Pending ladder: a hash-named release of several pieces gets a lone target

The edge gave an unnamed release a "lone" probe target only when it had
exactly one file, so a release of several random-named pieces (Bob's,
1.55M rows in five groups) reached the pending store with no target at
all: never claimed, never named by a twin, its class never learned.
candidates_of now takes the first random-named file when there is no
par2, archive or 7z volume. The batch store writes a finished release
without a target as exhausted instead of waiting, and leaves it out of
its class's waiting count. LOG.md (140).

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

edge/src/indexer.rs

@@ -1608,8 +1608,13 @@ fn candidates_of(key: &str, files: &[Vec<Seg>], upload: usize) -> Vec<Candidate>
     if let Some((_, f)) = tail {
         out.push(Candidate { release_key: key.to_string(), upload, kind: "7z-tail", message_id: f.last().unwrap().message_id.clone(), file: f[0].file.name.clone(), bytes: f.last().unwrap().bytes });
     }
-    if out.is_empty() && files.len() == 1 && is_random_file(&files[0][0].file.name) {
-        out.push(c("lone", &files[0][0]));
+    // No set and no archive: the first random-named file's first segment, for its yEnc name or a twin by content
+    // (hash_twins.ts). Any count of files: a hash-named release of several pieces (Bob's, LOG.md (140)) had no
+    // target at all, so the ladder never probed it, never named it and never learned its class.
+    if out.is_empty() {
+        if let Some(f) = files.iter().find(|f| is_random_file(&f[0].file.name)) {
+            out.push(c("lone", &f[0]));
+        }
     }
     out.truncate(4);
     out
@@ -1738,6 +1743,30 @@ mod tests {
         assert_eq!(ix.pending(), 0);
     }
 
+    #[test]
+    fn a_multi_file_random_release_gets_a_lone_target() {
+        let mut priorities = FxHashMap::default();
+        priorities.insert(GROUP.to_string(), 1);
+        let mut ix = RangeIndexer::new(GROUP, 1, 10_000, 1, Rules::defaults(priorities), 5);
+        // Three hash-named pieces of one hash-named upload, five segments each (more than a per-article post): no
+        // archive, no par2, no 7z volume.
+        let mut lines = Vec::new();
+        for (i, name) in ["9e7fc2741cdd450287aff2733ca4c193", "c5ebdd5487f5b132c76e8d5c2572e560", "8114c42c9694380c8b25857e8b3331c3"].iter().enumerate() {
+            for part in 0..5 {
+                lines.push(line(100 + (i * 5 + part) as i64, &format!(r#"b3a75d234aa73891e78a70fc1f5496b1 [{}/3] - "{name}" yEnc ({}/5)"#, i + 1, part + 1), (i * 5 + part) as i64));
+            }
+        }
+        ix.add_text(&lines.join("\n"), 10_001);
+        ix.finish();
+        let batch = ix.take();
+        assert_eq!(batch.releases.len(), 1, "counts {:?}", batch.counts);
+        let r = &batch.releases[0];
+        assert!(!r.readable && r.files == 3 && r.segments == 15, "readable {} files {} segments {}", r.readable, r.files, r.segments);
+        let kinds: Vec<_> = batch.candidates.iter().map(|c| (c.kind, c.file.as_str())).collect();
+        assert_eq!(kinds, vec![("lone", "9e7fc2741cdd450287aff2733ca4c193")]);
+        assert_eq!(batch.candidates[0].message_id, "u100@test");
+    }
+
     #[test]
     fn album_templates_and_names() {
         assert_eq!(album_template("1481439079025_014.jpg.data").as_deref(), Some("#_#.jpg.data"));