Update deps

vendor/google.golang.org/protobuf/internal/impl/api_export.go

@@ -167,7 +167,7 @@ func (Export) MessageTypeOf(m message) pref.MessageType {
 	if mv := (Export{}).protoMessageV2Of(m); mv != nil {
 		return mv.ProtoReflect().Type()
 	}
-	return legacyLoadMessageInfo(reflect.TypeOf(m), "")
+	return legacyLoadMessageType(reflect.TypeOf(m), "")
 }
 
 // MessageStringOf returns the message value as a string,

vendor/google.golang.org/protobuf/internal/impl/codec_field.go

@@ -10,6 +10,7 @@ import (
 	"sync"
 
 	"google.golang.org/protobuf/encoding/protowire"
+	"google.golang.org/protobuf/internal/errors"
 	"google.golang.org/protobuf/proto"
 	pref "google.golang.org/protobuf/reflect/protoreflect"
 	preg "google.golang.org/protobuf/reflect/protoregistry"
@@ -20,6 +21,7 @@ type errInvalidUTF8 struct{}
 
 func (errInvalidUTF8) Error() string     { return "string field contains invalid UTF-8" }
 func (errInvalidUTF8) InvalidUTF8() bool { return true }
+func (errInvalidUTF8) Unwrap() error     { return errors.Error }
 
 // initOneofFieldCoders initializes the fast-path functions for the fields in a oneof.
 //
@@ -242,7 +244,7 @@ func consumeMessageInfo(b []byte, p pointer, wtyp protowire.Type, f *coderFieldI
 	}
 	v, n := protowire.ConsumeBytes(b)
 	if n < 0 {
-		return out, protowire.ParseError(n)
+		return out, errDecode
 	}
 	if p.Elem().IsNil() {
 		p.SetPointer(pointerOfValue(reflect.New(f.mi.GoReflectType.Elem())))
@@ -276,7 +278,7 @@ func consumeMessage(b []byte, m proto.Message, wtyp protowire.Type, opts unmarsh
 	}
 	v, n := protowire.ConsumeBytes(b)
 	if n < 0 {
-		return out, protowire.ParseError(n)
+		return out, errDecode
 	}
 	o, err := opts.Options().UnmarshalState(piface.UnmarshalInput{
 		Buf:     v,
@@ -420,7 +422,7 @@ func consumeGroup(b []byte, m proto.Message, num protowire.Number, wtyp protowir
 	}
 	b, n := protowire.ConsumeGroup(num, b)
 	if n < 0 {
-		return out, protowire.ParseError(n)
+		return out, errDecode
 	}
 	o, err := opts.Options().UnmarshalState(piface.UnmarshalInput{
 		Buf:     b,
@@ -494,7 +496,7 @@ func consumeMessageSliceInfo(b []byte, p pointer, wtyp protowire.Type, f *coderF
 	}
 	v, n := protowire.ConsumeBytes(b)
 	if n < 0 {
-		return out, protowire.ParseError(n)
+		return out, errDecode
 	}
 	m := reflect.New(f.mi.GoReflectType.Elem()).Interface()
 	mp := pointerOfIface(m)
@@ -550,7 +552,7 @@ func consumeMessageSlice(b []byte, p pointer, goType reflect.Type, wtyp protowir
 	}
 	v, n := protowire.ConsumeBytes(b)
 	if n < 0 {
-		return out, protowire.ParseError(n)
+		return out, errDecode
 	}
 	mp := reflect.New(goType.Elem())
 	o, err := opts.Options().UnmarshalState(piface.UnmarshalInput{
@@ -613,7 +615,7 @@ func consumeMessageSliceValue(b []byte, listv pref.Value, _ protowire.Number, wt
 	}
 	v, n := protowire.ConsumeBytes(b)
 	if n < 0 {
-		return pref.Value{}, out, protowire.ParseError(n)
+		return pref.Value{}, out, errDecode
 	}
 	m := list.NewElement()
 	o, err := opts.Options().UnmarshalState(piface.UnmarshalInput{
@@ -681,7 +683,7 @@ func consumeGroupSliceValue(b []byte, listv pref.Value, num protowire.Number, wt
 	}
 	b, n := protowire.ConsumeGroup(num, b)
 	if n < 0 {
-		return pref.Value{}, out, protowire.ParseError(n)
+		return pref.Value{}, out, errDecode
 	}
 	m := list.NewElement()
 	o, err := opts.Options().UnmarshalState(piface.UnmarshalInput{
@@ -767,7 +769,7 @@ func consumeGroupSlice(b []byte, p pointer, num protowire.Number, wtyp protowire
 	}
 	b, n := protowire.ConsumeGroup(num, b)
 	if n < 0 {
-		return out, protowire.ParseError(n)
+		return out, errDecode
 	}
 	mp := reflect.New(goType.Elem())
 	o, err := opts.Options().UnmarshalState(piface.UnmarshalInput{

vendor/google.golang.org/protobuf/internal/impl/codec_map.go

@@ -5,7 +5,6 @@
 package impl
 
 import (
-	"errors"
 	"reflect"
 	"sort"
 
@@ -118,7 +117,7 @@ func consumeMap(b []byte, mapv reflect.Value, wtyp protowire.Type, mapi *mapInfo
 	}
 	b, n := protowire.ConsumeBytes(b)
 	if n < 0 {
-		return out, protowire.ParseError(n)
+		return out, errDecode
 	}
 	var (
 		key = mapi.keyZero
@@ -127,10 +126,10 @@ func consumeMap(b []byte, mapv reflect.Value, wtyp protowire.Type, mapi *mapInfo
 	for len(b) > 0 {
 		num, wtyp, n := protowire.ConsumeTag(b)
 		if n < 0 {
-			return out, protowire.ParseError(n)
+			return out, errDecode
 		}
 		if num > protowire.MaxValidNumber {
-			return out, errors.New("invalid field number")
+			return out, errDecode
 		}
 		b = b[n:]
 		err := errUnknown
@@ -157,7 +156,7 @@ func consumeMap(b []byte, mapv reflect.Value, wtyp protowire.Type, mapi *mapInfo
 		if err == errUnknown {
 			n = protowire.ConsumeFieldValue(num, wtyp, b)
 			if n < 0 {
-				return out, protowire.ParseError(n)
+				return out, errDecode
 			}
 		} else if err != nil {
 			return out, err
@@ -175,7 +174,7 @@ func consumeMapOfMessage(b []byte, mapv reflect.Value, wtyp protowire.Type, mapi
 	}
 	b, n := protowire.ConsumeBytes(b)
 	if n < 0 {
-		return out, protowire.ParseError(n)
+		return out, errDecode
 	}
 	var (
 		key = mapi.keyZero
@@ -184,10 +183,10 @@ func consumeMapOfMessage(b []byte, mapv reflect.Value, wtyp protowire.Type, mapi
 	for len(b) > 0 {
 		num, wtyp, n := protowire.ConsumeTag(b)
 		if n < 0 {
-			return out, protowire.ParseError(n)
+			return out, errDecode
 		}
 		if num > protowire.MaxValidNumber {
-			return out, errors.New("invalid field number")
+			return out, errDecode
 		}
 		b = b[n:]
 		err := errUnknown
@@ -208,7 +207,7 @@ func consumeMapOfMessage(b []byte, mapv reflect.Value, wtyp protowire.Type, mapi
 			var v []byte
 			v, n = protowire.ConsumeBytes(b)
 			if n < 0 {
-				return out, protowire.ParseError(n)
+				return out, errDecode
 			}
 			var o unmarshalOutput
 			o, err = f.mi.unmarshalPointer(v, pointerOfValue(val), 0, opts)
@@ -221,7 +220,7 @@ func consumeMapOfMessage(b []byte, mapv reflect.Value, wtyp protowire.Type, mapi
 		if err == errUnknown {
 			n = protowire.ConsumeFieldValue(num, wtyp, b)
 			if n < 0 {
-				return out, protowire.ParseError(n)
+				return out, errDecode
 			}
 		} else if err != nil {
 			return out, err

