series: Fix panic from previous changes when data sizes vary

series.go

@@ -158,7 +158,7 @@ func (sl SeriesList) getMinMaxSumMax(yaxisIndex int, calcSum bool) (float64, flo
 	max := -math.MaxFloat64
 	var sums []float64
 	if calcSum {
-		sums = make([]float64, len(sl[0].Data)) // all data sizes assumed to be the same
+		sums = make([]float64, sl.getMaxDataCount(""))
 	}
 	for _, series := range sl {
 		if series.YAxisIndex != yaxisIndex {

series_test.go

@@ -29,12 +29,14 @@ func TestSeriesLists(t *testing.T) {
 	seriesList := NewSeriesListBar([][]float64{
 		{1, 2},
 		{10},
+		{1, 2, 3, 4, 5, 6, 7, 8, 9},
 	})
 
-	assert.Len(t, seriesList.Filter(ChartTypeBar), 2)
+	assert.Len(t, seriesList.Filter(ChartTypeBar), 3)
 	assert.Empty(t, seriesList.Filter(ChartTypeLine))
 
-	min, max := seriesList.GetMinMax(0)
+	min, max, maxSum := seriesList.getMinMaxSumMax(0, true)
+	assert.InDelta(t, float64(12), maxSum, 0)
 	assert.InDelta(t, float64(10), max, 0)
 	assert.InDelta(t, float64(1), min, 0)
 }