_Schema_Description
+            });
+
+        Arguments.Add(
+            new MutableInputFieldDefinition(AssumedSize, intType)
+            {
+                Description = FusionListSizeMutableDirectiveDefinition_Argument_AssumedSize_Description
+            });
+
+        Arguments.Add(
+            new MutableInputFieldDefinition(SlicingArguments, new ListType(new NonNullType(stringType)))
+            {
+                Description = FusionListSizeMutableDirectiveDefinition_Argument_SlicingArguments_Description
+            });
+
+        Arguments.Add(
+            new MutableInputFieldDefinition(SlicingArgumentDefaultValue, intType)
+            {
+                Description = FusionListSizeMutableDirectiveDefinition_Argument_SlicingArgumentDefaultValue_Description
+            });
+
+        Arguments.Add(
+            new MutableInputFieldDefinition(SizedFields, new ListType(new NonNullType(stringType)))
+            {
+                Description = FusionListSizeMutableDirectiveDefinition_Argument_SizedFields_Description
+            });
+
+        Arguments.Add(
+            new MutableInputFieldDefinition(RequireOneSlicingArgument, booleanType)
+            {
+                Description = FusionListSizeMutableDirectiveDefinition_Argument_RequireOneSlicingArgument_Description
+            });
+
+        IsRepeatable = true;
+
+        Locations = DirectiveLocation.FieldDefinition;
+    }
+}

src/HotChocolate/Fusion-vnext/src/Fusion.Composition/Definitions/ListSizeMutableDirectiveDefinition.cs

@@ -0,0 +1,61 @@
+using HotChocolate.Types;
+using HotChocolate.Types.Mutable;
+
+namespace HotChocolate.Fusion.Definitions;
+
+internal sealed class ListSizeMutableDirectiveDefinition : MutableDirectiveDefinition
+{
+    public ListSizeMutableDirectiveDefinition(
+        MutableScalarTypeDefinition intType,
+        MutableScalarTypeDefinition stringType,
+        MutableScalarTypeDefinition booleanType)
+        : base(DirectiveNames.ListSize.Name)
+    {
+        Arguments.Add(
+            new MutableInputFieldDefinition(
+                DirectiveNames.ListSize.Arguments.AssumedSize,
+                intType));
+
+        Arguments.Add(
+            new MutableInputFieldDefinition(
+                DirectiveNames.ListSize.Arguments.SlicingArguments,
+                new ListType(new NonNullType(stringType))));
+
+        Arguments.Add(
+            new MutableInputFieldDefinition(
+                DirectiveNames.ListSize.Arguments.SlicingArgumentDefaultValue,
+                intType));
+
+        Arguments.Add(
+            new MutableInputFieldDefinition(
+                DirectiveNames.ListSize.Arguments.SizedFields,
+                new ListType(new NonNullType(stringType))));
+
+        Arguments.Add(
+            new MutableInputFieldDefinition(
+                DirectiveNames.ListSize.Arguments.RequireOneSlicingArgument,
+                booleanType));
+
+        Locations = DirectiveLocation.FieldDefinition;
+    }
+
+    public static ListSizeMutableDirectiveDefinition Create(ISchemaDefinition schema)
+    {
+        if (!schema.Types.TryGetType<MutableScalarTypeDefinition>(SpecScalarNames.Int.Name, out var intType))
+        {
+            intType = BuiltIns.Int.Create();
+        }
+
+        if (!schema.Types.TryGetType<MutableScalarTypeDefinition>(SpecScalarNames.String.Name, out var stringType))
+        {
+            stringType = BuiltIns.String.Create();
+        }
+
+        if (!schema.Types.TryGetType<MutableScalarTypeDefinition>(SpecScalarNames.Boolean.Name, out var booleanType))
+        {
+            booleanType = BuiltIns.Boolean.Create();
+        }
+
+        return new ListSizeMutableDirectiveDefinition(intType, stringType, booleanType);
+    }
+}

src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/CacheControlDirectiveMerger.cs

