Comply with W3C Baggage specification limits (#7880)

Updates the baggage implementation to comply with
https://www.w3.org/TR/baggage/#limits:

- Changed maxMembers from 180 to 64 (the W3C compliance requirement)

  > The resulting baggage-string contains 64 list-members or less.

- Removed maxBytesPerMembers (4096) - this per-member limit was not part
of the W3C spec
- Added limit checking in extractMultiBaggage for multiple baggage
headers:
  - Checks combined byte size across all headers (max 8192 bytes)
  - Checks combined member count across all headers (max 64 members)

This uses non-deterministic truncation when handling baggage limits.

CHANGELOG.md

@@ -15,6 +15,12 @@ The next release will require at least [Go 1.25].
 
 - Support testing of [Go 1.26]. (#7902)
 
+### Fixed
+
+- Update `Baggage` in `go.opentelemetry.io/otel/propagation` and `Parse` and `New` in `go.opentelemetry.io/otel/baggage` to comply with W3C Baggage specification limits.
+  `New` and `Parse` now return partial baggage along with an error when limits are exceeded.
+  Errors from baggage extraction are reported to the global error handler. (#7880)
+
 <!-- Released section -->
 <!-- Don't change this section unless doing release -->
 

baggage/baggage.go

@@ -14,8 +14,7 @@ import (
 )
 
 const (
-	maxMembers               = 180
-	maxBytesPerMembers       = 4096
+	maxMembers               = 64
 	maxBytesPerBaggageString = 8192
 
 	listDelimiter     = ","
@@ -29,7 +28,6 @@ var (
 	errInvalidProperty = errors.New("invalid baggage list-member property")
 	errInvalidMember   = errors.New("invalid baggage list-member")
 	errMemberNumber    = errors.New("too many list-members in baggage-string")
-	errMemberBytes     = errors.New("list-member too large")
 	errBaggageBytes    = errors.New("baggage-string too large")
 )
 
@@ -309,10 +307,6 @@ func newInvalidMember() Member {
 // an error if the input is invalid according to the W3C Baggage
 // specification.
 func parseMember(member string) (Member, error) {
-	if n := len(member); n > maxBytesPerMembers {
-		return newInvalidMember(), fmt.Errorf("%w: %d", errMemberBytes, n)
-	}
-
 	var props properties
 	keyValue, properties, found := strings.Cut(member, propertyDelimiter)
 	if found {
@@ -430,6 +424,10 @@ type Baggage struct { //nolint:golint
 // New returns a new valid Baggage. It returns an error if it results in a
 // Baggage exceeding limits set in that specification.
 //
+// If the resulting Baggage exceeds the maximum allowed members or bytes,
+// members are dropped until the limits are satisfied and an error is returned
+// along with the partial result.
+//
 // It expects all the provided members to have already been validated.
 func New(members ...Member) (Baggage, error) {
 	if len(members) == 0 {
@@ -441,7 +439,6 @@ func New(members ...Member) (Baggage, error) {
 		if !m.hasData {
 			return Baggage{}, errInvalidMember
 		}
-
 		// OpenTelemetry resolves duplicates by last-one-wins.
 		b[m.key] = baggage.Item{
 			Value:      m.value,
@@ -449,17 +446,42 @@ func New(members ...Member) (Baggage, error) {
 		}
 	}
 
-	// Check member numbers after deduplication.
+	var truncateErr error
+
+	// Check member count after deduplication.
 	if len(b) > maxMembers {
-		return Baggage{}, errMemberNumber
+		truncateErr = errors.Join(truncateErr, errMemberNumber)
+		for k := range b {
+			if len(b) <= maxMembers {
+				break
+			}
+			delete(b, k)
+		}
 	}
 
-	bag := Baggage{b}
-	if n := len(bag.String()); n > maxBytesPerBaggageString {
-		return Baggage{}, fmt.Errorf("%w: %d", errBaggageBytes, n)
+	// Check byte size and drop members if necessary.
+	totalBytes := 0
+	first := true
+	for k := range b {
+		m := Member{
+			key:        k,
+			value:      b[k].Value,
+			properties: fromInternalProperties(b[k].Properties),
+		}
+		memberSize := len(m.String())
+		if !first {
+			memberSize++ // comma separator
+		}
+		if totalBytes+memberSize > maxBytesPerBaggageString {
+			truncateErr = errors.Join(truncateErr, fmt.Errorf("%w: %d", errBaggageBytes, totalBytes+memberSize))
+			delete(b, k)
+			continue
+		}
+		totalBytes += memberSize
+		first = false
 	}
 
