vendor: update buildkit to v0.19.0-rc1

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

vendor/go.opentelemetry.io/otel/sdk/instrumentation/library.go

@@ -4,5 +4,6 @@
 package instrumentation // import "go.opentelemetry.io/otel/sdk/instrumentation"
 
 // Library represents the instrumentation library.
-// Deprecated: please use Scope instead.
+//
+// Deprecated: use [Scope] instead.
 type Library = Scope

vendor/go.opentelemetry.io/otel/sdk/metric/config.go

@@ -8,6 +8,7 @@ import (
 	"fmt"
 	"sync"
 
+	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/sdk/resource"
 )
 
@@ -103,7 +104,11 @@ func (o optionFunc) apply(conf config) config {
 // go.opentelemetry.io/otel/sdk/resource package will be used.
 func WithResource(res *resource.Resource) Option {
 	return optionFunc(func(conf config) config {
-		conf.res = res
+		var err error
+		conf.res, err = resource.Merge(resource.Environment(), res)
+		if err != nil {
+			otel.Handle(err)
+		}
 		return conf
 	})
 }

vendor/go.opentelemetry.io/otel/sdk/metric/doc.go

@@ -31,6 +31,14 @@
 // is being run on. That way when multiple instances of the code are collected
 // at a single endpoint their origin is decipherable.
 //
+// To avoid leaking memory, the SDK returns the same instrument for calls to
+// create new instruments with the same Name, Unit, and Description.
+// Importantly, callbacks provided using metric.WithFloat64Callback or
+// metric.WithInt64Callback will only apply for the first instrument created
+// with a given Name, Unit, and Description. Instead, use
+// Meter.RegisterCallback and Registration.Unregister to add and remove
+// callbacks without leaking memory.
+//
 // See [go.opentelemetry.io/otel/metric] for more information about
 // the metric API.
 //

vendor/go.opentelemetry.io/otel/sdk/metric/exemplar.go

@@ -8,8 +8,8 @@ import (
 	"runtime"
 	"slices"
 
-	"go.opentelemetry.io/otel/sdk/metric/internal/exemplar"
-	"go.opentelemetry.io/otel/sdk/metric/internal/x"
+	"go.opentelemetry.io/otel/sdk/metric/exemplar"
+	"go.opentelemetry.io/otel/sdk/metric/internal/aggregate"
 )
 
 // reservoirFunc returns the appropriately configured exemplar reservoir
@@ -19,10 +19,7 @@ import (
 // Note: This will only return non-nil values when the experimental exemplar
 // feature is enabled and the OTEL_METRICS_EXEMPLAR_FILTER environment variable
 // is not set to always_off.
-func reservoirFunc[N int64 | float64](agg Aggregation) func() exemplar.FilteredReservoir[N] {
-	if !x.Exemplars.Enabled() {
-		return nil
-	}
+func reservoirFunc[N int64 | float64](agg Aggregation) func() aggregate.FilteredExemplarReservoir[N] {
 	// https://github.com/open-telemetry/opentelemetry-specification/blob/d4b241f451674e8f611bb589477680341006ad2b/specification/configuration/sdk-environment-variables.md#exemplar
 	const filterEnvKey = "OTEL_METRICS_EXEMPLAR_FILTER"
 
@@ -32,11 +29,11 @@ func reservoirFunc[N int64 | float64](agg Aggregation) func() exemplar.FilteredR
 	case "always_on":
 		filter = exemplar.AlwaysOnFilter
 	case "always_off":
-		return exemplar.Drop
+		return aggregate.DropReservoir
 	case "trace_based":
 		fallthrough
 	default:
-		filter = exemplar.SampledFilter
+		filter = exemplar.TraceBasedFilter
 	}
 
 	// https://github.com/open-telemetry/opentelemetry-specification/blob/d4b241f451674e8f611bb589477680341006ad2b/specification/metrics/sdk.md#exemplar-defaults
@@ -45,9 +42,9 @@ func reservoirFunc[N int64 | float64](agg Aggregation) func() exemplar.FilteredR
 	a, ok := agg.(AggregationExplicitBucketHistogram)
 	if ok && len(a.Boundaries) > 0 {
 		cp := slices.Clone(a.Boundaries)
-		return func() exemplar.FilteredReservoir[N] {
+		return func() aggregate.FilteredExemplarReservoir[N] {
 			bounds := cp
-			return exemplar.NewFilteredReservoir[N](filter, exemplar.Histogram(bounds))
+			return aggregate.NewFilteredExemplarReservoir[N](filter, exemplar.NewHistogramReservoir(bounds))
 		}
 	}
 
@@ -75,7 +72,7 @@ func reservoirFunc[N int64 | float64](agg Aggregation) func() exemplar.FilteredR
 		}
 	}
 
-	return func() exemplar.FilteredReservoir[N] {
-		return exemplar.NewFilteredReservoir[N](filter, exemplar.FixedSize(n))
+	return func() aggregate.FilteredExemplarReservoir[N] {
+		return aggregate.NewFilteredExemplarReservoir[N](filter, exemplar.NewFixedSizeReservoir(n))
 	}
 }

vendor/go.opentelemetry.io/otel/sdk/metric/exemplar/README.md

@@ -0,0 +1,3 @@
+# Metric SDK Exemplars
+
+[![PkgGoDev](https://pkg.go.dev/badge/go.opentelemetry.io/otel/sdk/metric/exemplar)](https://pkg.go.dev/go.opentelemetry.io/otel/sdk/metric/exemplar)

vendor/go.opentelemetry.io/otel/sdk/metric/exemplar/doc.go

@@ -3,4 +3,4 @@
 
 // Package exemplar provides an implementation of the OpenTelemetry exemplar
 // reservoir to be used in metric collection pipelines.
-package exemplar // import "go.opentelemetry.io/otel/sdk/metric/internal/exemplar"
+package exemplar // import "go.opentelemetry.io/otel/sdk/metric/exemplar"

vendor/go.opentelemetry.io/otel/sdk/metric/exemplar/exemplar.go

@@ -1,7 +1,7 @@
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0
 
-package exemplar // import "go.opentelemetry.io/otel/sdk/metric/internal/exemplar"
+package exemplar // import "go.opentelemetry.io/otel/sdk/metric/exemplar"
 
 import (
 	"time"

vendor/go.opentelemetry.io/otel/sdk/metric/exemplar/filter.go

@@ -1,7 +1,7 @@
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0
 
-package exemplar // import "go.opentelemetry.io/otel/sdk/metric/internal/exemplar"
+package exemplar // import "go.opentelemetry.io/otel/sdk/metric/exemplar"
 
 import (
 	"context"
@@ -16,10 +16,10 @@ import (
 // Reservoir in making a sampling decision.
 type Filter func(context.Context) bool
 
-// SampledFilter is a [Filter] that will only offer measurements
+// TraceBasedFilter is a [Filter] that will only offer measurements
 // if the passed context associated with the measurement contains a sampled
 // [go.opentelemetry.io/otel/trace.SpanContext].
-func SampledFilter(ctx context.Context) bool {
+func TraceBasedFilter(ctx context.Context) bool {
 	return trace.SpanContextFromContext(ctx).IsSampled()
 }
 

vendor/go.opentelemetry.io/otel/sdk/metric/exemplar/fixed_size_reservoir.go

@@ -1,31 +1,62 @@
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0
 
-package exemplar // import "go.opentelemetry.io/otel/sdk/metric/internal/exemplar"
+package exemplar // import "go.opentelemetry.io/otel/sdk/metric/exemplar"
 
 import (
 	"context"
 	"math"
 	"math/rand"
-	"sync"
 	"time"
 
 	"go.opentelemetry.io/otel/attribute"
 )
 
-var (
+// NewFixedSizeReservoir returns a [FixedSizeReservoir] that samples at most
+// k exemplars. If there are k or less measurements made, the Reservoir will
+// sample each one. If there are more than k, the Reservoir will then randomly
+// sample all additional measurement with a decreasing probability.
+func NewFixedSizeReservoir(k int) *FixedSizeReservoir {
+	return newFixedSizeReservoir(newStorage(k))
+}
+
+var _ Reservoir = &FixedSizeReservoir{}
+
+// FixedSizeReservoir is a [Reservoir] that samples at most k exemplars. If
+// there are k or less measurements made, the Reservoir will sample each one.
+// If there are more than k, the Reservoir will then randomly sample all
+// additional measurement with a decreasing probability.
+type FixedSizeReservoir struct {
+	*storage
+
+	// count is the number of measurement seen.
+	count int64
+	// next is the next count that will store a measurement at a random index
+	// once the reservoir has been filled.
+	next int64
+	// w is the largest random number in a distribution that is used to compute
+	// the next next.
+	w float64
+
 	// rng is used to make sampling decisions.
 	//
 	// Do not use crypto/rand. There is no reason for the decrease in performance
 	// given this is not a security sensitive decision.
-	rng = rand.New(rand.NewSource(time.Now().UnixNano()))
-	// Ensure concurrent safe accecess to rng and its underlying source.
-	rngMu sync.Mutex
-)
+	rng *rand.Rand
+}
 
-// random returns, as a float64, a uniform pseudo-random number in the open
-// interval (0.0,1.0).
-func random() float64 {
+func newFixedSizeReservoir(s *storage) *FixedSizeReservoir {
+	r := &FixedSizeReservoir{
+		storage: s,
+		rng:     rand.New(rand.NewSource(time.Now().UnixNano())),
+	}
+	r.reset()
+	return r
+}
+
+// randomFloat64 returns, as a float64, a uniform pseudo-random number in the
+// open interval (0.0,1.0).
+func (r *FixedSizeReservoir) randomFloat64() float64 {
 	// TODO: This does not return a uniform number. rng.Float64 returns a
 	// uniformly random int in [0,2^53) that is divided by 2^53. Meaning it
 	// returns multiples of 2^-53, and not all floating point numbers between 0
@@ -43,40 +74,25 @@ func random() float64 {
 	//
 	// There are likely many other methods to explore here as well.
 
