fix index bug the _right_ way

api/runnerpool/ch_placer.go

@@ -49,10 +49,14 @@ func (p *chPlacer) PlaceCall(ctx context.Context, rp RunnerPool, call RunnerCall
 	var runnerPoolErr error
 	for {
 		var runners []Runner
-		for j := 0; len(runners) > 0 && !state.IsDone(); j++ {
+		for j := 0; !state.IsDone(); j++ {
 			// refresh each iteration (should be cached...). detect if runner list changed, and reset j if so (?)
 			oldRunners := runners
 			runners, runnerPoolErr = rp.Runners(ctx, call)
+			if len(runners) == 0 {
+				j = -1 // TODO make j cleaner, this just fixes j to 0 if runners errors
+				break
+			}
 			if !equal(runners, oldRunners) {
 				j = 0
 			}