vendor/github.com/bufbuild/protocompile/internal/editions/editions.go - voltha-go - Gitiles

 // Copyright 2020-2024 Buf Technologies, Inc.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //      http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.

 // Package editions contains helpers related to resolving features for
 // Protobuf editions. These are lower-level helpers. Higher-level helpers
 // (which use this package under the hood) can be found in the exported
 // protoutil package.
 package editions

 import (
 	"fmt"
 	"strings"
 	"sync"

 	"google.golang.org/protobuf/encoding/prototext"
 	"google.golang.org/protobuf/proto"
 	"google.golang.org/protobuf/reflect/protoreflect"
 	"google.golang.org/protobuf/reflect/protoregistry"
 	"google.golang.org/protobuf/types/descriptorpb"
 	"google.golang.org/protobuf/types/dynamicpb"
 )

 const (
 	// MinSupportedEdition is the earliest edition supported by this module.
 	// It should be 2023 (the first edition) for the indefinite future.
 	MinSupportedEdition = descriptorpb.Edition_EDITION_2023

 	// MaxSupportedEdition is the most recent edition supported by this module.
 	MaxSupportedEdition = descriptorpb.Edition_EDITION_2023
 )

 var (
 	// SupportedEditions is the exhaustive set of editions that protocompile
 	// can support. We don't allow it to compile future/unknown editions, to
 	// make sure we don't generate incorrect descriptors, in the event that
 	// a future edition introduces a change or new feature that requires
 	// new logic in the compiler.
 	SupportedEditions = computeSupportedEditions(MinSupportedEdition, MaxSupportedEdition)

 	// FeatureSetDescriptor is the message descriptor for the compiled-in
 	// version (in the descriptorpb package) of the google.protobuf.FeatureSet
 	// message type.
 	FeatureSetDescriptor = (*descriptorpb.FeatureSet)(nil).ProtoReflect().Descriptor()
 	// FeatureSetType is the message type for the compiled-in version (in
 	// the descriptorpb package) of google.protobuf.FeatureSet.
 	FeatureSetType = (*descriptorpb.FeatureSet)(nil).ProtoReflect().Type()

 	editionDefaults     map[descriptorpb.Edition]*descriptorpb.FeatureSet
 	editionDefaultsInit sync.Once
 )

 // HasFeatures is implemented by all options messages and provides a
 // nil-receiver-safe way of accessing the features explicitly configured
 // in those options.
 type HasFeatures interface {
 	GetFeatures() *descriptorpb.FeatureSet
 }

 var _ HasFeatures = (*descriptorpb.FileOptions)(nil)
 var _ HasFeatures = (*descriptorpb.MessageOptions)(nil)
 var _ HasFeatures = (*descriptorpb.FieldOptions)(nil)
 var _ HasFeatures = (*descriptorpb.OneofOptions)(nil)
 var _ HasFeatures = (*descriptorpb.ExtensionRangeOptions)(nil)
 var _ HasFeatures = (*descriptorpb.EnumOptions)(nil)
 var _ HasFeatures = (*descriptorpb.EnumValueOptions)(nil)
 var _ HasFeatures = (*descriptorpb.ServiceOptions)(nil)
 var _ HasFeatures = (*descriptorpb.MethodOptions)(nil)

 // ResolveFeature resolves a feature for the given descriptor. This simple
 // helper examines the given element and its ancestors, searching for an
 // override. If there is no overridden value, it returns a zero value.
 func ResolveFeature(
 	element protoreflect.Descriptor,
 	fields ...protoreflect.FieldDescriptor,
 ) (protoreflect.Value, error) {
 	for {
 		var features *descriptorpb.FeatureSet
 		if withFeatures, ok := element.Options().(HasFeatures); ok {
 			// It should not really be possible for 'ok' to ever be false...
 			features = withFeatures.GetFeatures()
 		}

 		// TODO: adaptFeatureSet is only looking at the first field. But if we needed to
 		//       support an extension field inside a custom feature, we'd really need
 		//       to check all fields. That gets particularly complicated if the traversal
 		//       path of fields includes list and map values. Luckily, features are not
 		//       supposed to be repeated and not supposed to themselves have extensions.
 		//       So this should be fine, at least for now.
 		msgRef, err := adaptFeatureSet(features, fields[0])
 		if err != nil {
 			return protoreflect.Value{}, err
 		}
 		// Navigate the fields to find the value
 		var val protoreflect.Value
 		for i, field := range fields {
 			if i > 0 {
 				msgRef = val.Message()
 			}
 			if !msgRef.Has(field) {
 				val = protoreflect.Value{}
 				break
 			}
 			val = msgRef.Get(field)
 		}
 		if val.IsValid() {
 			// All fields were set!
 			return val, nil
 		}

 		parent := element.Parent()
 		if parent == nil {
 			// We've reached the end of the inheritance chain.
 			return protoreflect.Value{}, nil
 		}
 		element = parent
 	}
 }