-	rngMu.Lock()
-	defer rngMu.Unlock()
-
-	f := rng.Float64()
+	f := r.rng.Float64()
 	for f == 0 {
-		f = rng.Float64()
+		f = r.rng.Float64()
 	}
 	return f
 }
 
-// FixedSize returns a [Reservoir] that samples at most k exemplars. If there
-// are k or less measurements made, the Reservoir will sample each one. If
-// there are more than k, the Reservoir will then randomly sample all
-// additional measurement with a decreasing probability.
-func FixedSize(k int) Reservoir {
-	r := &randRes{storage: newStorage(k)}
-	r.reset()
-	return r
-}
-
-type randRes struct {
-	*storage
-
-	// count is the number of measurement seen.
-	count int64
-	// next is the next count that will store a measurement at a random index
-	// once the reservoir has been filled.
-	next int64
-	// w is the largest random number in a distribution that is used to compute
-	// the next next.
-	w float64
-}
-
-func (r *randRes) Offer(ctx context.Context, t time.Time, n Value, a []attribute.KeyValue) {
+// Offer accepts the parameters associated with a measurement. The
+// parameters will be stored as an exemplar if the Reservoir decides to
+// sample the measurement.
+//
+// The passed ctx needs to contain any baggage or span that were active
+// when the measurement was made. This information may be used by the
+// Reservoir in making a sampling decision.
+//
+// The time t is the time when the measurement was made. The v and a
+// parameters are the value and dropped (filtered) attributes of the
+// measurement respectively.
+func (r *FixedSizeReservoir) Offer(ctx context.Context, t time.Time, n Value, a []attribute.KeyValue) {
 	// The following algorithm is "Algorithm L" from Li, Kim-Hung (4 December
 	// 1994). "Reservoir-Sampling Algorithms of Time Complexity
 	// O(n(1+log(N/n)))". ACM Transactions on Mathematical Software. 20 (4):
@@ -123,7 +139,7 @@ func (r *randRes) Offer(ctx context.Context, t time.Time, n Value, a []attribute
 	} else {
 		if r.count == r.next {
 			// Overwrite a random existing measurement with the one offered.
-			idx := int(rng.Int63n(int64(cap(r.store))))
+			idx := int(r.rng.Int63n(int64(cap(r.store))))
 			r.store[idx] = newMeasurement(ctx, t, n, a)
 			r.advance()
 		}
@@ -132,7 +148,7 @@ func (r *randRes) Offer(ctx context.Context, t time.Time, n Value, a []attribute
 }
 
 // reset resets r to the initial state.
-func (r *randRes) reset() {
+func (r *FixedSizeReservoir) reset() {
 	// This resets the number of exemplars known.
 	r.count = 0
 	// Random index inserts should only happen after the storage is full.
@@ -147,14 +163,14 @@ func (r *randRes) reset() {
 	// This maps the uniform random number in (0,1) to a geometric distribution
 	// over the same interval. The mean of the distribution is inversely
 	// proportional to the storage capacity.
-	r.w = math.Exp(math.Log(random()) / float64(cap(r.store)))
+	r.w = math.Exp(math.Log(r.randomFloat64()) / float64(cap(r.store)))
 
 	r.advance()
 }
 
 // advance updates the count at which the offered measurement will overwrite an
 // existing exemplar.
-func (r *randRes) advance() {
+func (r *FixedSizeReservoir) advance() {
 	// Calculate the next value in the random number series.
 	//
 	// The current value of r.w is based on the max of a distribution of random
@@ -167,7 +183,7 @@ func (r *randRes) advance() {
 	// therefore the next r.w will be based on the same distribution (i.e.
 	// `max(u_1,u_2,...,u_k)`). Therefore, we can sample the next r.w by
 	// computing the next random number `u` and take r.w as `w * u^(1/k)`.
-	r.w *= math.Exp(math.Log(random()) / float64(cap(r.store)))
+	r.w *= math.Exp(math.Log(r.randomFloat64()) / float64(cap(r.store)))
 	// Use the new random number in the series to calculate the count of the
 	// next measurement that will be stored.
 	//
@@ -178,10 +194,13 @@ func (r *randRes) advance() {
 	//
 	// Important to note, the new r.next will always be at least 1 more than
 	// the last r.next.
-	r.next += int64(math.Log(random())/math.Log(1-r.w)) + 1
+	r.next += int64(math.Log(r.randomFloat64())/math.Log(1-r.w)) + 1
 }
 
-func (r *randRes) Collect(dest *[]Exemplar) {
+// Collect returns all the held exemplars.
+//
+// The Reservoir state is preserved after this call.
+func (r *FixedSizeReservoir) Collect(dest *[]Exemplar) {
 	r.storage.Collect(dest)
 	// Call reset here even though it will reset r.count and restart the random
 	// number series. This will persist any old exemplars as long as no new

vendor/go.opentelemetry.io/otel/sdk/metric/exemplar/histogram_reservoir.go

@@ -0,0 +1,62 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package exemplar // import "go.opentelemetry.io/otel/sdk/metric/exemplar"
+
+import (
+	"context"
+	"slices"
+	"sort"
+	"time"
+
+	"go.opentelemetry.io/otel/attribute"
+)
+
+// NewHistogramReservoir returns a [HistogramReservoir] that samples the last
+// measurement that falls within a histogram bucket. The histogram bucket
+// upper-boundaries are define by bounds.
+//
+// The passed bounds will be sorted by this function.
+func NewHistogramReservoir(bounds []float64) *HistogramReservoir {
+	slices.Sort(bounds)
+	return &HistogramReservoir{
+		bounds:  bounds,
+		storage: newStorage(len(bounds) + 1),
+	}
+}
+
+var _ Reservoir = &HistogramReservoir{}
+
+// HistogramReservoir is a [Reservoir] that samples the last measurement that
+// falls within a histogram bucket. The histogram bucket upper-boundaries are
+// define by bounds.
+type HistogramReservoir struct {
+	*storage
+
+	// bounds are bucket bounds in ascending order.
+	bounds []float64
+}
+
+// Offer accepts the parameters associated with a measurement. The
+// parameters will be stored as an exemplar if the Reservoir decides to
+// sample the measurement.
+//
+// The passed ctx needs to contain any baggage or span that were active
+// when the measurement was made. This information may be used by the
+// Reservoir in making a sampling decision.
+//
+// The time t is the time when the measurement was made. The v and a
+// parameters are the value and dropped (filtered) attributes of the
+// measurement respectively.
+func (r *HistogramReservoir) Offer(ctx context.Context, t time.Time, v Value, a []attribute.KeyValue) {
+	var x float64
+	switch v.Type() {
+	case Int64ValueType:
+		x = float64(v.Int64())
+	case Float64ValueType:
+		x = v.Float64()
+	default:
+		panic("unknown value type")
+	}
+	r.store[sort.SearchFloat64s(r.bounds, x)] = newMeasurement(ctx, t, v, a)
+}

vendor/go.opentelemetry.io/otel/sdk/metric/exemplar/reservoir.go

@@ -1,7 +1,7 @@
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0
 
-package exemplar // import "go.opentelemetry.io/otel/sdk/metric/internal/exemplar"
+package exemplar // import "go.opentelemetry.io/otel/sdk/metric/exemplar"
 
 import (
 	"context"

vendor/go.opentelemetry.io/otel/sdk/metric/exemplar/storage.go

@@ -1,7 +1,7 @@
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0
 
-package exemplar // import "go.opentelemetry.io/otel/sdk/metric/internal/exemplar"
+package exemplar // import "go.opentelemetry.io/otel/sdk/metric/exemplar"
 
 import (
 	"context"
@@ -35,7 +35,7 @@ func (r *storage) Collect(dest *[]Exemplar) {
 			continue
 		}
 
-		m.Exemplar(&(*dest)[n])
+		m.exemplar(&(*dest)[n])
 		n++
 	}
 	*dest = (*dest)[:n]
@@ -66,8 +66,8 @@ func newMeasurement(ctx context.Context, ts time.Time, v Value, droppedAttr []at
 	}
 }
 
-// Exemplar returns m as an [Exemplar].
-func (m measurement) Exemplar(dest *Exemplar) {
+// exemplar returns m as an [Exemplar].
+func (m measurement) exemplar(dest *Exemplar) {
 	dest.FilteredAttributes = m.FilteredAttributes
 	dest.Time = m.Time
 	dest.Value = m.Value

vendor/go.opentelemetry.io/otel/sdk/metric/exemplar/value.go

@@ -1,7 +1,7 @@
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0
 
-package exemplar // import "go.opentelemetry.io/otel/sdk/metric/internal/exemplar"
+package exemplar // import "go.opentelemetry.io/otel/sdk/metric/exemplar"
 
 import "math"
 