-	return bag, nil
+	return Baggage{b}, truncateErr
 }
 
 // Parse attempts to decode a baggage-string from the passed string. It
@@ -470,36 +492,71 @@ func New(members ...Member) (Baggage, error) {
 // defined (reading left-to-right) will be the only one kept. This diverges
 // from the W3C Baggage specification which allows duplicate list-members, but
 // conforms to the OpenTelemetry Baggage specification.
+//
+// If the baggage-string exceeds the maximum allowed members (64) or bytes
+// (8192), members are dropped until the limits are satisfied and an error is
+// returned along with the partial result.
+//
+// Invalid members are skipped and the error is returned along with the
+// partial result containing the valid members.
 func Parse(bStr string) (Baggage, error) {
 	if bStr == "" {
 		return Baggage{}, nil
 	}
 
-	if n := len(bStr); n > maxBytesPerBaggageString {
-		return Baggage{}, fmt.Errorf("%w: %d", errBaggageBytes, n)
-	}
-
 	b := make(baggage.List)
+	sizes := make(map[string]int) // Track per-key byte sizes
+	var totalBytes int
+	var truncateErr error
 	for memberStr := range strings.SplitSeq(bStr, listDelimiter) {
+		// Check member count limit.
+		if len(b) >= maxMembers {
+			truncateErr = errors.Join(truncateErr, errMemberNumber)
+			break
+		}
+
 		m, err := parseMember(memberStr)
 		if err != nil {
-			return Baggage{}, err
+			truncateErr = errors.Join(truncateErr, err)
+			continue // skip invalid member, keep processing
 		}
+
+		// Check byte size limit.
+		// Account for comma separator between members.
+		memberBytes := len(m.String())
+		_, existingKey := b[m.key]
+		if !existingKey && len(b) > 0 {
+			memberBytes++ // comma separator only for new keys
+		}
+
+		// Calculate new totalBytes if we add/overwrite this key
+		var newTotalBytes int
+		if oldSize, exists := sizes[m.key]; exists {
+			// Overwriting existing key: subtract old size, add new size
+			newTotalBytes = totalBytes - oldSize + memberBytes
+		} else {
+			// New key
+			newTotalBytes = totalBytes + memberBytes
+		}
+
+		if newTotalBytes > maxBytesPerBaggageString {
+			truncateErr = errors.Join(truncateErr, errBaggageBytes)
+			break
+		}
+
 		// OpenTelemetry resolves duplicates by last-one-wins.
 		b[m.key] = baggage.Item{
 			Value:      m.value,
 			Properties: m.properties.asInternal(),
 		}
+		sizes[m.key] = memberBytes
+		totalBytes = newTotalBytes
 	}
 
-	// OpenTelemetry does not allow for duplicate list-members, but the W3C
-	// specification does. Now that we have deduplicated, ensure the baggage
-	// does not exceed list-member limits.
-	if len(b) > maxMembers {
-		return Baggage{}, errMemberNumber
+	if len(b) == 0 {
+		return Baggage{}, truncateErr
 	}
-
-	return Baggage{b}, nil
+	return Baggage{b}, truncateErr
 }
 
 // Member returns the baggage list-member identified by key.

baggage/baggage_test.go

@@ -257,12 +257,18 @@ func key(n int) string {
 }
 
 func TestNewBaggageErrorTooManyBytes(t *testing.T) {
-	m := make([]Member, (maxBytesPerBaggageString/maxBytesPerMembers)+1)
+	// Create members that together exceed maxBytesPerBaggageString.
+	// Each member needs key + "=" so use keys that sum to > 8192 bytes.
+	keySize := maxBytesPerBaggageString / maxMembers
+	m := make([]Member, maxMembers)
 	for i := range m {
-		m[i] = Member{key: key(maxBytesPerMembers), hasData: true}
+		m[i] = Member{key: key(keySize), hasData: true}
 	}
-	_, err := New(m...)
+	b, err := New(m...)
 	assert.ErrorIs(t, err, errBaggageBytes)
+	// Partial result should contain members that fit within the byte limit.
+	assert.Positive(t, b.Len(), "should return partial baggage")
+	assert.LessOrEqual(t, len(b.String()), maxBytesPerBaggageString, "partial baggage should be within byte limit")
 }
 
 func TestNewBaggageErrorTooManyMembers(t *testing.T) {
@@ -270,15 +276,15 @@ func TestNewBaggageErrorTooManyMembers(t *testing.T) {
 	for i := range m {
 		m[i] = Member{key: fmt.Sprintf("%d", i), hasData: true}
 	}
-	_, err := New(m...)
+	b, err := New(m...)
 	assert.ErrorIs(t, err, errMemberNumber)
+	// Partial result should contain exactly maxMembers.
+	assert.Equal(t, maxMembers, b.Len(), "should return first %d members", maxMembers)
 }
 
 func TestBaggageParse(t *testing.T) {
 	tooLarge := key(maxBytesPerBaggageString + 1)
 
