ensure scalars are wired up if no existing wiring (#382)

Fixes #380 

This restructures the scalar transformation logic to ensure that both
the type definition and wiring are added correctly if necessary. This
allows consumers to define the scalars in their schema, but not assign
runtime wiring. This can be nice to support other tools like linters or
graphql-faker that require the schema to be a valid schema file.

graphql-java-support/src/main/java/com/apollographql/federation/graphqljava/Federation.java

@@ -163,15 +163,18 @@ private static RuntimeWiring ensureFederationV2DirectiveDefinitionsExist(
           if (def instanceof DirectiveDefinition
               && !typeRegistry.getDirectiveDefinition(def.getName()).isPresent()) {
             typeRegistry.add(def);
-          } else if (def instanceof ScalarTypeDefinition
-              && !typeRegistry.scalars().containsKey(def.getName())) {
-            typeRegistry.add(def);
-            scalarTypesToAdd.add(
-                GraphQLScalarType.newScalar()
-                    .name(def.getName())
-                    .description(null)
-                    .coercing(_Any.type.getCoercing())
-                    .build());
+          } else if (def instanceof ScalarTypeDefinition) {
+            if (!typeRegistry.scalars().containsKey(def.getName())) {
+              typeRegistry.add(def);
+            }
+            if (!runtimeWiring.getScalars().containsKey(def.getName())) {
+              scalarTypesToAdd.add(
+                  GraphQLScalarType.newScalar()
+                      .name(def.getName())
+                      .description(null)
+                      .coercing(_Any.type.getCoercing())
+                      .build());
+            }
           } else if (def instanceof EnumTypeDefinition
               && !typeRegistry.types().containsKey(def.getName())) {
             typeRegistry.add(def);

graphql-java-support/src/test/java/com/apollographql/federation/graphqljava/FederationTest.java

@@ -356,6 +356,11 @@ public void verifyFederationV2Transformation_progressiveOverride() {
         () -> Federation.transform(schemaSDL).fetchEntities(env -> null).build());
   }
 
+  @Test
+  public void verifyFederationV2Transformation_scalarsDefinedInSchemaButNotWired() {
+    verifyFederationTransformation("schemas/federationV2_defined_scalars.graphql", true);
+  }
+
   private GraphQLSchema verifyFederationTransformation(
       String schemaFileName, boolean isFederationV2) {
     final RuntimeWiring runtimeWiring = RuntimeWiring.newRuntimeWiring().build();

graphql-java-support/src/test/resources/schemas/federationV2_defined_scalars.graphql

@@ -0,0 +1,84 @@
+extend schema
+  @link(
+    url: "https://specs.apollo.dev/federation/v2.3"
+    import: [
+      "@composeDirective"
+      "@extends"
+      "@external"
+      "@key"
+      "@inaccessible"
+      "@interfaceObject"
+      "@override"
+      "@provides"
+      "@requires"
+      "@shareable"
+      "@tag"
+    ]
+  )
+  @link(url: "https://myspecs.dev/myCustomDirective/v1.0", import: ["@custom"])
+  @composeDirective(name: "@custom")
+
+scalar federation__FieldSet
+
+directive @custom on OBJECT
+directive @key(fields: federation__FieldSet!, resolvable: Boolean = true) repeatable on OBJECT | INTERFACE
+
+type Product
+  @custom
+  @key(fields: "id")
+  @key(fields: "sku package")
+  @key(fields: "sku variation { id }") {
+    id: ID!
+    sku: String
+    package: String
+    variation: ProductVariation
+    dimensions: ProductDimension
+    createdBy: User @provides(fields: "totalProductsCreated")
+    notes: String @tag(name: "internal")
+    research: [ProductResearch!]!
+}
+
+type DeprecatedProduct @key(fields: "sku package") {
+  sku: String!
+  package: String!
+  reason: String
+  createdBy: User
+}
+
+type ProductVariation {
+  id: ID!
+}
+
+type ProductResearch @key(fields: "study { caseNumber }") {
+  study: CaseStudy!
+  outcome: String
+}
+
+type CaseStudy {
+  caseNumber: ID!
+  description: String
+}
+
+type ProductDimension @shareable {
+  size: String
+  weight: Float
+  unit: String @inaccessible
+}
+
+type Query {
+  product(id: ID!): Product
+  deprecatedProduct(sku: String!, package: String!): DeprecatedProduct @deprecated(reason: "Use product query instead")
+}
+
+type User @key(fields: "email") {
+  averageProductsCreatedPerYear: Int @requires(fields: "totalProductsCreated yearsOfEmployment")
+  email: ID! @external
+  name: String @override(from: "users")
+  totalProductsCreated: Int @external
+  yearsOfEmployment: Int! @external
+}
+
+type Inventory @interfaceObject @key(fields: "id") {
+  id: ID!
+  deprecatedProducts: [DeprecatedProduct!]!
+}

graphql-java-support/src/test/resources/schemas/federationV2_defined_scalars_federated.graphql

