Change default histogram buckets from {-infinity,0} to {-infinity,fir…

…st_defined} (#61)

histogram.go

@@ -125,6 +125,7 @@ func (v DurationBuckets) AsDurations() []time.Duration {
 func BucketPairs(buckets Buckets) []BucketPair {
 	if buckets == nil || buckets.Len() < 1 {
 		return []BucketPair{
+
 			bucketPair{
 				lowerBoundValue:    -math.MaxFloat64,
 				upperBoundValue:    math.MaxFloat64,
@@ -134,24 +135,6 @@ func BucketPairs(buckets Buckets) []BucketPair {
 		}
 	}
 
-	if durationBuckets, ok := buckets.(DurationBuckets); ok {
-		// If using duration buckets separating negative times and
-		// positive times is very much desirable as depending on the
-		// reporter will create buckets "-infinity,0" and "0,{first_bucket}"
-		// instead of just "-infinity,{first_bucket}" which for time
-		// durations is not desirable nor pragmatic
-		hasZero := false
-		for _, b := range buckets.AsDurations() {
-			if b == 0 {
-				hasZero = true
-				break
-			}
-		}
-		if !hasZero {
-			buckets = append(DurationBuckets{0}, durationBuckets...)
-		}
-	}
-
 	// Sort before iterating to create pairs
 	sort.Sort(buckets)
 
@@ -160,6 +143,7 @@ func BucketPairs(buckets Buckets) []BucketPair {
 		asDurationBuckets = buckets.AsDurations()
 		pairs             = make([]BucketPair, 0, buckets.Len()+2)
 	)
+
 	pairs = append(pairs, bucketPair{
 		lowerBoundValue:    -math.MaxFloat64,
 		upperBoundValue:    asValueBuckets[0],
@@ -169,6 +153,7 @@ func BucketPairs(buckets Buckets) []BucketPair {
 
 	prevValueBucket, prevDurationBucket :=
 		asValueBuckets[0], asDurationBuckets[0]
+
 	for i := 1; i < buckets.Len(); i++ {
 		pairs = append(pairs, bucketPair{
 			lowerBoundValue:    prevValueBucket,

histogram_test.go

@@ -86,25 +86,6 @@ func TestBucketPairsSortsDurationBuckets(t *testing.T) {
 	assert.Equal(t, time.Duration(math.MaxInt64), pairs[3].UpperBoundDuration())
 }
 
-func TestBucketPairsDurationBucketsInsertsMissingZero(t *testing.T) {
-	initial := 10
-	buckets, err := LinearDurationBuckets(
-		10*time.Millisecond,
-		10*time.Millisecond,
-		initial,
-	)
-	require.NoError(t, err)
-	require.Equal(t, initial, len(buckets))
-
-	pairs := BucketPairs(buckets)
-	assert.Equal(t, initial+2, len(pairs))
-	assert.Equal(t, time.Duration(math.MinInt64), pairs[0].LowerBoundDuration())
-	assert.Equal(t, time.Duration(0), pairs[0].UpperBoundDuration())
-
-	assert.Equal(t, 100*time.Millisecond, pairs[len(pairs)-1].LowerBoundDuration())
-	assert.Equal(t, time.Duration(math.MaxInt64), pairs[len(pairs)-1].UpperBoundDuration())
-}
-
 func TestMustMakeLinearValueBuckets(t *testing.T) {
 	assert.NotPanics(t, func() {
 		assert.Equal(t, ValueBuckets{

scope_test.go

@@ -689,7 +689,6 @@ func TestSnapshot(t *testing.T) {
 
 	assert.EqualValues(t, map[float64]int64(nil), histograms["foo.buzz+env=test"].Values())
 	assert.EqualValues(t, map[time.Duration]int64{
-		0:               0,
 		time.Second * 2: 1,
 		time.Second * 4: 0,
 		math.MaxInt64:   0,