-	tooLargeMember := key(maxBytesPerMembers + 1)
-
 	m := make([]string, maxMembers+1)
 	for i := range m {
 		m[i] = fmt.Sprintf("a%d=", i)
@@ -468,7 +474,11 @@ func TestBaggageParse(t *testing.T) {
 		{
 			name: "invalid member: empty",
 			in:   "foo=,,bar=",
-			err:  errInvalidMember,
+			want: baggage.List{
+				"foo": {},
+				"bar": {},
+			},
+			err: errInvalidMember,
 		},
 		{
 			name: "invalid member: no key",
@@ -518,17 +528,47 @@ func TestBaggageParse(t *testing.T) {
 		{
 			name: "invalid baggage string: too large",
 			in:   tooLarge,
-			err:  errBaggageBytes,
+			// tooLarge is a single key without "=", so parseMember fails
+			err: errInvalidMember,
 		},
 		{
-			name: "invalid baggage string: member too large",
-			in:   tooLargeMember,
-			err:  errMemberBytes,
-		},
-		{
-			name: "invalid baggage string: too many members",
+			name: "baggage string with too many members keeps first 64",
 			in:   tooManyMembers,
-			err:  errMemberNumber,
+			want: func() baggage.List {
+				b := make(baggage.List)
+				for i := range maxMembers {
+					b[fmt.Sprintf("a%d", i)] = baggage.Item{Value: ""}
+				}
+				return b
+			}(),
+			err: errMemberNumber,
+		},
+		{
+			name: "baggage string exceeds byte limit returns partial result",
+			in: func() string {
+				// Create members that collectively exceed maxBytesPerBaggageString.
+				// Each member: "kN=" + value. We use values large enough that
+				// a few members fit but the total exceeds 8192 bytes.
+				var parts []string
+				val := strings.Repeat("v", 2000)
+				for i := range 10 {
+					parts = append(parts, fmt.Sprintf("k%d=%s", i, val))
+				}
+				return strings.Join(parts, ",")
+			}(),
+			want: func() baggage.List {
+				// Only members that fit within 8192 bytes should be kept.
+				// Each member is ~2003 bytes ("kN=" + 2000 "v"s), plus comma.
+				// 4 members = 4*2003 + 3 commas = 8015 bytes (fits).
+				// 5 members = 5*2003 + 4 commas = 10019 bytes (exceeds).
+				b := make(baggage.List)
+				val := strings.Repeat("v", 2000)
+				for i := range 4 {
+					b[fmt.Sprintf("k%d", i)] = baggage.Item{Value: val}
+				}
+				return b
+			}(),
+			err: errBaggageBytes,
 		},
 		{
 			name: "percent-encoded octet sequences do not match the UTF-8 encoding scheme",

