distro_info: fix sid keyring url

src/distro_info.rs

@@ -135,11 +135,23 @@ pub async fn get_keyring_url(series: &str) -> Result<String, Box<dyn Error>> {
 
     // For Debian, we need the series number to form the keyring URL
     if dist == "debian" {
+        // Special case for 'sid' - use the latest version
+        if series == "sid" {
+            let latest_series = get_ordered_series("debian").await?;
+            // Get the first non-sid series (which should be the latest stable)
+            let latest_stable = latest_series.iter().find(|&s| s != "sid").unwrap();
+            let series_num = get_debian_series_number(latest_stable).await?.unwrap();
+            // Replace {series_num} placeholder with the latest stable series number
+            Ok(dist_data
+                .archive_keyring
+                .replace("{series_num}", &series_num))
+        } else {
             let series_num = get_debian_series_number(series).await?.unwrap();
             // Replace {series_num} placeholder with the actual series number
             Ok(dist_data
                 .archive_keyring
                 .replace("{series_num}", &series_num))
+        }
     } else {
         // For other distributions like Ubuntu, use the keyring directly
         Ok(dist_data.archive_keyring.clone())
@@ -258,4 +270,16 @@ mod tests {
         let unknown_number = get_debian_series_number("unknown").await.unwrap();
         assert!(unknown_number.is_none());
     }
+
+    #[tokio::test]
+    async fn test_get_keyring_url_sid() {
+        // Test that 'sid' uses the latest stable version for keyring URL
+        let sid_keyring = get_keyring_url("sid").await.unwrap();
+        let latest_series = get_ordered_series("debian").await.unwrap();
+        let latest_stable = latest_series.iter().find(|&s| s != "sid").unwrap();
+        let latest_keyring = get_keyring_url(latest_stable).await.unwrap();
+
+        // The keyring URL for 'sid' should be the same as the latest stable version
+        assert_eq!(sid_keyring, latest_keyring);
+    }
 }