Support directives declared stitched schemas (#936)

src/Stitching/Stitching.Tests/Merge/Handlers/DirectiveTypeMergeHandlerTests.cs

@@ -0,0 +1,147 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using HotChocolate.Language;
+using Snapshooter.Xunit;
+using Xunit;
+
+namespace HotChocolate.Stitching.Merge.Handlers
+{
+    public class DirectiveTypeMergeHandlerTests
+    {
+        [Fact]
+        public void Merge_SimpleIdenticalDirectives_TypeMerges()
+        {
+            // arrange
+            DocumentNode schema_a =
+                Parser.Default.Parse("directive @test(arg: String) on OBJECT");
+            DocumentNode schema_b =
+                Parser.Default.Parse("directive @test(arg: String) on OBJECT");
+
+            var types = new List<IDirectiveTypeInfo>
+            {
+                new DirectiveTypeInfo(schema_a.Definitions.OfType<DirectiveDefinitionNode>().First(),
+                    new SchemaInfo("Schema_A", schema_a)),
+                new DirectiveTypeInfo(schema_b.Definitions.OfType<DirectiveDefinitionNode>().First(),
+                    new SchemaInfo("Schema_B", schema_b)),
+            };
+
+            var context = new SchemaMergeContext();
+
+            // act
+            var typeMerger = new DirectiveTypeMergeHandler((c, t) => { });
+            typeMerger.Merge(context, types);
+
+            // assert
+            SchemaSyntaxSerializer.Serialize(context.CreateSchema())
+                .MatchSnapshot();
+        }
+
+        [Fact]
+        public void Merge_DifferentArguments_ThrowsException()
+        {
+            // arrange
+            DocumentNode schema_a =
+                Parser.Default.Parse("directive @test(arg: Int) on OBJECT");
+            DocumentNode schema_b =
+                Parser.Default.Parse("directive @test(arg: String) on OBJECT");
+
+            var types = new List<IDirectiveTypeInfo>
+            {
+                new DirectiveTypeInfo(schema_a.Definitions.OfType<DirectiveDefinitionNode>().First(),
+                    new SchemaInfo("Schema_A", schema_a)),
+                new DirectiveTypeInfo(schema_b.Definitions.OfType<DirectiveDefinitionNode>().First(),
+                    new SchemaInfo("Schema_B", schema_b))
+            };
+
+            var context = new SchemaMergeContext();
+
+            // act
+            var typeMerger = new DirectiveTypeMergeHandler((c, t) => { });
+
+            Assert.Throws<InvalidOperationException>(() => typeMerger.Merge(context, types));
+        }
+
+        [Fact]
+        public void Merge_DifferentLocations_ThrowsException()
+        {
+            // arrange
+            DocumentNode schema_a =
+                Parser.Default.Parse("directive @test(arg: String) on OBJECT | INTERFACE");
+            DocumentNode schema_b =
+                Parser.Default.Parse("directive @test(arg: String) on OBJECT");
+
+            var types = new List<IDirectiveTypeInfo>
+            {
+                new DirectiveTypeInfo(schema_a.Definitions.OfType<DirectiveDefinitionNode>().First(),
+                    new SchemaInfo("Schema_A", schema_a)),
+                new DirectiveTypeInfo(schema_b.Definitions.OfType<DirectiveDefinitionNode>().First(),
+                    new SchemaInfo("Schema_B", schema_b))
+            };
+
+            var context = new SchemaMergeContext();
+
+            // act
+            var typeMerger = new DirectiveTypeMergeHandler((c, t) => { });
+
+            Assert.Throws<InvalidOperationException>(() => typeMerger.Merge(context, types));
+        }
+
+        [Fact]
+        public void Merge_DifferentRepeatable_ThrowsException()
+        {
+            // arrange
+            DocumentNode schema_a =
+                Parser.Default.Parse("directive @test(arg: String) repeatable on OBJECT");
+            DocumentNode schema_b =
+                Parser.Default.Parse("directive @test(arg: String) on OBJECT");
+
+            var types = new List<IDirectiveTypeInfo>
+            {
+                new DirectiveTypeInfo(schema_a.Definitions.OfType<DirectiveDefinitionNode>().First(),
+                    new SchemaInfo("Schema_A", schema_a)),
+                new DirectiveTypeInfo(schema_b.Definitions.OfType<DirectiveDefinitionNode>().First(),
+                    new SchemaInfo("Schema_B", schema_b))
+            };
+
+            var context = new SchemaMergeContext();
+
+            // act
+            var typeMerger = new DirectiveTypeMergeHandler((c, t) => { });
+
+            Assert.Throws<InvalidOperationException>(() => typeMerger.Merge(context, types));
+        }
+
+        [Fact]
+        public void Merge_ThreeDirectivessWhereTwoAreIdentical_TwoTypesAfterMerge()
+        {
+            // arrange
+            DocumentNode schema_a =
+                Parser.Default.Parse("directive @test(arg: String) on OBJECT");
+            DocumentNode schema_b =
+                Parser.Default.Parse("directive @test1(arg: String) on OBJECT");
+            DocumentNode schema_c =
+                Parser.Default.Parse("directive @test(arg: String) on OBJECT");
+
+            var types = new List<IDirectiveTypeInfo>
+            {
+                new DirectiveTypeInfo(schema_a.Definitions.OfType<DirectiveDefinitionNode>().First(),
+                    new SchemaInfo("Schema_A", schema_a)),
+                new DirectiveTypeInfo(schema_b.Definitions.OfType<DirectiveDefinitionNode>().First(),
+                    new SchemaInfo("Schema_B", schema_b)),
+                new DirectiveTypeInfo(schema_c.Definitions.OfType<DirectiveDefinitionNode>().First(),
+                    new SchemaInfo("Schema_C", schema_c))
+            };
+
+            var context = new SchemaMergeContext();
+
+            // act
+            var typeMerger = new DirectiveTypeMergeHandler((c, t) => { });
+            typeMerger.Merge(context, types);
+
+            // assert
+            SchemaSyntaxSerializer.Serialize(context.CreateSchema())
+                .MatchSnapshot();
+        }
+    }
+}