vendor/google.golang.org/protobuf/internal/impl/codec_message.go

@@ -11,7 +11,7 @@ import (
 
 	"google.golang.org/protobuf/encoding/protowire"
 	"google.golang.org/protobuf/internal/encoding/messageset"
-	"google.golang.org/protobuf/internal/fieldsort"
+	"google.golang.org/protobuf/internal/order"
 	pref "google.golang.org/protobuf/reflect/protoreflect"
 	piface "google.golang.org/protobuf/runtime/protoiface"
 )
@@ -27,6 +27,7 @@ type coderMessageInfo struct {
 	coderFields        map[protowire.Number]*coderFieldInfo
 	sizecacheOffset    offset
 	unknownOffset      offset
+	unknownPtrKind     bool
 	extensionOffset    offset
 	needsInitCheck     bool
 	isMessageSet       bool
@@ -47,9 +48,20 @@ type coderFieldInfo struct {
 }
 
 func (mi *MessageInfo) makeCoderMethods(t reflect.Type, si structInfo) {
-	mi.sizecacheOffset = si.sizecacheOffset
-	mi.unknownOffset = si.unknownOffset
-	mi.extensionOffset = si.extensionOffset
+	mi.sizecacheOffset = invalidOffset
+	mi.unknownOffset = invalidOffset
+	mi.extensionOffset = invalidOffset
+
+	if si.sizecacheOffset.IsValid() && si.sizecacheType == sizecacheType {
+		mi.sizecacheOffset = si.sizecacheOffset
+	}
+	if si.unknownOffset.IsValid() && (si.unknownType == unknownFieldsAType || si.unknownType == unknownFieldsBType) {
+		mi.unknownOffset = si.unknownOffset
+		mi.unknownPtrKind = si.unknownType.Kind() == reflect.Ptr
+	}
+	if si.extensionOffset.IsValid() && si.extensionType == extensionFieldsType {
+		mi.extensionOffset = si.extensionOffset
+	}
 
 	mi.coderFields = make(map[protowire.Number]*coderFieldInfo)
 	fields := mi.Desc.Fields()
@@ -73,6 +85,27 @@ func (mi *MessageInfo) makeCoderMethods(t reflect.Type, si structInfo) {
 		var funcs pointerCoderFuncs
 		var childMessage *MessageInfo
 		switch {
+		case ft == nil:
+			// This never occurs for generated message types.
+			// It implies that a hand-crafted type has missing Go fields
+			// for specific protobuf message fields.
+			funcs = pointerCoderFuncs{
+				size: func(p pointer, f *coderFieldInfo, opts marshalOptions) int {
+					return 0
+				},
+				marshal: func(b []byte, p pointer, f *coderFieldInfo, opts marshalOptions) ([]byte, error) {
+					return nil, nil
+				},
+				unmarshal: func(b []byte, p pointer, wtyp protowire.Type, f *coderFieldInfo, opts unmarshalOptions) (unmarshalOutput, error) {
+					panic("missing Go struct field for " + string(fd.FullName()))
+				},
+				isInit: func(p pointer, f *coderFieldInfo) error {
+					panic("missing Go struct field for " + string(fd.FullName()))
+				},
+				merge: func(dst, src pointer, f *coderFieldInfo, opts mergeOptions) {
+					panic("missing Go struct field for " + string(fd.FullName()))
+				},
+			}
 		case isOneof:
 			fieldOffset = offsetOf(fs, mi.Exporter)
 		case fd.IsWeak():
@@ -136,7 +169,7 @@ func (mi *MessageInfo) makeCoderMethods(t reflect.Type, si structInfo) {
 		sort.Slice(mi.orderedCoderFields, func(i, j int) bool {
 			fi := fields.ByNumber(mi.orderedCoderFields[i].num)
 			fj := fields.ByNumber(mi.orderedCoderFields[j].num)
-			return fieldsort.Less(fi, fj)
+			return order.LegacyFieldOrder(fi, fj)
 		})
 	}
 
@@ -157,3 +190,28 @@ func (mi *MessageInfo) makeCoderMethods(t reflect.Type, si structInfo) {
 		mi.methods.Merge = mi.merge
 	}
 }
+
+// getUnknownBytes returns a *[]byte for the unknown fields.
+// It is the caller's responsibility to check whether the pointer is nil.
+// This function is specially designed to be inlineable.
+func (mi *MessageInfo) getUnknownBytes(p pointer) *[]byte {
+	if mi.unknownPtrKind {
+		return *p.Apply(mi.unknownOffset).BytesPtr()
+	} else {
+		return p.Apply(mi.unknownOffset).Bytes()
+	}
+}
+
+// mutableUnknownBytes returns a *[]byte for the unknown fields.
+// The returned pointer is guaranteed to not be nil.
+func (mi *MessageInfo) mutableUnknownBytes(p pointer) *[]byte {
+	if mi.unknownPtrKind {
+		bp := p.Apply(mi.unknownOffset).BytesPtr()
+		if *bp == nil {
+			*bp = new([]byte)
+		}
+		return *bp
+	} else {
+		return p.Apply(mi.unknownOffset).Bytes()
+	}
+}

vendor/google.golang.org/protobuf/internal/impl/codec_messageset.go

@@ -29,8 +29,9 @@ func sizeMessageSet(mi *MessageInfo, p pointer, opts marshalOptions) (size int)
 		size += xi.funcs.size(x.Value(), protowire.SizeTag(messageset.FieldMessage), opts)
 	}
 
-	unknown := *p.Apply(mi.unknownOffset).Bytes()
-	size += messageset.SizeUnknown(unknown)
+	if u := mi.getUnknownBytes(p); u != nil {
+		size += messageset.SizeUnknown(*u)
+	}
 
 	return size
 }
@@ -69,10 +70,12 @@ func marshalMessageSet(mi *MessageInfo, b []byte, p pointer, opts marshalOptions
 		}
 	}
 
