Use task exit codes when shutdown via SIGINT

[chris-olszewski]

Opening a RFC for this comment in #3711 which is a specific issue of wanting the underling task exit code to be returned by turbo.

I want to exit with code zero if and only if the process is able to exit gracefully with no issues. For that reason I want to trap '' instead, propagating the exit code.

#3711 (comment)

For example a task could return a 1 if it shut down successfully or a 2 if it wasn't able to clean up all resources.

turbo obviously could not forward all exit codes, but I think returning the maximum exit code still could be useful.

[Netail]

returning the maximum exit code still could be useful

Agreed, which it currently already does from what I understood from Anthony. However when a persistent task is exited by the user, it should return with 130 instead of e.g. exit code 1 (hinting an error occurred, while the user just ctrl + c'ed)

[chris-olszewski]

Agreed, which it currently already does from what I understood from Anthony

You're correct, I should clarify. For runs that complete without being interrupted by a signal, we return the highest of all exit codes. However, when we prematurely shut down due to a signal we always have an exit code 1.