fix openbsd

vendor/google.golang.org/protobuf/proto/decode.go

@@ -47,10 +47,18 @@ type UnmarshalOptions struct {
 	// RecursionLimit limits how deeply messages may be nested.
 	// If zero, a default limit is applied.
 	RecursionLimit int
+
+	//
+	// NoLazyDecoding turns off lazy decoding, which otherwise is enabled by
+	// default. Lazy decoding only affects submessages (annotated with [lazy =
+	// true] in the .proto file) within messages that use the Opaque API.
+	NoLazyDecoding bool
 }
 
 // Unmarshal parses the wire-format message in b and places the result in m.
 // The provided message must be mutable (e.g., a non-nil pointer to a message).
+//
+// See the [UnmarshalOptions] type if you need more control.
 func Unmarshal(b []byte, m Message) error {
 	_, err := UnmarshalOptions{RecursionLimit: protowire.DefaultRecursionLimit}.unmarshal(b, m.ProtoReflect())
 	return err
@@ -69,7 +77,7 @@ func (o UnmarshalOptions) Unmarshal(b []byte, m Message) error {
 // UnmarshalState parses a wire-format message and places the result in m.
 //
 // This method permits fine-grained control over the unmarshaler.
-// Most users should use Unmarshal instead.
+// Most users should use [Unmarshal] instead.
 func (o UnmarshalOptions) UnmarshalState(in protoiface.UnmarshalInput) (protoiface.UnmarshalOutput, error) {
 	if o.RecursionLimit == 0 {
 		o.RecursionLimit = protowire.DefaultRecursionLimit
@@ -102,6 +110,16 @@ func (o UnmarshalOptions) unmarshal(b []byte, m protoreflect.Message) (out proto
 		if o.DiscardUnknown {
 			in.Flags |= protoiface.UnmarshalDiscardUnknown
 		}
+
+		if !allowPartial {
+			// This does not affect how current unmarshal functions work, it just allows them
+			// to record this for lazy the decoding case.
+			in.Flags |= protoiface.UnmarshalCheckRequired
+		}
+		if o.NoLazyDecoding {
+			in.Flags |= protoiface.UnmarshalNoLazyDecoding
+		}
+
 		out, err = methods.Unmarshal(in)
 	} else {
 		o.RecursionLimit--
@@ -154,7 +172,7 @@ func (o UnmarshalOptions) unmarshalMessageSlow(b []byte, m protoreflect.Message)
 		var err error
 		if fd == nil {
 			err = errUnknown
-		} else if flags.ProtoLegacy {
+		} else if flags.ProtoLegacyWeak {
 			if fd.IsWeak() && fd.Message().IsPlaceholder() {
 				err = errUnknown // weak referent is not linked in
 			}

