sbt not showing full output of 'runMain' - scala

Question

When running scala in sbt via runMain I have the issue that some output written via println is cut off. If I run the following code by running sbt "runMain aw.OutputTry" the output start to get cut off around at some point.
package aw
object OutputTry {
def main(args: Array[String]) {
for(i <- 1 to 5000) {
println(f"${i}")
}
}
}
Example output (I snipped the output at the '...'):
uhu01#DESKTOP-4LSJM58:~/git/spinal$ sbt "runMain aw.OutputTry"
[info] Loading settings for project spinal-build from metals.sbt,plugins.sbt ...
[info] Loading project definition from /home/uhu01/git/spinal/project
[info] Loading settings for project spinal from build.sbt ...
[info] Set current project to aw (in build file:/home/uhu01/git/spinal/)
[info] sbt server started at local:///home/uhu01/.sbt/1.0/server/771a115d7899feb4b3f3/sock
sbt:aw> runMain aw.OutputTry
[warn] Multiple main classes detected. Run 'show discoveredMainClasses' to see the list
[info] Running (fork) aw.OutputTry
[info] 1
[info] 2
[info] 3
...
[info] 963
[info] 964
[info] 965
[success] Total time: 4 s, completed Apr 13, 2020 11:15:55 PM
I assume some buffering is going on in sbt to e.g. prepend the output with the [info] tag? To me the behavior looks a bit like a buffer in sbt is not flushed after the program exists.
Things I tried:
Flushing the output in the scala code (by calling Console.flush() in the loop, after println) - does not help
In the sbt documentation I could find the setting logBuffered, I checked this and it's already set to false
Pipe the output of the sbt call to a file - then all lines are visible as expected
Calling Thread.sleep(1000) before exiting only moves the problem, and would not be a solution in any case
I first suspected my environment (shell, etc.) but running the code directly in a scala REPL works as expected
Is there some sbt setting that I did overlook during my search? Any tips how to get shown the full output?
Environment: I'm using sbt 1.2.7, Scala 2.11.12 and openjdk 1.8.0_424 on Ubuntu 18.04 in WSL

Answer 1

sbt 1.2.7 is a pretty old version. Try 1.3.9 (latest as of April 2020).
(And remember that in order to keep builds reproducible, your sbt version is determined by your project/build.properties file, not by what you have installed.)