 // HasEdition should be implemented by values that implement
 // [protoreflect.FileDescriptor], to provide access to the file's
 // edition when its syntax is [protoreflect.Editions].
 type HasEdition interface {
 	// Edition returns the numeric value of a google.protobuf.Edition enum
 	// value that corresponds to the edition of this file. If the file does
 	// not use editions, it should return the enum value that corresponds
 	// to the syntax level, EDITION_PROTO2 or EDITION_PROTO3.
 	Edition() int32
 }

 // GetEdition returns the edition for a given element. It returns
 // EDITION_PROTO2 or EDITION_PROTO3 if the element is in a file that
 // uses proto2 or proto3 syntax, respectively. It returns EDITION_UNKNOWN
 // if the syntax of the given element is not recognized or if the edition
 // cannot be ascertained from the element's [protoreflect.FileDescriptor].
 func GetEdition(d protoreflect.Descriptor) descriptorpb.Edition {
 	switch d.ParentFile().Syntax() {
 	case protoreflect.Proto2:
 		return descriptorpb.Edition_EDITION_PROTO2
 	case protoreflect.Proto3:
 		return descriptorpb.Edition_EDITION_PROTO3
 	case protoreflect.Editions:
 		withEdition, ok := d.ParentFile().(HasEdition)
 		if !ok {
 			// The parent file should always be a *result, so we should
 			// never be able to actually get in here. If we somehow did
 			// have another implementation of protoreflect.FileDescriptor,
 			// it doesn't provide a way to get the edition, other than the
 			// potentially expensive step of generating a FileDescriptorProto
 			// and then querying for the edition from that. :/
 			return descriptorpb.Edition_EDITION_UNKNOWN
 		}
 		return descriptorpb.Edition(withEdition.Edition())
 	default:
 		return descriptorpb.Edition_EDITION_UNKNOWN
 	}
 }

 // GetEditionDefaults returns the default feature values for the given edition.
 // It returns nil if the given edition is not known.
 //
 // This only populates known features, those that are fields of [*descriptorpb.FeatureSet].
 // It does not populate any extension fields.
 //
 // The returned value must not be mutated as it references shared package state.
 func GetEditionDefaults(edition descriptorpb.Edition) *descriptorpb.FeatureSet {
 	editionDefaultsInit.Do(func() {
 		editionDefaults = make(map[descriptorpb.Edition]*descriptorpb.FeatureSet, len(descriptorpb.Edition_name))
 		// Compute default for all known editions in descriptorpb.
 		for editionInt := range descriptorpb.Edition_name {
 			edition := descriptorpb.Edition(editionInt)
 			defaults := &descriptorpb.FeatureSet{}
 			defaultsRef := defaults.ProtoReflect()
 			fields := defaultsRef.Descriptor().Fields()
 			// Note: we are not computing defaults for extensions. Those are not needed
 			// by anything in the compiler, so we can get away with just computing
 			// defaults for these static, non-extension fields.
 			for i, length := 0, fields.Len(); i < length; i++ {
 				field := fields.Get(i)
 				val, err := GetFeatureDefault(edition, FeatureSetType, field)
 				if err != nil {
 					// should we fail somehow??
 					continue
 				}
 				defaultsRef.Set(field, val)
 			}
 			editionDefaults[edition] = defaults
 		}
 	})
 	return editionDefaults[edition]
 }