vendor/google.golang.org/protobuf/proto/doc.go

@@ -18,27 +18,27 @@
 // This package contains functions to convert to and from the wire format,
 // an efficient binary serialization of protocol buffers.
 //
-// • Size reports the size of a message in the wire format.
+//   - [Size] reports the size of a message in the wire format.
 //
-// • Marshal converts a message to the wire format.
-// The MarshalOptions type provides more control over wire marshaling.
+//   - [Marshal] converts a message to the wire format.
+//     The [MarshalOptions] type provides more control over wire marshaling.
 //
-// • Unmarshal converts a message from the wire format.
-// The UnmarshalOptions type provides more control over wire unmarshaling.
+//   - [Unmarshal] converts a message from the wire format.
+//     The [UnmarshalOptions] type provides more control over wire unmarshaling.
 //
 // # Basic message operations
 //
-// • Clone makes a deep copy of a message.
+//   - [Clone] makes a deep copy of a message.
 //
-// • Merge merges the content of a message into another.
+//   - [Merge] merges the content of a message into another.
 //
-// • Equal compares two messages. For more control over comparisons
-// and detailed reporting of differences, see package
-// "google.golang.org/protobuf/testing/protocmp".
+//   - [Equal] compares two messages. For more control over comparisons
+//     and detailed reporting of differences, see package
+//     [google.golang.org/protobuf/testing/protocmp].
 //
-// • Reset clears the content of a message.
+//   - [Reset] clears the content of a message.
 //
-// • CheckInitialized reports whether all required fields in a message are set.
+//   - [CheckInitialized] reports whether all required fields in a message are set.
 //
 // # Optional scalar constructors
 //
@@ -46,9 +46,9 @@
 // as pointers to a value. For example, an optional string field has the
 // Go type *string.
 //
-// • Bool, Int32, Int64, Uint32, Uint64, Float32, Float64, and String
-// take a value and return a pointer to a new instance of it,
-// to simplify construction of optional field values.
+//   - [Bool], [Int32], [Int64], [Uint32], [Uint64], [Float32], [Float64], and [String]
+//     take a value and return a pointer to a new instance of it,
+//     to simplify construction of optional field values.
 //
 // Generated enum types usually have an Enum method which performs the
 // same operation.
@@ -57,29 +57,29 @@
 //
 // # Extension accessors
 //
-// • HasExtension, GetExtension, SetExtension, and ClearExtension
-// access extension field values in a protocol buffer message.
+//   - [HasExtension], [GetExtension], [SetExtension], and [ClearExtension]
+//     access extension field values in a protocol buffer message.
 //
 // Extension fields are only supported in proto2.
 //
 // # Related packages
 //
-// • Package "google.golang.org/protobuf/encoding/protojson" converts messages to
-// and from JSON.
+//   - Package [google.golang.org/protobuf/encoding/protojson] converts messages to
+//     and from JSON.
 //
-// • Package "google.golang.org/protobuf/encoding/prototext" converts messages to
-// and from the text format.
+//   - Package [google.golang.org/protobuf/encoding/prototext] converts messages to
+//     and from the text format.
 //
-// • Package "google.golang.org/protobuf/reflect/protoreflect" provides a
-// reflection interface for protocol buffer data types.
+//   - Package [google.golang.org/protobuf/reflect/protoreflect] provides a
+//     reflection interface for protocol buffer data types.
 //
-// • Package "google.golang.org/protobuf/testing/protocmp" provides features
-// to compare protocol buffer messages with the "github.com/google/go-cmp/cmp"
-// package.
+//   - Package [google.golang.org/protobuf/testing/protocmp] provides features
+//     to compare protocol buffer messages with the [github.com/google/go-cmp/cmp]
+//     package.
 //
-// • Package "google.golang.org/protobuf/types/dynamicpb" provides a dynamic
-// message type, suitable for working with messages where the protocol buffer
-// type is only known at runtime.
+//   - Package [google.golang.org/protobuf/types/dynamicpb] provides a dynamic
+//     message type, suitable for working with messages where the protocol buffer
+//     type is only known at runtime.
 //
 // This module contains additional packages for more specialized use cases.
 // Consult the individual package documentation for details.

vendor/google.golang.org/protobuf/proto/encode.go

@@ -5,12 +5,17 @@
 package proto
 
 import (
+	"errors"
+	"fmt"
+
 	"google.golang.org/protobuf/encoding/protowire"
 	"google.golang.org/protobuf/internal/encoding/messageset"
 	"google.golang.org/protobuf/internal/order"
 	"google.golang.org/protobuf/internal/pragma"
 	"google.golang.org/protobuf/reflect/protoreflect"
 	"google.golang.org/protobuf/runtime/protoiface"
+
+	protoerrors "google.golang.org/protobuf/internal/errors"
 )
 