-	unknown := *p.Apply(mi.unknownOffset).Bytes()
-	b, err := messageset.AppendUnknown(b, unknown)
-	if err != nil {
-		return b, err
+	if u := mi.getUnknownBytes(p); u != nil {
+		var err error
+		b, err = messageset.AppendUnknown(b, *u)
+		if err != nil {
+			return b, err
+		}
 	}
 
 	return b, nil
@@ -100,13 +103,13 @@ func unmarshalMessageSet(mi *MessageInfo, b []byte, p pointer, opts unmarshalOpt
 		*ep = make(map[int32]ExtensionField)
 	}
 	ext := *ep
-	unknown := p.Apply(mi.unknownOffset).Bytes()
 	initialized := true
 	err = messageset.Unmarshal(b, true, func(num protowire.Number, v []byte) error {
 		o, err := mi.unmarshalExtension(v, num, protowire.BytesType, ext, opts)
 		if err == errUnknown {
-			*unknown = protowire.AppendTag(*unknown, num, protowire.BytesType)
-			*unknown = append(*unknown, v...)
+			u := mi.mutableUnknownBytes(p)
+			*u = protowire.AppendTag(*u, num, protowire.BytesType)
+			*u = append(*u, v...)
 			return nil
 		}
 		if !o.initialized {

vendor/google.golang.org/protobuf/internal/impl/codec_reflect.go

@@ -30,7 +30,7 @@ func consumeEnum(b []byte, p pointer, wtyp protowire.Type, f *coderFieldInfo, _
 	}
 	v, n := protowire.ConsumeVarint(b)
 	if n < 0 {
-		return out, protowire.ParseError(n)
+		return out, errDecode
 	}
 	p.v.Elem().SetInt(int64(v))
 	out.n = n
@@ -130,12 +130,12 @@ func consumeEnumSlice(b []byte, p pointer, wtyp protowire.Type, f *coderFieldInf
 	if wtyp == protowire.BytesType {
 		b, n := protowire.ConsumeBytes(b)
 		if n < 0 {
-			return out, protowire.ParseError(n)
+			return out, errDecode
 		}
 		for len(b) > 0 {
 			v, n := protowire.ConsumeVarint(b)
 			if n < 0 {
-				return out, protowire.ParseError(n)
+				return out, errDecode
 			}
 			rv := reflect.New(s.Type().Elem()).Elem()
 			rv.SetInt(int64(v))
@@ -150,7 +150,7 @@ func consumeEnumSlice(b []byte, p pointer, wtyp protowire.Type, f *coderFieldInf
 	}
 	v, n := protowire.ConsumeVarint(b)
 	if n < 0 {
-		return out, protowire.ParseError(n)
+		return out, errDecode
 	}
 	rv := reflect.New(s.Type().Elem()).Elem()
 	rv.SetInt(int64(v))

vendor/google.golang.org/protobuf/internal/impl/convert.go

@@ -423,6 +423,13 @@ func (c *messageConverter) PBValueOf(v reflect.Value) pref.Value {
 	if v.Type() != c.goType {
 		panic(fmt.Sprintf("invalid type: got %v, want %v", v.Type(), c.goType))
 	}
+	if c.isNonPointer() {
+		if v.CanAddr() {
+			v = v.Addr() // T => *T
+		} else {
+			v = reflect.Zero(reflect.PtrTo(v.Type()))
+		}
+	}
 	if m, ok := v.Interface().(pref.ProtoMessage); ok {
 		return pref.ValueOfMessage(m.ProtoReflect())
 	}
@@ -437,6 +444,16 @@ func (c *messageConverter) GoValueOf(v pref.Value) reflect.Value {
 	} else {
 		rv = reflect.ValueOf(m.Interface())
 	}
+	if c.isNonPointer() {
+		if rv.Type() != reflect.PtrTo(c.goType) {
+			panic(fmt.Sprintf("invalid type: got %v, want %v", rv.Type(), reflect.PtrTo(c.goType)))
+		}
+		if !rv.IsNil() {
+			rv = rv.Elem() // *T => T
+		} else {
+			rv = reflect.Zero(rv.Type().Elem())
+		}
+	}
 	if rv.Type() != c.goType {
 		panic(fmt.Sprintf("invalid type: got %v, want %v", rv.Type(), c.goType))
 	}
@@ -451,6 +468,9 @@ func (c *messageConverter) IsValidPB(v pref.Value) bool {
 	} else {
 		rv = reflect.ValueOf(m.Interface())
 	}
+	if c.isNonPointer() {
+		return rv.Type() == reflect.PtrTo(c.goType)
+	}
 	return rv.Type() == c.goType
 }
 
@@ -459,9 +479,18 @@ func (c *messageConverter) IsValidGo(v reflect.Value) bool {
 }
 
 func (c *messageConverter) New() pref.Value {
+	if c.isNonPointer() {
+		return c.PBValueOf(reflect.New(c.goType).Elem())
+	}
 	return c.PBValueOf(reflect.New(c.goType.Elem()))
 }
 
 func (c *messageConverter) Zero() pref.Value {
 	return c.PBValueOf(reflect.Zero(c.goType))
 }
+
+// isNonPointer reports whether the type is a non-pointer type.
+// This never occurs for generated message types.
+func (c *messageConverter) isNonPointer() bool {
+	return c.goType.Kind() != reflect.Ptr
+}

vendor/google.golang.org/protobuf/internal/impl/decode.go

@@ -17,6 +17,8 @@ import (
 	piface "google.golang.org/protobuf/runtime/protoiface"
 )
 
+var errDecode = errors.New("cannot parse invalid wire-format data")
+
 type unmarshalOptions struct {
 	flags    protoiface.UnmarshalInputFlags
 	resolver interface {
@@ -100,13 +102,13 @@ func (mi *MessageInfo) unmarshalPointer(b []byte, p pointer, groupTag protowire.
 			var n int
 			tag, n = protowire.ConsumeVarint(b)
 			if n < 0 {
-				return out, protowire.ParseError(n)
+				return out, errDecode
 			}
 			b = b[n:]
 		}
 		var num protowire.Number
 		if n := tag >> 3; n < uint64(protowire.MinValidNumber) || n > uint64(protowire.MaxValidNumber) {
-			return out, errors.New("invalid field number")
+			return out, errDecode
 		} else {
 			num = protowire.Number(n)
 		}
@@ -114,7 +116,7 @@ func (mi *MessageInfo) unmarshalPointer(b []byte, p pointer, groupTag protowire.
 
 		if wtyp == protowire.EndGroupType {
 			if num != groupTag {
-				return out, errors.New("mismatching end group marker")
+				return out, errDecode
 			}
 			groupTag = 0
 			break
@@ -170,10 +172,10 @@ func (mi *MessageInfo) unmarshalPointer(b []byte, p pointer, groupTag protowire.
 			}
 			n = protowire.ConsumeFieldValue(num, wtyp, b)
 			if n < 0 {
-				return out, protowire.ParseError(n)
+				return out, errDecode
 			}
 			if !opts.DiscardUnknown() && mi.unknownOffset.IsValid() {
-				u := p.Apply(mi.unknownOffset).Bytes()
+				u := mi.mutableUnknownBytes(p)
 				*u = protowire.AppendTag(*u, num, wtyp)
 				*u = append(*u, b[:n]...)
 			}
@@ -181,7 +183,7 @@ func (mi *MessageInfo) unmarshalPointer(b []byte, p pointer, groupTag protowire.
 		b = b[n:]
 	}
 	if groupTag != 0 {
-		return out, errors.New("missing end group marker")
+		return out, errDecode
 	}
 	if mi.numRequiredFields > 0 && bits.OnesCount64(requiredMask) != int(mi.numRequiredFields) {
 		initialized = false
@@ -221,7 +223,7 @@ func (mi *MessageInfo) unmarshalExtension(b []byte, num protowire.Number, wtyp p
 					return out, nil
 				}
 			case ValidationInvalid:
-				return out, errors.New("invalid wire format")
+				return out, errDecode
 			case ValidationUnknown:
 			}
 		}