 // GetFeatureDefault computes the default value for a feature. The given container
 // is the message type that contains the field. This should usually be the descriptor
 // for google.protobuf.FeatureSet, but can be a different message for computing the
 // default value of custom features.
 //
 // Note that this always re-computes the default. For known fields of FeatureSet,
 // it is more efficient to query from the statically computed default messages,
 // like so:
 //
 //	editions.GetEditionDefaults(edition).ProtoReflect().Get(feature)
 func GetFeatureDefault(edition descriptorpb.Edition, container protoreflect.MessageType, feature protoreflect.FieldDescriptor) (protoreflect.Value, error) {
 	opts, ok := feature.Options().(*descriptorpb.FieldOptions)
 	if !ok {
 		// this is most likely impossible except for contrived use cases...
 		return protoreflect.Value{}, fmt.Errorf("options is %T instead of *descriptorpb.FieldOptions", feature.Options())
 	}
 	maxEdition := descriptorpb.Edition(-1)
 	var maxVal string
 	for _, def := range opts.EditionDefaults {
 		if def.GetEdition() <= edition && def.GetEdition() > maxEdition {
 			maxEdition = def.GetEdition()
 			maxVal = def.GetValue()
 		}
 	}
 	if maxEdition == -1 {
 		// no matching default found
 		return protoreflect.Value{}, fmt.Errorf("no relevant default for edition %s", edition)
 	}
 	// We use a typed nil so that it won't fall back to the global registry. Features
 	// should not use extensions or google.protobuf.Any, so a nil *Types is fine.
 	unmarshaler := prototext.UnmarshalOptions{Resolver: (*protoregistry.Types)(nil)}
 	// The string value is in the text format: either a field value literal or a
 	// message literal. (Repeated and map features aren't supported, so there's no
 	// array or map literal syntax to worry about.)
 	if feature.Kind() == protoreflect.MessageKind || feature.Kind() == protoreflect.GroupKind {
 		fldVal := container.Zero().NewField(feature)
 		err := unmarshaler.Unmarshal([]byte(maxVal), fldVal.Message().Interface())
 		if err != nil {
 			return protoreflect.Value{}, err
 		}
 		return fldVal, nil
 	}
 	// The value is the textformat for the field. But prototext doesn't provide a way
 	// to unmarshal a single field value. To work around, we unmarshal into an enclosing
 	// message, which means we must prefix the value with the field name.
 	if feature.IsExtension() {
 		maxVal = fmt.Sprintf("[%s]: %s", feature.FullName(), maxVal)
 	} else {
 		maxVal = fmt.Sprintf("%s: %s", feature.Name(), maxVal)
 	}
 	empty := container.New()
 	err := unmarshaler.Unmarshal([]byte(maxVal), empty.Interface())
 	if err != nil {
 		return protoreflect.Value{}, err
 	}
 	return empty.Get(feature), nil
 }

 func adaptFeatureSet(msg *descriptorpb.FeatureSet, field protoreflect.FieldDescriptor) (protoreflect.Message, error) {
 	msgRef := msg.ProtoReflect()
 	var actualField protoreflect.FieldDescriptor
 	switch {
 	case field.IsExtension():
 		// Extensions can be used directly with the feature set, even if
 		// field.ContainingMessage() != FeatureSetDescriptor. But only if
 		// the value is either not a message or is a message with the
 		// right descriptor, i.e. val.Descriptor() == field.Message().
 		if actualField = actualDescriptor(msgRef, field); actualField == nil || actualField == field {
 			if msgRef.Has(field) || len(msgRef.GetUnknown()) == 0 {
 				return msgRef, nil
 			}
 			// The field is not present, but the message has unrecognized values. So
 			// let's try to parse the unrecognized bytes, just in case they contain
 			// this extension.
 			temp := &descriptorpb.FeatureSet{}
 			unmarshaler := proto.UnmarshalOptions{
 				AllowPartial: true,
 				Resolver:     resolverForExtension{field},
 			}
 			if err := unmarshaler.Unmarshal(msgRef.GetUnknown(), temp); err != nil {
 				return nil, fmt.Errorf("failed to parse unrecognized fields of FeatureSet: %w", err)
 			}
 			return temp.ProtoReflect(), nil
 		}
 	case field.ContainingMessage() == FeatureSetDescriptor:
 		// Known field, not dynamically generated. Can directly use with the feature set.
 		return msgRef, nil
 	default:
 		actualField = FeatureSetDescriptor.Fields().ByNumber(field.Number())
 	}