internal/errorhandler/errorhandler.go

@@ -0,0 +1,96 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+// Package errorhandler provides the global error handler for OpenTelemetry.
+//
+// This package has no OTel dependencies, allowing it to be imported by any
+// package in the module without creating import cycles.
+package errorhandler // import "go.opentelemetry.io/otel/internal/errorhandler"
+
+import (
+	"errors"
+	"log"
+	"sync"
+	"sync/atomic"
+)
+
+// ErrorHandler handles irremediable events.
+type ErrorHandler interface {
+	// Handle handles any error deemed irremediable by an OpenTelemetry
+	// component.
+	Handle(error)
+}
+
+type ErrDelegator struct {
+	delegate atomic.Pointer[ErrorHandler]
+}
+
+// Compile-time check that delegator implements ErrorHandler.
+var _ ErrorHandler = (*ErrDelegator)(nil)
+
+func (d *ErrDelegator) Handle(err error) {
+	if eh := d.delegate.Load(); eh != nil {
+		(*eh).Handle(err)
+		return
+	}
+	log.Print(err)
+}
+
+// setDelegate sets the ErrorHandler delegate.
+func (d *ErrDelegator) setDelegate(eh ErrorHandler) {
+	d.delegate.Store(&eh)
+}
+
+type errorHandlerHolder struct {
+	eh ErrorHandler
+}
+
+var (
+	globalErrorHandler       = defaultErrorHandler()
+	delegateErrorHandlerOnce sync.Once
+)
+
+// GetErrorHandler returns the global ErrorHandler instance.
+//
+// The default ErrorHandler instance returned will log all errors to STDERR
+// until an override ErrorHandler is set with SetErrorHandler. All
+// ErrorHandler returned prior to this will automatically forward errors to
+// the set instance instead of logging.
+//
+// Subsequent calls to SetErrorHandler after the first will not forward errors
+// to the new ErrorHandler for prior returned instances.
+func GetErrorHandler() ErrorHandler {
+	return globalErrorHandler.Load().(errorHandlerHolder).eh
+}
+
+// SetErrorHandler sets the global ErrorHandler to h.
+//
+// The first time this is called all ErrorHandler previously returned from
+// GetErrorHandler will send errors to h instead of the default logging
+// ErrorHandler. Subsequent calls will set the global ErrorHandler, but not
+// delegate errors to h.
+func SetErrorHandler(h ErrorHandler) {
+	current := GetErrorHandler()
+
+	if _, cOk := current.(*ErrDelegator); cOk {
+		if _, ehOk := h.(*ErrDelegator); ehOk && current == h {
+			// Do not assign to the delegate of the default ErrDelegator to be
+			// itself.
+			log.Print(errors.New("no ErrorHandler delegate configured"), " ErrorHandler remains its current value.")
+			return
+		}
+	}
+
+	delegateErrorHandlerOnce.Do(func() {
+		if def, ok := current.(*ErrDelegator); ok {
+			def.setDelegate(h)
+		}
+	})
+	globalErrorHandler.Store(errorHandlerHolder{eh: h})
+}
+
+func defaultErrorHandler() *atomic.Value {
+	v := &atomic.Value{}
+	v.Store(errorHandlerHolder{eh: &ErrDelegator{}})
+	return v
+}

internal/errorhandler/errorhandler_test.go

@@ -0,0 +1,113 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package errorhandler
+
+import (
+	"bytes"
+	"errors"
+	"log"
+	"os"
+	"strings"
+	"sync"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+type fnErrHandler func(error)
+
+func (f fnErrHandler) Handle(err error) { f(err) }
+
+var noopEH = fnErrHandler(func(error) {})
+
+type nonComparableErrorHandler struct {
+	ErrorHandler
+
+	nonComparable func() //nolint:unused  // This is not called.
+}
+
+func resetForTest(t testing.TB) {
+	t.Cleanup(func() {
+		globalErrorHandler = defaultErrorHandler()
+		delegateErrorHandlerOnce = sync.Once{}
+	})
+}
+
+func TestErrDelegator(t *testing.T) {
+	buf := new(bytes.Buffer)
+	log.Default().SetOutput(buf)
+	t.Cleanup(func() { log.Default().SetOutput(os.Stderr) })
+
+	e := &ErrDelegator{}
+
+	err := errors.New("testing")
+	e.Handle(err)
+
+	got := buf.String()
+	if !strings.Contains(got, err.Error()) {
+		t.Error("default handler did not log")
+	}
+	buf.Reset()
+
+	var gotErr error
+	e.setDelegate(fnErrHandler(func(e error) { gotErr = e }))
+	e.Handle(err)
+
+	if buf.String() != "" {
+		t.Error("delegate not set")
+	} else if !errors.Is(gotErr, err) {
+		t.Error("error not passed to delegate")
+	}
+}
+
+func TestSetErrorHandler(t *testing.T) {
+	t.Run("Set With default is a noop", func(t *testing.T) {
+		resetForTest(t)
+		SetErrorHandler(GetErrorHandler())
+
+		eh, ok := GetErrorHandler().(*ErrDelegator)
+		if !ok {
+			t.Fatal("Global ErrorHandler should be the default ErrorHandler")
+		}
+
+		if eh.delegate.Load() != nil {
+			t.Fatal("ErrorHandler should not delegate when setting itself")
+		}
+	})
+
+	t.Run("First Set() should replace the delegate", func(t *testing.T) {
+		resetForTest(t)
+
+		SetErrorHandler(noopEH)
+
+		_, ok := GetErrorHandler().(*ErrDelegator)
+		if ok {
+			t.Fatal("Global ErrorHandler was not changed")
+		}
+	})
+
+	t.Run("Set() should delegate existing ErrorHandlers", func(t *testing.T) {
+		resetForTest(t)
+
+		eh := GetErrorHandler()
+		SetErrorHandler(noopEH)
+
+		errDel, ok := eh.(*ErrDelegator)
+		if !ok {
+			t.Fatal("Wrong ErrorHandler returned")
+		}
+
+		if errDel.delegate.Load() == nil {
+			t.Fatal("The ErrDelegator should have a delegate")
+		}
+	})
+
+	t.Run("non-comparable types should not panic", func(t *testing.T) {
+		resetForTest(t)
+
+		eh := nonComparableErrorHandler{}
+		assert.NotPanics(t, func() { SetErrorHandler(eh) }, "delegate")
+		assert.NotPanics(t, func() { SetErrorHandler(eh) }, "replacement")
+	})
+}