vendor/google.golang.org/protobuf/internal/impl/encode.go

@@ -79,8 +79,9 @@ func (mi *MessageInfo) sizePointerSlow(p pointer, opts marshalOptions) (size int
 		size += f.funcs.size(fptr, f, opts)
 	}
 	if mi.unknownOffset.IsValid() {
-		u := *p.Apply(mi.unknownOffset).Bytes()
-		size += len(u)
+		if u := mi.getUnknownBytes(p); u != nil {
+			size += len(*u)
+		}
 	}
 	if mi.sizecacheOffset.IsValid() {
 		if size > math.MaxInt32 {
@@ -141,8 +142,9 @@ func (mi *MessageInfo) marshalAppendPointer(b []byte, p pointer, opts marshalOpt
 		}
 	}
 	if mi.unknownOffset.IsValid() && !mi.isMessageSet {
-		u := *p.Apply(mi.unknownOffset).Bytes()
-		b = append(b, u...)
+		if u := mi.getUnknownBytes(p); u != nil {
+			b = append(b, (*u)...)
+		}
 	}
 	return b, nil
 }

vendor/google.golang.org/protobuf/internal/impl/legacy_export.go

@@ -30,7 +30,7 @@ func (Export) LegacyMessageTypeOf(m piface.MessageV1, name pref.FullName) pref.M
 	if mv := (Export{}).protoMessageV2Of(m); mv != nil {
 		return mv.ProtoReflect().Type()
 	}
-	return legacyLoadMessageInfo(reflect.TypeOf(m), name)
+	return legacyLoadMessageType(reflect.TypeOf(m), name)
 }
 
 // UnmarshalJSONEnum unmarshals an enum from a JSON-encoded input.

vendor/google.golang.org/protobuf/internal/impl/legacy_extension.go

@@ -154,7 +154,8 @@ func (x placeholderExtension) Number() pref.FieldNumber                   { retu
 func (x placeholderExtension) Cardinality() pref.Cardinality              { return 0 }
 func (x placeholderExtension) Kind() pref.Kind                            { return 0 }
 func (x placeholderExtension) HasJSONName() bool                          { return false }
-func (x placeholderExtension) JSONName() string                           { return "" }
+func (x placeholderExtension) JSONName() string                           { return "[" + string(x.name) + "]" }
+func (x placeholderExtension) TextName() string                           { return "[" + string(x.name) + "]" }
 func (x placeholderExtension) HasPresence() bool                          { return false }
 func (x placeholderExtension) HasOptionalKeyword() bool                   { return false }
 func (x placeholderExtension) IsExtension() bool                          { return true }

vendor/google.golang.org/protobuf/internal/impl/legacy_message.go

@@ -24,14 +24,24 @@ import (
 // legacyWrapMessage wraps v as a protoreflect.Message,
 // where v must be a *struct kind and not implement the v2 API already.
 func legacyWrapMessage(v reflect.Value) pref.Message {
-	typ := v.Type()
-	if typ.Kind() != reflect.Ptr || typ.Elem().Kind() != reflect.Struct {
+	t := v.Type()
+	if t.Kind() != reflect.Ptr || t.Elem().Kind() != reflect.Struct {
 		return aberrantMessage{v: v}
 	}
-	mt := legacyLoadMessageInfo(typ, "")
+	mt := legacyLoadMessageInfo(t, "")
 	return mt.MessageOf(v.Interface())
 }
 
+// legacyLoadMessageType dynamically loads a protoreflect.Type for t,
+// where t must be not implement the v2 API already.
+// The provided name is used if it cannot be determined from the message.
+func legacyLoadMessageType(t reflect.Type, name pref.FullName) protoreflect.MessageType {
+	if t.Kind() != reflect.Ptr || t.Elem().Kind() != reflect.Struct {
+		return aberrantMessageType{t}
+	}
+	return legacyLoadMessageInfo(t, name)
+}
+
 var legacyMessageTypeCache sync.Map // map[reflect.Type]*MessageInfo
 
 // legacyLoadMessageInfo dynamically loads a *MessageInfo for t,
@@ -49,8 +59,9 @@ func legacyLoadMessageInfo(t reflect.Type, name pref.FullName) *MessageInfo {
 		GoReflectType: t,
 	}
 
+	var hasMarshal, hasUnmarshal bool
 	v := reflect.Zero(t).Interface()
-	if _, ok := v.(legacyMarshaler); ok {
+	if _, hasMarshal = v.(legacyMarshaler); hasMarshal {
 		mi.methods.Marshal = legacyMarshal
 
 		// We have no way to tell whether the type's Marshal method
@@ -59,10 +70,10 @@ func legacyLoadMessageInfo(t reflect.Type, name pref.FullName) *MessageInfo {
 		// calling Marshal methods when present.
 		mi.methods.Flags |= piface.SupportMarshalDeterministic
 	}
-	if _, ok := v.(legacyUnmarshaler); ok {
+	if _, hasUnmarshal = v.(legacyUnmarshaler); hasUnmarshal {
 		mi.methods.Unmarshal = legacyUnmarshal
 	}
-	if _, ok := v.(legacyMerger); ok {
+	if _, hasMerge := v.(legacyMerger); hasMerge || (hasMarshal && hasUnmarshal) {
 		mi.methods.Merge = legacyMerge
 	}
 
@@ -75,7 +86,7 @@ func legacyLoadMessageInfo(t reflect.Type, name pref.FullName) *MessageInfo {
 var legacyMessageDescCache sync.Map // map[reflect.Type]protoreflect.MessageDescriptor
 
 // LegacyLoadMessageDesc returns an MessageDescriptor derived from the Go type,
-// which must be a *struct kind and not implement the v2 API already.
+// which should be a *struct kind and must not implement the v2 API already.
 //
 // This is exported for testing purposes.
 func LegacyLoadMessageDesc(t reflect.Type) pref.MessageDescriptor {
@@ -114,17 +125,19 @@ func legacyLoadMessageDesc(t reflect.Type, name pref.FullName) pref.MessageDescr
 	// If the Go type has no fields, then this might be a proto3 empty message
 	// from before the size cache was added. If there are any fields, check to
 	// see that at least one of them looks like something we generated.
-	if nfield := t.Elem().NumField(); nfield > 0 {
-		hasProtoField := false
-		for i := 0; i < nfield; i++ {
-			f := t.Elem().Field(i)
-			if f.Tag.Get("protobuf") != "" || f.Tag.Get("protobuf_oneof") != "" || strings.HasPrefix(f.Name, "XXX_") {
-				hasProtoField = true
-				break
+	if t.Elem().Kind() == reflect.Struct {
+		if nfield := t.Elem().NumField(); nfield > 0 {
+			hasProtoField := false
+			for i := 0; i < nfield; i++ {
+				f := t.Elem().Field(i)
+				if f.Tag.Get("protobuf") != "" || f.Tag.Get("protobuf_oneof") != "" || strings.HasPrefix(f.Name, "XXX_") {
+					hasProtoField = true
+					break
+				}
+			}
+			if !hasProtoField {
+				return aberrantLoadMessageDesc(t, name)
 			}
-		}
-		if !hasProtoField {
-			return aberrantLoadMessageDesc(t, name)
 		}
 	}
 