 // MarshalOptions configures the marshaler.
@@ -58,7 +63,8 @@ type MarshalOptions struct {
 	// options (except for UseCachedSize itself).
 	//
 	// 2. The message and all its submessages have not changed in any
-	// way since the Size call.
+	// way since the Size call. For lazily decoded messages, accessing
+	// a message results in decoding the message, which is a change.
 	//
 	// If either of these invariants is violated,
 	// the results are undefined and may include panics or corrupted output.
@@ -70,7 +76,32 @@ type MarshalOptions struct {
 	UseCachedSize bool
 }
 
+// flags turns the specified MarshalOptions (user-facing) into
+// protoiface.MarshalInputFlags (used internally by the marshaler).
+//
+// See impl.marshalOptions.Options for the inverse operation.
+func (o MarshalOptions) flags() protoiface.MarshalInputFlags {
+	var flags protoiface.MarshalInputFlags
+
+	// Note: o.AllowPartial is always forced to true by MarshalOptions.marshal,
+	// which is why it is not a part of MarshalInputFlags.
+
+	if o.Deterministic {
+		flags |= protoiface.MarshalDeterministic
+	}
+
+	if o.UseCachedSize {
+		flags |= protoiface.MarshalUseCachedSize
+	}
+
+	return flags
+}
+
 // Marshal returns the wire-format encoding of m.
+//
+// This is the most common entry point for encoding a Protobuf message.
+//
+// See the [MarshalOptions] type if you need more control.
 func Marshal(m Message) ([]byte, error) {
 	// Treat nil message interface as an empty message; nothing to output.
 	if m == nil {
@@ -116,6 +147,9 @@ func emptyBytesForMessage(m Message) []byte {
 
 // MarshalAppend appends the wire-format encoding of m to b,
 // returning the result.
+//
+// This is a less common entry point than [Marshal], which is only needed if you
+// need to supply your own buffers for performance reasons.
 func (o MarshalOptions) MarshalAppend(b []byte, m Message) ([]byte, error) {
 	// Treat nil message interface as an empty message; nothing to append.
 	if m == nil {
@@ -129,7 +163,7 @@ func (o MarshalOptions) MarshalAppend(b []byte, m Message) ([]byte, error) {
 // MarshalState returns the wire-format encoding of a message.
 //
 // This method permits fine-grained control over the marshaler.
-// Most users should use Marshal instead.
+// Most users should use [Marshal] instead.
 func (o MarshalOptions) MarshalState(in protoiface.MarshalInput) (protoiface.MarshalOutput, error) {
 	return o.marshal(in.Buf, in.Message)
 }
@@ -145,12 +179,7 @@ func (o MarshalOptions) marshal(b []byte, m protoreflect.Message) (out protoifac
 		in := protoiface.MarshalInput{
 			Message: m,
 			Buf:     b,
-		}
-		if o.Deterministic {
-			in.Flags |= protoiface.MarshalDeterministic
-		}
-		if o.UseCachedSize {
-			in.Flags |= protoiface.MarshalUseCachedSize
+			Flags:   o.flags(),
 		}
 		if methods.Size != nil {
 			sout := methods.Size(protoiface.SizeInput{
@@ -168,6 +197,10 @@ func (o MarshalOptions) marshal(b []byte, m protoreflect.Message) (out protoifac
 		out.Buf, err = o.marshalMessageSlow(b, m)
 	}
 	if err != nil {
+		var mismatch *protoerrors.SizeMismatchError
+		if errors.As(err, &mismatch) {
+			return out, fmt.Errorf("marshaling %s: %v", string(m.Descriptor().FullName()), err)
+		}
 		return out, err
 	}
 	if allowPartial {

vendor/google.golang.org/protobuf/proto/equal.go

@@ -8,6 +8,7 @@ import (
 	"reflect"
 
 	"google.golang.org/protobuf/reflect/protoreflect"
+	"google.golang.org/protobuf/runtime/protoiface"
 )
 