 	// If we get here, we have a dynamic field descriptor or an extension
 	// descriptor whose message type does not match the descriptor of the
 	// stored value. We need to copy its value into a dynamic message,
 	// which requires marshalling/unmarshalling.
 	// We only need to copy over the unrecognized bytes (if any)
 	// and the same field (if present).
 	data := msgRef.GetUnknown()
 	if actualField != nil && msgRef.Has(actualField) {
 		subset := &descriptorpb.FeatureSet{}
 		subset.ProtoReflect().Set(actualField, msgRef.Get(actualField))
 		var err error
 		data, err = proto.MarshalOptions{AllowPartial: true}.MarshalAppend(data, subset)
 		if err != nil {
 			return nil, fmt.Errorf("failed to marshal FeatureSet field %s to bytes: %w", field.Name(), err)
 		}
 	}
 	if len(data) == 0 {
 		// No relevant data to copy over, so we can just return
 		// a zero value message
 		return dynamicpb.NewMessageType(field.ContainingMessage()).Zero(), nil
 	}

 	other := dynamicpb.NewMessage(field.ContainingMessage())
 	// We don't need to use a resolver for this step because we know that
 	// field is not an extension. And features are not allowed to themselves
 	// have extensions.
 	if err := (proto.UnmarshalOptions{AllowPartial: true}).Unmarshal(data, other); err != nil {
 		return nil, fmt.Errorf("failed to marshal FeatureSet field %s to bytes: %w", field.Name(), err)
 	}
 	return other, nil
 }

 type resolverForExtension struct {
 	ext protoreflect.ExtensionDescriptor
 }

 func (r resolverForExtension) FindMessageByName(_ protoreflect.FullName) (protoreflect.MessageType, error) {
 	return nil, protoregistry.NotFound
 }

 func (r resolverForExtension) FindMessageByURL(_ string) (protoreflect.MessageType, error) {
 	return nil, protoregistry.NotFound
 }

 func (r resolverForExtension) FindExtensionByName(field protoreflect.FullName) (protoreflect.ExtensionType, error) {
 	if field == r.ext.FullName() {
 		return asExtensionType(r.ext), nil
 	}
 	return nil, protoregistry.NotFound
 }

 func (r resolverForExtension) FindExtensionByNumber(message protoreflect.FullName, field protoreflect.FieldNumber) (protoreflect.ExtensionType, error) {
 	if message == r.ext.ContainingMessage().FullName() && field == r.ext.Number() {
 		return asExtensionType(r.ext), nil
 	}
 	return nil, protoregistry.NotFound
 }

 func asExtensionType(ext protoreflect.ExtensionDescriptor) protoreflect.ExtensionType {
 	if xtd, ok := ext.(protoreflect.ExtensionTypeDescriptor); ok {
 		return xtd.Type()
 	}
 	return dynamicpb.NewExtensionType(ext)
 }

 func computeSupportedEditions(minEdition, maxEdition descriptorpb.Edition) map[string]descriptorpb.Edition {
 	supportedEditions := map[string]descriptorpb.Edition{}
 	for editionNum := range descriptorpb.Edition_name {
 		edition := descriptorpb.Edition(editionNum)
 		if edition >= minEdition && edition <= maxEdition {
 			name := strings.TrimPrefix(edition.String(), "EDITION_")
 			supportedEditions[name] = edition
 		}
 	}
 	return supportedEditions
 }

 // actualDescriptor returns the actual field descriptor referenced by msg that
 // corresponds to the given ext (i.e. same number). It returns nil if msg has
 // no reference, if the actual descriptor is the same as ext, or if ext is
 // otherwise safe to use as is.
 func actualDescriptor(msg protoreflect.Message, ext protoreflect.ExtensionDescriptor) protoreflect.FieldDescriptor {
 	if !msg.Has(ext) || ext.Message() == nil {
 		// nothing to match; safe as is
 		return nil
 	}
 	val := msg.Get(ext)
 	switch {
 	case ext.IsMap(): // should not actually be possible
 		expectedDescriptor := ext.MapValue().Message()
 		if expectedDescriptor == nil {
 			return nil // nothing to match
 		}
 		// We know msg.Has(field) is true, from above, so there's at least one entry.
 		var matches bool
 		val.Map().Range(func(_ protoreflect.MapKey, val protoreflect.Value) bool {
 			matches = val.Message().Descriptor() == expectedDescriptor
 			return false
 		})
 		if matches {
 			return nil
 		}
 	case ext.IsList():
 		// We know msg.Has(field) is true, from above, so there's at least one entry.
 		if val.List().Get(0).Message().Descriptor() == ext.Message() {
 			return nil
 		}
 	case !ext.IsMap():
 		if val.Message().Descriptor() == ext.Message() {
 			return nil
 		}
 	}
 	// The underlying message descriptors do not match. So we need to return
 	// the actual field descriptor. Sadly, protoreflect.Message provides no way
 	// to query the field descriptor in a message by number. For non-extensions,
 	// one can query the associated message descriptor. But for extensions, we
 	// have to do the slow thing, and range through all fields looking for it.
 	var actualField protoreflect.FieldDescriptor
 	msg.Range(func(fd protoreflect.FieldDescriptor, _ protoreflect.Value) bool {
 		if fd.Number() == ext.Number() {
 			actualField = fd
 			return false
 		}
 		return true
 	})
 	return actualField
 }
	// Copyright 2020-2024 Buf Technologies, Inc.
	//
	// Licensed under the Apache License, Version 2.0 (the "License");
	// you may not use this file except in compliance with the License.
	// You may obtain a copy of the License at
	//
	// http://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing, software
	// distributed under the License is distributed on an "AS IS" BASIS,
	// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	// See the License for the specific language governing permissions and
	// limitations under the License.