@@ -370,7 +383,7 @@ type legacyMerger interface {
 	Merge(protoiface.MessageV1)
 }
 
-var legacyProtoMethods = &piface.Methods{
+var aberrantProtoMethods = &piface.Methods{
 	Marshal:   legacyMarshal,
 	Unmarshal: legacyUnmarshal,
 	Merge:     legacyMerge,
@@ -401,18 +414,47 @@ func legacyUnmarshal(in piface.UnmarshalInput) (piface.UnmarshalOutput, error) {
 	v := in.Message.(unwrapper).protoUnwrap()
 	unmarshaler, ok := v.(legacyUnmarshaler)
 	if !ok {
-		return piface.UnmarshalOutput{}, errors.New("%T does not implement Marshal", v)
+		return piface.UnmarshalOutput{}, errors.New("%T does not implement Unmarshal", v)
 	}
 	return piface.UnmarshalOutput{}, unmarshaler.Unmarshal(in.Buf)
 }
 
 func legacyMerge(in piface.MergeInput) piface.MergeOutput {
+	// Check whether this supports the legacy merger.
 	dstv := in.Destination.(unwrapper).protoUnwrap()
 	merger, ok := dstv.(legacyMerger)
+	if ok {
+		merger.Merge(Export{}.ProtoMessageV1Of(in.Source))
+		return piface.MergeOutput{Flags: piface.MergeComplete}
+	}
+
+	// If legacy merger is unavailable, implement merge in terms of
+	// a marshal and unmarshal operation.
+	srcv := in.Source.(unwrapper).protoUnwrap()
+	marshaler, ok := srcv.(legacyMarshaler)
 	if !ok {
 		return piface.MergeOutput{}
 	}
-	merger.Merge(Export{}.ProtoMessageV1Of(in.Source))
+	dstv = in.Destination.(unwrapper).protoUnwrap()
+	unmarshaler, ok := dstv.(legacyUnmarshaler)
+	if !ok {
+		return piface.MergeOutput{}
+	}
+	if !in.Source.IsValid() {
+		// Legacy Marshal methods may not function on nil messages.
+		// Check for a typed nil source only after we confirm that
+		// legacy Marshal/Unmarshal methods are present, for
+		// consistency.
+		return piface.MergeOutput{Flags: piface.MergeComplete}
+	}
+	b, err := marshaler.Marshal()
+	if err != nil {
+		return piface.MergeOutput{}
+	}
+	err = unmarshaler.Unmarshal(b)
+	if err != nil {
+		return piface.MergeOutput{}
+	}
 	return piface.MergeOutput{Flags: piface.MergeComplete}
 }
 
@@ -422,6 +464,9 @@ type aberrantMessageType struct {
 }
 
 func (mt aberrantMessageType) New() pref.Message {
+	if mt.t.Kind() == reflect.Ptr {
+		return aberrantMessage{reflect.New(mt.t.Elem())}
+	}
 	return aberrantMessage{reflect.Zero(mt.t)}
 }
 func (mt aberrantMessageType) Zero() pref.Message {
@@ -443,6 +488,17 @@ type aberrantMessage struct {
 	v reflect.Value
 }
 
+// Reset implements the v1 proto.Message.Reset method.
+func (m aberrantMessage) Reset() {
+	if mr, ok := m.v.Interface().(interface{ Reset() }); ok {
+		mr.Reset()
+		return
+	}
+	if m.v.Kind() == reflect.Ptr && !m.v.IsNil() {
+		m.v.Elem().Set(reflect.Zero(m.v.Type().Elem()))
+	}
+}
+
 func (m aberrantMessage) ProtoReflect() pref.Message {
 	return m
 }
@@ -454,33 +510,40 @@ func (m aberrantMessage) Type() pref.MessageType {
 	return aberrantMessageType{m.v.Type()}
 }
 func (m aberrantMessage) New() pref.Message {
+	if m.v.Type().Kind() == reflect.Ptr {
+		return aberrantMessage{reflect.New(m.v.Type().Elem())}
+	}
 	return aberrantMessage{reflect.Zero(m.v.Type())}
 }
 func (m aberrantMessage) Interface() pref.ProtoMessage {
 	return m
 }
 func (m aberrantMessage) Range(f func(pref.FieldDescriptor, pref.Value) bool) {
+	return
 }
 func (m aberrantMessage) Has(pref.FieldDescriptor) bool {
-	panic("invalid field descriptor")
+	return false
 }
 func (m aberrantMessage) Clear(pref.FieldDescriptor) {
-	panic("invalid field descriptor")
+	panic("invalid Message.Clear on " + string(m.Descriptor().FullName()))
 }
-func (m aberrantMessage) Get(pref.FieldDescriptor) pref.Value {
-	panic("invalid field descriptor")
+func (m aberrantMessage) Get(fd pref.FieldDescriptor) pref.Value {
+	if fd.Default().IsValid() {
+		return fd.Default()
+	}
+	panic("invalid Message.Get on " + string(m.Descriptor().FullName()))
 }
 func (m aberrantMessage) Set(pref.FieldDescriptor, pref.Value) {
-	panic("invalid field descriptor")
+	panic("invalid Message.Set on " + string(m.Descriptor().FullName()))
 }
 func (m aberrantMessage) Mutable(pref.FieldDescriptor) pref.Value {
-	panic("invalid field descriptor")
+	panic("invalid Message.Mutable on " + string(m.Descriptor().FullName()))
 }
 func (m aberrantMessage) NewField(pref.FieldDescriptor) pref.Value {
-	panic("invalid field descriptor")
+	panic("invalid Message.NewField on " + string(m.Descriptor().FullName()))
 }
 func (m aberrantMessage) WhichOneof(pref.OneofDescriptor) pref.FieldDescriptor {
-	panic("invalid oneof descriptor")
+	panic("invalid Message.WhichOneof descriptor on " + string(m.Descriptor().FullName()))
 }
 func (m aberrantMessage) GetUnknown() pref.RawFields {
 	return nil
@@ -489,13 +552,13 @@ func (m aberrantMessage) SetUnknown(pref.RawFields) {
 	// SetUnknown discards its input on messages which don't support unknown field storage.
 }
 func (m aberrantMessage) IsValid() bool {
-	// An invalid message is a read-only, empty message. Since we don't know anything
-	// about the alleged contents of this message, we can't say with confidence that
-	// it is invalid in this sense. Therefore, report it as valid.
-	return true
+	if m.v.Kind() == reflect.Ptr {
+		return !m.v.IsNil()
+	}
+	return false
 }
 func (m aberrantMessage) ProtoMethods() *piface.Methods {
-	return legacyProtoMethods
+	return aberrantProtoMethods
 }
 func (m aberrantMessage) protoUnwrap() interface{} {
 	return m.v.Interface()

vendor/google.golang.org/protobuf/internal/impl/merge.go

@@ -77,9 +77,9 @@ func (mi *MessageInfo) mergePointer(dst, src pointer, opts mergeOptions) {
 		}
 	}
 	if mi.unknownOffset.IsValid() {
-		du := dst.Apply(mi.unknownOffset).Bytes()
-		su := src.Apply(mi.unknownOffset).Bytes()
-		if len(*su) > 0 {
+		su := mi.getUnknownBytes(src)
+		if su != nil && len(*su) > 0 {
+			du := mi.mutableUnknownBytes(dst)
 			*du = append(*du, *su...)
 		}
 	}

vendor/google.golang.org/protobuf/internal/impl/message.go

@@ -15,6 +15,7 @@ import (
 	"google.golang.org/protobuf/internal/genid"
 	"google.golang.org/protobuf/reflect/protoreflect"
 	pref "google.golang.org/protobuf/reflect/protoreflect"
+	preg "google.golang.org/protobuf/reflect/protoregistry"
 )
 