 // Equal reports whether two messages are equal,
@@ -51,6 +52,14 @@ func Equal(x, y Message) bool {
 	if mx.IsValid() != my.IsValid() {
 		return false
 	}
+
+	// Only one of the messages needs to implement the fast-path for it to work.
+	pmx := protoMethods(mx)
+	pmy := protoMethods(my)
+	if pmx != nil && pmy != nil && pmx.Equal != nil && pmy.Equal != nil {
+		return pmx.Equal(protoiface.EqualInput{MessageA: mx, MessageB: my}).Equal
+	}
+
 	vx := protoreflect.ValueOfMessage(mx)
 	vy := protoreflect.ValueOfMessage(my)
 	return vx.Equal(vy)

vendor/google.golang.org/protobuf/proto/extension.go

@@ -11,22 +11,25 @@ import (
 // HasExtension reports whether an extension field is populated.
 // It returns false if m is invalid or if xt does not extend m.
 func HasExtension(m Message, xt protoreflect.ExtensionType) bool {
-	// Treat nil message interface as an empty message; no populated fields.
-	if m == nil {
+	// Treat nil message interface or descriptor as an empty message; no populated
+	// fields.
+	if m == nil || xt == nil {
 		return false
 	}
 
 	// As a special-case, we reports invalid or mismatching descriptors
 	// as always not being populated (since they aren't).
-	if xt == nil || m.ProtoReflect().Descriptor() != xt.TypeDescriptor().ContainingMessage() {
+	mr := m.ProtoReflect()
+	xd := xt.TypeDescriptor()
+	if mr.Descriptor() != xd.ContainingMessage() {
 		return false
 	}
 
-	return m.ProtoReflect().Has(xt.TypeDescriptor())
+	return mr.Has(xd)
 }
 
 // ClearExtension clears an extension field such that subsequent
-// HasExtension calls return false.
+// [HasExtension] calls return false.
 // It panics if m is invalid or if xt does not extend m.
 func ClearExtension(m Message, xt protoreflect.ExtensionType) {
 	m.ProtoReflect().Clear(xt.TypeDescriptor())
@@ -36,7 +39,49 @@ func ClearExtension(m Message, xt protoreflect.ExtensionType) {
 // If the field is unpopulated, it returns the default value for
 // scalars and an immutable, empty value for lists or messages.
 // It panics if xt does not extend m.
-func GetExtension(m Message, xt protoreflect.ExtensionType) interface{} {
+//
+// The type of the value is dependent on the field type of the extension.
+// For extensions generated by protoc-gen-go, the Go type is as follows:
+//
+//	╔═══════════════════╤═════════════════════════╗
+//	║ Go type           │ Protobuf kind           ║
+//	╠═══════════════════╪═════════════════════════╣
+//	║ bool              │ bool                    ║
+//	║ int32             │ int32, sint32, sfixed32 ║
+//	║ int64             │ int64, sint64, sfixed64 ║
+//	║ uint32            │ uint32, fixed32         ║
+//	║ uint64            │ uint64, fixed64         ║
+//	║ float32           │ float                   ║
+//	║ float64           │ double                  ║
+//	║ string            │ string                  ║
+//	║ []byte            │ bytes                   ║
+//	║ protoreflect.Enum │ enum                    ║
+//	║ proto.Message     │ message, group          ║
+//	╚═══════════════════╧═════════════════════════╝
+//
+// The protoreflect.Enum and proto.Message types are the concrete Go type
