I'm getting an error when running suspending function (even simple `delay()`) after webpack hot relo...

# javascript

[Robert Jaros]

I'm getting an error when running suspending function (even simple delay()) after webpack hot reload. It seems to be new issue with Kotlin JS/IR 1.5.2x or coroutines 1.5.1.

[Robert Jaros]

Don't know how to debug this - I only have this stack trace:

"ClassCastException
    at THROW_CCE (webpack-internal:///./kotlin/showcase.js:19003:11)
    at _get_DefaultDelay_ (webpack-internal:///./kotlin/showcase.js:79393:44)
    at _get_delay__0 (webpack-internal:///./kotlin/showcase.js:75356:37)
    at delay (webpack-internal:///./kotlin/showcase.js:75329:7)
    at _no_name_provided__896.doResume_0_k$ (webpack-internal:///./kotlin/showcase.js:117391:29)
    at _no_name_provided__896.invoke_2i3g7c_k$ (webpack-internal:///./kotlin/showcase.js:117371:16)
    at _no_name_provided__1_3.l [as _$this_createCoroutineUnintercepted] (webpack-internal:///./kotlin/showcase.js:117939:16)
    at _no_name_provided__1_3.doResume_2_0_k$ (webpack-internal:///./kotlin/showcase.js:20517:17)
    at _no_name_provided__1_3.doResume_0_k$ (webpack-internal:///./kotlin/showcase.js:20520:17)
    at _no_name_provided__1_3.CoroutineImpl_0.resumeWith_jccoe6_k$ (webpack-internal:///./kotlin/showcase.js:20419:37)"

[Robert Jaros]

The problem is with IR only (works fine with legacy backend)

[Robert Jaros]

I'm using full HMR with config.devServer.hot = true;

[Robert Jaros]

No error with standard hot reload.

[Big Chungus]

Have you tried 1.5.30-M1? If it won't fix the issue, at least it'll give you a propper stack trace for ir

[Robert Jaros]

Opened a ticked: https://youtrack.jetbrains.com/issue/KT-47832

[Robert Jaros]

Haven't tried 1.5.30 yet

[Robert Jaros]

Creating a sample project with full HMR without KVision is so hard ... ;]

[Robert Jaros]

I've manged to reproduce the issue on Kotlin 1.4.30 as well.

[Robert Jaros]

And on 1.5.30-M1 as well (stacktrace doesn't seem to be any better 😞)

[Big Chungus]

It was supposed to generate source maps. Guess that's not quite there still

[Robert Jaros]

in fact it does generate source maps

[Robert Jaros]

but the main stack trace with kotlin sources is not useful because it seems to be different coroutine (?)

[Robert Jaros]

only the stacktrace inside the exception itself (javascript stacktrace) seems to give some info about the problem

[Robert Jaros]

you can play with my sample if you want 🙂
https://github.com/rjaros/kt47832