Threads in waitInNativeState never gets closed in KMM project.

[JohnnyXplor]

Version

3.0.0 and above

Summary

Hi guys,
We have a KMM project that uses the Apollo library. It can then run builds for our iOS and Android mobile apps to be consumed. It works well in version 2.x.x. However after we upgraded it to a new version (I tried 3.0.0, 3.8.4 and 4.0.0) it started to have an issue in iOS app where it keeps creating new threads that don't complete. Within a few hours it could create over 2500 threads created, eventually the app would crash. I think it creates the threads to handle the graphql queries (our apps) but somehow those threads are hung there forever.

Some related log:
2 xxx 0x7ce46c (anonymous namespace)::waitInNativeState(_opaque_pthread_cond_t*, _opaque_pthread_mutex_t*) + 68
3 xxx 0x7cd554 Worker::processQueueElement(bool) + 752
4 xxx 0x7cd1c0 (anonymous namespace)::workerRoutine(void*) + 104

Any inputs would be appreciated.

Steps to reproduce the behavior

No response

Logs

(Your logs here)

[martinbonnin]

Thanks for opening this. 2500 threads sounds huge indeed. Are you even running that many queries?

I can try to run thousands of queries on an iOS device, see what's happening but my hunch is that there's something else to it. I'll try that and report back. In the meantime, would you have a reproducer around that would help diagnose this issue?

[martinbonnin]

Tried running 100 queries and I don't get too many threads (reproducer repo here):

A reproducer would help a ton. A thread dump of a few of the extra threads would also be interesting to investigate.

[JohnnyXplor]

Thanks for opening this. 2500 threads sounds huge indeed. Are you even running that many queries?

I can try to run thousands of queries on an iOS device, see what's happening but my hunch is that there's something else to it. I'll try that and report back. In the meantime, would you have a reproducer around that would help diagnose this issue?

Thanks @martinbonnin for looking into it. Yes, there is a timer that triggers a few queries so over time it can be a huge number of queries.

[JohnnyXplor]

Tried running 100 queries and I don't get too many threads (reproducer repo here):

A reproducer would help a ton. A thread dump of a few of the extra threads would also be interesting to investigate.

Hm, I can try. And maybe a dumb question, how did you get your reproducer repo project compiling? it says cannot find "apollo_kotlin_ios_playground" for me.

[martinbonnin]

how did you get your reproducer repo project compiling?

Hi 👋 I just open iosApp in Xcode and break after a few iterations:

Screen.Recording.2025-01-06.at.09.49.09.mov

it says cannot find "apollo_kotlin_ios_playground" for me.

Can you share the full error?

[martinbonnin]

If the error is the import apollo_kotlin_ios_playground line being red in Xcode, this is expected, you need to build the Kotlin framework before it is recognized. This shuold be done automatically with a build phase:

I've just let it run again with 1000 queries and ended up with ~20 threads.

[JohnnyXplor]

Not sure why, the project doesn't compile for me in Xcode16. I will try to create a reproducer project.

[martinbonnin]

I think this is because the project name wasn't enforced so if you cloned your project under a different directory name, Xcode wouldn't find it. Can you try again with martinbonnin/apollo-kotlin-ios-playground@faa8ce4?

[martinbonnin]

@JohnnyXplor I'm not sure what to do here. Did you find a solution to this problem?

[martinbonnin]

Closing for now. Feel free to leave a comment if you want us to reopen.