Protobuf编译器for Go structs没有为导入生成正确的包名?

github.com/kurtpeek/proto-example 以及以下目录结构(使用 .proto 中的文件 proto 目录和生成的Go代码 gen/go

.
├── gen
│   └── go
│       ├── author
│       │   └── author.pb.go
│       └── book
│           └── book.pb.go
├── go.mod
├── go.sum
├── main.go
└── proto
    ├── author
    │   └── author.proto
    └── book
        └── book.proto

在这里 author.proto

syntax="proto3";
package author;

message Author {
    string name = 1;
}

和 book.proto 进口 是这样的:

syntax="proto3";
package book;

import "author/author.proto";

message Book {
    string title = 1;
    author.Author author = 2;
}

我已经生成了 .pb.go 文件,在 proto/

protoc book/book.proto --go_out=../gen/go

和

protoc author/author.proto --go_out=../gen/go

author 已导入 book.pb.go "author" :

// Code generated by protoc-gen-go. DO NOT EDIT.
// source: book/book.proto

package book

import (
    author "author"
    fmt "fmt"
    proto "github.com/golang/protobuf/proto"
    math "math"
)

// Reference imports to suppress errors if they are not otherwise used.
var _ = proto.Marshal
var _ = fmt.Errorf
var _ = math.Inf

// This is a compile-time assertion to ensure that this generated file
// is compatible with the proto package it is being compiled against.
// A compilation error at this line likely means your copy of the
// proto package needs to be updated.
const _ = proto.ProtoPackageIsVersion3 // please upgrade the proto package

type Book struct {
    Title                string         `protobuf:"bytes,1,opt,name=title,proto3" json:"title,omitempty"`
    Author               *author.Author `protobuf:"bytes,2,opt,name=author,proto3" json:"author,omitempty"`
    XXX_NoUnkeyedLiteral struct{}       `json:"-"`
    XXX_unrecognized     []byte         `json:"-"`
    XXX_sizecache        int32          `json:"-"`
}

func (m *Book) Reset()         { *m = Book{} }
func (m *Book) String() string { return proto.CompactTextString(m) }
func (*Book) ProtoMessage()    {}
func (*Book) Descriptor() ([]byte, []int) {
    return fileDescriptor_ee9082fb44230b1b, []int{0}
}

func (m *Book) XXX_Unmarshal(b []byte) error {
    return xxx_messageInfo_Book.Unmarshal(m, b)
}
func (m *Book) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
    return xxx_messageInfo_Book.Marshal(b, m, deterministic)
}
func (m *Book) XXX_Merge(src proto.Message) {
    xxx_messageInfo_Book.Merge(m, src)
}
func (m *Book) XXX_Size() int {
    return xxx_messageInfo_Book.Size(m)
}
func (m *Book) XXX_DiscardUnknown() {
    xxx_messageInfo_Book.DiscardUnknown(m)
}

var xxx_messageInfo_Book proto.InternalMessageInfo

func (m *Book) GetTitle() string {
    if m != nil {
        return m.Title
    }
    return ""
}

func (m *Book) GetAuthor() *author.Author {
    if m != nil {
        return m.Author
    }
    return nil
}

func init() {
    proto.RegisterType((*Book)(nil), "book.Book")
}

func init() { proto.RegisterFile("book/book.proto", fileDescriptor_ee9082fb44230b1b) }

var fileDescriptor_ee9082fb44230b1b = []byte{
    // 108 bytes of a gzipped FileDescriptorProto
    0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0xe2, 0xe2, 0x4f, 0xca, 0xcf, 0xcf,
    0xd6, 0x07, 0x11, 0x7a, 0x05, 0x45, 0xf9, 0x25, 0xf9, 0x42, 0x2c, 0x20, 0xb6, 0x94, 0x70, 0x62,
    0x69, 0x49, 0x46, 0x7e, 0x91, 0x3e, 0x84, 0x82, 0x48, 0x29, 0xb9, 0x70, 0xb1, 0x38, 0xe5, 0xe7,
    0x67, 0x0b, 0x89, 0x70, 0xb1, 0x96, 0x64, 0x96, 0xe4, 0xa4, 0x4a, 0x30, 0x2a, 0x30, 0x6a, 0x70,
    0x06, 0x41, 0x38, 0x42, 0x6a, 0x5c, 0x6c, 0x10, 0xd5, 0x12, 0x4c, 0x0a, 0x8c, 0x1a, 0xdc, 0x46,
    0x7c, 0x7a, 0x50, 0xcd, 0x8e, 0x60, 0x2a, 0x08, 0x2a, 0x9b, 0xc4, 0x06, 0x36, 0xcc, 0x18, 0x10,
    0x00, 0x00, 0xff, 0xff, 0x2c, 0x89, 0x1f, 0x45, 0x7a, 0x00, 0x00, 0x00,
}

book.pb.go

package book

import (
    fmt "fmt"
    math "math"

    proto "github.com/golang/protobuf/proto"
    author "github.com/kurtpeek/proto-example/gen/go/author"
)

如何让Protobuf编译器“知道”生成的代码所在的Go模块?

(我怀疑我需要指定 option go_package https://developers.google.com/protocol-buffers/docs/gotutorial ),但这样做似乎不会改变生成的代码)。