Let one job be claimed by one torrent

Matching on the infohash fixes the repack, but the title fallback is still a
substring test in both directions, so two torrents in the category whose
names both contain a job's title each merged with that same job -- and the
endpoint emitted the one job as two cards, which is the duplicate this is
meant to remove.

The first torrent to match takes the job; a later one is listed as the bare
torrent it is, rather than dropped.

Author: JeremiahM37

internal/api/api.go

@@ -694,6 +694,13 @@ func (s *Server) handleDownloads(w http.ResponseWriter, r *http.Request) {
 		// were both emitted and the UI drew two cards for one download.
 		found := false
 		for _, item := range jobs.Items() {
+			// One job belongs to one torrent. A job with no infohash falls back to
+			// a substring match on the title, which two torrents in the category
+			// can both satisfy, and merging it twice draws the same job as two
+			// cards - the duplicate this endpoint is meant to stop.
+			if matchedJobIDs[item.ID] {
+				continue
+			}
 			jobTitle, _ := item.Data["title"].(string)
 			jobHash, _ := item.Data["info_hash"].(string)
 			if download.JobMatchesTorrent(jobHash, jobTitle, t.Hash, t.Name) {

internal/api/handlers_crud_test.go

@@ -284,6 +284,52 @@ func TestDownloadsMergesTorrentWithJobByHash(t *testing.T) {
 	}
 }
 
+func TestDownloadsClaimsAJobOnlyOnce(t *testing.T) {
+	// A job recorded before the infohash was stored matches on the title, and
+	// titlesMatch is a substring test either way -- so a second torrent whose
+	// name contains the same title matches the very same job.
+	const jobName = "Hollow Knight Silksong"
+
+	qb := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if strings.HasSuffix(r.URL.Path, "/auth/login") {
+			w.Write([]byte("Ok."))
+			return
+		}
+		json.NewEncoder(w).Encode([]map[string]interface{}{
+			{"name": jobName + " [FitGirl Repack]", "hash": "aaaa", "progress": 0.4,
+				"state": "downloading", "total_size": 100, "dlspeed": 1, "eta": 60},
+			{"name": jobName + " (Update v1.1)", "hash": "bbbb", "progress": 0.8,
+				"state": "downloading", "total_size": 100, "dlspeed": 1, "eta": 60},
+		})
+	}))
+	defer qb.Close()
+
+	env := newTestEnv(t, func(c *config.Config) { c.QBURL = qb.URL })
+	env.jobs.Set("job-silksong", map[string]interface{}{
+		"status": "downloading", "title": jobName,
+	})
+
+	rr := env.do("GET", "/api/downloads", "")
+	wantStatus(t, rr, 200)
+	downloads, _ := decodeMap(t, rr)["downloads"].([]interface{})
+
+	seen := map[string]int{}
+	for _, d := range downloads {
+		entry, _ := d.(map[string]interface{})
+		if id, _ := entry["job_id"].(string); id != "" {
+			seen[id]++
+		}
+	}
+	if seen["job-silksong"] != 1 {
+		t.Errorf("job-silksong appears in %d entries, want 1", seen["job-silksong"])
+	}
+	// The torrent that lost the claim is still a real download and has to be
+	// listed -- dropping it would trade a duplicate for a disappearance.
+	if len(downloads) != 2 {
+		t.Errorf("downloads = %d entries, want 2 (one merged job, one bare torrent)", len(downloads))
+	}
+}
+
 func TestDownloadsListClearAndDelete(t *testing.T) {
 	env := newTestEnv(t, nil)