 // MessageInfo provides protobuf related functionality for a given Go type
@@ -109,22 +110,29 @@ func (mi *MessageInfo) getPointer(m pref.Message) (p pointer, ok bool) {
 type (
 	SizeCache       = int32
 	WeakFields      = map[int32]protoreflect.ProtoMessage
-	UnknownFields   = []byte
+	UnknownFields   = unknownFieldsA // TODO: switch to unknownFieldsB
+	unknownFieldsA  = []byte
+	unknownFieldsB  = *[]byte
 	ExtensionFields = map[int32]ExtensionField
 )
 
 var (
 	sizecacheType       = reflect.TypeOf(SizeCache(0))
 	weakFieldsType      = reflect.TypeOf(WeakFields(nil))
-	unknownFieldsType   = reflect.TypeOf(UnknownFields(nil))
+	unknownFieldsAType  = reflect.TypeOf(unknownFieldsA(nil))
+	unknownFieldsBType  = reflect.TypeOf(unknownFieldsB(nil))
 	extensionFieldsType = reflect.TypeOf(ExtensionFields(nil))
 )
 
 type structInfo struct {
 	sizecacheOffset offset
+	sizecacheType   reflect.Type
 	weakOffset      offset
+	weakType        reflect.Type
 	unknownOffset   offset
+	unknownType     reflect.Type
 	extensionOffset offset
+	extensionType   reflect.Type
 
 	fieldsByNumber        map[pref.FieldNumber]reflect.StructField
 	oneofsByName          map[pref.Name]reflect.StructField
@@ -151,18 +159,22 @@ fieldLoop:
 		case genid.SizeCache_goname, genid.SizeCacheA_goname:
 			if f.Type == sizecacheType {
 				si.sizecacheOffset = offsetOf(f, mi.Exporter)
+				si.sizecacheType = f.Type
 			}
 		case genid.WeakFields_goname, genid.WeakFieldsA_goname:
 			if f.Type == weakFieldsType {
 				si.weakOffset = offsetOf(f, mi.Exporter)
+				si.weakType = f.Type
 			}
 		case genid.UnknownFields_goname, genid.UnknownFieldsA_goname:
-			if f.Type == unknownFieldsType {
+			if f.Type == unknownFieldsAType || f.Type == unknownFieldsBType {
 				si.unknownOffset = offsetOf(f, mi.Exporter)
+				si.unknownType = f.Type
 			}
 		case genid.ExtensionFields_goname, genid.ExtensionFieldsA_goname, genid.ExtensionFieldsB_goname:
 			if f.Type == extensionFieldsType {
 				si.extensionOffset = offsetOf(f, mi.Exporter)
+				si.extensionType = f.Type
 			}
 		default:
 			for _, s := range strings.Split(f.Tag.Get("protobuf"), ",") {
@@ -212,4 +224,53 @@ func (mi *MessageInfo) New() protoreflect.Message {
 func (mi *MessageInfo) Zero() protoreflect.Message {
 	return mi.MessageOf(reflect.Zero(mi.GoReflectType).Interface())
 }
-func (mi *MessageInfo) Descriptor() protoreflect.MessageDescriptor { return mi.Desc }
+func (mi *MessageInfo) Descriptor() protoreflect.MessageDescriptor {
+	return mi.Desc
+}
+func (mi *MessageInfo) Enum(i int) protoreflect.EnumType {
+	mi.init()
+	fd := mi.Desc.Fields().Get(i)
+	return Export{}.EnumTypeOf(mi.fieldTypes[fd.Number()])
+}
+func (mi *MessageInfo) Message(i int) protoreflect.MessageType {
+	mi.init()
+	fd := mi.Desc.Fields().Get(i)
+	switch {
+	case fd.IsWeak():
+		mt, _ := preg.GlobalTypes.FindMessageByName(fd.Message().FullName())
+		return mt
+	case fd.IsMap():
+		return mapEntryType{fd.Message(), mi.fieldTypes[fd.Number()]}
+	default:
+		return Export{}.MessageTypeOf(mi.fieldTypes[fd.Number()])
+	}
+}
+
+type mapEntryType struct {
+	desc    protoreflect.MessageDescriptor
+	valType interface{} // zero value of enum or message type
+}
+
+func (mt mapEntryType) New() protoreflect.Message {
+	return nil
+}
+func (mt mapEntryType) Zero() protoreflect.Message {
+	return nil
+}
+func (mt mapEntryType) Descriptor() protoreflect.MessageDescriptor {
+	return mt.desc
+}
+func (mt mapEntryType) Enum(i int) protoreflect.EnumType {
+	fd := mt.desc.Fields().Get(i)
+	if fd.Enum() == nil {
+		return nil
+	}
+	return Export{}.EnumTypeOf(mt.valType)
+}
+func (mt mapEntryType) Message(i int) protoreflect.MessageType {
+	fd := mt.desc.Fields().Get(i)
+	if fd.Message() == nil {
+		return nil
+	}
+	return Export{}.MessageTypeOf(mt.valType)
+}

vendor/google.golang.org/protobuf/internal/impl/message_reflect.go

@@ -8,6 +8,7 @@ import (
 	"fmt"
 	"reflect"
 
+	"google.golang.org/protobuf/internal/detrand"
 	"google.golang.org/protobuf/internal/pragma"
 	pref "google.golang.org/protobuf/reflect/protoreflect"
 )
@@ -16,6 +17,11 @@ type reflectMessageInfo struct {
 	fields map[pref.FieldNumber]*fieldInfo
 	oneofs map[pref.Name]*oneofInfo
 
+	// fieldTypes contains the zero value of an enum or message field.
+	// For lists, it contains the element type.
+	// For maps, it contains the entry value type.
+	fieldTypes map[pref.FieldNumber]interface{}
+
 	// denseFields is a subset of fields where:
 	//	0 < fieldDesc.Number() < len(denseFields)
 	// It provides faster access to the fieldInfo, but may be incomplete.
@@ -36,6 +42,7 @@ func (mi *MessageInfo) makeReflectFuncs(t reflect.Type, si structInfo) {
 	mi.makeKnownFieldsFunc(si)
 	mi.makeUnknownFieldsFunc(t, si)
 	mi.makeExtensionFieldsFunc(t, si)
+	mi.makeFieldTypes(si)
 }
 