@@ -0,0 +1,104 @@
+schema @composeDirective(name : "@custom") @link(import : ["@composeDirective", "@extends", "@external", "@key", "@inaccessible", "@interfaceObject", "@override", "@provides", "@requires", "@shareable", "@tag"], url : "https://specs.apollo.dev/federation/v2.3") @link(import : ["@custom"], url : "https://myspecs.dev/myCustomDirective/v1.0"){
+  query: Query
+}
+
+directive @composeDirective(name: String!) repeatable on SCHEMA
+
+directive @custom on OBJECT
+
+directive @extends on OBJECT | INTERFACE
+
+directive @external on OBJECT | FIELD_DEFINITION
+
+directive @inaccessible on SCALAR | OBJECT | FIELD_DEFINITION | ARGUMENT_DEFINITION | INTERFACE | UNION | ENUM | ENUM_VALUE | INPUT_OBJECT | INPUT_FIELD_DEFINITION
+
+directive @interfaceObject on OBJECT
+
+directive @key(fields: federation__FieldSet!, resolvable: Boolean = true) repeatable on OBJECT | INTERFACE
+
+directive @link(as: String, for: link__Purpose, import: [link__Import], url: String!) repeatable on SCHEMA
+
+directive @override(from: String!) on FIELD_DEFINITION
+
+directive @provides(fields: federation__FieldSet!) on FIELD_DEFINITION
+
+directive @requires(fields: federation__FieldSet!) on FIELD_DEFINITION
+
+directive @shareable repeatable on OBJECT | FIELD_DEFINITION
+
+directive @tag(name: String!) repeatable on SCALAR | OBJECT | FIELD_DEFINITION | ARGUMENT_DEFINITION | INTERFACE | UNION | ENUM | ENUM_VALUE | INPUT_OBJECT | INPUT_FIELD_DEFINITION
+
+union _Entity = DeprecatedProduct | Inventory | Product | ProductResearch | User
+
+type CaseStudy {
+  caseNumber: ID!
+  description: String
+}
+
+type DeprecatedProduct @key(fields : "sku package", resolvable : true) {
+  createdBy: User
+  package: String!
+  reason: String
+  sku: String!
+}
+
+type Inventory @interfaceObject @key(fields : "id", resolvable : true) {
+  deprecatedProducts: [DeprecatedProduct!]!
+  id: ID!
+}
+
+type Product @custom @key(fields : "id", resolvable : true) @key(fields : "sku package", resolvable : true) @key(fields : "sku variation { id }", resolvable : true) {
+  createdBy: User @provides(fields : "totalProductsCreated")
+  dimensions: ProductDimension
+  id: ID!
+  notes: String @tag(name : "internal")
+  package: String
+  research: [ProductResearch!]!
+  sku: String
+  variation: ProductVariation
+}
+
+type ProductDimension @shareable {
+  size: String
+  unit: String @inaccessible
+  weight: Float
+}
+
+type ProductResearch @key(fields : "study { caseNumber }", resolvable : true) {
+  outcome: String
+  study: CaseStudy!
+}
+
+type ProductVariation {
+  id: ID!
+}
+
+type Query {
+  _entities(representations: [_Any!]!): [_Entity]!
+  _service: _Service!
+  deprecatedProduct(package: String!, sku: String!): DeprecatedProduct @deprecated(reason : "Use product query instead")
+  product(id: ID!): Product
+}
+
+type User @key(fields : "email", resolvable : true) {
+  averageProductsCreatedPerYear: Int @requires(fields : "totalProductsCreated yearsOfEmployment")
+  email: ID! @external
+  name: String @override(from : "users")
+  totalProductsCreated: Int @external
+  yearsOfEmployment: Int! @external
+}
+
+type _Service {
+  sdl: String!
+}
+
+enum link__Purpose {
+  EXECUTION
+  SECURITY
+}
+
+scalar _Any
+
+scalar federation__FieldSet
+
+scalar link__Import