Backfill: Do not query after --end (#9340)

Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>

cmd/promtool/rules.go

@@ -105,11 +105,15 @@ func (importer *ruleImporter) importRule(ctx context.Context, ruleExpr, ruleName
 		for startWithAlignment.Unix() < currStart {
 			startWithAlignment = startWithAlignment.Add(grp.Interval())
 		}
+		end := time.Unix(min(endOfBlock/int64(time.Second/time.Millisecond), end.Unix()), 0).UTC()
+		if end.Before(startWithAlignment) {
+			break
+		}
 		val, warnings, err := importer.apiClient.QueryRange(ctx,
 			ruleExpr,
 			v1.Range{
 				Start: startWithAlignment,
-				End:   time.Unix(min(endOfBlock/int64(time.Second/time.Millisecond), end.Unix()), 0).UTC(),
+				End:   end,
 				Step:  grp.Interval(),
 			},
 		)