 // makeKnownFieldsFunc generates functions for operations that can be performed
@@ -51,17 +58,23 @@ func (mi *MessageInfo) makeKnownFieldsFunc(si structInfo) {
 	for i := 0; i < fds.Len(); i++ {
 		fd := fds.Get(i)
 		fs := si.fieldsByNumber[fd.Number()]
+		isOneof := fd.ContainingOneof() != nil && !fd.ContainingOneof().IsSynthetic()
+		if isOneof {
+			fs = si.oneofsByName[fd.ContainingOneof().Name()]
+		}
 		var fi fieldInfo
 		switch {
-		case fd.ContainingOneof() != nil && !fd.ContainingOneof().IsSynthetic():
-			fi = fieldInfoForOneof(fd, si.oneofsByName[fd.ContainingOneof().Name()], mi.Exporter, si.oneofWrappersByNumber[fd.Number()])
+		case fs.Type == nil:
+			fi = fieldInfoForMissing(fd) // never occurs for officially generated message types
+		case isOneof:
+			fi = fieldInfoForOneof(fd, fs, mi.Exporter, si.oneofWrappersByNumber[fd.Number()])
 		case fd.IsMap():
 			fi = fieldInfoForMap(fd, fs, mi.Exporter)
 		case fd.IsList():
 			fi = fieldInfoForList(fd, fs, mi.Exporter)
 		case fd.IsWeak():
 			fi = fieldInfoForWeakMessage(fd, si.weakOffset)
-		case fd.Kind() == pref.MessageKind || fd.Kind() == pref.GroupKind:
+		case fd.Message() != nil:
 			fi = fieldInfoForMessage(fd, fs, mi.Exporter)
 		default:
 			fi = fieldInfoForScalar(fd, fs, mi.Exporter)
@@ -92,27 +105,53 @@ func (mi *MessageInfo) makeKnownFieldsFunc(si structInfo) {
 			i++
 		}
 	}
+
+	// Introduce instability to iteration order, but keep it deterministic.
+	if len(mi.rangeInfos) > 1 && detrand.Bool() {
+		i := detrand.Intn(len(mi.rangeInfos) - 1)
+		mi.rangeInfos[i], mi.rangeInfos[i+1] = mi.rangeInfos[i+1], mi.rangeInfos[i]
+	}
 }
 
 func (mi *MessageInfo) makeUnknownFieldsFunc(t reflect.Type, si structInfo) {
-	mi.getUnknown = func(pointer) pref.RawFields { return nil }
-	mi.setUnknown = func(pointer, pref.RawFields) { return }
-	if si.unknownOffset.IsValid() {
+	switch {
+	case si.unknownOffset.IsValid() && si.unknownType == unknownFieldsAType:
+		// Handle as []byte.
 		mi.getUnknown = func(p pointer) pref.RawFields {
 			if p.IsNil() {
 				return nil
 			}
-			rv := p.Apply(si.unknownOffset).AsValueOf(unknownFieldsType)
-			return pref.RawFields(*rv.Interface().(*[]byte))
+			return *p.Apply(mi.unknownOffset).Bytes()
 		}
 		mi.setUnknown = func(p pointer, b pref.RawFields) {
 			if p.IsNil() {
 				panic("invalid SetUnknown on nil Message")
 			}
-			rv := p.Apply(si.unknownOffset).AsValueOf(unknownFieldsType)
-			*rv.Interface().(*[]byte) = []byte(b)
+			*p.Apply(mi.unknownOffset).Bytes() = b
 		}
-	} else {
+	case si.unknownOffset.IsValid() && si.unknownType == unknownFieldsBType:
+		// Handle as *[]byte.
+		mi.getUnknown = func(p pointer) pref.RawFields {
+			if p.IsNil() {
+				return nil
+			}
+			bp := p.Apply(mi.unknownOffset).BytesPtr()
+			if *bp == nil {
+				return nil
+			}
+			return **bp
+		}
+		mi.setUnknown = func(p pointer, b pref.RawFields) {
+			if p.IsNil() {
+				panic("invalid SetUnknown on nil Message")
+			}
+			bp := p.Apply(mi.unknownOffset).BytesPtr()
+			if *bp == nil {
+				*bp = new([]byte)
+			}
+			**bp = b
+		}
+	default:
 		mi.getUnknown = func(pointer) pref.RawFields {
 			return nil
 		}
@@ -139,6 +178,58 @@ func (mi *MessageInfo) makeExtensionFieldsFunc(t reflect.Type, si structInfo) {
 		}
 	}
 }
+func (mi *MessageInfo) makeFieldTypes(si structInfo) {
+	md := mi.Desc
+	fds := md.Fields()
+	for i := 0; i < fds.Len(); i++ {
+		var ft reflect.Type
+		fd := fds.Get(i)
+		fs := si.fieldsByNumber[fd.Number()]
+		isOneof := fd.ContainingOneof() != nil && !fd.ContainingOneof().IsSynthetic()
+		if isOneof {
+			fs = si.oneofsByName[fd.ContainingOneof().Name()]
+		}
+		var isMessage bool
+		switch {
+		case fs.Type == nil:
+			continue // never occurs for officially generated message types
+		case isOneof:
+			if fd.Enum() != nil || fd.Message() != nil {
+				ft = si.oneofWrappersByNumber[fd.Number()].Field(0).Type
+			}
+		case fd.IsMap():
+			if fd.MapValue().Enum() != nil || fd.MapValue().Message() != nil {
+				ft = fs.Type.Elem()
+			}
+			isMessage = fd.MapValue().Message() != nil
+		case fd.IsList():
+			if fd.Enum() != nil || fd.Message() != nil {
+				ft = fs.Type.Elem()
+			}
+			isMessage = fd.Message() != nil
+		case fd.Enum() != nil:
+			ft = fs.Type
+			if fd.HasPresence() && ft.Kind() == reflect.Ptr {
+				ft = ft.Elem()
+			}
+		case fd.Message() != nil:
+			ft = fs.Type
+			if fd.IsWeak() {
+				ft = nil
+			}
+			isMessage = true
+		}
+		if isMessage && ft != nil && ft.Kind() != reflect.Ptr {
+			ft = reflect.PtrTo(ft) // never occurs for officially generated message types
+		}
+		if ft != nil {
+			if mi.fieldTypes == nil {
+				mi.fieldTypes = make(map[pref.FieldNumber]interface{})
+			}
+			mi.fieldTypes[fd.Number()] = reflect.Zero(ft).Interface()
+		}
+	}
+}
 
 type extensionMap map[int32]ExtensionField
 
@@ -306,7 +397,6 @@ var (
 // pointer to a named Go struct. If the provided type has a ProtoReflect method,
 // it must be implemented by calling this method.
 func (mi *MessageInfo) MessageOf(m interface{}) pref.Message {
-	// TODO: Switch the input to be an opaque Pointer.
 	if reflect.TypeOf(m) != mi.GoReflectType {
 		panic(fmt.Sprintf("type mismatch: got %T, want %v", m, mi.GoReflectType))
 	}
@@ -320,6 +410,17 @@ func (mi *MessageInfo) MessageOf(m interface{}) pref.Message {
 func (m *messageReflectWrapper) pointer() pointer          { return m.p }
 func (m *messageReflectWrapper) messageInfo() *MessageInfo { return m.mi }
 