@@ -28,7 +28,8 @@ type Value struct {
 func NewValue[N int64 | float64](value N) Value {
 	switch v := any(value).(type) {
 	case int64:
-		return Value{t: Int64ValueType, val: uint64(v)}
+		// This can be later converted back to int64 (overflow not checked).
+		return Value{t: Int64ValueType, val: uint64(v)} // nolint:gosec
 	case float64:
 		return Value{t: Float64ValueType, val: math.Float64bits(v)}
 	}
@@ -42,7 +43,8 @@ func (v Value) Type() ValueType { return v.t }
 // Int64ValueType, 0 is returned.
 func (v Value) Int64() int64 {
 	if v.t == Int64ValueType {
-		return int64(v.val)
+		// Assumes the correct int64 was stored in v.val based on type.
+		return int64(v.val) // nolint: gosec
 	}
 	return 0
 }

vendor/go.opentelemetry.io/otel/sdk/metric/instrument.go

@@ -234,8 +234,8 @@ func (i *float64Inst) aggregate(ctx context.Context, val float64, s attribute.Se
 	}
 }
 
-// observablID is a comparable unique identifier of an observable.
-type observablID[N int64 | float64] struct {
+// observableID is a comparable unique identifier of an observable.
+type observableID[N int64 | float64] struct {
 	name        string
 	description string
 	kind        InstrumentKind
@@ -287,7 +287,7 @@ func newInt64Observable(m *meter, kind InstrumentKind, name, desc, u string) int
 
 type observable[N int64 | float64] struct {
 	metric.Observable
-	observablID[N]
+	observableID[N]
 
 	meter           *meter
 	measures        measures[N]
@@ -296,7 +296,7 @@ type observable[N int64 | float64] struct {
 
 func newObservable[N int64 | float64](m *meter, kind InstrumentKind, name, desc, u string) *observable[N] {
 	return &observable[N]{
-		observablID: observablID[N]{
+		observableID: observableID[N]{
 			name:        name,
 			description: desc,
 			kind:        kind,

vendor/go.opentelemetry.io/otel/sdk/metric/internal/aggregate/aggregate.go

@@ -8,7 +8,6 @@ import (
 	"time"
 
 	"go.opentelemetry.io/otel/attribute"
-	"go.opentelemetry.io/otel/sdk/metric/internal/exemplar"
 	"go.opentelemetry.io/otel/sdk/metric/metricdata"
 )
 
@@ -38,8 +37,8 @@ type Builder[N int64 | float64] struct {
 	// create new exemplar reservoirs for a new seen attribute set.
 	//
 	// If this is not provided a default factory function that returns an
-	// exemplar.Drop reservoir will be used.
-	ReservoirFunc func() exemplar.FilteredReservoir[N]
+	// DropReservoir reservoir will be used.
+	ReservoirFunc func() FilteredExemplarReservoir[N]
 	// AggregationLimit is the cardinality limit of measurement attributes. Any
 	// measurement for new attributes once the limit has been reached will be
 	// aggregated into a single aggregate for the "otel.metric.overflow"
@@ -50,12 +49,12 @@ type Builder[N int64 | float64] struct {
 	AggregationLimit int
 }
 
-func (b Builder[N]) resFunc() func() exemplar.FilteredReservoir[N] {
+func (b Builder[N]) resFunc() func() FilteredExemplarReservoir[N] {
 	if b.ReservoirFunc != nil {
 		return b.ReservoirFunc
 	}
 
-	return exemplar.Drop
+	return DropReservoir
 }
 
 type fltrMeasure[N int64 | float64] func(ctx context.Context, value N, fltrAttr attribute.Set, droppedAttr []attribute.KeyValue)

vendor/go.opentelemetry.io/otel/sdk/metric/internal/aggregate/drop.go

@@ -1,16 +1,17 @@
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0
 
-package exemplar // import "go.opentelemetry.io/otel/sdk/metric/internal/exemplar"
+package aggregate // import "go.opentelemetry.io/otel/sdk/metric/internal/aggregate"
 
 import (
 	"context"
 
 	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/sdk/metric/exemplar"
 )
 
-// Drop returns a [FilteredReservoir] that drops all measurements it is offered.
-func Drop[N int64 | float64]() FilteredReservoir[N] { return &dropRes[N]{} }
+// DropReservoir returns a [FilteredReservoir] that drops all measurements it is offered.
+func DropReservoir[N int64 | float64]() FilteredExemplarReservoir[N] { return &dropRes[N]{} }
 
 type dropRes[N int64 | float64] struct{}
 
@@ -18,6 +19,6 @@ type dropRes[N int64 | float64] struct{}
 func (r *dropRes[N]) Offer(context.Context, N, []attribute.KeyValue) {}
 
 // Collect resets dest. No exemplars will ever be returned.
-func (r *dropRes[N]) Collect(dest *[]Exemplar) {
+func (r *dropRes[N]) Collect(dest *[]exemplar.Exemplar) {
 	*dest = (*dest)[:0]
 }

vendor/go.opentelemetry.io/otel/sdk/metric/internal/aggregate/exemplar.go

@@ -6,7 +6,7 @@ package aggregate // import "go.opentelemetry.io/otel/sdk/metric/internal/aggreg
 import (
 	"sync"
 
-	"go.opentelemetry.io/otel/sdk/metric/internal/exemplar"
+	"go.opentelemetry.io/otel/sdk/metric/exemplar"
 	"go.opentelemetry.io/otel/sdk/metric/metricdata"
 )
 

vendor/go.opentelemetry.io/otel/sdk/metric/internal/aggregate/exponential_histogram.go

@@ -12,7 +12,6 @@ import (
 
 	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/attribute"
-	"go.opentelemetry.io/otel/sdk/metric/internal/exemplar"
 	"go.opentelemetry.io/otel/sdk/metric/metricdata"
 )
 
@@ -31,7 +30,7 @@ const (
 // expoHistogramDataPoint is a single data point in an exponential histogram.
 type expoHistogramDataPoint[N int64 | float64] struct {
 	attrs attribute.Set
-	res   exemplar.FilteredReservoir[N]
+	res   FilteredExemplarReservoir[N]
 
 	count uint64
 	min   N
@@ -42,14 +41,14 @@ type expoHistogramDataPoint[N int64 | float64] struct {
 	noMinMax bool
 	noSum    bool
 
-	scale int
+	scale int32
 
 	posBuckets expoBuckets
 	negBuckets expoBuckets
 	zeroCount  uint64
 }
 
-func newExpoHistogramDataPoint[N int64 | float64](attrs attribute.Set, maxSize, maxScale int, noMinMax, noSum bool) *expoHistogramDataPoint[N] {
+func newExpoHistogramDataPoint[N int64 | float64](attrs attribute.Set, maxSize int, maxScale int32, noMinMax, noSum bool) *expoHistogramDataPoint[N] {
 	f := math.MaxFloat64
 	max := N(f) // if N is int64, max will overflow to -9223372036854775808
 	min := N(-f)
@@ -119,11 +118,13 @@ func (p *expoHistogramDataPoint[N]) record(v N) {
 }
 
 // getBin returns the bin v should be recorded into.
-func (p *expoHistogramDataPoint[N]) getBin(v float64) int {
-	frac, exp := math.Frexp(v)
+func (p *expoHistogramDataPoint[N]) getBin(v float64) int32 {
+	frac, expInt := math.Frexp(v)
+	// 11-bit exponential.
+	exp := int32(expInt) // nolint: gosec
 	if p.scale <= 0 {
 		// Because of the choice of fraction is always 1 power of two higher than we want.
-		correction := 1
+		var correction int32 = 1
 		if frac == .5 {
 			// If v is an exact power of two the frac will be .5 and the exp
 			// will be one higher than we want.
@@ -131,7 +132,7 @@ func (p *expoHistogramDataPoint[N]) getBin(v float64) int {
 		}
 		return (exp - correction) >> (-p.scale)
 	}
-	return exp<<p.scale + int(math.Log(frac)*scaleFactors[p.scale]) - 1
+	return exp<<p.scale + int32(math.Log(frac)*scaleFactors[p.scale]) - 1
 }
 
 // scaleFactors are constants used in calculating the logarithm index. They are
@@ -162,20 +163,20 @@ var scaleFactors = [21]float64{
 
 // scaleChange returns the magnitude of the scale change needed to fit bin in
 // the bucket. If no scale change is needed 0 is returned.
-func (p *expoHistogramDataPoint[N]) scaleChange(bin, startBin, length int) int {
+func (p *expoHistogramDataPoint[N]) scaleChange(bin, startBin int32, length int) int32 {
 	if length == 0 {
 		// No need to rescale if there are no buckets.
 		return 0
 	}
 
-	low := startBin
-	high := bin
+	low := int(startBin)
+	high := int(bin)
 	if startBin >= bin {
-		low = bin
-		high = startBin + length - 1
+		low = int(bin)
+		high = int(startBin) + length - 1
 	}
 
-	count := 0
+	var count int32
 	for high-low >= p.maxSize {
 		low = low >> 1
 		high = high >> 1
@@ -189,39 +190,39 @@ func (p *expoHistogramDataPoint[N]) scaleChange(bin, startBin, length int) int {
 
 // expoBuckets is a set of buckets in an exponential histogram.
 type expoBuckets struct {
-	startBin int
+	startBin int32
 	counts   []uint64
 }
 
 // record increments the count for the given bin, and expands the buckets if needed.
 // Size changes must be done before calling this function.
-func (b *expoBuckets) record(bin int) {
+func (b *expoBuckets) record(bin int32) {
 	if len(b.counts) == 0 {
 		b.counts = []uint64{1}
 		b.startBin = bin
 		return
 	}
 
-	endBin := b.startBin + len(b.counts) - 1
+	endBin := int(b.startBin) + len(b.counts) - 1
 
