Memory Leak with Queue Scheduler and Subject

[MikeRyanDev]

RxJS version: 5.0.2

Code to reproduce:
Observing a subject using the queue scheduler creates many QueueActions that are never freed.

Plnkr demonstrating issue: https://plnkr.co/edit/BBkHlpIf6MiP2eOPdIlz

Minimal code to reproduce:

import 'rxjs/add/operator/observeOn';
import { interval } from 'rxjs/observable/interval';
import { BehaviorSubject } from 'rxjs/BehaviorSubject';
import { queue } from 'rxjs/scheduler/queue';

const source$ = new BehaviorSubject(0);

source$.observeOn(queue).subscribe();

interval(50).subscribe(source$);

Create two heap allocation snapshots about 20 seconds apart and use the comparison tools to see the allocation delta. Example:

Expected behavior:
No memory leak of previous values.

Actual behavior:
Previous values are retained in QueueActions

[kwonoj]

So the issue seems occurring on observeOn operator by holding observed notification's subscription. Please check #2245 for reference, local verification shows leaks are gone with given changes.

(and this can be reproduced with any other scheduler like async via observeOn)

[MikeRyanDev]

@kwonoj Pulled down the latest from your branch and I am still seeing a leak of QueueActions. Also seeing a leak of instances of ObserveOnContext. All are being held by ObserveOnSubscriber._subscriptions

[kwonoj]

@MikeRyan52 can you share setup you've used to repro issue (maybe github repo)?

[MikeRyanDev]

@kwonoj I created a demo repository here that reproduces the problem with both the latest published release of rxjs and your branch: https://github.com/MikeRyan52/rxjs-memory-leak

[benlesh]

I see the problem right now and I'm working on a solution.

[benlesh]

@MikeRyan52 try the PR #2248 ... it should solve your problem.

Thank you so much for reporting this one.