From 9a954daa860aee74b924122d7f02b1bd800d1534 Mon Sep 17 00:00:00 2001
From: Jason Wilder <jason@influxdb.com>
Date: Thu, 23 Apr 2015 11:10:19 -0600
Subject: [PATCH] Fix panic: interface conversion: interface is nil, not
 []interface {}

Fixes #2374
---
 influxql/functions.go      |  4 ++++
 influxql/functions_test.go | 14 ++++++++++++++
 2 files changed, 18 insertions(+)

diff --git a/influxql/functions.go b/influxql/functions.go
index ef9704c33e3..e4cae8508dd 100644
--- a/influxql/functions.go
+++ b/influxql/functions.go
@@ -556,6 +556,10 @@ func ReducePercentile(percentile float64) ReduceFunc {
 		var allValues []float64
 
 		for _, v := range values {
+			if v == nil {
+				continue
+			}
+
 			vals := v.([]interface{})
 			for _, v := range vals {
 				allValues = append(allValues, v.(float64))
diff --git a/influxql/functions_test.go b/influxql/functions_test.go
index 1f965e256f4..c08ae6ee3c0 100644
--- a/influxql/functions_test.go
+++ b/influxql/functions_test.go
@@ -98,3 +98,17 @@ func TestInitializeReduceFuncPercentile(t *testing.T) {
 		t.Errorf("InitializedReduceFunc(%v) mismatch. exp %v got %v", c, exp, err.Error())
 	}
 }
+
+func TestReducePercentileNil(t *testing.T) {
+
+	// ReducePercentile should ignore nil values when calculating the percentile
+	fn := ReducePercentile(100)
+	input := []interface{}{
+		nil,
+	}
+
+	got := fn(input)
+	if got != nil {
+		t.Fatalf("ReducePercentile(100) returned wrong type. exp nil got %v", got)
+	}
+}