fakeAsync in node throws TypeError: Cannot read property 'length' of undefined

[tbosch]

Node 6.9.5.

Stack:

TypeError: Cannot read property 'length' of undefined
    at onwriteDrain (_stream_writable.js:396:12)
    at afterWrite (_stream_writable.js:386:5)
    at ZoneDelegate.invokeTask (/Users/tbosch/projects/angular/node_modules/zone.js/dist/zone-node.js:399:31)
    at ProxyZoneSpec.onInvokeTask (/Users/tbosch/projects/angular/node_modules/zone.js/dist/proxy.js:103:39)
    at ZoneDelegate.invokeTask (/Users/tbosch/projects/angular/node_modules/zone.js/dist/zone-node.js:398:36)
    at Zone.runTask (/Users/tbosch/projects/angular/node_modules/zone.js/dist/zone-node.js:165:47)
    at ZoneTask.ZoneTask.cancelFn.invoke (/Users/tbosch/projects/angular/node_modules/zone.js/dist/zone-node.js:466:38)
    at FakeAsyncTestZoneSpec.flushMicrotasks (/Users/tbosch/projects/angular/node_modules/zone.js/dist/fake-async-test.js:204:17)
    at flushMicrotasks (../../../../../../packages/core/testing/src/fake_async.ts:135:27)

This happens after the test is done and fakeAsync flushes the microtasks.
The code in _stream_writable.js is from node, and contains the following:

process.nextTick(afterWrite, stream, state, finished, cb);
...
function afterWrite(stream, state, finished, cb) { ...}

The error above occurs because the call to process.nextTick does not forward the extra arguments to the afterWrite callback when it happens.

Workaround / patch in zone-node.js:

function patchMicroTask(obj, funcName, metaCreator) {
    var setNative = null;
    function scheduleTask(task) {
        var data = task.data;
        data.args[data.callbackIndex] = function () {
            task.invoke.apply(this, arguments);
        };
        // old: setNative.apply(data.target, data.args);
        // new:
        setNative.apply(data.target, [].slice.call(data.args, 0, data.callbackIndex+1));
        return task;
    }
    setNative = patchMethod(obj, funcName, function (delegate) { return function (self, args) {
        var meta = metaCreator(self, args);
        if (meta.callbackIndex >= 0 && typeof args[meta.callbackIndex] === 'function') {
            // new
            var cbArgs = [].slice.call(args, meta.callbackIndex+1);
            cbArgs.unshift(null);
            var task = Zone.current.scheduleMicroTask(meta.name, Function.bind.apply(args[meta.callbackIndex], cbArgs), meta, scheduleTask);
            // old: var task = Zone.current.scheduleMicroTask(meta.name, args[meta.callbackIndex], meta, scheduleTask);
            return task;
        }
        else {
            // cause an error by calling it directly.
            return delegate.apply(self, args);
        }
    }; });
}

I.e. bind the arguments early to the callback, so that fakeAsync does not have to pass them anymore.

Note that this is probably a design bug as:

• the last argument to Zone.current.scheduleMicroTask contains method specific knowledge (in this case that the remaining argument have to be passed to the callback)
• fakeAsync is never calling this callback.

[mhevery]

The issue is that the FakeAsync ZoneSpec should emulate the semantics (just as it emulates the semantics of setTimeout) of the process.nextTick to correctly pass the additional arguments to it.

The fix is to have FakeAsync know to append the extra arguments when process.nextTick is flushed.

[JiaLiPassion]

I will try to fix it.

[JiaLiPassion]

@tbosch , I have fixed it in #762, could you please use the attached dist.zip to test it is ok or not?
I also added test case look like below

it('should be able to schedule microTask with additional arguments', () => {
               const process = global['process'];
               const nextTick = process && process['nextTick'];
               if (!nextTick) {
                 return;
               }
               fakeAsyncTestZone.run(() => {
                 let tickRun = false;
                 let cbArgRun = false;
                 nextTick(
                     (strArg: string, cbArg: Function) => {
                       tickRun = true;
                       expect(strArg).toEqual('stringArg');
                       cbArg();
                     },
                     'stringArg',
                     () => {
                       cbArgRun = true;
                     });

                 expect(tickRun).toEqual(false);

                 testZoneSpec.flushMicrotasks();
                 expect(tickRun).toEqual(true);
                 expect(cbArgRun).toEqual(true);
               });

             });

I think it should work!

dist.zip

[tbosch]

@JiaLiPassion yes, this is working now, thanks!

[JiaLiPassion]

@tbosch , ok, got it! thank you for confirm.