add failing tests

Currently:

When list item completion fails for a stream with a non-nullable list:
1. the entire list must be nulled within the given AsyncPayloadRecord
2. any other pending AsyncPayloadRecords must be filtered
3. async iteration powering the stream must be cancelled

Currently, the third objective is accomplished by way of the second; during AsyncPayloadRecord filtering, if a stream record is filtered and has an associated asyncIterator, its return() method is called, which _should_ end the stream.

This can go wrong in a few ways:
A: The return() method may not exist; by specification, the return() method exists for the caller to notify the callee that the caller no longer intends to call next(), allowing for early cleanup. The method is optional, however, and so should not be relied on.
B: The return method, even if it exists, may not be set up to block any next() calls while it operates. Async generators have next and return methods that always settle in call order, but async iterables do not.

Author: yaacovCR

src/execution/__tests__/stream-test.ts

@@ -2,6 +2,7 @@ import { assert } from 'chai';
 import { describe, it } from 'mocha';
 
 import { expectJSON } from '../../__testUtils__/expectJSON.js';
+import { resolveOnNextTick } from '../../__testUtils__/resolveOnNextTick.js';
 
 import type { PromiseOrValue } from '../../jsutils/PromiseOrValue.js';
 
@@ -1134,7 +1135,7 @@ describe('Execute: stream directive', () => {
       },
     ]);
   });
-  it('Handles async errors thrown by completeValue after initialCount is reached from async iterable for a non-nullable list', async () => {
+  it('Handles async errors thrown by completeValue after initialCount is reached from async generator for a non-nullable list', async () => {
     const document = parse(`
       query { 
         nonNullFriendList @stream(initialCount: 1) {
@@ -1174,9 +1175,152 @@ describe('Execute: stream directive', () => {
             ],
           },
         ],
+        hasNext: false,
+      },
+    ]);
+  });
+  it('Handles async errors thrown by completeValue after initialCount is reached from async iterable for a non-nullable list when the async iterable does not provide a return method) ', async () => {
+    const document = parse(`
+      query { 
+        nonNullFriendList @stream(initialCount: 1) {
+          nonNullName
+        }
+      }
+    `);
+    let count = 0;
+    const result = await complete(document, {
+      nonNullFriendList: {
+        [Symbol.asyncIterator]: () => ({
+          next: async () => {
+            switch (count++) {
+              case 0:
+                return Promise.resolve({
+                  done: false,
+                  value: { nonNullName: friends[0].name },
+                });
+              case 1:
+                return Promise.resolve({
+                  done: false,
+                  value: {
+                    nonNullName: () => Promise.reject(new Error('Oops')),
+                  },
+                });
+              case 2:
+                return Promise.resolve({
+                  done: false,
+                  value: { nonNullName: friends[1].name },
+                });
+              // Not reached
+              /* c8 ignore next 5 */
+              case 3:
+                return Promise.resolve({
+                  done: false,
+                  value: { nonNullName: friends[2].name },
+                });
+            }
+          },
+        }),
+      },
+    });
+    expectJSON(result).toDeepEqual([
+      {
+        data: {
+          nonNullFriendList: [{ nonNullName: 'Luke' }],
+        },
+        hasNext: true,
+      },
+      {
+        incremental: [
+          {
+            items: null,
+            path: ['nonNullFriendList', 1],
+            errors: [
+              {
+                message: 'Oops',
+                locations: [{ line: 4, column: 11 }],
+                path: ['nonNullFriendList', 1, 'nonNullName'],
+              },
+            ],
+          },
+        ],
+        hasNext: false,
+      },
+    ]);
+  });
+  it('Handles async errors thrown by completeValue after initialCount is reached from async iterable for a non-nullable list when the async iterable provides concurrent next/return methods and has a slow return ', async () => {
+    const document = parse(`
+      query { 
+        nonNullFriendList @stream(initialCount: 1) {
+          nonNullName
+        }
+      }
+    `);
+    let count = 0;
+    let returned = false;
+    const result = await complete(document, {
+      nonNullFriendList: {
+        [Symbol.asyncIterator]: () => ({
+          next: async () => {
+            /* c8 ignore next 3 */
+            if (returned) {
+              return Promise.resolve({ done: true });
+            }
+            switch (count++) {
+              case 0:
+                return Promise.resolve({
+                  done: false,
+                  value: { nonNullName: friends[0].name },
+                });
+              case 1:
+                return Promise.resolve({
+                  done: false,
+                  value: {
+                    nonNullName: () => Promise.reject(new Error('Oops')),
+                  },
+                });
+              case 2:
+                return Promise.resolve({
+                  done: false,
+                  value: { nonNullName: friends[1].name },
+                });
+              // Not reached
+              /* c8 ignore next 5 */
+              case 3:
+                return Promise.resolve({
+                  done: false,
+                  value: { nonNullName: friends[2].name },
+                });
+            }
+          },
+          return: async () => {
+            await resolveOnNextTick();
+            returned = true;
+            return { done: true };
+          },
+        }),
+      },
+    });
+    expectJSON(result).toDeepEqual([
+      {
+        data: {
+          nonNullFriendList: [{ nonNullName: 'Luke' }],
+        },
         hasNext: true,
       },
       {
+        incremental: [
+          {
+            items: null,
+            path: ['nonNullFriendList', 1],
+            errors: [
+              {
+                message: 'Oops',
+                locations: [{ line: 4, column: 11 }],
+                path: ['nonNullFriendList', 1, 'nonNullName'],
+              },
+            ],
+          },
+        ],
         hasNext: false,
       },
     ]);