fix: accept status text as an OpenF1 session result position

latest.go

@@ -106,6 +106,9 @@ func (a *app) latestSession(c echo.Context) error {
 			if cached, ok := a.cache.getDurable(sessionResultsKey(year, s), now); ok {
 				fallback := a.sessionResponse(year, s, cached)
 				fallback["pending"] = result["session"]
+				if upstreamErr, ok := result["upstream_error"]; ok {
+					fallback["upstream_error"] = upstreamErr
+				}
 				result, ttl = fallback, 2*time.Minute
 				break
 			}
@@ -125,7 +128,7 @@ func (a *app) fetchSessionResults(key string, at, now time.Time) ([]map[string]a
 		return nil, false, fmt.Errorf("session not on OpenF1 yet")
 	}
 	var results []struct {
-		Position     *int            `json:"position"`
+		Position     sessionPosition `json:"position"`
 		DriverNumber int             `json:"driver_number"`
 		Duration     json.RawMessage `json:"duration"`
 		Gap          json.RawMessage `json:"gap_to_leader"`
@@ -151,10 +154,10 @@ func (a *app) fetchSessionResults(key string, at, now time.Time) ([]map[string]a
 		byNumber[d.Number] = i
 	}
 	sort.SliceStable(results, func(i, j int) bool {
-		if results[i].Position == nil || results[j].Position == nil {
-			return results[i].Position != nil
+		if results[i].Position.n == nil || results[j].Position.n == nil {
+			return results[i].Position.n != nil
 		}
-		return *results[i].Position < *results[j].Position
+		return *results[i].Position.n < *results[j].Position.n
 	})
 	rows := make([]map[string]any, 0, len(results))
 	for _, r := range results {
@@ -163,16 +166,43 @@ func (a *app) fetchSessionResults(key string, at, now time.Time) ([]map[string]a
 		if i, ok := byNumber[r.DriverNumber]; ok {
 			row["driver"], row["surname"], row["team"] = drivers[i].Acronym, drivers[i].LastName, shortTeamName(drivers[i].Team)
 		}
-		if r.Position != nil {
-			row["position"] = *r.Position
+		if r.Position.n != nil {
+			row["position"] = *r.Position.n
+		}
+		row["time"] = sessionTimeCell(r.Duration, r.Gap, r.DNF, r.DNS, r.DSQ, r.Position.n != nil && *r.Position.n == 1)
+		if row["time"] == "" && r.Position.text != "" {
+			row["time"] = r.Position.text
 		}
-		row["time"] = sessionTimeCell(r.Duration, r.Gap, r.DNF, r.DNS, r.DSQ, r.Position != nil && *r.Position == 1)
 		rows = append(rows, row)
 	}
 	end, err := time.Parse(time.RFC3339, match.End)
 	return rows, err == nil && end.Before(now), nil
 }
 
+// sessionPosition is OpenF1's `position`: an integer, null, or a status string
+// like "RT" for a driver who didn't set a time. One string used to fail the
+// whole result list.
+type sessionPosition struct {
+	n    *int
+	text string
+}
+
+func (p *sessionPosition) UnmarshalJSON(raw []byte) error {
+	if string(raw) == "null" {
+		return nil
+	}
+	var n int
+	if json.Unmarshal(raw, &n) == nil {
+		p.n = &n
+		return nil
+	}
+	var text string
+	if json.Unmarshal(raw, &text) == nil {
+		p.text = text
+	}
+	return nil
+}
+
 func sessionTimeCell(duration, gap json.RawMessage, dnf, dns, dsq, leader bool) string {
 	switch {
 	case dsq:

main_test.go

@@ -238,6 +238,20 @@ func TestLatestSessionContract(t *testing.T) {
 	}
 }
 
+// OpenF1 sends "RT" as the position of a driver with no time; one string used to
+// fail the whole qualifying result list and leave the fallback session showing.
+func TestSessionPositionAcceptsStatusText(t *testing.T) {
+	var rows []struct {
+		Position sessionPosition `json:"position"`
+	}
+	if err := json.Unmarshal([]byte(`[{"position":1},{"position":null},{"position":"RT"}]`), &rows); err != nil {
+		t.Fatal(err)
+	}
+	if rows[0].Position.n == nil || *rows[0].Position.n != 1 || rows[1].Position.n != nil || rows[2].Position.n != nil || rows[2].Position.text != "RT" {
+		t.Fatalf("unexpected positions: %#v", rows)
+	}
+}
+
 func TestLatestSessionExcludesRaceAndSurvivesLockout(t *testing.T) {
 	mock := newUpstreamMock(t)
 	a := testApp(t, mock)
@@ -324,7 +338,7 @@ func TestLatestSessionFallsBackToLastCompleteSessionDuringLockout(t *testing.T)
 	// A later session has finished but OpenF1 is locked out: keep showing the cached one.
 	a.now = func() time.Time { return time.Date(2026, 3, 7, 17, 0, 0, 0, time.UTC) }
 	result := decode(t, request(t, server, "/f1/latest_session/"))
-	if result["pending"] == nil || result["session"] == result["pending"] || len(result["results"].([]any)) != 3 {
+	if result["pending"] == nil || result["session"] == result["pending"] || result["upstream_error"] == nil || len(result["results"].([]any)) != 3 {
 		t.Fatalf("expected earlier cached session plus pending note (before=%v): %#v", before["session"], result)
 	}
 }