Starting with sbt 1.8.0-RC1 a LoggerContext will set its internal closed status to true:

The line closed.set(true) was introduced in #6992.

Because this AtomicBoolean is true now, it of course is not possible to re use a LoggerContext anymore:

So far so good, this seems correct.

However this is causing problems with the Play Framework, which now runs into that exception with sbt 1.8, see playframework/playframework#11527

So basically Play has a special NonBlockingInteractionMode which causes an app to continue to run in the background when calling run in a sbt console. That means, when run is "finished", there is still a (server) thread running that can serve requests. We use that for scripted tests. It's actually the same mechanism that sbt's bgRun is using, only that NonBlockingInteractionMode was implemented long time before bgRun was introduced in sbt 1.0.
Until sbt 1.7.x this was working fine, even though the background thread was using a state's loggercontext that, in theory, was closed already, but wasn't marked as closed (even thought the close method ran).

To test things out, I also came up with a clean room bgRun implementation in Play, that resembled what the NonBlockingInteractionMode is doing and I was running in the exact same exception. That bgRun looked somehow like this:

// Not the full code, just for demonstration purposes
bgRun: Initialize[InputTask[JobHandle]] = Def.inputTask {
    val service = bgJobService.value
    service.runInBackground(resolvedScoped.value, state.value) { (logger, workingDir) =>
      // At some point later, triggered by the Play server when a request comes in and the app has code changes:
      Project.runTask(Compile / compile, state) // re-compile the project
    }
}.evaluated

The problem is that the body of runInBackground, which at some point may calls Project.runTask, is not running in the bgRun lifetime anymore, but in a background thread, so after the bgRun task finishes the loggercontext gets closed. Project.runTask(...) however tries to access the loggercontext of the passed state which of course is closed now.

I tried a lot to workaround that or to come up with another solution. However the only solution that I found and IMHO think is the only one to be able to resolve that (right now) is to "wrap" Project.runTask(...) calls with an open loggercontext, which needs to be attached to the state. To do that, I need to be able to

1. initialized a LoggerContext - but the apply method is private right now
2. attach that loggerContext to the state with state.put(Keys.loggerContext,..). - but Keys.loggerContext is private right now

Using this patch here I was able to make both, Play's NonBlockingInteractionMode and sbt's bgRun, work in Play.
These lines of playframework/playframework#11441 create a loggercontext and closes it afterwards. I also finally was able to implement bgRun in Play in the last commit of that PR.

@eed3si9n If there is nothing that speaks against opening up this key and method I would be happy if you can merge this, I will provide PRs for the 1.9.x and develop branch afterwards.