internal/global/handler.go

@@ -5,33 +5,13 @@
 package global // import "go.opentelemetry.io/otel/internal/global"
 
 import (
-	"log"
-	"sync/atomic"
+	"go.opentelemetry.io/otel/internal/errorhandler"
 )
 
-// ErrorHandler handles irremediable events.
-type ErrorHandler interface {
-	// Handle handles any error deemed irremediable by an OpenTelemetry
-	// component.
-	Handle(error)
-}
+// ErrorHandler is an alias for errorhandler.ErrorHandler, kept for backward
+// compatibility with existing callers of internal/global.
+type ErrorHandler = errorhandler.ErrorHandler
 
-type ErrDelegator struct {
-	delegate atomic.Pointer[ErrorHandler]
-}
-
-// Compile-time check that delegator implements ErrorHandler.
-var _ ErrorHandler = (*ErrDelegator)(nil)
-
-func (d *ErrDelegator) Handle(err error) {
-	if eh := d.delegate.Load(); eh != nil {
-		(*eh).Handle(err)
-		return
-	}
-	log.Print(err)
-}
-
-// setDelegate sets the ErrorHandler delegate.
-func (d *ErrDelegator) setDelegate(eh ErrorHandler) {
-	d.delegate.Store(&eh)
-}
+// ErrDelegator is an alias for errorhandler.ErrDelegator, kept for backward
+// compatibility with existing callers of internal/global.
+type ErrDelegator = errorhandler.ErrDelegator

internal/global/handler_test.go

@@ -1,40 +0,0 @@
-// Copyright The OpenTelemetry Authors
-// SPDX-License-Identifier: Apache-2.0
-
-package global
-
-import (
-	"bytes"
-	"errors"
-	"log"
-	"os"
-	"strings"
-	"testing"
-)
-
-func TestErrDelegator(t *testing.T) {
-	buf := new(bytes.Buffer)
-	log.Default().SetOutput(buf)
-	t.Cleanup(func() { log.Default().SetOutput(os.Stderr) })
-
-	e := &ErrDelegator{}
-
-	err := errors.New("testing")
-	e.Handle(err)
-
-	got := buf.String()
-	if !strings.Contains(got, err.Error()) {
-		t.Error("default handler did not log")
-	}
-	buf.Reset()
-
-	var gotErr error
-	e.setDelegate(fnErrHandler(func(e error) { gotErr = e }))
-	e.Handle(err)
-
-	if buf.String() != "" {
-		t.Error("delegate not set")
-	} else if !errors.Is(gotErr, err) {
-		t.Error("error not passed to delegate")
-	}
-}

internal/global/state.go

@@ -8,16 +8,13 @@ import (
 	"sync"
 	"sync/atomic"
 
+	"go.opentelemetry.io/otel/internal/errorhandler"
 	"go.opentelemetry.io/otel/metric"
 	"go.opentelemetry.io/otel/propagation"
 	"go.opentelemetry.io/otel/trace"
 )
 
 type (
-	errorHandlerHolder struct {
-		eh ErrorHandler
-	}
-
 	tracerProviderHolder struct {
 		tp trace.TracerProvider
 	}
@@ -32,12 +29,10 @@ type (
 )
 
 var (
-	globalErrorHandler  = defaultErrorHandler()
 	globalTracer        = defaultTracerValue()
 	globalPropagators   = defaultPropagatorsValue()
 	globalMeterProvider = defaultMeterProvider()
 
-	delegateErrorHandlerOnce      sync.Once
 	delegateTraceOnce             sync.Once
 	delegateTextMapPropagatorOnce sync.Once
 	delegateMeterOnce             sync.Once
@@ -53,7 +48,7 @@ var (
 // Subsequent calls to SetErrorHandler after the first will not forward errors
 // to the new ErrorHandler for prior returned instances.
 func GetErrorHandler() ErrorHandler {
-	return globalErrorHandler.Load().(errorHandlerHolder).eh
+	return errorhandler.GetErrorHandler()
 }
 