@@ -2,6 +2,7 @@
 using HotChocolate.Fusion.Definitions;
 using HotChocolate.Fusion.Directives;
 using HotChocolate.Fusion.Extensions;
+using HotChocolate.Fusion.Info;
 using HotChocolate.Fusion.Options;
 using HotChocolate.Language;
 using HotChocolate.Types;
@@ -40,7 +41,7 @@ public override void MergeDirectiveDefinition(
 
     public override void MergeDirectives(
         IDirectivesProvider mergedMember,
-        ImmutableArray<IDirectivesProvider> memberDefinitions,
+        ImmutableArray<DirectivesProviderInfo> memberDefinitions,
         MutableSchemaDefinition mergedSchema)
     {
         if (MergeBehavior is DirectiveMergeBehavior.Ignore)
@@ -57,7 +58,7 @@ public override void MergeDirectives(
         var cacheControlDirectives =
             memberDefinitions
                 .SelectMany(
-                    d => d.Directives.Where(dir => dir.Name == DirectiveNames.CacheControl))
+                    d => d.Member.Directives.Where(dir => dir.Name == DirectiveNames.CacheControl))
                 .Select(CacheControlDirective.From)
                 .ToArray();
 

src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/CostDirectiveMerger.cs

@@ -0,0 +1,54 @@
+using System.Collections.Immutable;
+using System.Globalization;
+using HotChocolate.Fusion.Definitions;
+using HotChocolate.Fusion.Directives;
+using HotChocolate.Fusion.Extensions;
+using HotChocolate.Fusion.Info;
+using HotChocolate.Fusion.Options;
+using HotChocolate.Types;
+using HotChocolate.Types.Mutable;
+using ArgumentNames = HotChocolate.Fusion.WellKnownArgumentNames;
+using DirectiveNames = HotChocolate.Fusion.WellKnownDirectiveNames;
+
+namespace HotChocolate.Fusion.DirectiveMergers;
+
+internal class CostDirectiveMerger(DirectiveMergeBehavior mergeBehavior)
+    : DirectiveMergerBase(mergeBehavior)
+{
+    public override string DirectiveName => DirectiveNames.Cost;
+
+    public override MutableDirectiveDefinition GetCanonicalDirectiveDefinition(ISchemaDefinition schema)
+    {
+        return CostMutableDirectiveDefinition.Create(schema);
+    }
+
+    public override void MergeDirectives(
+        IDirectivesProvider mergedMember,
+        ImmutableArray<DirectivesProviderInfo> memberDefinitions,
+        MutableSchemaDefinition mergedSchema)
+    {
+        if (!mergedSchema.DirectiveDefinitions.TryGetDirective(DirectiveName, out var directiveDefinition))
+        {
+            // Merged definition not found.
+            return;
+        }
+
+        var costDirectives =
+            memberDefinitions
+                .SelectMany(d => d.Member.Directives.Where(dir => dir.Name == DirectiveNames.Cost))
+                .Select(CostDirective.From)
+                .ToArray();
+
+        if (costDirectives.Length == 0)
+        {
+            return;
+        }
+
+        var maxWeight = costDirectives.Max(d => d.Weight);
+        var weightArgument =
+            new ArgumentAssignment(ArgumentNames.Weight, maxWeight.ToString(CultureInfo.InvariantCulture));
+        var costDirective = new Directive(directiveDefinition, weightArgument);
+
+        mergedMember.AddDirective(costDirective);
+    }
+}

src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/DirectiveMergerBase.cs

@@ -1,4 +1,5 @@
 using System.Collections.Immutable;
+using HotChocolate.Fusion.Info;
 using HotChocolate.Fusion.Options;
 using HotChocolate.Types;
 using HotChocolate.Types.Mutable;
@@ -27,6 +28,6 @@ public virtual void MergeDirectiveDefinition(
 
     public abstract void MergeDirectives(
         IDirectivesProvider mergedMember,
-        ImmutableArray<IDirectivesProvider> memberDefinitions,
+        ImmutableArray<DirectivesProviderInfo> memberDefinitions,
         MutableSchemaDefinition mergedSchema);
 }

src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/IDirectiveMerger.cs

@@ -1,4 +1,5 @@
 using System.Collections.Immutable;
+using HotChocolate.Fusion.Info;
 using HotChocolate.Fusion.Options;
 using HotChocolate.Types;
 using HotChocolate.Types.Mutable;
@@ -19,6 +20,6 @@ void MergeDirectiveDefinition(
 
     void MergeDirectives(
         IDirectivesProvider mergedMember,
-        ImmutableArray<IDirectivesProvider> memberDefinitions,
+        ImmutableArray<DirectivesProviderInfo> memberDefinitions,
         MutableSchemaDefinition mergedSchema);
 }