[query] Fix Graphite nil arg not interpreted as explicit nil (#3481)

src/query/graphite/native/builtin_functions.go

@@ -1112,24 +1112,15 @@ func asPercent(ctx *common.Context, input singlePathSpec, total genericInterface
 				"require total to be missing, float, single series or same number of series: series=%d, total=%d",
 				len(input.Values), total.Len()))
 		}
-		if total.Len() == 0 {
-			// Same as nil take as sum of input.
-			sum, err := sumSeries(ctx, multiplePathSpecs(input))
-			if err != nil {
-				return ts.NewSeriesList(), err
-			}
-			totalSeriesList = sum
-		} else {
-			// Sort both by name so they get divided by same name if same length
-			// or closest match.
-			sort.Slice(input.Values, func(i, j int) bool {
-				return strings.Compare(input.Values[i].Name(), input.Values[j].Name()) < 0
-			})
-			sort.Slice(total.Values, func(i, j int) bool {
-				return strings.Compare(total.Values[i].Name(), total.Values[j].Name()) < 0
-			})
-			totalSeriesList = total
-		}
+		// Sort both by name so they get divided by same name if same length
+		// or closest match.
+		sort.Slice(input.Values, func(i, j int) bool {
+			return strings.Compare(input.Values[i].Name(), input.Values[j].Name()) < 0
+		})
+		sort.Slice(total.Values, func(i, j int) bool {
+			return strings.Compare(total.Values[i].Name(), total.Values[j].Name()) < 0
+		})
+		totalSeriesList = total
 	default:
 		err := xerrors.NewInvalidParamsError(errors.New(
 			"total must be either an nil, float, a series or same number of series"))
@@ -2568,7 +2559,7 @@ func init() {
 		4: "", // newName
 	})
 	MustRegisterFunction(asPercent).WithDefaultParams(map[uint8]interface{}{
-		2: []*ts.Series(nil), // total
+		2: nil, // total
 	})
 	MustRegisterFunction(averageAbove)
 	MustRegisterFunction(averageSeries)

src/query/graphite/native/builtin_functions_test.go

@@ -36,7 +36,6 @@ import (
 	"github.com/m3db/m3/src/query/graphite/ts"
 	querystorage "github.com/m3db/m3/src/query/storage"
 	"github.com/m3db/m3/src/query/storage/m3/consolidators"
-	xerrors "github.com/m3db/m3/src/x/errors"
 	xgomock "github.com/m3db/m3/src/x/test"
 
 	"github.com/golang/mock/gomock"
@@ -2460,21 +2459,36 @@ func TestAsPercentWithSeriesListAndEmptyTotalSeriesList(t *testing.T) {
 	ctx := common.NewTestContext()
 	defer func() { _ = ctx.Close() }()
 
-	nan := math.NaN()
 	inputs := []struct {
 		name   string
 		step   int
 		values []float64
 	}{
 		{
-			"foo.value",
+			"foo.bar",
 			100,
-			[]float64{12.0, 14.0, 16.0, nan, 20.0, 30.0},
+			[]float64{2.5, 5, 7.5, 10},
 		},
 		{
-			"bar.value",
-			200,
-			[]float64{7.0, nan, 25.0},
+			"foo.baz",
+			100,
+			[]float64{10, 20, 30, 40},
+		},
+	}
+	outputs := []struct {
+		name   string
+		step   int
+		values []float64
+	}{
+		{
+			"asPercent(foo.bar,sumSeries(foo.*))",
+			100,
+			[]float64{20, 20, 20, 20},
+		},
+		{
+			"asPercent(foo.baz,sumSeries(foo.*))",
+			100,
+			[]float64{80, 80, 80, 80},
 		},
 	}
 
@@ -2486,16 +2500,26 @@ func TestAsPercentWithSeriesListAndEmptyTotalSeriesList(t *testing.T) {
 			ctx.StartTime,
 			common.NewTestSeriesValues(ctx, input.step, input.values),
 		)
+		timeSeries.Specification = "foo.*"
 		inputSeries = append(inputSeries, timeSeries)
 	}
 
-	_, err := asPercent(ctx, singlePathSpec{
+	var expected []*ts.Series // nolint: prealloc
+	for _, output := range outputs {
+		timeSeries := ts.NewSeries(
+			ctx,
+			output.name,
+			ctx.StartTime,
+			common.NewTestSeriesValues(ctx, output.step, output.values),
+		)
+		expected = append(expected, timeSeries)
+	}
+
+	r, err := asPercent(ctx, singlePathSpec{
 		Values: inputSeries,
-	}, singlePathSpec{
-		Values: []*ts.Series{},
-	})
-	require.Error(t, err)
-	require.True(t, xerrors.IsInvalidParams(err))
+	}, nil)
+	require.NoError(t, err)
+	requireEqual(t, expected, r.Values)
 }
 
 func TestAsPercentWithNodesAndTotalNil(t *testing.T) {

src/query/graphite/native/compiler_test.go

@@ -406,7 +406,12 @@ func assertExprTree(t *testing.T, expected interface{}, actual interface{}, msg
 	case constFuncArg:
 		a, ok := actual.(constFuncArg)
 		require.True(t, ok, msg)
-		xtest.Equalish(t, e.value.Interface(), a.value.Interface(), msg)
+		if !a.value.IsValid() {
+			// Explicit nil.
+			require.True(t, e.value.IsZero())
+		} else {
+			xtest.Equalish(t, e.value.Interface(), a.value.Interface(), msg)
+		}
 	default:
 		assert.Equal(t, expected, actual, msg)
 	}

src/query/graphite/native/functions.go

@@ -444,6 +444,11 @@ func (f *Function) reflectCall(ctx *common.Context, args []reflect.Value) (refle
 
 	// Cast to the expected typealias type of ts.SeriesList before calling
 	for i, arg := range in {
+		if !arg.IsValid() {
+			// Zero value arg is a nil.
+			in[i] = reflect.New(genericInterfaceType).Elem()
+			continue
+		}
 		typeArg := arg.Type()
 		if typeArg != seriesListType {
 			continue
@@ -625,12 +630,12 @@ func (call *functionCall) String() string {
 // isTimeSeries checks whether the given value contains a timeseries or
 // timeseries list
 func isTimeSeries(v reflect.Value) bool {
-	return v.Type() == seriesListType
+	return v.IsValid() && v.Type() == seriesListType
 }
 
 // getStats gets trace stats for the given timeseries argument
 func getStats(v reflect.Value) common.TraceStats {
-	if v.Type() == timeSeriesType {
+	if v.IsValid() && v.Type() == timeSeriesType {
 		return common.TraceStats{NumSeries: 1}
 	}