 // SetErrorHandler sets the global ErrorHandler to h.
@@ -63,26 +58,7 @@ func GetErrorHandler() ErrorHandler {
 // ErrorHandler. Subsequent calls will set the global ErrorHandler, but not
 // delegate errors to h.
 func SetErrorHandler(h ErrorHandler) {
-	current := GetErrorHandler()
-
-	if _, cOk := current.(*ErrDelegator); cOk {
-		if _, ehOk := h.(*ErrDelegator); ehOk && current == h {
-			// Do not assign to the delegate of the default ErrDelegator to be
-			// itself.
-			Error(
-				errors.New("no ErrorHandler delegate configured"),
-				"ErrorHandler remains its current value.",
-			)
-			return
-		}
-	}
-
-	delegateErrorHandlerOnce.Do(func() {
-		if def, ok := current.(*ErrDelegator); ok {
-			def.setDelegate(h)
-		}
-	})
-	globalErrorHandler.Store(errorHandlerHolder{eh: h})
+	errorhandler.SetErrorHandler(h)
 }
 
 // TracerProvider is the internal implementation for global.TracerProvider.
@@ -174,12 +150,6 @@ func SetMeterProvider(mp metric.MeterProvider) {
 	globalMeterProvider.Store(meterProviderHolder{mp: mp})
 }
 
-func defaultErrorHandler() *atomic.Value {
-	v := &atomic.Value{}
-	v.Store(errorHandlerHolder{eh: &ErrDelegator{}})
-	return v
-}
-
 func defaultTracerValue() *atomic.Value {
 	v := &atomic.Value{}
 	v.Store(tracerProviderHolder{tp: &tracerProvider{}})

internal/global/state_test.go

@@ -15,12 +15,6 @@ import (
 	tracenoop "go.opentelemetry.io/otel/trace/noop"
 )
 
-type nonComparableErrorHandler struct {
-	ErrorHandler
-
-	nonComparable func() //nolint:unused  // This is not called.
-}
-
 type nonComparableTracerProvider struct {
 	trace.TracerProvider
 
@@ -33,63 +27,6 @@ type nonComparableMeterProvider struct {
 	nonComparable func() //nolint:unused  // This is not called.
 }
 
-type fnErrHandler func(error)
-
-func (f fnErrHandler) Handle(err error) { f(err) }
-
-var noopEH = fnErrHandler(func(error) {})
-
-func TestSetErrorHandler(t *testing.T) {
-	t.Run("Set With default is a noop", func(t *testing.T) {
-		ResetForTest(t)
-		SetErrorHandler(GetErrorHandler())
-
-		eh, ok := GetErrorHandler().(*ErrDelegator)
-		if !ok {
-			t.Fatal("Global ErrorHandler should be the default ErrorHandler")
-		}
-
-		if eh.delegate.Load() != nil {
-			t.Fatal("ErrorHandler should not delegate when setting itself")
-		}
-	})
-
-	t.Run("First Set() should replace the delegate", func(t *testing.T) {
-		ResetForTest(t)
-
-		SetErrorHandler(noopEH)
-
-		_, ok := GetErrorHandler().(*ErrDelegator)
-		if ok {
-			t.Fatal("Global ErrorHandler was not changed")
-		}
-	})
-
-	t.Run("Set() should delegate existing ErrorHandlers", func(t *testing.T) {
-		ResetForTest(t)
-
-		eh := GetErrorHandler()
-		SetErrorHandler(noopEH)
-
-		errDel, ok := eh.(*ErrDelegator)
-		if !ok {
-			t.Fatal("Wrong ErrorHandler returned")
-		}
-
-		if errDel.delegate.Load() == nil {
-			t.Fatal("The ErrDelegator should have a delegate")
-		}
-	})
-
-	t.Run("non-comparable types should not panic", func(t *testing.T) {
-		ResetForTest(t)
-
-		eh := nonComparableErrorHandler{}
-		assert.NotPanics(t, func() { SetErrorHandler(eh) }, "delegate")
-		assert.NotPanics(t, func() { SetErrorHandler(eh) }, "replacement")
-	})
-}
-
 func TestSetTracerProvider(t *testing.T) {
 	t.Run("Set With default is a noop", func(t *testing.T) {
 		ResetForTest(t)

internal/global/util_test.go

@@ -12,11 +12,9 @@ import (
 // its Cleanup step.
 func ResetForTest(t testing.TB) {
 	t.Cleanup(func() {
-		globalErrorHandler = defaultErrorHandler()
 		globalTracer = defaultTracerValue()
 		globalPropagators = defaultPropagatorsValue()
 		globalMeterProvider = defaultMeterProvider()
-		delegateErrorHandlerOnce = sync.Once{}
 		delegateTraceOnce = sync.Once{}
 		delegateTextMapPropagatorOnce = sync.Once{}
 		delegateMeterOnce = sync.Once{}

propagation/baggage.go

@@ -7,9 +7,16 @@ import (
 	"context"
 