 	// if the new bin is inside the current range
-	if bin >= b.startBin && bin <= endBin {
+	if bin >= b.startBin && int(bin) <= endBin {
 		b.counts[bin-b.startBin]++
 		return
 	}
 	// if the new bin is before the current start add spaces to the counts
 	if bin < b.startBin {
 		origLen := len(b.counts)
-		newLength := endBin - bin + 1
+		newLength := endBin - int(bin) + 1
 		shift := b.startBin - bin
 
 		if newLength > cap(b.counts) {
 			b.counts = append(b.counts, make([]uint64, newLength-len(b.counts))...)
 		}
 
-		copy(b.counts[shift:origLen+shift], b.counts[:])
+		copy(b.counts[shift:origLen+int(shift)], b.counts[:])
 		b.counts = b.counts[:newLength]
-		for i := 1; i < shift; i++ {
+		for i := 1; i < int(shift); i++ {
 			b.counts[i] = 0
 		}
 		b.startBin = bin
@@ -229,17 +230,17 @@ func (b *expoBuckets) record(bin int) {
 		return
 	}
 	// if the new is after the end add spaces to the end
-	if bin > endBin {
-		if bin-b.startBin < cap(b.counts) {
+	if int(bin) > endBin {
+		if int(bin-b.startBin) < cap(b.counts) {
 			b.counts = b.counts[:bin-b.startBin+1]
-			for i := endBin + 1 - b.startBin; i < len(b.counts); i++ {
+			for i := endBin + 1 - int(b.startBin); i < len(b.counts); i++ {
 				b.counts[i] = 0
 			}
 			b.counts[bin-b.startBin] = 1
 			return
 		}
 
-		end := make([]uint64, bin-b.startBin-len(b.counts)+1)
+		end := make([]uint64, int(bin-b.startBin)-len(b.counts)+1)
 		b.counts = append(b.counts, end...)
 		b.counts[bin-b.startBin] = 1
 	}
@@ -247,7 +248,7 @@ func (b *expoBuckets) record(bin int) {
 
 // downscale shrinks a bucket by a factor of 2*s. It will sum counts into the
 // correct lower resolution bucket.
-func (b *expoBuckets) downscale(delta int) {
+func (b *expoBuckets) downscale(delta int32) {
 	// Example
 	// delta = 2
 	// Original offset: -6
@@ -262,19 +263,19 @@ func (b *expoBuckets) downscale(delta int) {
 		return
 	}
 
-	steps := 1 << delta
+	steps := int32(1) << delta
 	offset := b.startBin % steps
 	offset = (offset + steps) % steps // to make offset positive
 	for i := 1; i < len(b.counts); i++ {
-		idx := i + offset
-		if idx%steps == 0 {
-			b.counts[idx/steps] = b.counts[i]
+		idx := i + int(offset)
+		if idx%int(steps) == 0 {
+			b.counts[idx/int(steps)] = b.counts[i]
 			continue
 		}
-		b.counts[idx/steps] += b.counts[i]
+		b.counts[idx/int(steps)] += b.counts[i]
 	}
 
-	lastIdx := (len(b.counts) - 1 + offset) / steps
+	lastIdx := (len(b.counts) - 1 + int(offset)) / int(steps)
 	b.counts = b.counts[:lastIdx+1]
 	b.startBin = b.startBin >> delta
 }
@@ -282,12 +283,12 @@ func (b *expoBuckets) downscale(delta int) {
 // newExponentialHistogram returns an Aggregator that summarizes a set of
 // measurements as an exponential histogram. Each histogram is scoped by attributes
 // and the aggregation cycle the measurements were made in.
-func newExponentialHistogram[N int64 | float64](maxSize, maxScale int32, noMinMax, noSum bool, limit int, r func() exemplar.FilteredReservoir[N]) *expoHistogram[N] {
+func newExponentialHistogram[N int64 | float64](maxSize, maxScale int32, noMinMax, noSum bool, limit int, r func() FilteredExemplarReservoir[N]) *expoHistogram[N] {
 	return &expoHistogram[N]{
 		noSum:    noSum,
 		noMinMax: noMinMax,
 		maxSize:  int(maxSize),
-		maxScale: int(maxScale),
+		maxScale: maxScale,
 
 		newRes: r,
 		limit:  newLimiter[*expoHistogramDataPoint[N]](limit),
@@ -303,9 +304,9 @@ type expoHistogram[N int64 | float64] struct {
 	noSum    bool
 	noMinMax bool
 	maxSize  int
-	maxScale int
+	maxScale int32
 
-	newRes   func() exemplar.FilteredReservoir[N]
+	newRes   func() FilteredExemplarReservoir[N]
 	limit    limiter[*expoHistogramDataPoint[N]]
 	values   map[attribute.Distinct]*expoHistogramDataPoint[N]
 	valuesMu sync.Mutex
@@ -354,15 +355,15 @@ func (e *expoHistogram[N]) delta(dest *metricdata.Aggregation) int {
 		hDPts[i].StartTime = e.start
 		hDPts[i].Time = t
 		hDPts[i].Count = val.count
-		hDPts[i].Scale = int32(val.scale)
+		hDPts[i].Scale = val.scale
 		hDPts[i].ZeroCount = val.zeroCount
 		hDPts[i].ZeroThreshold = 0.0
 
-		hDPts[i].PositiveBucket.Offset = int32(val.posBuckets.startBin)
+		hDPts[i].PositiveBucket.Offset = val.posBuckets.startBin
 		hDPts[i].PositiveBucket.Counts = reset(hDPts[i].PositiveBucket.Counts, len(val.posBuckets.counts), len(val.posBuckets.counts))
 		copy(hDPts[i].PositiveBucket.Counts, val.posBuckets.counts)
 
-		hDPts[i].NegativeBucket.Offset = int32(val.negBuckets.startBin)
+		hDPts[i].NegativeBucket.Offset = val.negBuckets.startBin
 		hDPts[i].NegativeBucket.Counts = reset(hDPts[i].NegativeBucket.Counts, len(val.negBuckets.counts), len(val.negBuckets.counts))
 		copy(hDPts[i].NegativeBucket.Counts, val.negBuckets.counts)
 
@@ -407,15 +408,15 @@ func (e *expoHistogram[N]) cumulative(dest *metricdata.Aggregation) int {
 		hDPts[i].StartTime = e.start
 		hDPts[i].Time = t
 		hDPts[i].Count = val.count
-		hDPts[i].Scale = int32(val.scale)
+		hDPts[i].Scale = val.scale
 		hDPts[i].ZeroCount = val.zeroCount
 		hDPts[i].ZeroThreshold = 0.0
 
-		hDPts[i].PositiveBucket.Offset = int32(val.posBuckets.startBin)
+		hDPts[i].PositiveBucket.Offset = val.posBuckets.startBin
 		hDPts[i].PositiveBucket.Counts = reset(hDPts[i].PositiveBucket.Counts, len(val.posBuckets.counts), len(val.posBuckets.counts))
 		copy(hDPts[i].PositiveBucket.Counts, val.posBuckets.counts)
 
-		hDPts[i].NegativeBucket.Offset = int32(val.negBuckets.startBin)
+		hDPts[i].NegativeBucket.Offset = val.negBuckets.startBin
 		hDPts[i].NegativeBucket.Counts = reset(hDPts[i].NegativeBucket.Counts, len(val.negBuckets.counts), len(val.negBuckets.counts))
 		copy(hDPts[i].NegativeBucket.Counts, val.negBuckets.counts)
 

vendor/go.opentelemetry.io/otel/sdk/metric/internal/aggregate/filtered_reservoir.go

@@ -0,0 +1,50 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package aggregate // import "go.opentelemetry.io/otel/sdk/metric/internal/aggregate"
+
+import (
+	"context"
+	"time"
+
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/sdk/metric/exemplar"
+)
+
+// FilteredExemplarReservoir wraps a [exemplar.Reservoir] with a filter.
+type FilteredExemplarReservoir[N int64 | float64] interface {
+	// Offer accepts the parameters associated with a measurement. The
+	// parameters will be stored as an exemplar if the filter decides to
+	// sample the measurement.
+	//
+	// The passed ctx needs to contain any baggage or span that were active
+	// when the measurement was made. This information may be used by the
+	// Reservoir in making a sampling decision.
+	Offer(ctx context.Context, val N, attr []attribute.KeyValue)
+	// Collect returns all the held exemplars in the reservoir.
+	Collect(dest *[]exemplar.Exemplar)
+}
+
+// filteredExemplarReservoir handles the pre-sampled exemplar of measurements made.
+type filteredExemplarReservoir[N int64 | float64] struct {
+	filter    exemplar.Filter
+	reservoir exemplar.Reservoir
+}
+
+// NewFilteredExemplarReservoir creates a [FilteredExemplarReservoir] which only offers values
+// that are allowed by the filter.
+func NewFilteredExemplarReservoir[N int64 | float64](f exemplar.Filter, r exemplar.Reservoir) FilteredExemplarReservoir[N] {
+	return &filteredExemplarReservoir[N]{
+		filter:    f,
+		reservoir: r,
+	}
+}
+
+func (f *filteredExemplarReservoir[N]) Offer(ctx context.Context, val N, attr []attribute.KeyValue) {
+	if f.filter(ctx) {
+		// only record the current time if we are sampling this measurement.
+		f.reservoir.Offer(ctx, time.Now(), exemplar.NewValue(val), attr)
+	}
+}
+
+func (f *filteredExemplarReservoir[N]) Collect(dest *[]exemplar.Exemplar) { f.reservoir.Collect(dest) }

vendor/go.opentelemetry.io/otel/sdk/metric/internal/aggregate/histogram.go

@@ -11,13 +11,12 @@ import (
 	"time"
 