	// Package editions contains helpers related to resolving features for
	// Protobuf editions. These are lower-level helpers. Higher-level helpers
	// (which use this package under the hood) can be found in the exported
	// protoutil package.
	package editions

	import (
	"fmt"
	"strings"
	"sync"

	"google.golang.org/protobuf/encoding/prototext"
	"google.golang.org/protobuf/proto"
	"google.golang.org/protobuf/reflect/protoreflect"
	"google.golang.org/protobuf/reflect/protoregistry"
	"google.golang.org/protobuf/types/descriptorpb"
	"google.golang.org/protobuf/types/dynamicpb"
	)

	const (
	// MinSupportedEdition is the earliest edition supported by this module.
	// It should be 2023 (the first edition) for the indefinite future.
	MinSupportedEdition = descriptorpb.Edition_EDITION_2023

	// MaxSupportedEdition is the most recent edition supported by this module.
	MaxSupportedEdition = descriptorpb.Edition_EDITION_2023
	)

	var (
	// SupportedEditions is the exhaustive set of editions that protocompile
	// can support. We don't allow it to compile future/unknown editions, to
	// make sure we don't generate incorrect descriptors, in the event that
	// a future edition introduces a change or new feature that requires
	// new logic in the compiler.
	SupportedEditions = computeSupportedEditions(MinSupportedEdition, MaxSupportedEdition)

	// FeatureSetDescriptor is the message descriptor for the compiled-in
	// version (in the descriptorpb package) of the google.protobuf.FeatureSet
	// message type.
	FeatureSetDescriptor = (*descriptorpb.FeatureSet)(nil).ProtoReflect().Descriptor()
	// FeatureSetType is the message type for the compiled-in version (in
	// the descriptorpb package) of google.protobuf.FeatureSet.
	FeatureSetType = (*descriptorpb.FeatureSet)(nil).ProtoReflect().Type()

	editionDefaults map[descriptorpb.Edition]*descriptorpb.FeatureSet
	editionDefaultsInit sync.Once
	)

	// HasFeatures is implemented by all options messages and provides a
	// nil-receiver-safe way of accessing the features explicitly configured
	// in those options.
	type HasFeatures interface {
	GetFeatures() *descriptorpb.FeatureSet
	}

	var _ HasFeatures = (*descriptorpb.FileOptions)(nil)
	var _ HasFeatures = (*descriptorpb.MessageOptions)(nil)
	var _ HasFeatures = (*descriptorpb.FieldOptions)(nil)
	var _ HasFeatures = (*descriptorpb.OneofOptions)(nil)
	var _ HasFeatures = (*descriptorpb.ExtensionRangeOptions)(nil)
	var _ HasFeatures = (*descriptorpb.EnumOptions)(nil)
	var _ HasFeatures = (*descriptorpb.EnumValueOptions)(nil)
	var _ HasFeatures = (*descriptorpb.ServiceOptions)(nil)
	var _ HasFeatures = (*descriptorpb.MethodOptions)(nil)

	// ResolveFeature resolves a feature for the given descriptor. This simple
	// helper examines the given element and its ancestors, searching for an
	// override. If there is no overridden value, it returns a zero value.
	func ResolveFeature(
	element protoreflect.Descriptor,
	fields ...protoreflect.FieldDescriptor,
	) (protoreflect.Value, error) {
	for {
	var features *descriptorpb.FeatureSet
	if withFeatures, ok := element.Options().(HasFeatures); ok {
	// It should not really be possible for 'ok' to ever be false...
	features = withFeatures.GetFeatures()
	}

