ConcurrentModificationException in Sentry.currentBreadcrumbs

[fab1an]

I'm getting this error now and then:

java.util.ConcurrentModificationException: null
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:960)
    at java.lang.reflect.Method.invoke(Method.java:372)
    at java.lang.reflect.Method.invoke(Method.java)
    at android.app.ActivityThread.main(ActivityThread.java:5593)
    at android.os.Looper.loop(Looper.java:135)
    at android.os.Handler.dispatchMessage(Handler.java:95)
    at android.os.Handler.handleCallback(Handler.java:739)
    at retrofit2.ExecutorCallAdapterFactory$ExecutorCallbackCall$1$1.run(ExecutorCallAdapterFactory.java:68)
    at mypackage.RequestAdapter$enqueue$1.onResponse(NetworkManager.kt:166)
    at mypackage.SentryLog.captureFailedRetrofitResponse(SentryLog.kt:99)
    at com.joshdholtz.sentry.Sentry.captureEvent(Sentry.java:310)
    at com.joshdholtz.sentry.Sentry.currentBreadcrumbs(Sentry.java:735)
    at java.util.LinkedList$LinkIterator.next(LinkedList.java:124)

captureFailedRetrofitResponse looks just like this:

Sentry.captureEvent(SentryEventBuilder()
    .setMessage(message)
    .setExtra(mapOf(
         "errorBody" to "string"
    )))

[marcomorain]

Hi @fab1an - Sorry about the crash. I'll take a look into this today.

[fab1an]

Great thank you. Maybe you can leverage a BlockingQueue for this.

Or better just sychronized the access with a ReadWriteLock.

[fab1an]

Do you need help on this?

[marcomorain]

Yes please @fab1an - can you take a look at the approach in #111 please? What do you think?

[fab1an]

@marcomorain I think the BlockingQueue was the wrong idea.

It's probably easiest to use a ReadWriteLock: https://docs.oracle.com/javase/7/docs/api/java/util/concurrent/locks/ReentrantReadWriteLock.html

private final ReentrantReadWriteLock breadcrumbLock = ReentrantReadWriteLock()

When reading the list wrap it like this:

try {
   breadcrumbLock.readLock().lock()

   ...use or copy the list ...

} finally {
   breadcrumbLock.readLock().unlock()
}

When writing:

try {
   breadcrumbLock.writeLock().lock()

   ...modify the list...

} finally {
   breadcrumbLock.writeLock().unlock()
}

[marcomorain]

Hi @fab1an - I have not had much time to look into this over the holidays.

Can you take a look at PR #111 please? I had not used ReadWriteLocks before, thanks for showing me that pattern.