+// associated with the named enum or message. Repeated fields are represented
+// using a Go slice of the base element type.
+//
+// If a generated extension descriptor variable is directly passed to
+// GetExtension, then the call should be followed immediately by a
+// type assertion to the expected output value. For example:
+//
+//	mm := proto.GetExtension(m, foopb.E_MyExtension).(*foopb.MyMessage)
+//
+// This pattern enables static analysis tools to verify that the asserted type
+// matches the Go type associated with the extension field and
+// also enables a possible future migration to a type-safe extension API.
+//
+// Since singular messages are the most common extension type, the pattern of
+// calling HasExtension followed by GetExtension may be simplified to:
+//
+//	if mm := proto.GetExtension(m, foopb.E_MyExtension).(*foopb.MyMessage); mm != nil {
+//	    ... // make use of mm
+//	}
+//
+// The mm variable is non-nil if and only if HasExtension reports true.
+func GetExtension(m Message, xt protoreflect.ExtensionType) any {
 	// Treat nil message interface as an empty message; return the default.
 	if m == nil {
 		return xt.InterfaceOf(xt.Zero())
@@ -48,7 +93,36 @@ func GetExtension(m Message, xt protoreflect.ExtensionType) interface{} {
 // SetExtension stores the value of an extension field.
 // It panics if m is invalid, xt does not extend m, or if type of v
 // is invalid for the specified extension field.
-func SetExtension(m Message, xt protoreflect.ExtensionType, v interface{}) {
+//
+// The type of the value is dependent on the field type of the extension.
+// For extensions generated by protoc-gen-go, the Go type is as follows:
+//
+//	╔═══════════════════╤═════════════════════════╗
+//	║ Go type           │ Protobuf kind           ║
+//	╠═══════════════════╪═════════════════════════╣
+//	║ bool              │ bool                    ║
+//	║ int32             │ int32, sint32, sfixed32 ║
+//	║ int64             │ int64, sint64, sfixed64 ║
+//	║ uint32            │ uint32, fixed32         ║
+//	║ uint64            │ uint64, fixed64         ║
+//	║ float32           │ float                   ║
+//	║ float64           │ double                  ║
+//	║ string            │ string                  ║
+//	║ []byte            │ bytes                   ║
+//	║ protoreflect.Enum │ enum                    ║
+//	║ proto.Message     │ message, group          ║
+//	╚═══════════════════╧═════════════════════════╝
+//
+// The protoreflect.Enum and proto.Message types are the concrete Go type
+// associated with the named enum or message. Repeated fields are represented
+// using a Go slice of the base element type.
+//
+// If a generated extension descriptor variable is directly passed to
+// SetExtension (e.g., foopb.E_MyExtension), then the value should be a
+// concrete type that matches the expected Go type for the extension descriptor
+// so that static analysis tools can verify type correctness.
+// This also enables a possible future migration to a type-safe extension API.
+func SetExtension(m Message, xt protoreflect.ExtensionType, v any) {
 	xd := xt.TypeDescriptor()
 	pv := xt.ValueOf(v)
 