 	"go.opentelemetry.io/otel/attribute"
-	"go.opentelemetry.io/otel/sdk/metric/internal/exemplar"
 	"go.opentelemetry.io/otel/sdk/metric/metricdata"
 )
 
 type buckets[N int64 | float64] struct {
 	attrs attribute.Set
-	res   exemplar.FilteredReservoir[N]
+	res   FilteredExemplarReservoir[N]
 
 	counts   []uint64
 	count    uint64
@@ -48,13 +47,13 @@ type histValues[N int64 | float64] struct {
 	noSum  bool
 	bounds []float64
 
-	newRes   func() exemplar.FilteredReservoir[N]
+	newRes   func() FilteredExemplarReservoir[N]
 	limit    limiter[*buckets[N]]
 	values   map[attribute.Distinct]*buckets[N]
 	valuesMu sync.Mutex
 }
 
-func newHistValues[N int64 | float64](bounds []float64, noSum bool, limit int, r func() exemplar.FilteredReservoir[N]) *histValues[N] {
+func newHistValues[N int64 | float64](bounds []float64, noSum bool, limit int, r func() FilteredExemplarReservoir[N]) *histValues[N] {
 	// The responsibility of keeping all buckets correctly associated with the
 	// passed boundaries is ultimately this type's responsibility. Make a copy
 	// here so we can always guarantee this. Or, in the case of failure, have
@@ -109,7 +108,7 @@ func (s *histValues[N]) measure(ctx context.Context, value N, fltrAttr attribute
 
 // newHistogram returns an Aggregator that summarizes a set of measurements as
 // an histogram.
-func newHistogram[N int64 | float64](boundaries []float64, noMinMax, noSum bool, limit int, r func() exemplar.FilteredReservoir[N]) *histogram[N] {
+func newHistogram[N int64 | float64](boundaries []float64, noMinMax, noSum bool, limit int, r func() FilteredExemplarReservoir[N]) *histogram[N] {
 	return &histogram[N]{
 		histValues: newHistValues[N](boundaries, noSum, limit, r),
 		noMinMax:   noMinMax,

vendor/go.opentelemetry.io/otel/sdk/metric/internal/aggregate/lastvalue.go

@@ -9,7 +9,6 @@ import (
 	"time"
 
 	"go.opentelemetry.io/otel/attribute"
-	"go.opentelemetry.io/otel/sdk/metric/internal/exemplar"
 	"go.opentelemetry.io/otel/sdk/metric/metricdata"
 )
 
@@ -17,10 +16,10 @@ import (
 type datapoint[N int64 | float64] struct {
 	attrs attribute.Set
 	value N
-	res   exemplar.FilteredReservoir[N]
+	res   FilteredExemplarReservoir[N]
 }
 
-func newLastValue[N int64 | float64](limit int, r func() exemplar.FilteredReservoir[N]) *lastValue[N] {
+func newLastValue[N int64 | float64](limit int, r func() FilteredExemplarReservoir[N]) *lastValue[N] {
 	return &lastValue[N]{
 		newRes: r,
 		limit:  newLimiter[datapoint[N]](limit),
@@ -33,7 +32,7 @@ func newLastValue[N int64 | float64](limit int, r func() exemplar.FilteredReserv
 type lastValue[N int64 | float64] struct {
 	sync.Mutex
 
-	newRes func() exemplar.FilteredReservoir[N]
+	newRes func() FilteredExemplarReservoir[N]
 	limit  limiter[datapoint[N]]
 	values map[attribute.Distinct]datapoint[N]
 	start  time.Time
@@ -115,7 +114,7 @@ func (s *lastValue[N]) copyDpts(dest *[]metricdata.DataPoint[N], t time.Time) in
 
 // newPrecomputedLastValue returns an aggregator that summarizes a set of
 // observations as the last one made.
-func newPrecomputedLastValue[N int64 | float64](limit int, r func() exemplar.FilteredReservoir[N]) *precomputedLastValue[N] {
+func newPrecomputedLastValue[N int64 | float64](limit int, r func() FilteredExemplarReservoir[N]) *precomputedLastValue[N] {
 	return &precomputedLastValue[N]{lastValue: newLastValue[N](limit, r)}
 }
 

vendor/go.opentelemetry.io/otel/sdk/metric/internal/aggregate/sum.go

@@ -9,25 +9,24 @@ import (
 	"time"
 
 	"go.opentelemetry.io/otel/attribute"
-	"go.opentelemetry.io/otel/sdk/metric/internal/exemplar"
 	"go.opentelemetry.io/otel/sdk/metric/metricdata"
 )
 
 type sumValue[N int64 | float64] struct {
 	n     N
-	res   exemplar.FilteredReservoir[N]
+	res   FilteredExemplarReservoir[N]
 	attrs attribute.Set
 }
 
 // valueMap is the storage for sums.
 type valueMap[N int64 | float64] struct {
 	sync.Mutex
-	newRes func() exemplar.FilteredReservoir[N]
+	newRes func() FilteredExemplarReservoir[N]
 	limit  limiter[sumValue[N]]
 	values map[attribute.Distinct]sumValue[N]
 }
 
-func newValueMap[N int64 | float64](limit int, r func() exemplar.FilteredReservoir[N]) *valueMap[N] {
+func newValueMap[N int64 | float64](limit int, r func() FilteredExemplarReservoir[N]) *valueMap[N] {
 	return &valueMap[N]{
 		newRes: r,
 		limit:  newLimiter[sumValue[N]](limit),
@@ -55,7 +54,7 @@ func (s *valueMap[N]) measure(ctx context.Context, value N, fltrAttr attribute.S
 // newSum returns an aggregator that summarizes a set of measurements as their
 // arithmetic sum. Each sum is scoped by attributes and the aggregation cycle
 // the measurements were made in.
-func newSum[N int64 | float64](monotonic bool, limit int, r func() exemplar.FilteredReservoir[N]) *sum[N] {
+func newSum[N int64 | float64](monotonic bool, limit int, r func() FilteredExemplarReservoir[N]) *sum[N] {
 	return &sum[N]{
 		valueMap:  newValueMap[N](limit, r),
 		monotonic: monotonic,
@@ -142,9 +141,9 @@ func (s *sum[N]) cumulative(dest *metricdata.Aggregation) int {
 }
 
 // newPrecomputedSum returns an aggregator that summarizes a set of
-// observatrions as their arithmetic sum. Each sum is scoped by attributes and
+// observations as their arithmetic sum. Each sum is scoped by attributes and
 // the aggregation cycle the measurements were made in.
-func newPrecomputedSum[N int64 | float64](monotonic bool, limit int, r func() exemplar.FilteredReservoir[N]) *precomputedSum[N] {
+func newPrecomputedSum[N int64 | float64](monotonic bool, limit int, r func() FilteredExemplarReservoir[N]) *precomputedSum[N] {
 	return &precomputedSum[N]{
 		valueMap:  newValueMap[N](limit, r),
 		monotonic: monotonic,
@@ -152,7 +151,7 @@ func newPrecomputedSum[N int64 | float64](monotonic bool, limit int, r func() ex
 	}
 }
 
-// precomputedSum summarizes a set of observatrions as their arithmetic sum.
+// precomputedSum summarizes a set of observations as their arithmetic sum.
 type precomputedSum[N int64 | float64] struct {
 	*valueMap[N]
 

vendor/go.opentelemetry.io/otel/sdk/metric/internal/exemplar/filtered_reservoir.go

@@ -1,49 +0,0 @@
-// Copyright The OpenTelemetry Authors
-// SPDX-License-Identifier: Apache-2.0
-
-package exemplar // import "go.opentelemetry.io/otel/sdk/metric/internal/exemplar"
-
-import (
-	"context"
-	"time"
-
-	"go.opentelemetry.io/otel/attribute"
-)
-
-// FilteredReservoir wraps a [Reservoir] with a filter.
-type FilteredReservoir[N int64 | float64] interface {
-	// Offer accepts the parameters associated with a measurement. The
-	// parameters will be stored as an exemplar if the filter decides to
-	// sample the measurement.
-	//
-	// The passed ctx needs to contain any baggage or span that were active
-	// when the measurement was made. This information may be used by the
-	// Reservoir in making a sampling decision.
-	Offer(ctx context.Context, val N, attr []attribute.KeyValue)
-	// Collect returns all the held exemplars in the reservoir.
-	Collect(dest *[]Exemplar)
-}
-
-// filteredReservoir handles the pre-sampled exemplar of measurements made.
-type filteredReservoir[N int64 | float64] struct {
-	filter    Filter
-	reservoir Reservoir
-}
-
-// NewFilteredReservoir creates a [FilteredReservoir] which only offers values
-// that are allowed by the filter.
-func NewFilteredReservoir[N int64 | float64](f Filter, r Reservoir) FilteredReservoir[N] {
-	return &filteredReservoir[N]{
-		filter:    f,
-		reservoir: r,
-	}
-}
-
-func (f *filteredReservoir[N]) Offer(ctx context.Context, val N, attr []attribute.KeyValue) {
-	if f.filter(ctx) {
-		// only record the current time if we are sampling this measurment.
-		f.reservoir.Offer(ctx, time.Now(), NewValue(val), attr)
-	}
-}
-
-func (f *filteredReservoir[N]) Collect(dest *[]Exemplar) { f.reservoir.Collect(dest) }

vendor/go.opentelemetry.io/otel/sdk/metric/internal/exemplar/hist.go

@@ -1,46 +0,0 @@
-// Copyright The OpenTelemetry Authors
-// SPDX-License-Identifier: Apache-2.0
-
-package exemplar // import "go.opentelemetry.io/otel/sdk/metric/internal/exemplar"
-
-import (
-	"context"
-	"slices"
-	"sort"
-	"time"
-
-	"go.opentelemetry.io/otel/attribute"
-)
-
-// Histogram returns a [Reservoir] that samples the last measurement that falls
-// within a histogram bucket. The histogram bucket upper-boundaries are define
-// by bounds.
-//
-// The passed bounds will be sorted by this function.
-func Histogram(bounds []float64) Reservoir {
-	slices.Sort(bounds)
-	return &histRes{
-		bounds:  bounds,
-		storage: newStorage(len(bounds) + 1),
-	}
-}
-
-type histRes struct {
-	*storage
-
-	// bounds are bucket bounds in ascending order.
-	bounds []float64
-}
-
-func (r *histRes) Offer(ctx context.Context, t time.Time, v Value, a []attribute.KeyValue) {
-	var x float64
-	switch v.Type() {
-	case Int64ValueType:
-		x = float64(v.Int64())
-	case Float64ValueType:
-		x = v.Float64()
-	default:
-		panic("unknown value type")
-	}
-	r.store[sort.SearchFloat64s(r.bounds, x)] = newMeasurement(ctx, t, v, a)
-}

vendor/go.opentelemetry.io/otel/sdk/metric/internal/x/x.go

@@ -10,39 +10,23 @@ package x // import "go.opentelemetry.io/otel/sdk/metric/internal/x"
 import (
 	"os"
 	"strconv"
-	"strings"
 )
 