	// TODO: adaptFeatureSet is only looking at the first field. But if we needed to
	// support an extension field inside a custom feature, we'd really need
	// to check all fields. That gets particularly complicated if the traversal
	// path of fields includes list and map values. Luckily, features are not
	// supposed to be repeated and not supposed to themselves have extensions.
	// So this should be fine, at least for now.
	msgRef, err := adaptFeatureSet(features, fields[0])
	if err != nil {
	return protoreflect.Value{}, err
	}
	// Navigate the fields to find the value
	var val protoreflect.Value
	for i, field := range fields {
	if i > 0 {
	msgRef = val.Message()
	}
	if !msgRef.Has(field) {
	val = protoreflect.Value{}
	break
	}
	val = msgRef.Get(field)
	}
	if val.IsValid() {
	// All fields were set!
	return val, nil
	}

	parent := element.Parent()
	if parent == nil {
	// We've reached the end of the inheritance chain.
	return protoreflect.Value{}, nil
	}
	element = parent
	}
	}

	// HasEdition should be implemented by values that implement
	// [protoreflect.FileDescriptor], to provide access to the file's
	// edition when its syntax is [protoreflect.Editions].
	type HasEdition interface {
	// Edition returns the numeric value of a google.protobuf.Edition enum
	// value that corresponds to the edition of this file. If the file does
	// not use editions, it should return the enum value that corresponds
	// to the syntax level, EDITION_PROTO2 or EDITION_PROTO3.
	Edition() int32
	}

	// GetEdition returns the edition for a given element. It returns
	// EDITION_PROTO2 or EDITION_PROTO3 if the element is in a file that
	// uses proto2 or proto3 syntax, respectively. It returns EDITION_UNKNOWN
	// if the syntax of the given element is not recognized or if the edition
	// cannot be ascertained from the element's [protoreflect.FileDescriptor].
	func GetEdition(d protoreflect.Descriptor) descriptorpb.Edition {
	switch d.ParentFile().Syntax() {
	case protoreflect.Proto2:
	return descriptorpb.Edition_EDITION_PROTO2
	case protoreflect.Proto3:
	return descriptorpb.Edition_EDITION_PROTO3
	case protoreflect.Editions:
	withEdition, ok := d.ParentFile().(HasEdition)
	if !ok {
	// The parent file should always be a *result, so we should
	// never be able to actually get in here. If we somehow did
	// have another implementation of protoreflect.FileDescriptor,
	// it doesn't provide a way to get the edition, other than the
	// potentially expensive step of generating a FileDescriptorProto
	// and then querying for the edition from that. :/
	return descriptorpb.Edition_EDITION_UNKNOWN
	}
	return descriptorpb.Edition(withEdition.Edition())
	default:
	return descriptorpb.Edition_EDITION_UNKNOWN
	}
	}

	// GetEditionDefaults returns the default feature values for the given edition.
	// It returns nil if the given edition is not known.
	//
	// This only populates known features, those that are fields of [*descriptorpb.FeatureSet].
	// It does not populate any extension fields.
	//
	// The returned value must not be mutated as it references shared package state.
	func GetEditionDefaults(edition descriptorpb.Edition) *descriptorpb.FeatureSet {
	editionDefaultsInit.Do(func() {
	editionDefaults = make(map[descriptorpb.Edition]*descriptorpb.FeatureSet, len(descriptorpb.Edition_name))
	// Compute default for all known editions in descriptorpb.
	for editionInt := range descriptorpb.Edition_name {
	edition := descriptorpb.Edition(editionInt)
	defaults := &descriptorpb.FeatureSet{}
	defaultsRef := defaults.ProtoReflect()
	fields := defaultsRef.Descriptor().Fields()
	// Note: we are not computing defaults for extensions. Those are not needed
	// by anything in the compiler, so we can get away with just computing
	// defaults for these static, non-extension fields.
	for i, length := 0, fields.Len(); i < length; i++ {
	field := fields.Get(i)
	val, err := GetFeatureDefault(edition, FeatureSetType, field)
	if err != nil {
	// should we fail somehow??
	continue
	}
	defaultsRef.Set(field, val)
	}
	editionDefaults[edition] = defaults
	}
	})
	return editionDefaults[edition]
	}