 	"go.opentelemetry.io/otel/baggage"
+	"go.opentelemetry.io/otel/internal/errorhandler"
 )
 
-const baggageHeader = "baggage"
+const (
+	baggageHeader = "baggage"
+
+	// W3C Baggage specification limits.
+	// https://www.w3.org/TR/baggage/#limits
+	maxMembers = 64
+)
 
 // Baggage is a propagator that supports the W3C Baggage format.
 //
@@ -50,6 +57,9 @@ func extractSingleBaggage(parent context.Context, carrier TextMapCarrier) contex
 
 	bag, err := baggage.Parse(bStr)
 	if err != nil {
+		errorhandler.GetErrorHandler().Handle(err)
+	}
+	if bag.Len() == 0 {
 		return parent
 	}
 	return baggage.ContextWithBaggage(parent, bag)
@@ -60,17 +70,27 @@ func extractMultiBaggage(parent context.Context, carrier ValuesGetter) context.C
 	if len(bVals) == 0 {
 		return parent
 	}
+
 	var members []baggage.Member
 	for _, bStr := range bVals {
 		currBag, err := baggage.Parse(bStr)
 		if err != nil {
+			errorhandler.GetErrorHandler().Handle(err)
+		}
+		if currBag.Len() == 0 {
 			continue
 		}
 		members = append(members, currBag.Members()...)
+		if len(members) >= maxMembers {
+			break
+		}
 	}
 
 	b, err := baggage.New(members...)
-	if err != nil || b.Len() == 0 {
+	if err != nil {
+		errorhandler.GetErrorHandler().Handle(err)
+	}
+	if b.Len() == 0 {
 		return parent
 	}
 	return baggage.ContextWithBaggage(parent, b)

propagation/baggage_test.go

@@ -4,6 +4,7 @@
 package propagation_test
 
 import (
+	"fmt"
 	"net/http"
 	"strings"
 	"testing"
@@ -95,7 +96,10 @@ func TestExtractValidBaggage(t *testing.T) {
 		{
 			name:   "valid header with an invalid header",
 			header: "key1=val1,key2=val2,a,val3",
-			want:   members{},
+			want: members{
+				{Key: "key1", Value: "val1"},
+				{Key: "key2", Value: "val2"},
+			},
 		},
 		{
 			name:   "valid header with no value",
@@ -139,12 +143,36 @@ func TestExtractValidBaggage(t *testing.T) {
 	}
 }
 