@@ -75,7 +149,7 @@ func SetExtension(m Message, xt protoreflect.ExtensionType, v interface{}) {
 // It returns immediately if f returns false.
 // While iterating, mutating operations may only be performed
 // on the current extension field.
-func RangeExtensions(m Message, f func(protoreflect.ExtensionType, interface{}) bool) {
+func RangeExtensions(m Message, f func(protoreflect.ExtensionType, any) bool) {
 	// Treat nil message interface as an empty message; nothing to range over.
 	if m == nil {
 		return

vendor/google.golang.org/protobuf/proto/merge.go

@@ -21,7 +21,7 @@ import (
 // The unknown fields of src are appended to the unknown fields of dst.
 //
 // It is semantically equivalent to unmarshaling the encoded form of src
-// into dst with the UnmarshalOptions.Merge option specified.
+// into dst with the [UnmarshalOptions.Merge] option specified.
 func Merge(dst, src Message) {
 	// TODO: Should nil src be treated as semantically equivalent to a
 	// untyped, read-only, empty message? What about a nil dst?

vendor/google.golang.org/protobuf/proto/messageset.go

@@ -47,11 +47,16 @@ func (o MarshalOptions) marshalMessageSet(b []byte, m protoreflect.Message) ([]b
 func (o MarshalOptions) marshalMessageSetField(b []byte, fd protoreflect.FieldDescriptor, value protoreflect.Value) ([]byte, error) {
 	b = messageset.AppendFieldStart(b, fd.Number())
 	b = protowire.AppendTag(b, messageset.FieldMessage, protowire.BytesType)
-	b = protowire.AppendVarint(b, uint64(o.Size(value.Message().Interface())))
+	calculatedSize := o.Size(value.Message().Interface())
+	b = protowire.AppendVarint(b, uint64(calculatedSize))
+	before := len(b)
 	b, err := o.marshalMessage(b, value.Message())
 	if err != nil {
 		return b, err
 	}
+	if measuredSize := len(b) - before; calculatedSize != measuredSize {
+		return nil, errors.MismatchedSizeCalculation(calculatedSize, measuredSize)
+	}
 	b = messageset.AppendFieldEnd(b)
 	return b, nil
 }

vendor/google.golang.org/protobuf/proto/proto.go

@@ -15,18 +15,20 @@ import (
 // protobuf module that accept a Message, except where otherwise specified.
 //
 // This is the v2 interface definition for protobuf messages.
-// The v1 interface definition is "github.com/golang/protobuf/proto".Message.
+// The v1 interface definition is [github.com/golang/protobuf/proto.Message].
 //
-// To convert a v1 message to a v2 message,
-// use "github.com/golang/protobuf/proto".MessageV2.
-// To convert a v2 message to a v1 message,
-// use "github.com/golang/protobuf/proto".MessageV1.
+//   - To convert a v1 message to a v2 message,
+//     use [google.golang.org/protobuf/protoadapt.MessageV2Of].
+//   - To convert a v2 message to a v1 message,
+//     use [google.golang.org/protobuf/protoadapt.MessageV1Of].
 type Message = protoreflect.ProtoMessage
 
-// Error matches all errors produced by packages in the protobuf module.
+// Error matches all errors produced by packages in the protobuf module
+// according to [errors.Is].
 //
-// That is, errors.Is(err, Error) reports whether an error is produced
-// by this module.
+// Example usage:
+//
+//	if errors.Is(err, proto.Error) { ... }
 var Error error
 
 func init() {

vendor/google.golang.org/protobuf/proto/size.go

@@ -12,11 +12,19 @@ import (
 )
 
 // Size returns the size in bytes of the wire-format encoding of m.
+//
+// Note that Size might return more bytes than Marshal will write in the case of
+// lazily decoded messages that arrive in non-minimal wire format: see
+// https://protobuf.dev/reference/go/size/ for more details.
 func Size(m Message) int {
 	return MarshalOptions{}.Size(m)
 }
 
 // Size returns the size in bytes of the wire-format encoding of m.
+//
+// Note that Size might return more bytes than Marshal will write in the case of
+// lazily decoded messages that arrive in non-minimal wire format: see
+// https://protobuf.dev/reference/go/size/ for more details.
 func (o MarshalOptions) Size(m Message) int {
 	// Treat a nil message interface as an empty message; nothing to output.
 	if m == nil {
@@ -34,6 +42,7 @@ func (o MarshalOptions) size(m protoreflect.Message) (size int) {
 	if methods != nil && methods.Size != nil {
 		out := methods.Size(protoiface.SizeInput{
 			Message: m,
+			Flags:   o.flags(),
 		})
 		return out.Size
 	}
@@ -42,6 +51,7 @@ func (o MarshalOptions) size(m protoreflect.Message) (size int) {
 		// This case is mainly used for legacy types with a Marshal method.
 		out, _ := methods.Marshal(protoiface.MarshalInput{
 			Message: m,
+			Flags:   o.flags(),
 		})
 		return len(out.Buf)
 	}
@@ -73,23 +83,27 @@ func (o MarshalOptions) sizeField(fd protoreflect.FieldDescriptor, value protore
 }
 
