The handler of the signals of the operating system in the binary

The default handler of OTP stops the VM in order for a SIGTERM. That stop waits for each application to stop, and the command of the binary runs in Expresso.BurritoEntryPoint.start/2, before the application starts. The stop then waits for ever, and the logger writes to the standard output while it waits.

The launcher of Burrito 1.6 sends SIGTERM when the reader of the standard output stops, as | head does. The launcher passes the standard output of the VM through a pipe, and it stops the read of that pipe first. Thus each write to the standard output also waits for ever, and the binary did not stop. See stdoutCopyThread in deps/burrito/src/erlang_launcher.zig.

This handler halts the VM at once for a SIGTERM, and it does not write to the standard output. The default handler of OTP handles the other signals.

The launcher does not send on a SIGTERM that the user sends to the binary. Expresso.LauncherWatch halts the VM when the launcher stops.

The exit status is 0. The launcher waits for the VM in two threads, and the thread that reads the exit status first decides the status of the binary. When the thread that sent SIGTERM reads it first, the binary gives 0 for each status of the VM. A different status of the VM then gives 0 or that status by chance. With 0, a closed pipe always gives 0, as mix expresso does.