Concurrent modification during iteration bug fix

[aNOOBisTheGod]

Hey there!

Sometimes I am getting a bug like this:

Concurrent modification during iteration: _Map len:1.
StackTrace: #0      _LinkedHashMapMixin.forEach (dart:collection-patch/compact_hash.dart:635)
#1      UA.stop (package:sip_ua/src/ua.dart:325)

I was wondering what causes the bug and found that there is a case when call is stopping but package is trying to destroy session in sessions list at the same time. I saw that you have _stopping flag already in your stop function and use it to prevent list modifications if they can cause an error. So I taught that I can use that flag to fix my problem.

Seems like I am not getting this error any more :)

[aNOOBisTheGod]

@mikaelwills take a look please :)

[mikaelwills]

@aNOOBisTheGod the issue is that the _sessions map is being modified during interation. ua.dart:325

 _sessions.forEach((String? key, _) {
      if (_sessions.containsKey(key)) {
        logger.d('closing session $key');
        try {
          RTCSession rtcSession = _sessions[key]!;
          if (!rtcSession.isEnded()) {
            rtcSession.terminate();
          }
        } catch (e, s) {
          logger.e(e.toString(), error: e, stackTrace: s);
        }
      }
    });

Can you test what might be two better solutions:

1: Replace the _sessions.forEach with a for loop

for (String? key in _sessions.keys) {}

2: Create a copy of the map to iterate over

_sessions.keys.toList().forEach((String? key) {}

[aNOOBisTheGod]

@aNOOBisTheGod the issue is that the _sessions map is being modified during interation. ua.dart:325

 _sessions.forEach((String? key, _) {
      if (_sessions.containsKey(key)) {
        logger.d('closing session $key');
        try {
          RTCSession rtcSession = _sessions[key]!;
          if (!rtcSession.isEnded()) {
            rtcSession.terminate();
          }
        } catch (e, s) {
          logger.e(e.toString(), error: e, stackTrace: s);
        }
      }
    });

Can you test what might be two better solutions:

1: Replace the _sessions.forEach with a for loop

for (String? key in _sessions.keys) {}

2: Create a copy of the map to iterate over

_sessions.keys.toList().forEach((String? key) {}

The second solution had fixed the bug. PR updated