	// GetFeatureDefault computes the default value for a feature. The given container
	// is the message type that contains the field. This should usually be the descriptor
	// for google.protobuf.FeatureSet, but can be a different message for computing the
	// default value of custom features.
	//
	// Note that this always re-computes the default. For known fields of FeatureSet,
	// it is more efficient to query from the statically computed default messages,
	// like so:
	//
	// editions.GetEditionDefaults(edition).ProtoReflect().Get(feature)
	func GetFeatureDefault(edition descriptorpb.Edition, container protoreflect.MessageType, feature protoreflect.FieldDescriptor) (protoreflect.Value, error) {
	opts, ok := feature.Options().(*descriptorpb.FieldOptions)
	if !ok {
	// this is most likely impossible except for contrived use cases...
	return protoreflect.Value{}, fmt.Errorf("options is %T instead of *descriptorpb.FieldOptions", feature.Options())
	}
	maxEdition := descriptorpb.Edition(-1)
	var maxVal string
	for _, def := range opts.EditionDefaults {
	if def.GetEdition() <= edition && def.GetEdition() > maxEdition {
	maxEdition = def.GetEdition()
	maxVal = def.GetValue()
	}
	}
	if maxEdition == -1 {
	// no matching default found
	return protoreflect.Value{}, fmt.Errorf("no relevant default for edition %s", edition)
	}
	// We use a typed nil so that it won't fall back to the global registry. Features
	// should not use extensions or google.protobuf.Any, so a nil *Types is fine.
	unmarshaler := prototext.UnmarshalOptions{Resolver: (*protoregistry.Types)(nil)}
	// The string value is in the text format: either a field value literal or a
	// message literal. (Repeated and map features aren't supported, so there's no
	// array or map literal syntax to worry about.)
	if feature.Kind() == protoreflect.MessageKind \|\| feature.Kind() == protoreflect.GroupKind {
	fldVal := container.Zero().NewField(feature)
	err := unmarshaler.Unmarshal([]byte(maxVal), fldVal.Message().Interface())
	if err != nil {
	return protoreflect.Value{}, err
	}
	return fldVal, nil
	}
	// The value is the textformat for the field. But prototext doesn't provide a way
	// to unmarshal a single field value. To work around, we unmarshal into an enclosing
	// message, which means we must prefix the value with the field name.
	if feature.IsExtension() {
	maxVal = fmt.Sprintf("[%s]: %s", feature.FullName(), maxVal)
	} else {
	maxVal = fmt.Sprintf("%s: %s", feature.Name(), maxVal)
	}
	empty := container.New()
	err := unmarshaler.Unmarshal([]byte(maxVal), empty.Interface())
	if err != nil {
	return protoreflect.Value{}, err
	}
	return empty.Get(feature), nil
	}

	func adaptFeatureSet(msg *descriptorpb.FeatureSet, field protoreflect.FieldDescriptor) (protoreflect.Message, error) {
	msgRef := msg.ProtoReflect()
	var actualField protoreflect.FieldDescriptor
	switch {
	case field.IsExtension():
	// Extensions can be used directly with the feature set, even if
	// field.ContainingMessage() != FeatureSetDescriptor. But only if
	// the value is either not a message or is a message with the
	// right descriptor, i.e. val.Descriptor() == field.Message().
	if actualField = actualDescriptor(msgRef, field); actualField == nil \|\| actualField == field {
	if msgRef.Has(field) \|\| len(msgRef.GetUnknown()) == 0 {
	return msgRef, nil
	}
	// The field is not present, but the message has unrecognized values. So
	// let's try to parse the unrecognized bytes, just in case they contain
	// this extension.
	temp := &descriptorpb.FeatureSet{}
	unmarshaler := proto.UnmarshalOptions{
	AllowPartial: true,
	Resolver: resolverForExtension{field},
	}
	if err := unmarshaler.Unmarshal(msgRef.GetUnknown(), temp); err != nil {
	return nil, fmt.Errorf("failed to parse unrecognized fields of FeatureSet: %w", err)
	}
	return temp.ProtoReflect(), nil
	}
	case field.ContainingMessage() == FeatureSetDescriptor:
	// Known field, not dynamically generated. Can directly use with the feature set.
	return msgRef, nil
	default:
	actualField = FeatureSetDescriptor.Fields().ByNumber(field.Number())
	}

	// If we get here, we have a dynamic field descriptor or an extension
	// descriptor whose message type does not match the descriptor of the
	// stored value. We need to copy its value into a dynamic message,
	// which requires marshalling/unmarshalling.
	// We only need to copy over the unrecognized bytes (if any)
	// and the same field (if present).
	data := msgRef.GetUnknown()
	if actualField != nil && msgRef.Has(actualField) {
	subset := &descriptorpb.FeatureSet{}
	subset.ProtoReflect().Set(actualField, msgRef.Get(actualField))
	var err error
	data, err = proto.MarshalOptions{AllowPartial: true}.MarshalAppend(data, subset)
	if err != nil {
	return nil, fmt.Errorf("failed to marshal FeatureSet field %s to bytes: %w", field.Name(), err)
	}
	}
	if len(data) == 0 {
	// No relevant data to copy over, so we can just return
	// a zero value message
	return dynamicpb.NewMessageType(field.ContainingMessage()).Zero(), nil
	}