+// generateBaggageHeader creates a baggage header string with n members.
+func generateBaggageHeader(n int, prefix string) string {
+	parts := make([]string, n)
+	for i := range parts {
+		parts[i] = fmt.Sprintf("%s%d=v%d", prefix, i, i)
+	}
+	return strings.Join(parts, ",")
+}
+
+// generateMembers creates n members with keys like "prefix0", "prefix1", etc.
+func generateMembers(n int, prefix string) members {
+	m := make(members, n)
+	for i := range m {
+		m[i] = member{Key: fmt.Sprintf("%s%d", prefix, i), Value: fmt.Sprintf("v%d", i)}
+	}
+	return m
+}
+
 func TestExtractValidMultipleBaggageHeaders(t *testing.T) {
+	// W3C Baggage spec limits: https://www.w3.org/TR/baggage/#limits
+	const maxMembers = 64
+	const maxBytesPerBaggageString = 8192
+
 	prop := propagation.TextMapPropagator(propagation.Baggage{})
 	tests := []struct {
-		name    string
-		headers []string
-		want    members
+		name         string
+		headers      []string
+		want         members
+		wantCount    int // Used when want is nil and we only care about count.
+		wantMaxBytes int // Used to check that baggage size doesn't exceed limit.
 	}{
 		{
 			name:    "non conflicting headers",
@@ -178,6 +206,109 @@ func TestExtractValidMultipleBaggageHeaders(t *testing.T) {
 			headers: []string{},
 			want:    members{},
 		},
+		{
+			name:    "single header with one invalid skips invalid",
+			headers: []string{"key1=val1,invalid-no-equals,key2=val2"},
+			want: members{
+				{Key: "key1", Value: "val1"},
+				{Key: "key2", Value: "val2"},
+			},
+		},
+		{
+			name: "multiple headers with one invalid skips invalid and continues",
+			headers: []string{
+				"key1=val1",
+				"invalid-no-equals",
+				"key2=val2",
+			},
+			want: members{
+				{Key: "key1", Value: "val1"},
+				{Key: "key2", Value: "val2"},
+			},
+		},
+		{
+			name:    "single header at max members limit",
+			headers: []string{generateBaggageHeader(maxMembers, "k")},
+			want:    generateMembers(maxMembers, "k"),
+		},
+		{
+			name:    "single header exceeds max members limit keeps 64",
+			headers: []string{generateBaggageHeader(maxMembers+1, "k")},
+			want:    generateMembers(maxMembers, "k"),
+		},
+		{
+			name: "multiple headers exceeds total max members limit keeps 64",
+			headers: []string{
+				generateBaggageHeader(maxMembers/2, "a"),
+				generateBaggageHeader(maxMembers/2, "b"),
+				generateBaggageHeader(1, "c"),
+			},
+			want:         nil, // Non-deterministic truncation by baggage.New()
+			wantCount:    maxMembers,
+			wantMaxBytes: maxBytesPerBaggageString,
+		},
+		{
+			name:    "single header at max bytes limit",
+			headers: []string{"k=" + strings.Repeat("v", maxBytesPerBaggageString-2)},
+			want: members{
+				{Key: "k", Value: strings.Repeat("v", maxBytesPerBaggageString-2)},
+			},
+		},
+		{
+			name:    "single header exceeds max bytes limit drops oversized member",
+			headers: []string{"k=" + strings.Repeat("v", maxBytesPerBaggageString-1)},
+			want:    members{},
+		},
+		{
+			name: "multiple headers exceed total max bytes keeps one that fits",
+			headers: []string{
+				"k=" + strings.Repeat("v", maxBytesPerBaggageString-2),
+				"y=" + strings.Repeat("v", maxBytesPerBaggageString-2),
+			},
+			want:         nil, // Non-deterministic: either k or y will be kept
+			wantCount:    1,   // Only one member fits
+			wantMaxBytes: maxBytesPerBaggageString,
+		},
+		{
+			name: "multiple headers within total max bytes",
+			headers: []string{
+				"k=" + strings.Repeat("v", maxBytesPerBaggageString/2-2),
+				// The comma as the separator of member would take 1 byte.
+				"y=" + strings.Repeat("v", maxBytesPerBaggageString/2-2-1),
+			},
+			want: members{
+				{Key: "k", Value: strings.Repeat("v", maxBytesPerBaggageString/2-2)},
+				{Key: "y", Value: strings.Repeat("v", maxBytesPerBaggageString/2-2-1)},
+			},
+		},
+		{
+			name: "many headers exceeding member limit caps collection early",
+			headers: func() []string {
+				// 100 headers with 10 members each = 1000 total members.
+				// The cap should stop collecting after ~maxMembers and
+				// New() truncates to exactly maxMembers.
+				h := make([]string, 100)
+				for i := range h {
+					h[i] = generateBaggageHeader(10, fmt.Sprintf("h%d_k", i))
+				}
+				return h
+			}(),
+			wantCount:    maxMembers,
+			wantMaxBytes: maxBytesPerBaggageString,
+		},
+		{
+			name: "skips large member that exceeds byte limit and continues",
+			headers: []string{
+				"small1=v1,small2=v2",
+				"large=" + strings.Repeat("x", maxBytesPerBaggageString),
+				"small3=v3",
+			},
+			want: members{
+				{Key: "small1", Value: "v1"},
+				{Key: "small2", Value: "v2"},
+				{Key: "small3", Value: "v3"},
+			},
+		},
 	}
 
 	for _, tt := range tests {
@@ -187,8 +318,17 @@ func TestExtractValidMultipleBaggageHeaders(t *testing.T) {
 
 			ctx := t.Context()
 			ctx = prop.Extract(ctx, propagation.HeaderCarrier(req.Header))
-			expected := tt.want.Baggage(t)
-			assert.Equal(t, expected, baggage.FromContext(ctx))
+			got := baggage.FromContext(ctx)
+
+			// If want is specified, check exact match
+			if tt.want != nil {
+				expected := tt.want.Baggage(t)
+				assert.Equal(t, expected, got)
+			} else if tt.wantCount > 0 {
+				// If only count is specified, verify count and byte limit
+				assert.Equal(t, tt.wantCount, got.Len(), "expected member count")
+				assert.LessOrEqual(t, len(got.String()), tt.wantMaxBytes, "baggage size exceeds limit")
+			}
 		})
 	}
 }