 func (o MarshalOptions) sizeList(num protowire.Number, fd protoreflect.FieldDescriptor, list protoreflect.List) (size int) {
+	sizeTag := protowire.SizeTag(num)
+
 	if fd.IsPacked() && list.Len() > 0 {
 		content := 0
 		for i, llen := 0, list.Len(); i < llen; i++ {
 			content += o.sizeSingular(num, fd.Kind(), list.Get(i))
 		}
-		return protowire.SizeTag(num) + protowire.SizeBytes(content)
+		return sizeTag + protowire.SizeBytes(content)
 	}
 
 	for i, llen := 0, list.Len(); i < llen; i++ {
-		size += protowire.SizeTag(num) + o.sizeSingular(num, fd.Kind(), list.Get(i))
+		size += sizeTag + o.sizeSingular(num, fd.Kind(), list.Get(i))
 	}
 	return size
 }
 
 func (o MarshalOptions) sizeMap(num protowire.Number, fd protoreflect.FieldDescriptor, mapv protoreflect.Map) (size int) {
+	sizeTag := protowire.SizeTag(num)
+
 	mapv.Range(func(key protoreflect.MapKey, value protoreflect.Value) bool {
-		size += protowire.SizeTag(num)
+		size += sizeTag
 		size += protowire.SizeBytes(o.sizeField(fd.MapKey(), key.Value()) + o.sizeField(fd.MapValue(), value))
 		return true
 	})

vendor/google.golang.org/protobuf/proto/wrapperopaque.go

@@ -0,0 +1,80 @@
+// Copyright 2024 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package proto
+
+// ValueOrNil returns nil if has is false, or a pointer to a new variable
+// containing the value returned by the specified getter.
+//
+// This function is similar to the wrappers (proto.Int32(), proto.String(),
+// etc.), but is generic (works for any field type) and works with the hasser
+// and getter of a field, as opposed to a value.
+//
+// This is convenient when populating builder fields.
+//
+// Example:
+//
+//	hop := attr.GetDirectHop()
+//	injectedRoute := ripb.InjectedRoute_builder{
+//	  Prefixes: route.GetPrefixes(),
+//	  NextHop:  proto.ValueOrNil(hop.HasAddress(), hop.GetAddress),
+//	}
+func ValueOrNil[T any](has bool, getter func() T) *T {
+	if !has {
+		return nil
+	}
+	v := getter()
+	return &v
+}
+
+// ValueOrDefault returns the protobuf message val if val is not nil, otherwise
+// it returns a pointer to an empty val message.
+//
+// This function allows for translating code from the old Open Struct API to the
+// new Opaque API.
+//
+// The old Open Struct API represented oneof fields with a wrapper struct:
+//
+//	var signedImg *accountpb.SignedImage
+//	profile := &accountpb.Profile{
+//		// The Avatar oneof will be set, with an empty SignedImage.
+//		Avatar: &accountpb.Profile_SignedImage{signedImg},
+//	}
+//
+// The new Opaque API treats oneof fields like regular fields, there are no more
+// wrapper structs:
+//
+//	var signedImg *accountpb.SignedImage
+//	profile := &accountpb.Profile{}
+//	profile.SetSignedImage(signedImg)
+//
+// For convenience, the Opaque API also offers Builders, which allow for a
+// direct translation of struct initialization. However, because Builders use
+// nilness to represent field presence (but there is no non-nil wrapper struct
+// anymore), Builders cannot distinguish between an unset oneof and a set oneof
+// with nil message. The above code would need to be translated with help of the
+// ValueOrDefault function to retain the same behavior:
+//
+//	var signedImg *accountpb.SignedImage
+//	return &accountpb.Profile_builder{
+//		SignedImage: proto.ValueOrDefault(signedImg),
+//	}.Build()
+func ValueOrDefault[T interface {
+	*P
+	Message
+}, P any](val T) T {
+	if val == nil {
+		return T(new(P))
+	}
+	return val
+}
+
+// ValueOrDefaultBytes is like ValueOrDefault but for working with fields of
+// type []byte.
+func ValueOrDefaultBytes(val []byte) []byte {
+	if val == nil {
+		return []byte{}
+	}
+	return val
+}