Catch unhandled exception in abstract resolution

Author: JoviDeCroock

src/execution/__tests__/union-interface-test.ts

@@ -12,7 +12,7 @@ import {
 import { GraphQLBoolean, GraphQLString } from '../../type/scalars';
 import { GraphQLSchema } from '../../type/schema';
 
-import { executeSync } from '../execute';
+import { execute, executeSync } from '../execute';
 
 class Dog {
   name: string;
@@ -154,6 +154,72 @@ odie.mother.progeny = [odie];
 const liz = new Person('Liz');
 const john = new Person('John', [garfield, odie], [liz, odie]);
 
+// New types for the unhandled rejection test
+const SearchableInterface = new GraphQLInterfaceType({
+  name: 'Searchable',
+  fields: {
+    id: { type: GraphQLString },
+  },
+  // Deliberately no resolveType, to use isTypeOf from concrete types
+});
+
+const TypeA = new GraphQLObjectType({
+  name: 'TypeA',
+  interfaces: [SearchableInterface],
+  fields: () => ({
+    id: { type: GraphQLString },
+    nameA: { type: GraphQLString },
+  }),
+  isTypeOf: (_value, _context, _info) => {
+    return new Promise((_resolve, reject) => {
+      setTimeout(() => {
+        reject(new Error('TypeA_isTypeOf_rejected'));
+      }, 10);
+    });
+  },
+});
+
+const TypeB = new GraphQLObjectType({
+  name: 'TypeB',
+  interfaces: [SearchableInterface],
+  fields: () => ({
+    id: { type: GraphQLString },
+    nameB: { type: GraphQLString },
+  }),
+  isTypeOf: (value: any, _context, _info) => {
+    return value.id === 'b';
+  },
+});
+
+const queryTypeWithSearchable = new GraphQLObjectType({
+  name: 'Query',
+  fields: {
+    person: {
+      type: PersonType,
+      resolve: () => john,
+    },
+    search: {
+      type: SearchableInterface,
+      args: { id: { type: GraphQLString } },
+      resolve: (_source, { id }) => {
+        /* c8 ignore start */
+        if (id === 'a') {
+          return { id: 'a', nameA: 'Object A' };
+          /* c8 ignore end */
+        } else if (id === 'b') {
+          return { id: 'b', nameB: 'Object B' };
+        }
+      },
+    },
+  },
+});
+
+const schemaWithSearchable = new GraphQLSchema({
+  query: queryTypeWithSearchable,
+  types: [PetType, TypeA, TypeB, SearchableInterface, PersonType, DogType, CatType], // Added new types
+});
+// End of new types
+
 describe('Execute: Union and intersection types', () => {
   it('can introspect on union and intersection types', () => {
     const document = parse(`
@@ -545,4 +611,50 @@ describe('Execute: Union and intersection types', () => {
     expect(encounteredRootValue).to.equal(rootValue);
     expect(encounteredContext).to.equal(contextValue);
   });
+
+  it('handles promises from isTypeOf correctly when a later type matches synchronously', async () => {
+    const document = parse(`
+      query TestSearch {
+        search(id: "b") {
+          __typename
+          id
+          ... on TypeA {
+            nameA
+          }
+          ... on TypeB {
+            nameB
+          }
+        }
+      }
+    `);
+
+    let unhandledRejection: any = null;
+    /* c8 ignore start */
+    const unhandledRejectionListener = (reason: any) => {
+      unhandledRejection = reason;
+    };
+    process.on('unhandledRejection', unhandledRejectionListener);
+    /* c8 ignore end */
+
+    const result = await execute({
+      schema: schemaWithSearchable,
+      document,
+    });
+
+    expect(result.errors).to.be.undefined;
+    expect(result.data).to.deep.equal({
+      search: {
+        __typename: 'TypeB',
+        id: 'b',
+        nameB: 'Object B',
+      },
+    });
+
+    // Give the TypeA promise a chance to reject and the listener to fire
+    await new Promise((resolve) => setTimeout(resolve, 20));
+
+    process.removeListener('unhandledRejection', unhandledRejectionListener);
+
+    expect(unhandledRejection).to.be.null; 
+  });
 });

src/execution/execute.ts

@@ -1002,6 +1002,9 @@ export const defaultTypeResolver: GraphQLTypeResolver<unknown, unknown> =
         if (isPromise(isTypeOfResult)) {
           promisedIsTypeOfResults[i] = isTypeOfResult;
         } else if (isTypeOfResult) {
+          if (promisedIsTypeOfResults.length) {
+            Promise.allSettled(promisedIsTypeOfResults);
+          }
           return type.name;
         }
       }