A clean-up with the downloads folder gone forgets no file (#293)

missing_files took every path that did not exist() as deleted by hand.
With /downloads out of reach (the array stopped, shfs dropped) that is
every file, and each would have been marked reaped at once.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

crates/ipx/src/retention.rs

@@ -45,9 +45,17 @@ pub fn aged(candidates: &[Candidate], cutoff: i64) -> Vec<Candidate> {
 pub async fn run(cfg: &Config, db: &Db, dry_run: bool) -> Result<Report> {
     let mut report = Report::default();
 
-    // Someone may have deleted a file by hand; the row must stop claiming it exists.
+    // Someone may have deleted a file by hand; the row must stop claiming it exists. Not while
+    // the folder itself is gone (the array stopped, shfs dropped): every file would look deleted
+    // and the whole library be forgotten at once (#293).
     // Each step is a span of the reap's trace, so a slow one says which part was slow.
-    for (id, path) in db.missing_files().instrument(step("missing_files")).await? {
+    let missing = if cfg.general.download_dir.is_dir() {
+        db.missing_files().instrument(step("missing_files")).await?
+    } else {
+        tracing::warn!(dir = %cfg.general.download_dir.display(), "the downloads folder is not there; left every file as it was");
+        vec![]
+    };
+    for (id, path) in missing {
         if !dry_run {
             db.mark_reaped(id).await?;
         }
@@ -204,6 +212,23 @@ mod tests {
         assert_eq!(db.prune_entries(500).await.unwrap(), 1, "the old item goes, a leaver's pin or not");
     }
 
+    #[tokio::test]
+    async fn a_downloads_folder_that_is_gone_forgets_no_file() {
+        let db = Db::memory().await.unwrap();
+        db.exec_for_test(
+            "INSERT INTO enclosures (id, feed_id, guid, url, path, state) VALUES
+                (1, 'f', 'a', 'u1', '/nowhere/ipx-test/a.mp3', 'done');",
+        )
+        .await
+        .unwrap();
+        let mut cfg = Config::default();
+        cfg.general.download_dir = "/nowhere/ipx-test".into();
+        assert_eq!(run(&cfg, &db, false).await.unwrap().reconciled, 0, "the folder is gone, not the file");
+
+        cfg.general.download_dir = std::env::temp_dir();
+        assert_eq!(run(&cfg, &db, false).await.unwrap().reconciled, 1, "the folder is there and the file is not");
+    }
+
     #[tokio::test]
     async fn prune_keeps_entries_that_still_have_a_file() {
         let db = Db::memory().await.unwrap();