-var (
-	// Exemplars is an experimental feature flag that defines if exemplars
-	// should be recorded for metric data-points.
-	//
-	// To enable this feature set the OTEL_GO_X_EXEMPLAR environment variable
-	// to the case-insensitive string value of "true" (i.e. "True" and "TRUE"
-	// will also enable this).
-	Exemplars = newFeature("EXEMPLAR", func(v string) (string, bool) {
-		if strings.ToLower(v) == "true" {
-			return v, true
-		}
-		return "", false
-	})
-
-	// CardinalityLimit is an experimental feature flag that defines if
-	// cardinality limits should be applied to the recorded metric data-points.
-	//
-	// To enable this feature set the OTEL_GO_X_CARDINALITY_LIMIT environment
-	// variable to the integer limit value you want to use.
-	//
-	// Setting OTEL_GO_X_CARDINALITY_LIMIT to a value less than or equal to 0
-	// will disable the cardinality limits.
-	CardinalityLimit = newFeature("CARDINALITY_LIMIT", func(v string) (int, bool) {
-		n, err := strconv.Atoi(v)
-		if err != nil {
-			return 0, false
-		}
-		return n, true
-	})
-)
+// CardinalityLimit is an experimental feature flag that defines if
+// cardinality limits should be applied to the recorded metric data-points.
+//
+// To enable this feature set the OTEL_GO_X_CARDINALITY_LIMIT environment
+// variable to the integer limit value you want to use.
+//
+// Setting OTEL_GO_X_CARDINALITY_LIMIT to a value less than or equal to 0
+// will disable the cardinality limits.
+var CardinalityLimit = newFeature("CARDINALITY_LIMIT", func(v string) (int, bool) {
+	n, err := strconv.Atoi(v)
+	if err != nil {
+		return 0, false
+	}
+	return n, true
+})
 
 // Feature is an experimental feature control flag. It provides a uniform way
 // to interact with these feature flags and parse their values.

vendor/go.opentelemetry.io/otel/sdk/metric/meter.go

@@ -185,6 +185,11 @@ func (m *meter) Int64ObservableCounter(name string, options ...metric.Int64Obser
 // configured with options. The instrument is used to asynchronously record
 // int64 measurements once per a measurement collection cycle. Only the
 // measurements recorded during the collection cycle are exported.
+//
+// If Int64ObservableUpDownCounter is invoked repeatedly with the same Name,
+// Description, and Unit, only the first set of callbacks provided are used.
+// Use meter.RegisterCallback and Registration.Unregister to manage callbacks
+// if instrumentation can be created multiple times with different callbacks.
 func (m *meter) Int64ObservableUpDownCounter(name string, options ...metric.Int64ObservableUpDownCounterOption) (metric.Int64ObservableUpDownCounter, error) {
 	cfg := metric.NewInt64ObservableUpDownCounterConfig(options...)
 	id := Instrument{
@@ -201,6 +206,11 @@ func (m *meter) Int64ObservableUpDownCounter(name string, options ...metric.Int6
 // configured with options. The instrument is used to asynchronously record
 // instantaneous int64 measurements once per a measurement collection cycle.
 // Only the measurements recorded during the collection cycle are exported.
+//
+// If Int64ObservableGauge is invoked repeatedly with the same Name,
+// Description, and Unit, only the first set of callbacks provided are used.
+// Use meter.RegisterCallback and Registration.Unregister to manage callbacks
+// if instrumentation can be created multiple times with different callbacks.
 func (m *meter) Int64ObservableGauge(name string, options ...metric.Int64ObservableGaugeOption) (metric.Int64ObservableGauge, error) {
 	cfg := metric.NewInt64ObservableGaugeConfig(options...)
 	id := Instrument{
@@ -334,6 +344,11 @@ func (m *meter) Float64ObservableCounter(name string, options ...metric.Float64O
 // and configured with options. The instrument is used to asynchronously record
 // float64 measurements once per a measurement collection cycle. Only the
 // measurements recorded during the collection cycle are exported.
+//
+// If Float64ObservableUpDownCounter is invoked repeatedly with the same Name,
+// Description, and Unit, only the first set of callbacks provided are used.
+// Use meter.RegisterCallback and Registration.Unregister to manage callbacks
+// if instrumentation can be created multiple times with different callbacks.
 func (m *meter) Float64ObservableUpDownCounter(name string, options ...metric.Float64ObservableUpDownCounterOption) (metric.Float64ObservableUpDownCounter, error) {
 	cfg := metric.NewFloat64ObservableUpDownCounterConfig(options...)
 	id := Instrument{
@@ -350,6 +365,11 @@ func (m *meter) Float64ObservableUpDownCounter(name string, options ...metric.Fl
 // configured with options. The instrument is used to asynchronously record
 // instantaneous float64 measurements once per a measurement collection cycle.
 // Only the measurements recorded during the collection cycle are exported.
+//
+// If Float64ObservableGauge is invoked repeatedly with the same Name,
+// Description, and Unit, only the first set of callbacks provided are used.
+// Use meter.RegisterCallback and Registration.Unregister to manage callbacks
+// if instrumentation can be created multiple times with different callbacks.
 func (m *meter) Float64ObservableGauge(name string, options ...metric.Float64ObservableGaugeOption) (metric.Float64ObservableGauge, error) {
 	cfg := metric.NewFloat64ObservableGaugeConfig(options...)
 	id := Instrument{
@@ -439,7 +459,7 @@ func (m *meter) RegisterCallback(f metric.Callback, insts ...metric.Observable)
 				}
 				continue
 			}
-			reg.registerInt64(o.observablID)
+			reg.registerInt64(o.observableID)
 		case float64Observable:
 			if err := o.registerable(m); err != nil {
 				if !errors.Is(err, errEmptyAgg) {
@@ -447,7 +467,7 @@ func (m *meter) RegisterCallback(f metric.Callback, insts ...metric.Observable)
 				}
 				continue
 			}
-			reg.registerFloat64(o.observablID)
+			reg.registerFloat64(o.observableID)
 		default:
 			// Instrument external to the SDK.
 			return nil, fmt.Errorf("invalid observable: from different implementation")
@@ -468,14 +488,14 @@ func (m *meter) RegisterCallback(f metric.Callback, insts ...metric.Observable)
 type observer struct {
 	embedded.Observer
 
-	float64 map[observablID[float64]]struct{}
-	int64   map[observablID[int64]]struct{}
+	float64 map[observableID[float64]]struct{}
+	int64   map[observableID[int64]]struct{}
 }
 
 func newObserver() observer {
 	return observer{
-		float64: make(map[observablID[float64]]struct{}),
-		int64:   make(map[observablID[int64]]struct{}),
+		float64: make(map[observableID[float64]]struct{}),
+		int64:   make(map[observableID[int64]]struct{}),
 	}
 }
 
@@ -483,11 +503,11 @@ func (r observer) len() int {
 	return len(r.float64) + len(r.int64)
 }
 
-func (r observer) registerFloat64(id observablID[float64]) {
+func (r observer) registerFloat64(id observableID[float64]) {
 	r.float64[id] = struct{}{}
 }
 
-func (r observer) registerInt64(id observablID[int64]) {
+func (r observer) registerInt64(id observableID[int64]) {
 	r.int64[id] = struct{}{}
 }
 
@@ -516,7 +536,7 @@ func (r observer) ObserveFloat64(o metric.Float64Observable, v float64, opts ...
 		return
 	}
 
-	if _, registered := r.float64[oImpl.observablID]; !registered {
+	if _, registered := r.float64[oImpl.observableID]; !registered {
 		if !oImpl.dropAggregation {
 			global.Error(errUnregObserver, "failed to record",
 				"name", oImpl.name,
@@ -551,7 +571,7 @@ func (r observer) ObserveInt64(o metric.Int64Observable, v int64, opts ...metric
 		return
 	}
 