+// Reset implements the v1 proto.Message.Reset method.
+func (m *messageIfaceWrapper) Reset() {
+	if mr, ok := m.protoUnwrap().(interface{ Reset() }); ok {
+		mr.Reset()
+		return
+	}
+	rv := reflect.ValueOf(m.protoUnwrap())
+	if rv.Kind() == reflect.Ptr && !rv.IsNil() {
+		rv.Elem().Set(reflect.Zero(rv.Type().Elem()))
+	}
+}
 func (m *messageIfaceWrapper) ProtoReflect() pref.Message {
 	return (*messageReflectWrapper)(m)
 }

vendor/google.golang.org/protobuf/internal/impl/message_reflect_field.go

@@ -28,6 +28,39 @@ type fieldInfo struct {
 	newField   func() pref.Value
 }
 
+func fieldInfoForMissing(fd pref.FieldDescriptor) fieldInfo {
+	// This never occurs for generated message types.
+	// It implies that a hand-crafted type has missing Go fields
+	// for specific protobuf message fields.
+	return fieldInfo{
+		fieldDesc: fd,
+		has: func(p pointer) bool {
+			return false
+		},
+		clear: func(p pointer) {
+			panic("missing Go struct field for " + string(fd.FullName()))
+		},
+		get: func(p pointer) pref.Value {
+			return fd.Default()
+		},
+		set: func(p pointer, v pref.Value) {
+			panic("missing Go struct field for " + string(fd.FullName()))
+		},
+		mutable: func(p pointer) pref.Value {
+			panic("missing Go struct field for " + string(fd.FullName()))
+		},
+		newMessage: func() pref.Message {
+			panic("missing Go struct field for " + string(fd.FullName()))
+		},
+		newField: func() pref.Value {
+			if v := fd.Default(); v.IsValid() {
+				return v
+			}
+			panic("missing Go struct field for " + string(fd.FullName()))
+		},
+	}
+}
+
 func fieldInfoForOneof(fd pref.FieldDescriptor, fs reflect.StructField, x exporter, ot reflect.Type) fieldInfo {
 	ft := fs.Type
 	if ft.Kind() != reflect.Interface {
@@ -97,7 +130,7 @@ func fieldInfoForOneof(fd pref.FieldDescriptor, fs reflect.StructField, x export
 				rv.Set(reflect.New(ot))
 			}
 			rv = rv.Elem().Elem().Field(0)
-			if rv.IsNil() {
+			if rv.Kind() == reflect.Ptr && rv.IsNil() {
 				rv.Set(conv.GoValueOf(pref.ValueOfMessage(conv.New().Message())))
 			}
 			return conv.PBValueOf(rv)
@@ -225,7 +258,10 @@ func fieldInfoForScalar(fd pref.FieldDescriptor, fs reflect.StructField, x expor
 	isBytes := ft.Kind() == reflect.Slice && ft.Elem().Kind() == reflect.Uint8
 	if nullable {
 		if ft.Kind() != reflect.Ptr && ft.Kind() != reflect.Slice {
-			panic(fmt.Sprintf("field %v has invalid type: got %v, want pointer", fd.FullName(), ft))
+			// This never occurs for generated message types.
+			// Despite the protobuf type system specifying presence,
+			// the Go field type cannot represent it.
+			nullable = false
 		}
 		if ft.Kind() == reflect.Ptr {
 			ft = ft.Elem()
@@ -388,6 +424,9 @@ func fieldInfoForMessage(fd pref.FieldDescriptor, fs reflect.StructField, x expo
 				return false
 			}
 			rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
+			if fs.Type.Kind() != reflect.Ptr {
+				return !isZero(rv)
+			}
 			return !rv.IsNil()
 		},
 		clear: func(p pointer) {
@@ -404,13 +443,13 @@ func fieldInfoForMessage(fd pref.FieldDescriptor, fs reflect.StructField, x expo
 		set: func(p pointer, v pref.Value) {
 			rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
 			rv.Set(conv.GoValueOf(v))
-			if rv.IsNil() {
+			if fs.Type.Kind() == reflect.Ptr && rv.IsNil() {
 				panic(fmt.Sprintf("field %v has invalid nil pointer", fd.FullName()))
 			}
 		},
 		mutable: func(p pointer) pref.Value {
 			rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
-			if rv.IsNil() {
+			if fs.Type.Kind() == reflect.Ptr && rv.IsNil() {
 				rv.Set(conv.GoValueOf(conv.New()))
 			}
 			return conv.PBValueOf(rv)
@@ -464,3 +503,41 @@ func makeOneofInfo(od pref.OneofDescriptor, si structInfo, x exporter) *oneofInf
 	}
 	return oi
 }
+
+// isZero is identical to reflect.Value.IsZero.
+// TODO: Remove this when Go1.13 is the minimally supported Go version.
+func isZero(v reflect.Value) bool {
+	switch v.Kind() {
+	case reflect.Bool:
+		return !v.Bool()
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return v.Int() == 0
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		return v.Uint() == 0
+	case reflect.Float32, reflect.Float64:
+		return math.Float64bits(v.Float()) == 0
+	case reflect.Complex64, reflect.Complex128:
+		c := v.Complex()
+		return math.Float64bits(real(c)) == 0 && math.Float64bits(imag(c)) == 0
+	case reflect.Array:
+		for i := 0; i < v.Len(); i++ {
+			if !isZero(v.Index(i)) {
+				return false
+			}
+		}
+		return true
+	case reflect.Chan, reflect.Func, reflect.Interface, reflect.Map, reflect.Ptr, reflect.Slice, reflect.UnsafePointer:
+		return v.IsNil()
+	case reflect.String:
+		return v.Len() == 0
+	case reflect.Struct:
+		for i := 0; i < v.NumField(); i++ {
+			if !isZero(v.Field(i)) {
+				return false
+			}
+		}
+		return true
+	default:
+		panic(&reflect.ValueError{"reflect.Value.IsZero", v.Kind()})
+	}
+}

vendor/google.golang.org/protobuf/internal/impl/pointer_reflect.go

@@ -121,6 +121,7 @@ func (p pointer) String() *string          { return p.v.Interface().(*string) }
 func (p pointer) StringPtr() **string      { return p.v.Interface().(**string) }
 func (p pointer) StringSlice() *[]string   { return p.v.Interface().(*[]string) }
 func (p pointer) Bytes() *[]byte           { return p.v.Interface().(*[]byte) }
+func (p pointer) BytesPtr() **[]byte       { return p.v.Interface().(**[]byte) }
 func (p pointer) BytesSlice() *[][]byte    { return p.v.Interface().(*[][]byte) }
 func (p pointer) WeakFields() *weakFields  { return (*weakFields)(p.v.Interface().(*WeakFields)) }
 func (p pointer) Extensions() *map[int32]ExtensionField {

vendor/google.golang.org/protobuf/internal/impl/pointer_unsafe.go

@@ -109,6 +109,7 @@ func (p pointer) String() *string                       { return (*string)(p.p)
 func (p pointer) StringPtr() **string                   { return (**string)(p.p) }
 func (p pointer) StringSlice() *[]string                { return (*[]string)(p.p) }
 func (p pointer) Bytes() *[]byte                        { return (*[]byte)(p.p) }
+func (p pointer) BytesPtr() **[]byte                    { return (**[]byte)(p.p) }
 func (p pointer) BytesSlice() *[][]byte                 { return (*[][]byte)(p.p) }
 func (p pointer) WeakFields() *weakFields               { return (*weakFields)(p.p) }
 func (p pointer) Extensions() *map[int32]ExtensionField { return (*map[int32]ExtensionField)(p.p) }