Merge pull request #17248 from prometheus/beorn7/histogram

model/histogram: Validate non-negative count and zero bucket

model/histogram/float_histogram.go

@@ -826,12 +826,18 @@ func (h *FloatHistogram) Validate() error {
 		if err != nil {
 			return fmt.Errorf("negative side: %w", err)
 		}
+		if h.ZeroCount < 0 {
+			return fmt.Errorf("zero bucket has observation count of %v: %w", h.ZeroCount, ErrHistogramNegativeBucketCount)
+		}
 		if h.CustomValues != nil {
 			return ErrHistogramExpSchemaCustomBounds
 		}
 	default:
 		return InvalidSchemaError(h.Schema)
 	}
+	if h.Count < 0 {
+		return fmt.Errorf("observation count is  %v: %w", h.Count, ErrHistogramNegativeCount)
+	}
 	err := checkHistogramBuckets(h.PositiveBuckets, &pCount, false)
 	if err != nil {
 		return fmt.Errorf("positive side: %w", err)

model/histogram/float_histogram_test.go

@@ -3527,6 +3527,100 @@ func TestFloatHistogramString(t *testing.T) {
 	}
 }
 
+func TestFloatHistogramValidateNegativeHistogram(t *testing.T) {
+	cases := []struct {
+		name string
+		fh   *FloatHistogram
+	}{
+		{
+			"positive bucket with negative population",
+			&FloatHistogram{
+				Schema:        1,
+				ZeroThreshold: 0.01,
+				ZeroCount:     5.5,
+				Count:         3493.3,
+				Sum:           2349209.324,
+				PositiveSpans: []Span{
+					{-2, 1},
+					{2, 3},
+				},
+				PositiveBuckets: []float64{1, 3.3, -4.2, 0.1},
+				NegativeSpans: []Span{
+					{3, 2},
+					{3, 2},
+				},
+				NegativeBuckets: []float64{3.1, 3, 1.234e5, 1000},
+			},
+		},
+		{
+			"negative bucket with negative population",
+			&FloatHistogram{
+				Schema:        1,
+				ZeroThreshold: 0.01,
+				ZeroCount:     5.5,
+				Count:         3493.3,
+				Sum:           2349209.324,
+				PositiveSpans: []Span{
+					{-2, 1},
+					{2, 3},
+				},
+				PositiveBuckets: []float64{1, 3.3, 4.2, 0.1},
+				NegativeSpans: []Span{
+					{3, 2},
+					{3, 2},
+				},
+				NegativeBuckets: []float64{3.1, -3, 1.234e5, 1000},
+			},
+		},
+		{
+			"negative count",
+			&FloatHistogram{
+				Schema:        1,
+				ZeroThreshold: 0.01,
+				ZeroCount:     5.5,
+				Count:         -3493.3,
+				Sum:           2349209.324,
+				PositiveSpans: []Span{
+					{-2, 1},
+					{2, 3},
+				},
+				PositiveBuckets: []float64{1, 3.3, 4.2, 0.1},
+				NegativeSpans: []Span{
+					{3, 2},
+					{3, 2},
+				},
+				NegativeBuckets: []float64{3.1, 3, 1.234e5, 1000},
+			},
+		},
+		{
+			"zero bucket with negative population",
+			&FloatHistogram{
+				Schema:        1,
+				ZeroThreshold: 0.01,
+				ZeroCount:     -5.5,
+				Count:         3493.3,
+				Sum:           2349209.324,
+				PositiveSpans: []Span{
+					{-2, 1},
+					{2, 3},
+				},
+				PositiveBuckets: []float64{1, 3.3, 4.2, 0.1},
+				NegativeSpans: []Span{
+					{3, 2},
+					{3, 2},
+				},
+				NegativeBuckets: []float64{3.1, 3, 1.234e5, 1000},
+			},
+		},
+	}
+
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			require.Error(t, c.fh.Validate())
+		})
+	}
+}
+
 func BenchmarkFloatHistogramAllBucketIterator(b *testing.B) {
 	rng := rand.New(rand.NewSource(0))
 

model/histogram/generic.go

@@ -31,6 +31,7 @@ const (
 var (
 	ErrHistogramCountNotBigEnough       = errors.New("histogram's observation count should be at least the number of observations found in the buckets")
 	ErrHistogramCountMismatch           = errors.New("histogram's observation count should equal the number of observations found in the buckets (in absence of NaN)")
+	ErrHistogramNegativeCount           = errors.New("histogram's observation count is negative")
 	ErrHistogramNegativeBucketCount     = errors.New("histogram has a bucket whose observation count is negative")
 	ErrHistogramSpanNegativeOffset      = errors.New("histogram has a span whose offset is negative")
 	ErrHistogramSpansBucketsMismatch    = errors.New("histogram spans specify different number of buckets than provided")

storage/remote/write_handler.go

@@ -122,6 +122,7 @@ func isHistogramValidationError(err error) bool {
 	// TODO: Consider adding single histogram error type instead of individual sentinel errors.
 	return errors.Is(err, histogram.ErrHistogramCountMismatch) ||
 		errors.Is(err, histogram.ErrHistogramCountNotBigEnough) ||
+		errors.Is(err, histogram.ErrHistogramNegativeCount) ||
 		errors.Is(err, histogram.ErrHistogramNegativeBucketCount) ||
 		errors.Is(err, histogram.ErrHistogramSpanNegativeOffset) ||
 		errors.Is(err, histogram.ErrHistogramSpansBucketsMismatch) ||