[iOS] promisesByKey is not thread-safe

[lwansbrough]

Version of react-native-iap

0.3.0-beta3

Expected behavior

This dictionary can be accessed by multiple threads at the same time

Actual behavior

This dictionary crashes when accessed by multiple threads at the same time.

Steps to reproduce

Hard to reproduce, but here's a log:

The fix would probably be a semaphore or lock inside those add/remove methods.

[lwansbrough]

FYI I'm not working on a fix for this right now.

[JJMoon]

Thank you for your help. I will check.

[JJMoon]

@lwansbrough Looks like you got this error when you restore non-consumable purchases.
I think I got it.
It would happen when restoring failed. It calls rejectPromisesForKey method twice. And sometimes it throws exception.
I guess removing the method in restoreCompletedTransactionsFailedWithError would work. I hope you give me an opinion.

[JJMoon]

@lwansbrough I added some sync queue to manage the actions. I hope you check the source. It's on the PR.

[JJMoon]

This issue is applied on 1.0.4.