The code that can produce the error.
```scala
import cats.effect.*
import cats.effect.unsafe.implicits.global
import fs2.*
import scala.concurrent.duration.*
import cats.implicits.*
import cats.*
object Main extends IOApp.Simple {
def run = IO.deferred[Unit].flatMap { d =>
IO.ref(0).flatMap { ref =>
val s =
Stream
.resource(Resource.make(ref.update(_ + 1))(_ => ref.update(_ - 1)))
.pull
.uncons1
.flatMap {
case None => Pull.done
case Some((hd, tl)) =>
Pull.output1(hd) >>
Pull.extendScopeTo(Stream.unit.covary[IO]).flatMap {
killLease =>
Pull.eval(d.complete(()).void >> IO.never[Unit]) >>
Pull.eval(killLease.compile.drain) >>
tl.pull.echo
}
}
.streamNoScope
IO.race(s.compile.drain, d.get) >> ref.get.flatMap(IO.println(_))
}
}
}
```
Pull.bracketCase can be cancelled after the acquire and during use.
I don't know what uses Pull.bracketCase has, other than Pull#lease, but I think it should at least be documented that it shouldn't be used for resources, since release is not guaranteed.
Pull#lease is subject to the issues of bracketCase and can cause resources on the scope to never be released.
I think it could be implemented in a safe way using the new leaseScope introduced above.
Pull.extendScopeTohere A safer variant could be:The code that can produce the error.
```scala import cats.effect.* import cats.effect.unsafe.implicits.global import fs2.* import scala.concurrent.duration.* import cats.implicits.* import cats.* object Main extends IOApp.Simple { def run = IO.deferred[Unit].flatMap { d => IO.ref(0).flatMap { ref => val s = Stream .resource(Resource.make(ref.update(_ + 1))(_ => ref.update(_ - 1))) .pull .uncons1 .flatMap { case None => Pull.done case Some((hd, tl)) => Pull.output1(hd) >> Pull.extendScopeTo(Stream.unit.covary[IO]).flatMap { killLease => Pull.eval(d.complete(()).void >> IO.never[Unit]) >> Pull.eval(killLease.compile.drain) >> tl.pull.echo } } .streamNoScope IO.race(s.compile.drain, d.get) >> ref.get.flatMap(IO.println(_)) } } } ```Pull.bracketCasecan be cancelled after theacquireand duringuse. I don't know what usesPull.bracketCasehas, other thanPull#lease, but I think it should at least be documented that it shouldn't be used for resources, sincereleaseis not guaranteed.Pull#leaseis subject to the issues ofbracketCaseand can cause resources on the scope to never be released. I think it could be implemented in a safe way using the newleaseScopeintroduced above.Will make the PR, just wanted a discussion first.