The timeout() operator throws error prematurely

[martinsik]

RxJS version: 5.3.0

It seems like after the most recent changes in 5.3.0 the timeout() operator works differently. But I don't know whether this is intentional or not since it's not listed under either "Features" nor "Breaking Changes" in the change log.

Code to reproduce:

Observable
  .range(0, 10)
  .concatMap(val => Observable.of(val).delay(val >= 3 ? 5000 : 1000))
  .timeout(2000)
  .subscribe(
    val => console.log('next', val),
    err => console.log('error', err)
  );

First three items are delayed by 1 second while the fourth item is delayed by 5 seconds.

Expected behavior:

next 0
next 1
next 2
error { TimeoutError: Timeout has occurred
    at TimeoutError.Error (native)
...
  message: 'Timeout has occurred' }

Actual behavior:

next 0
error { TimeoutError: Timeout has occurred
    at TimeoutError.Error (native)
...
  message: 'Timeout has occurred' }

Additional information:

Only 5.3.0 is affected. I checked both 5.2.0 and 4.1.0 and in both cases it work as shown in Expected behavior. Also it looks like this situation is already tested: https://github.com/ReactiveX/rxjs/blob/master/spec/operators/timeout-spec.ts#L89

Demos:

RxJS 5.3.0: https://jsbin.com/wemuzuc/5/edit?html,js,console
RxJS 5.2.0: https://jsbin.com/nedagox/4/edit?html,js,console
RxJS 4.1.0: https://jsbin.com/ganofon/2/edit?html,js,console

[kwonoj]

gut guess (without any verification), maybe it's related to 3e9d529 **timeout: Cancels scheduled timeout, if no longer needed**? it has changed internals of timeout operator bit.

[trxcllnt]

@martinsik thanks for filing this issue. I've submitted a fix in PR #2580. This is pretty serious, so we'll see about getting a patch release out soon.

[lock]

This thread has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.