Exit with non-zero code when subprocess terminated by signal

[shadowspawn]

Pull Request

Problem

There are a couple of problems with the 'close' event handler from spawned executable subcommand:

• exit code is effectively zero if subprocess terminated due to a signal
• exit code passed to exit override is (probably) always zero

See #2021

Solution

Use the event codeargument, or 1 if code is null because of a signal.

Why 1 for signal? The exit code seen in the shell when a process terminates due to a signal is often the signal number plus an offset, like 128+n in bash. We don't have a good way of mapping a signal name to a signal number, and don't have a way of returning the right offset for the current shell through process.exit(). Using kill to terminate main process with the same signal as subprocess feels a bit heavy handed and dubious. So going for exit code of 1 as simple and an incremental improvement from existing code.

Targeting a major version as changing years old behaviour, although I think it is effectively a bug fix.

ChangeLog

• fix: use non-zero exit code when spawned executable subcommand terminates due to a signal

[abetomo]

LGTM