fix: panic on unexpected nix-index output (github #31)

core/src/system.rs

@@ -112,18 +112,21 @@ pub fn get_packages(
 			if result.is_empty() {
 				return None;
 			}
-			let packages: Vec<String> = result
+			let packages: Option<Vec<String>> = result
 				.lines()
 				.map(|line| {
-					line.split_whitespace()
+					let package = line.split_whitespace().next()?;
-						.next()
+					Some(package.rsplit_once('.')?.0.to_string())
-						.unwrap()
-						.rsplit_once('.')
-						.unwrap()
-						.0
-						.to_string()
 				})
 				.collect();
+			let Some(packages) = packages else {
+				eprintln!(
+					"Unexpected output from nix-index:\n  {}",
+					result.replace("\n", "\n  ")
+				);
+				return None;
+			};
+
 			if packages.is_empty() {
 				None
 			} else {