Importing wrong package when autogenerating code using proto buff (.proto files)

From your Makefile I assume you want your generated files in github.com/name/my_project/internal (since you have -input=./internal/models/*.pb.go).

Your protos/buf.gen.yaml would be something like:

version: v1
plugins:
  - plugin: buf.build/protocolbuffers/go:v1.34.0
    out: internal
    opt:
      - paths=source_relative

protos/requests/ad_request.proto would be:

syntax = "proto3";

package my_project.requests;

import "models/ad.proto";
import "models/enums.proto";

option go_package = "github.com/name/my_project/internal/requests";

message Msg {
  optional my_project.models.Enum enum = 1;
}

and protos/models/enums.proto:

syntax = "proto3";

package my_project.models;

option go_package = "github.com/name/my_project/internal/models";

enum Enum {
  A = 0;
}

Then you could do:

package main

import (
    "fmt"

    "github.com/name/my_project/internal/models"
    "github.com/name/my_project/internal/requests"
)

func main() {
    msg := &requests.Msg{Enum: models.Enum_A.Enum()}

    fmt.Println(msg)
}

assuming you have a go.mod:

module github.com/name/my_project

go 1.22.2

require google.golang.org/protobuf v1.34.0

A. side note on conventions: but.gen.yaml should be at the root of the project and the usage of ; in go_package is discouraged.

You added your comment after I started writing this.

I don't use buf so apologies that this is pure protoc.

I'm assuming you want to generate the Go sources alongside the protos.

The Protocol Buffers package hierarchy does not translate directly to the Golang module hierarchy. Your approach to using option go_package is correct but I would advise against using e.g. ...models;models"

Here's how I would generate your protos. I use the --go_opt=module=${MODULE} approach which works for me. There are other ways to achieve this.

NOTE If you subsequently want to compile Services for gRPC, you would mirror this approach by adding e.g. ... --go-gprc_out=${PWD} --go-grpc_opt=module=${MODULE} ...

In this approach ${MODULE} must match the prefix (as you have) for your options go_package={MODULE}/protos/...

Either:

MODULE="github.com/name/my_project"

PROTO_PATH=${PWD}/protos

protoc \
--proto_path=${PROTO_PATH} \
--go_out=${PWD} \
--go_opt=module=${MODULE} \
${PROTO_PATH}/requests/ad_requests.proto \
${PROTO_PATH}/models/ad.proto
${PROTO_PATH}/models/enums.proto

The rule here is that every *.proto must be prefixed with one (you only have one) of the defined --proto_path's

One caveat (but not bug) in your approach is that your Protocol Buffers packages should be models and requests and not my_project.models and my_project.requests.

If you want these to be e.g. package my_project.models then you should create:

.
└── protos
    └── my_project
        ├── models
        └── requests

This is because your current folder's protos is the root of your protocol buffers files. The convention (!?) is to then reproduce the package path as a folder structure. Because you start with my_project, the first folder within protos would be my_project etc.