src/Stitching/Stitching.Tests/Merge/Handlers/__snapshots__/DirectiveTypeMergeHandlerTests.Merge_SimpleIdenticalDirectives_TypeMerges.snap

@@ -0,0 +1 @@
+directive @test(arg: String) on OBJECT

src/Stitching/Stitching.Tests/Merge/Handlers/__snapshots__/DirectiveTypeMergeHandlerTests.Merge_ThreeDirectivessWhereTwoAreIdentical_TwoTypesAfterMerge.snap

@@ -0,0 +1,3 @@
+directive @test(arg: String) on OBJECT
+
+directive @test1(arg: String) on OBJECT

src/Stitching/Stitching.Tests/Middleware/DelegateToRemoteSchemaMiddlewareTests.cs

@@ -679,8 +679,6 @@ public async Task CustomDirectiveIsPassedOn()
             serviceCollection.AddStitchedSchema(builder =>
                 builder.AddSchemaFromHttp("contract")
                     .AddSchemaFromHttp("customer")
-                    .AddExtensionsFromString(
-                        "directive @custom(d: DateTime) on FIELD")
                     .AddSchemaConfiguration(c =>
                     {
                         c.RegisterExtendedScalarTypes();
@@ -728,8 +726,6 @@ public async Task DateTimeIsHandledCorrectly()
             serviceCollection.AddStitchedSchema(builder =>
                 builder.AddSchemaFromHttp("contract")
                     .AddSchemaFromHttp("customer")
-                    .AddExtensionsFromString(
-                        "directive @custom(d: DateTime) on FIELD")
                     .AddSchemaConfiguration(c =>
                     {
                         c.RegisterExtendedScalarTypes();

src/Stitching/Stitching.Tests/Middleware/__snapshots__/TypeSystemDirectivesTests.SourceSchemaHasTypeSystemDirectives_schema.snap

@@ -3,9 +3,11 @@
 }
 
 type Query {
-  foo: String @delegate(schema: "server_1")
+  foo: String @bar @delegate(schema: "server_1")
 }
 