	other := dynamicpb.NewMessage(field.ContainingMessage())
	// We don't need to use a resolver for this step because we know that
	// field is not an extension. And features are not allowed to themselves
	// have extensions.
	if err := (proto.UnmarshalOptions{AllowPartial: true}).Unmarshal(data, other); err != nil {
	return nil, fmt.Errorf("failed to marshal FeatureSet field %s to bytes: %w", field.Name(), err)
	}
	return other, nil
	}

	type resolverForExtension struct {
	ext protoreflect.ExtensionDescriptor
	}

	func (r resolverForExtension) FindMessageByName(_ protoreflect.FullName) (protoreflect.MessageType, error) {
	return nil, protoregistry.NotFound
	}

	func (r resolverForExtension) FindMessageByURL(_ string) (protoreflect.MessageType, error) {
	return nil, protoregistry.NotFound
	}

	func (r resolverForExtension) FindExtensionByName(field protoreflect.FullName) (protoreflect.ExtensionType, error) {
	if field == r.ext.FullName() {
	return asExtensionType(r.ext), nil
	}
	return nil, protoregistry.NotFound
	}

	func (r resolverForExtension) FindExtensionByNumber(message protoreflect.FullName, field protoreflect.FieldNumber) (protoreflect.ExtensionType, error) {
	if message == r.ext.ContainingMessage().FullName() && field == r.ext.Number() {
	return asExtensionType(r.ext), nil
	}
	return nil, protoregistry.NotFound
	}

	func asExtensionType(ext protoreflect.ExtensionDescriptor) protoreflect.ExtensionType {
	if xtd, ok := ext.(protoreflect.ExtensionTypeDescriptor); ok {
	return xtd.Type()
	}
	return dynamicpb.NewExtensionType(ext)
	}

	func computeSupportedEditions(minEdition, maxEdition descriptorpb.Edition) map[string]descriptorpb.Edition {
	supportedEditions := map[string]descriptorpb.Edition{}
	for editionNum := range descriptorpb.Edition_name {
	edition := descriptorpb.Edition(editionNum)
	if edition >= minEdition && edition <= maxEdition {
	name := strings.TrimPrefix(edition.String(), "EDITION_")
	supportedEditions[name] = edition
	}
	}
	return supportedEditions
	}

	// actualDescriptor returns the actual field descriptor referenced by msg that
	// corresponds to the given ext (i.e. same number). It returns nil if msg has
	// no reference, if the actual descriptor is the same as ext, or if ext is
	// otherwise safe to use as is.
	func actualDescriptor(msg protoreflect.Message, ext protoreflect.ExtensionDescriptor) protoreflect.FieldDescriptor {
	if !msg.Has(ext) \|\| ext.Message() == nil {
	// nothing to match; safe as is
	return nil
	}
	val := msg.Get(ext)
	switch {
	case ext.IsMap(): // should not actually be possible
	expectedDescriptor := ext.MapValue().Message()
	if expectedDescriptor == nil {
	return nil // nothing to match
	}
	// We know msg.Has(field) is true, from above, so there's at least one entry.
	var matches bool
	val.Map().Range(func(_ protoreflect.MapKey, val protoreflect.Value) bool {
	matches = val.Message().Descriptor() == expectedDescriptor
	return false
	})
	if matches {
	return nil
	}
	case ext.IsList():
	// We know msg.Has(field) is true, from above, so there's at least one entry.
	if val.List().Get(0).Message().Descriptor() == ext.Message() {
	return nil
	}
	case !ext.IsMap():
	if val.Message().Descriptor() == ext.Message() {
	return nil
	}
	}
	// The underlying message descriptors do not match. So we need to return
	// the actual field descriptor. Sadly, protoreflect.Message provides no way
	// to query the field descriptor in a message by number. For non-extensions,
	// one can query the associated message descriptor. But for extensions, we
	// have to do the slow thing, and range through all fields looking for it.
	var actualField protoreflect.FieldDescriptor
	msg.Range(func(fd protoreflect.FieldDescriptor, _ protoreflect.Value) bool {
	if fd.Number() == ext.Number() {
	actualField = fd
	return false
	}
	return true
	})
	return actualField
	}