Ensure unreferenced types that implement reference interfaces are detected

Author: dschafer

src/utilities/__tests__/buildASTSchema.js

@@ -253,6 +253,40 @@ type Mutation {
     var output = cycleOutput(body, 'HelloScalars', 'Mutation');
     expect(output).to.equal(body);
   });
+
+  it('Unreferenced type implementing referenced interface', () => {
+    var body = `
+type Concrete implements Iface {
+  key: String
+}
+
+interface Iface {
+  key: String
+}
+
+type Query {
+  iface: Iface
+}
+`;
+    var output = cycleOutput(body, 'Query');
+    expect(output).to.equal(body);
+  });
+
+  it('Unreferenced type implementing referenced union', () => {
+    var body = `
+type Concrete {
+  key: String
+}
+
+type Query {
+  union: Union
+}
+
+union Union = Concrete
+`;
+    var output = cycleOutput(body, 'Query');
+    expect(output).to.equal(body);
+  });
 });
 
 describe('Schema Parser Failures', () => {

src/utilities/buildASTSchema.js

@@ -136,6 +136,11 @@ export function buildASTSchema(
         throw new Error('Nothing constructed for ' + typeName);
       }
       innerTypeMap[typeName] = innerTypeDef;
+      if (astMap[typeName].kind === INTERFACE_DEFINITION) {
+        // Now that we've created and cached our interface, ensure
+        // we create all implementations to point to it.
+        makeInterfaceImplementations(astMap[typeName]);
+      }
       return buildWrappedType(innerTypeDef, typeAST);
     };
   }
@@ -211,6 +216,16 @@ export function buildASTSchema(
     return def.interfaces.map(inter => produceTypeDef(inter));
   }
 
+  function makeInterfaceImplementations(inter: InterfaceDefinition) {
+    var interName = inter.name.value;
+    var types = ast.definitions.filter(def => def.kind === TYPE_DEFINITION);
+    var implementingTypes = types.filter(def => {
+      var names = def.interfaces.map(namedType => namedType.name.value);
+      return names.indexOf(interName) !== -1;
+    });
+    implementingTypes.forEach(produceTypeDef);
+  }
+
   function makeInputValues(values: Array<InputValueDefinition>) {
     return keyValMap(
       values,