I was using Kotlin Coroutines version `1.6.4` in my project, after adding a library with dependency ...

# coroutines

[marcinmoskala]

I was using Kotlin Coroutines version 1.6.4 in my project, after adding a library with dependency to Kotlin Coroutines 1.7.0-Beta, tests using runTest started failing because of backgroundScope premature cancellation, the problem was gone after updating this project Kotlin Coroutines version to 1.7.0-Beta. Can anyone explain it to me?

[Dmitry Khalanskiy [JB]]

runTest was reworked quite a bit for 1.7.0-Beta, but there was no intention to change the behavior of backgroundScope. Maybe we introduced a bug (or accidentally fixed one). Could you file an issue at https://github.com/Kotlin/kotlinx.coroutines/issues with an example of the code that behaves incorrectly?

[Dmitry Khalanskiy [JB]]

Ah, sorry, I misread: your problem is not with the test module itself but with the incompatibility between 1.7.0-Beta and 1.6.4. If I understood correctly this time, the issue is with using kotlinx-coroutines-core:1.7.0-Beta with kotlinx-coroutines-test:1.6.4, right?

[marcinmoskala]

That is the strange part:
Project use coroutines regular and test 1.6.4
Lib use coroutines 1.7.0-Beta
Just adding lib (without using anything from inside) changed runTest behavior

[marcinmoskala]

Lib uses Gradle kts with coroutines in implementation block

[marcinmoskala]

I might try to make.a simple project that illustrates it, but likely not today

[Dmitry Khalanskiy [JB]]

Typically, gradle won't depend on several copies of the same library. Instead, it analyzes all the usages of a library and selects a single version that should suit everyone. In your case, kotlinx-coroutines-core would use the upgraded version for the whole project.

[Dmitry Khalanskiy [JB]]

https://stackoverflow.com/questions/29374885/multiple-version-of-dependencies-in-gradle