skip empty agent-config repos in the config-pr scan

swarm-controller/src/forge.rs

@@ -900,6 +900,9 @@ impl Client {
     ///
     /// A single repo's list failing does not fail the whole scan — logged and
     /// skipped, so one flaky repo can't blank out every other agent's status.
+    /// Repos the listing marks `empty` are skipped without a PR call: forgejo
+    /// answers 404 for the PR list of a repo with no branches, and such a repo
+    /// cannot carry a PR.
     pub async fn list_open_config_prs(
         &self,
     ) -> Result<std::collections::HashMap<String, ConfigPrStatus>> {
@@ -914,6 +917,9 @@ impl Client {
             let Some(agent) = repo.name.as_deref() else {
                 continue;
             };
+            if repo.empty.unwrap_or(false) {
+                continue;
+            }
             let query = RepoListPullRequestsQuery {
                 state: Some(RepoListPullRequestsQueryState::Open),
                 sort: None,
@@ -2771,6 +2777,58 @@ mod tests {
         (Client { api, url }, seen)
     }
 
+    #[tokio::test]
+    async fn the_config_pr_scan_skips_empty_repos_without_a_pr_call() {
+        use axum::http::{StatusCode, Uri};
+
+        let seen = Arc::new(std::sync::Mutex::new(Vec::new()));
+        let recorded = Arc::clone(&seen);
+        let app = axum::Router::new().fallback(move |uri: Uri| {
+            recorded.lock().unwrap().push(uri.path().to_owned());
+            let (status, count, body) = match uri.path() {
+                "/api/v1/orgs/agent-configs/repos" => (
+                    200,
+                    "2",
+                    r#"[{"name":"bare","empty":true},{"name":"full","empty":false}]"#,
+                ),
+                "/api/v1/repos/agent-configs/full/pulls" => (
+                    200,
+                    "1",
+                    r#"[{"number":4,"requested_reviewers":[],"html_url":"http://forge/agent-configs/full/pulls/4"}]"#,
+                ),
+                _ => (404, "0", r#"{"message":"not found"}"#),
+            };
+            async move {
+                (
+                    StatusCode::from_u16(status).unwrap(),
+                    [("x-total-count", count)],
+                    body,
+                )
+            }
+        });
+        let listener = tokio::net::TcpListener::bind("127.0.0.1:0").await.unwrap();
+        let url = url::Url::parse(&format!("http://{}/", listener.local_addr().unwrap())).unwrap();
+        tokio::spawn(async move { axum::serve(listener, app).await });
+        let api = crate::forge::api::tests::fixed(url.clone(), "stub-token");
+        let client = Client { api, url };
+
+        let out = client.list_open_config_prs().await.unwrap();
+
+        assert_eq!(out.keys().collect::<Vec<_>>(), ["full"]);
+        assert_eq!(out["full"].pr_number, 4);
+        let paths = seen.lock().unwrap();
+        assert!(
+            paths
+                .iter()
+                .any(|p| p.ends_with("/repos/agent-configs/full/pulls"))
+        );
+        assert!(
+            !paths
+                .iter()
+                .any(|p| p.contains("/repos/agent-configs/bare/"))
+        );
+    }
+
     /// One PR commit whose parent is `mb`.
     const ON_MB: &str = r#"[{"sha":"c1","parents":[{"sha":"mb"}]}]"#;