-	if _, registered := r.int64[oImpl.observablID]; !registered {
+	if _, registered := r.int64[oImpl.observableID]; !registered {
 		if !oImpl.dropAggregation {
 			global.Error(errUnregObserver, "failed to record",
 				"name", oImpl.name,

vendor/go.opentelemetry.io/otel/sdk/metric/reader.go

@@ -34,7 +34,7 @@ var errNonPositiveDuration = fmt.Errorf("non-positive duration")
 // start of bi-directional control flow.
 //
 // Typically, push-based exporters that are periodic will
-// implement PeroidicExporter themselves and construct a
+// implement PeriodicExporter themselves and construct a
 // PeriodicReader to satisfy this interface.
 //
 // Pull-based exporters will typically implement Register

vendor/go.opentelemetry.io/otel/sdk/metric/version.go

@@ -5,5 +5,5 @@ package metric // import "go.opentelemetry.io/otel/sdk/metric"
 
 // version is the current release version of the metric SDK in use.
 func version() string {
-	return "1.28.0"
+	return "1.31.0"
 }

vendor/go.opentelemetry.io/otel/sdk/resource/host_id_windows.go

@@ -10,17 +10,16 @@ import (
 	"golang.org/x/sys/windows/registry"
 )
 
-// implements hostIDReader
+// implements hostIDReader.
 type hostIDReaderWindows struct{}
 
-// read reads MachineGuid from the windows registry key:
-// SOFTWARE\Microsoft\Cryptography
+// read reads MachineGuid from the Windows registry key:
+// SOFTWARE\Microsoft\Cryptography.
 func (*hostIDReaderWindows) read() (string, error) {
 	k, err := registry.OpenKey(
 		registry.LOCAL_MACHINE, `SOFTWARE\Microsoft\Cryptography`,
 		registry.QUERY_VALUE|registry.WOW64_64KEY,
 	)
-
 	if err != nil {
 		return "", err
 	}

vendor/go.opentelemetry.io/otel/sdk/resource/os_windows.go

@@ -17,7 +17,6 @@ import (
 func platformOSDescription() (string, error) {
 	k, err := registry.OpenKey(
 		registry.LOCAL_MACHINE, `SOFTWARE\Microsoft\Windows NT\CurrentVersion`, registry.QUERY_VALUE)
-
 	if err != nil {
 		return "", err
 	}

vendor/go.opentelemetry.io/otel/sdk/trace/batch_span_processor.go

@@ -316,7 +316,11 @@ func (bsp *batchSpanProcessor) processQueue() {
 			bsp.batchMutex.Unlock()
 			if shouldExport {
 				if !bsp.timer.Stop() {
-					<-bsp.timer.C
+					// Handle both GODEBUG=asynctimerchan=[0|1] properly.
+					select {
+					case <-bsp.timer.C:
+					default:
+					}
 				}
 				if err := bsp.exportSpans(ctx); err != nil {
 					otel.Handle(err)

vendor/go.opentelemetry.io/otel/sdk/trace/evictedqueue.go

@@ -12,25 +12,26 @@ import (
 
 // evictedQueue is a FIFO queue with a configurable capacity.
 type evictedQueue[T any] struct {
-	queue        []T
-	capacity     int
-	droppedCount int
-	logDropped   func()
+	queue          []T
+	capacity       int
+	droppedCount   int
+	logDroppedMsg  string
+	logDroppedOnce sync.Once
 }
 
 func newEvictedQueueEvent(capacity int) evictedQueue[Event] {
 	// Do not pre-allocate queue, do this lazily.
 	return evictedQueue[Event]{
-		capacity:   capacity,
-		logDropped: sync.OnceFunc(func() { global.Warn("limit reached: dropping trace trace.Event") }),
+		capacity:      capacity,
+		logDroppedMsg: "limit reached: dropping trace trace.Event",
 	}
 }
 
 func newEvictedQueueLink(capacity int) evictedQueue[Link] {
 	// Do not pre-allocate queue, do this lazily.
 	return evictedQueue[Link]{
-		capacity:   capacity,
-		logDropped: sync.OnceFunc(func() { global.Warn("limit reached: dropping trace trace.Link") }),
+		capacity:      capacity,
+		logDroppedMsg: "limit reached: dropping trace trace.Link",
 	}
 }
 
@@ -53,6 +54,10 @@ func (eq *evictedQueue[T]) add(value T) {
 	eq.queue = append(eq.queue, value)
 }
 
+func (eq *evictedQueue[T]) logDropped() {
+	eq.logDroppedOnce.Do(func() { global.Warn(eq.logDroppedMsg) })
+}
+
 // copy returns a copy of the evictedQueue.
 func (eq *evictedQueue[T]) copy() []T {
 	return slices.Clone(eq.queue)

vendor/go.opentelemetry.io/otel/sdk/trace/snapshot.go

@@ -99,7 +99,7 @@ func (s snapshot) InstrumentationScope() instrumentation.Scope {
 
 // InstrumentationLibrary returns information about the instrumentation
 // library that created the span.
-func (s snapshot) InstrumentationLibrary() instrumentation.Library {
+func (s snapshot) InstrumentationLibrary() instrumentation.Library { //nolint:staticcheck // This method needs to be define for backwards compatibility
 	return s.instrumentationScope
 }
 

vendor/go.opentelemetry.io/otel/sdk/trace/span.go

@@ -62,7 +62,7 @@ type ReadOnlySpan interface {
 	// InstrumentationLibrary returns information about the instrumentation
 	// library that created the span.
 	// Deprecated: please use InstrumentationScope instead.
-	InstrumentationLibrary() instrumentation.Library
+	InstrumentationLibrary() instrumentation.Library //nolint:staticcheck // This method needs to be define for backwards compatibility
 	// Resource returns information about the entity that produced the span.
 	Resource() *resource.Resource
 	// DroppedAttributes returns the number of attributes dropped by the span
@@ -174,6 +174,17 @@ func (s *recordingSpan) IsRecording() bool {
 	s.mu.Lock()
 	defer s.mu.Unlock()
 
+	return s.isRecording()
+}
+
+// isRecording returns if this span is being recorded. If this span has ended
+// this will return false.
+//
+// This method assumes s.mu.Lock is held by the caller.
+func (s *recordingSpan) isRecording() bool {
+	if s == nil {
+		return false
+	}
 	return s.endTime.IsZero()
 }
 
@@ -182,11 +193,15 @@ func (s *recordingSpan) IsRecording() bool {
 // included in the set status when the code is for an error. If this span is
 // not being recorded than this method does nothing.
 func (s *recordingSpan) SetStatus(code codes.Code, description string) {
-	if !s.IsRecording() {
+	if s == nil {
 		return
 	}
+
 	s.mu.Lock()
 	defer s.mu.Unlock()
+	if !s.isRecording() {
+		return
+	}
 	if s.status.Code > code {
 		return
 	}
@@ -210,12 +225,15 @@ func (s *recordingSpan) SetStatus(code codes.Code, description string) {
 // attributes the span is configured to have, the last added attributes will
 // be dropped.
 func (s *recordingSpan) SetAttributes(attributes ...attribute.KeyValue) {
-	if !s.IsRecording() {
+	if s == nil || len(attributes) == 0 {
 		return
 	}
 
 	s.mu.Lock()
 	defer s.mu.Unlock()
+	if !s.isRecording() {
+		return
+	}
 
 	limit := s.tracer.provider.spanLimits.AttributeCountLimit
 	if limit == 0 {
@@ -233,7 +251,7 @@ func (s *recordingSpan) SetAttributes(attributes ...attribute.KeyValue) {
 
 	// Otherwise, add without deduplication. When attributes are read they
 	// will be deduplicated, optimizing the operation.
-	s.attributes = slices.Grow(s.attributes, len(s.attributes)+len(attributes))
+	s.attributes = slices.Grow(s.attributes, len(attributes))
 	for _, a := range attributes {
 		if !a.Valid() {
 			// Drop all invalid attributes.
@@ -280,13 +298,17 @@ func (s *recordingSpan) addOverCapAttrs(limit int, attrs []attribute.KeyValue) {
 
 	// Do not set a capacity when creating this map. Benchmark testing has
 	// showed this to only add unused memory allocations in general use.
-	exists := make(map[attribute.Key]int)
-	s.dedupeAttrsFromRecord(&exists)
+	exists := make(map[attribute.Key]int, len(s.attributes))
+	s.dedupeAttrsFromRecord(exists)
 
 	// Now that s.attributes is deduplicated, adding unique attributes up to
 	// the capacity of s will not over allocate s.attributes.
-	sum := len(attrs) + len(s.attributes)
-	s.attributes = slices.Grow(s.attributes, min(sum, limit))
+
+	// max size = limit
+	maxCap := min(len(attrs)+len(s.attributes), limit)
+	if cap(s.attributes) < maxCap {
+		s.attributes = slices.Grow(s.attributes, maxCap-cap(s.attributes))
+	}
 	for _, a := range attrs {
 		if !a.Valid() {
 			// Drop all invalid attributes.
@@ -296,6 +318,7 @@ func (s *recordingSpan) addOverCapAttrs(limit int, attrs []attribute.KeyValue) {
 
 		if idx, ok := exists[a.Key]; ok {
 			// Perform all updates before dropping, even when at capacity.
+			a = truncateAttr(s.tracer.provider.spanLimits.AttributeValueLengthLimit, a)
 			s.attributes[idx] = a
 			continue
 		}
@@ -386,9 +409,10 @@ func (s *recordingSpan) End(options ...trace.SpanEndOption) {
 	// the span's duration in case some operation below takes a while.
 	et := monotonicEndTime(s.startTime)
 
-	// Do relative expensive check now that we have an end time and see if we
-	// need to do any more processing.
-	if !s.IsRecording() {
+	// Lock the span now that we have an end time and see if we need to do any more processing.
+	s.mu.Lock()
+	if !s.isRecording() {
+		s.mu.Unlock()
 		return
 	}
 