+directive @bar on FIELD_DEFINITION
+
 directive @delegate(path: String "The name of the schema to which this field shall be delegated to." schema: Name!) on FIELD_DEFINITION
 
 "The name scalar represents a valid GraphQL name as specified in the spec and can be used to refer to fields or types."

src/Stitching/Stitching.Tests/__snapshots__/StitchingBuilderTests.AddSchemaFromHttp.snap

@@ -112,3 +112,17 @@ interface Contract @source(name: "Contract", schema: "contract") {
   customerId: ID!
   id: ID!
 }
+
+"Directs the executor to skip this field or fragment when the `if` argument is true."
+directive @skip("Skipped when true." if: Boolean!) on FIELD | FRAGMENT_SPREAD | INLINE_FRAGMENT
+
+"Directs the executor to include this field or fragment only when the `if` argument is true."
+directive @include("Included when true." if: Boolean!) on FIELD | FRAGMENT_SPREAD | INLINE_FRAGMENT
+
+"The cost directives is used to express the complexity of a field."
+directive @cost("Defines the complexity of the field." complexity: Int! = 1 "Defines field arguments that act as complexity multipliers." multipliers: [MultiplierPath!]) on FIELD_DEFINITION
+
+"The @deprecated directive is used within the type system definition language to indicate deprecated portions of a GraphQL service’s schema,such as deprecated fields on a type or deprecated enum values."
+directive @deprecated("Deprecations include a reason for why it is deprecated, which is formatted using Markdown syntax (as specified by CommonMark)." reason: String = "No longer supported") on FIELD_DEFINITION | ENUM_VALUE
+
+directive @custom(d: DateTime) on FIELD

src/Stitching/Stitching/Merge/DirectiveTypeInfo.cs

@@ -0,0 +1,19 @@
+using HotChocolate.Language;
+
+namespace HotChocolate.Stitching.Merge
+{
+    public class DirectiveTypeInfo : IDirectiveTypeInfo
+    {
+        public DirectiveTypeInfo(
+            DirectiveDefinitionNode definition,
+            ISchemaInfo schema)
+        {
+            Definition = definition;
+            Schema = schema;
+        }
+
+        public DirectiveDefinitionNode Definition { get; }
+
+        public ISchemaInfo Schema { get; }
+    }
+}

src/Stitching/Stitching/Merge/Handlers/ComplexTypeMergeHelpers.cs

@@ -60,24 +60,29 @@ private static bool HasSameShape(
                 && HasSameType(left.Type, right.Type)
                 && left.Arguments.Count == right.Arguments.Count)
             {
-                Dictionary<string, InputValueDefinitionNode> leftArgs =
-                    left.Arguments.ToDictionary(t => t.Name.Value);
-                Dictionary<string, InputValueDefinitionNode> rightArgs =
-                    right.Arguments.ToDictionary(t => t.Name.Value);
+                return HasSameArguments(left.Arguments, right.Arguments);
+            }
+            return false;
+        }
 
-                foreach (string name in leftArgs.Keys)
+        public static bool HasSameArguments(
+            IReadOnlyList<InputValueDefinitionNode> left,
+            IReadOnlyList<InputValueDefinitionNode> right)
+        {
+            var leftArgs = left.ToDictionary(t => t.Name.Value);
+            var rightArgs = right.ToDictionary(t => t.Name.Value);
+
+            foreach (string name in leftArgs.Keys)
+            {
+                InputValueDefinitionNode leftArgument = leftArgs[name];
+                if (!rightArgs.TryGetValue(name,
+                    out InputValueDefinitionNode rightArgument)
+                    || !HasSameType(leftArgument.Type, rightArgument.Type))
                 {
-                    InputValueDefinitionNode leftArgument = leftArgs[name];
-                    if (!rightArgs.TryGetValue(name,
-                        out InputValueDefinitionNode rightArgument)
-                        || !HasSameType(leftArgument.Type, rightArgument.Type))
-                    {
-                        return false;
-                    }
+                    return false;
                 }
-                return true;
             }
-            return false;
+            return true;
         }
 
