Fix #842 - merge schema with custom scalar usage (#895)

Author: pekkah

src/graphql/Tools/MergeTool.cs

@@ -15,16 +15,15 @@ public static void Schemas(SchemaBuilder target, params ISchema[] schemas)
 
         public static void Schema(SchemaBuilder target, ISchema right)
         {
+            foreach (var rightType in right.QueryTypes<ScalarType>())
+                MergeScalarType(right, target, rightType);
+
             foreach (var rightType in right.QueryTypes<EnumType>())
                 MergeEnumType(right, target, rightType);
 
             foreach (var rightType in right.QueryTypes<InputObjectType>()) 
                 MergeInputType(right, target, rightType);
 
-            foreach (var rightType in right.QueryTypes<ScalarType>())
-                MergeScalarType(right, target, rightType);
-
-
             foreach (var directiveType in right.QueryDirectiveTypes())
             {
                 target.TryGetDirective(directiveType.Name, out var leftDirective);

tests/graphql.tests/Tools/MakeExecutableWithIntrospectionFacts.cs

@@ -0,0 +1,56 @@
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using Tanka.GraphQL.SchemaBuilding;
+using Tanka.GraphQL.SDL;
+using Tanka.GraphQL.Tools;
+using Tanka.GraphQL.TypeSystem;
+using Tanka.GraphQL.TypeSystem.ValueSerialization;
+using Xunit;
+
+namespace Tanka.GraphQL.Tests.Tools
+{
+    public class MakeExecutableWithIntrospectionFacts
+    {
+        [Fact]
+        public async Task WithCustomScalar()
+        {
+            /* Given */
+            var builder = new SchemaBuilder();
+            await builder.SdlAsync(@"
+                    scalar Date
+
+                    input InputTest {
+                        timestamp: Date
+                    }
+
+                    type Query {
+                        getDate(date: Date): String 
+                    }
+
+                    type Mutation {
+                        addDate(date: Date, inputTest: InputTest): String
+                    }
+
+                    schema {
+                        query: Query
+                        mutation: Mutation
+                        subscription: Subscription
+                    }");
+               
+
+            /* When */
+            var schema = SchemaTools.MakeExecutableSchemaWithIntrospection(
+                builder,
+                converters: new Dictionary<string, IValueConverter>()
+                {
+                    ["Date"] = new StringConverter()
+                });
+
+            /* Then */
+            var date = schema.GetNamedType("Date");
+
+            Assert.NotNull(date);
+            Assert.IsType<ScalarType>(date);
+        }
+    }
+}

tests/graphql.tests/Tools/MergeSchemasFacts.cs

@@ -3,6 +3,7 @@
 using Tanka.GraphQL.SDL;
 using Tanka.GraphQL.Tools;
 using Tanka.GraphQL.TypeSystem;
+using Tanka.GraphQL.TypeSystem.ValueSerialization;
 using Xunit;
 
 namespace Tanka.GraphQL.Tests.Tools
@@ -163,5 +164,42 @@ type Query {
             var field = schema.GetField("Query", "color");
             Assert.Equal(newUnionType, field.Type);
         }
+
+        [Fact]
+        public void Merge_schema_with_new_CustomScalar()
+        {
+            /* Given */
+            var newTypes = new SchemaBuilder()
+                .Sdl(@"
+                    scalar Date
+
+                    input InputTest {
+                        timestamp: Date
+                    }   
+
+                    type Query {
+                        useRaw(date: Date!): Int
+                        useWithInput(inputWithDate: InputTest!): Int
+                    }
+                    ")
+                .Include("Date", new StringConverter())
+                .Build();
+
+            var builder = new SchemaBuilder()
+                .Sdl(@"
+                    schema {
+                        query: Query
+                    }
+                    ");
+
+
+            /* When */
+            var schema = builder.Merge(newTypes)
+                .Build();
+
+            /* Then */
+            var newScalarType = schema.GetNamedType<ScalarType>("Date");
+            Assert.NotNull(newScalarType);
+        }
     }
 }