@@ -413,10 +437,11 @@ func (s *recordingSpan) End(options ...trace.SpanEndOption) {
 	}
 
 	if s.executionTracerTaskEnd != nil {
+		s.mu.Unlock()
 		s.executionTracerTaskEnd()
+		s.mu.Lock()
 	}
 
-	s.mu.Lock()
 	// Setting endTime to non-zero marks the span as ended and not recording.
 	if config.Timestamp().IsZero() {
 		s.endTime = et
@@ -450,7 +475,13 @@ func monotonicEndTime(start time.Time) time.Time {
 // does not change the Span status. If this span is not being recorded or err is nil
 // than this method does nothing.
 func (s *recordingSpan) RecordError(err error, opts ...trace.EventOption) {
-	if s == nil || err == nil || !s.IsRecording() {
+	if s == nil || err == nil {
+		return
+	}
+
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if !s.isRecording() {
 		return
 	}
 
@@ -486,14 +517,23 @@ func recordStackTrace() string {
 }
 
 // AddEvent adds an event with the provided name and options. If this span is
-// not being recorded than this method does nothing.
+// not being recorded then this method does nothing.
 func (s *recordingSpan) AddEvent(name string, o ...trace.EventOption) {
-	if !s.IsRecording() {
+	if s == nil {
+		return
+	}
+
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if !s.isRecording() {
 		return
 	}
 	s.addEvent(name, o...)
 }
 
+// addEvent adds an event with the provided name and options.
+//
+// This method assumes s.mu.Lock is held by the caller.
 func (s *recordingSpan) addEvent(name string, o ...trace.EventOption) {
 	c := trace.NewEventConfig(o...)
 	e := Event{Name: name, Attributes: c.Attributes(), Time: c.Timestamp()}
@@ -510,20 +550,21 @@ func (s *recordingSpan) addEvent(name string, o ...trace.EventOption) {
 		e.Attributes = e.Attributes[:limit]
 	}
 
-	s.mu.Lock()
 	s.events.add(e)
-	s.mu.Unlock()
 }
 
 // SetName sets the name of this span. If this span is not being recorded than
 // this method does nothing.
 func (s *recordingSpan) SetName(name string) {
-	if !s.IsRecording() {
+	if s == nil {
 		return
 	}
 
 	s.mu.Lock()
 	defer s.mu.Unlock()
+	if !s.isRecording() {
+		return
+	}
 	s.name = name
 }
 
@@ -579,23 +620,23 @@ func (s *recordingSpan) Attributes() []attribute.KeyValue {
 func (s *recordingSpan) dedupeAttrs() {
 	// Do not set a capacity when creating this map. Benchmark testing has
 	// showed this to only add unused memory allocations in general use.
-	exists := make(map[attribute.Key]int)
-	s.dedupeAttrsFromRecord(&exists)
+	exists := make(map[attribute.Key]int, len(s.attributes))
+	s.dedupeAttrsFromRecord(exists)
 }
 
 // dedupeAttrsFromRecord deduplicates the attributes of s to fit capacity
 // using record as the record of unique attribute keys to their index.
 //
 // This method assumes s.mu.Lock is held by the caller.
-func (s *recordingSpan) dedupeAttrsFromRecord(record *map[attribute.Key]int) {
+func (s *recordingSpan) dedupeAttrsFromRecord(record map[attribute.Key]int) {
 	// Use the fact that slices share the same backing array.
 	unique := s.attributes[:0]
 	for _, a := range s.attributes {
-		if idx, ok := (*record)[a.Key]; ok {
+		if idx, ok := record[a.Key]; ok {
 			unique[idx] = a
 		} else {
 			unique = append(unique, a)
-			(*record)[a.Key] = len(unique) - 1
+			record[a.Key] = len(unique) - 1
 		}
 	}
 	// s.attributes have element types of attribute.KeyValue. These types are
@@ -642,7 +683,7 @@ func (s *recordingSpan) InstrumentationScope() instrumentation.Scope {
 
 // InstrumentationLibrary returns the instrumentation.Library associated with
 // the Tracer that created this span.
-func (s *recordingSpan) InstrumentationLibrary() instrumentation.Library {
+func (s *recordingSpan) InstrumentationLibrary() instrumentation.Library { //nolint:staticcheck // This method needs to be define for backwards compatibility
 	s.mu.Lock()
 	defer s.mu.Unlock()
 	return s.tracer.instrumentationScope
@@ -657,7 +698,7 @@ func (s *recordingSpan) Resource() *resource.Resource {
 }
 
 func (s *recordingSpan) AddLink(link trace.Link) {
-	if !s.IsRecording() {
+	if s == nil {
 		return
 	}
 	if !link.SpanContext.IsValid() && len(link.Attributes) == 0 &&
@@ -665,6 +706,12 @@ func (s *recordingSpan) AddLink(link trace.Link) {
 		return
 	}
 
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if !s.isRecording() {
+		return
+	}
+
 	l := Link{SpanContext: link.SpanContext, Attributes: link.Attributes}
 
 	// Discard attributes over limit.
@@ -678,9 +725,7 @@ func (s *recordingSpan) AddLink(link trace.Link) {
 		l.Attributes = l.Attributes[:limit]
 	}
 
-	s.mu.Lock()
 	s.links.add(l)
-	s.mu.Unlock()
 }
 
 // DroppedAttributes returns the number of attributes dropped by the span
@@ -755,12 +800,16 @@ func (s *recordingSpan) snapshot() ReadOnlySpan {
 }
 
 func (s *recordingSpan) addChild() {
-	if !s.IsRecording() {
+	if s == nil {
 		return
 	}
+
 	s.mu.Lock()
+	defer s.mu.Unlock()
+	if !s.isRecording() {
+		return
+	}
 	s.childSpanCount++
-	s.mu.Unlock()
 }
 
 func (*recordingSpan) private() {}

vendor/go.opentelemetry.io/otel/sdk/trace/tracetest/span.go

@@ -45,22 +45,25 @@ func (s SpanStubs) Snapshots() []tracesdk.ReadOnlySpan {
 
 // SpanStub is a stand-in for a Span.
 type SpanStub struct {
-	Name                   string
-	SpanContext            trace.SpanContext
-	Parent                 trace.SpanContext
-	SpanKind               trace.SpanKind
-	StartTime              time.Time
-	EndTime                time.Time
-	Attributes             []attribute.KeyValue
-	Events                 []tracesdk.Event
-	Links                  []tracesdk.Link
-	Status                 tracesdk.Status
-	DroppedAttributes      int
-	DroppedEvents          int
-	DroppedLinks           int
-	ChildSpanCount         int
-	Resource               *resource.Resource
-	InstrumentationLibrary instrumentation.Library
+	Name                 string
+	SpanContext          trace.SpanContext
+	Parent               trace.SpanContext
+	SpanKind             trace.SpanKind
+	StartTime            time.Time
+	EndTime              time.Time
+	Attributes           []attribute.KeyValue
+	Events               []tracesdk.Event
+	Links                []tracesdk.Link
+	Status               tracesdk.Status
+	DroppedAttributes    int
+	DroppedEvents        int
+	DroppedLinks         int
+	ChildSpanCount       int
+	Resource             *resource.Resource
+	InstrumentationScope instrumentation.Scope
+
+	// Deprecated: use InstrumentationScope instead.
+	InstrumentationLibrary instrumentation.Library //nolint:staticcheck // This method needs to be define for backwards compatibility
 }
 
 // SpanStubFromReadOnlySpan returns a SpanStub populated from ro.
@@ -85,12 +88,18 @@ func SpanStubFromReadOnlySpan(ro tracesdk.ReadOnlySpan) SpanStub {
 		DroppedLinks:           ro.DroppedLinks(),
 		ChildSpanCount:         ro.ChildSpanCount(),
 		Resource:               ro.Resource(),
+		InstrumentationScope:   ro.InstrumentationScope(),
 		InstrumentationLibrary: ro.InstrumentationScope(),
 	}
 }
 
 // Snapshot returns a read-only copy of the SpanStub.
 func (s SpanStub) Snapshot() tracesdk.ReadOnlySpan {
+	scopeOrLibrary := s.InstrumentationScope
+	if scopeOrLibrary.Name == "" && scopeOrLibrary.Version == "" && scopeOrLibrary.SchemaURL == "" {
+		scopeOrLibrary = s.InstrumentationLibrary
+	}
+
 	return spanSnapshot{
 		name:                 s.Name,
 		spanContext:          s.SpanContext,
@@ -107,7 +116,7 @@ func (s SpanStub) Snapshot() tracesdk.ReadOnlySpan {
 		droppedLinks:         s.DroppedLinks,
 		childSpanCount:       s.ChildSpanCount,
 		resource:             s.Resource,
-		instrumentationScope: s.InstrumentationLibrary,
+		instrumentationScope: scopeOrLibrary,
 	}
 }
 
@@ -152,6 +161,6 @@ func (s spanSnapshot) InstrumentationScope() instrumentation.Scope {
 	return s.instrumentationScope
 }
 
-func (s spanSnapshot) InstrumentationLibrary() instrumentation.Library {
+func (s spanSnapshot) InstrumentationLibrary() instrumentation.Library { //nolint:staticcheck // This method needs to be define for backwards compatibility
 	return s.instrumentationScope
 }

vendor/go.opentelemetry.io/otel/sdk/version.go

@@ -5,5 +5,5 @@ package sdk // import "go.opentelemetry.io/otel/sdk"
 
 // Version is the current release version of the OpenTelemetry SDK in use.
 func Version() string {
-	return "1.28.0"
+	return "1.31.0"
 }