         private static bool HasSameType(ITypeNode left, ITypeNode right)

src/Stitching/Stitching/Merge/Handlers/DirectiveTypeMergeHandler.cs

@@ -0,0 +1,107 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using HotChocolate.Language;
+
+namespace HotChocolate.Stitching.Merge.Handlers
+{
+    internal class DirectiveTypeMergeHandler
+    {
+        private readonly MergeDirectiveRuleDelegate _next;
+
+        public DirectiveTypeMergeHandler(MergeDirectiveRuleDelegate next)
+        {
+            _next = next ?? throw new ArgumentNullException(nameof(next));
+        }
+
+        public void Merge(
+            ISchemaMergeContext context,
+            IReadOnlyList<IDirectiveTypeInfo> types)
+        {
+            var notMerged = types.ToList();
+
+            while (notMerged.Count > 0)
+            {
+                MergeNextType(context, notMerged);
+            }
+        }
+
+        private void MergeNextType(
+           ISchemaMergeContext context,
+           List<IDirectiveTypeInfo> notMerged)
+        {
+            IDirectiveTypeInfo left = notMerged[0];
+
+            var readyToMerge = new List<IDirectiveTypeInfo>();
+            readyToMerge.Add(left);
+
+            for (int i = 1; i < notMerged.Count; i++)
+            {
+                if (CanBeMerged(left.Definition, notMerged[i].Definition))
+                {
+                    readyToMerge.Add(notMerged[i]);
+                }
+            }
+
+            NameString name = readyToMerge[0].Definition.Name.Value;
+
+            if (context.ContainsDirective(name))
+            {
+                throw new InvalidOperationException($"Unable to merge {name}, directive with this name already exists.");
+            }
+
+            MergeTypes(context, readyToMerge, name);
+            notMerged.RemoveAll(readyToMerge.Contains);
+        }
+
+        protected void MergeTypes(
+            ISchemaMergeContext context,
+            IReadOnlyList<IDirectiveTypeInfo> types,
+            NameString newTypeName)
+        {
+            var definitions = types
+                .Select(t => t.Definition)
+                .ToList();
+
+            DirectiveDefinitionNode definition =
+                definitions[0].Rename(
+                    newTypeName,
+                    types.Select(t => t.Schema.Name));
+
+            context.AddDirective(definition);
+        }
+
+        private static bool CanBeMerged(DirectiveDefinitionNode left, DirectiveDefinitionNode right)
+        {
+            if (!left.Name.Value.Equals(right.Name.Value, StringComparison.Ordinal))
+            {
+                return false;
+            }
+
+            if (left.Locations.Count != right.Locations.Count)
+            {
+                return false;
+            }
+
+            var leftLocations = left.Locations.Select(l => l.Value).OrderBy(l => l).ToList();
+            var rightLocations = right.Locations.Select(l => l.Value).OrderBy(l => l).ToList();
+
+            if (!leftLocations.SequenceEqual(rightLocations))
+            {
+                return false;
+            }
+
+            if (left.IsRepeatable != right.IsRepeatable)
+            {
+                return false;
+            }
+
+            if (left.Arguments.Count != right.Arguments.Count)
+            {
+                return false;
+            }
+
+            return ComplexTypeMergeHelpers.HasSameArguments(left.Arguments, right.Arguments);
+        }
+    }
+}

src/Stitching/Stitching/Merge/IDirectiveTypeInfo.cs

@@ -0,0 +1,10 @@
+using HotChocolate.Language;
+
+namespace HotChocolate.Stitching.Merge
+{
+    public interface IDirectiveTypeInfo
+    {
+        DirectiveDefinitionNode Definition { get; }
+        ISchemaInfo Schema { get; }
+    }
+}

src/Stitching/Stitching/Merge/MergeDirectiveRuleDelegate.cs

@@ -0,0 +1,8 @@
+using System.Collections.Generic;
+
+namespace HotChocolate.Stitching.Merge
+{
+    public delegate void MergeDirectiveRuleDelegate(
+        ISchemaMergeContext context,
+        IReadOnlyList<IDirectiveTypeInfo> types);
+}