support nil receivers

internal/record.go

@@ -18,22 +18,28 @@ type RecordQueue struct {
 	l *list.List
 }
 
+// Push inserts the Record at the back of the queue. If pushing a nil Record then it's a no-op.
 func (rq *RecordQueue) Push(r Record) {
-	if rq.l == nil {
-		rq.l = list.New()
-	}
-
 	if r == nil {
 		return
 	}
 
+	if rq == nil {
+		// This would cause a panic anyway so, we panic with a more meaningful message
+		panic("Push to nil RecordQueue")
+	}
+
+	if rq.l == nil {
+		rq.l = list.New()
+	}
+
 	rq.l.PushBack(r)
 }
 
 // Pop removes and returns the first element of the list as the first return value. If the list is
 // empty returns falso on the 2nd return value, true otherwise.
 func (rq *RecordQueue) Pop() (Record, bool) {
-	if rq.l == nil {
+	if rq == nil || rq.l == nil {
 		return nil, false
 	}
 
@@ -48,7 +54,7 @@ func (rq *RecordQueue) Pop() (Record, bool) {
 }
 
 func (rq *RecordQueue) Len() int {
-	if rq.l == nil {
+	if rq == nil || rq.l == nil {
 		return 0
 	}