kotlinx.coroutines.CoroutinesInternalError: Fatal exception in coroutines machinery for DispatchedContinuation

[benasher44]

Hi there! I've managed to trigger a fatal exception inside coroutines on native:

kotlinx.coroutines.CoroutinesInternalError: Fatal exception in coroutines machinery for DispatchedContinuation[EventLoopImpl@2cbfc8a8, Continuation @ $cancellation works across performAndWait boundary$lambda-24$lambda-21$lambda-20COROUTINE$16]. Please read KDoc to 'handleFatalException' method and report this incident to maintainers

The issue is visible in the following PRs:

• Kotlin 1.3.40: https://github.com/Autodesk/coroutineworker/pull/24
• Kotlin 1.3.50: https://github.com/Autodesk/coroutineworker/pull/22

In both PRs, you can repro by running ./gradlew testIosSim (need Xcode installed to run tests). Please let me know what other info I can provide, and I'd love to work toward some kind of workaround! Thanks!

[benasher44]

Note that CI might be green on those PRs, but that's only because the error/exception is logged silently.

[benasher44]

Figured this out. This is because I'm freezing coroutine internals that I shouldn't. this.ensureNeverFrozen (to protect against freezing the context) in runBlocking uncovered it. So my fault! Closing

[zach-klippenstein]

@elizarov Could the coroutines library automatically call ensureNeverFrozen to protect itself on Native? Seems like this is something everyone working with this stuff could hit pretty easily.

[elizarov]

@zach-klippenstein We'll take a different path as a part of #462. All coroutine internals will keep their state in "freezable atomics", this will make them "freeze transparent". They will continue to work even when they are shared (frozen).