//! Shell binary resolution for routine launches, split out of `service_trigger.rs`.
/// Resolve the `sh` executable to invoke for a routine launch.
///
/// Honours the `MOADIM_SH_BIN` environment variable when set, falling back to the platform shell
/// (`sh`) otherwise. The override exists so tests can point the spawn at a shim instead of running
/// a real login shell.
///
/// In **test builds**, when no `MOADIM_SH_BIN` shim is configured this never falls back to the
/// real `sh`: it returns a path that cannot exist, so the spawn fails harmlessly instead of
/// launching a real agent process. This closes the same structural gap `crontab_bin()` in
/// `crate::sync` closes for crontab I/O (issue #175) — a test that forgets to
/// clear `PATH` or shim this binary still cannot execute a real command on the developer's
/// machine (issue #217). Tests that need a working spawn set `MOADIM_SH_BIN` to a shim.
pub(crate) fn sh_bin() -> String {
if let Ok(bin) = std::env::var("MOADIM_SH_BIN") {
return bin;
}
#[cfg(test)]
let fallback = "/nonexistent/moadim-test-sh-guard".to_string();
#[cfg(not(test))]
let fallback = "sh".to_string();
fallback
}