Subcommand fails silently when main is not specified

[davireis]

Describe the bug

If you create a script with a subcommand but does not specify an empty main then then running the subcommand has no effect. It should either succeed or fail explicitly.

How to reproduce

1. Given the repro.nu script below

#!/usr/bin/env nu
# def main [] { }
def 'main subcommand' [] {
	print x
}

2. Run nu repro.nu
3. x does not get printed to the screen. If you uncomment the # def main [] {} line then x gets printed to the screen.

Expected behavior

I expected nushell to either print x or generate a failure saying that a main needs to be specified.

Configuration

key	value
version	0.98.0
major	0
minor	98
patch	0
branch	main
commit_hash	25a15d56f171313dd9e6170d427ba4c580c69ee4
build_os	macos-aarch64
build_target	aarch64-apple-darwin
rust_version	rustc 1.81.0-nightly (eeb90cda1 2024-09-04) (built from a source tarball)
cargo_version	cargo 1.64.0
build_time	2024-09-18 04:03:30 -04:00
build_rust_channel	release
allocator	mimalloc
features	default, sqlite, trash
installed_plugins