How to allow minus sign for package name in .proto file?

Question

Here is the .proto file I used:

pkg/apis/workflow/v1alpha1/generated.proto

syntax = 'proto2';

package go-server.com.argo-new.pkg.apis.workflow.v1alpha1;

import "k8s.io/api/core/v1/generated.proto";
import "k8s.io/api/policy/v1beta1/generated.proto";
import "k8s.io/apimachinery/pkg/apis/meta/v1/generated.proto";
import "k8s.io/apimachinery/pkg/runtime/generated.proto";
import "k8s.io/apimachinery/pkg/runtime/schema/generated.proto";

// Package-wide variables from generator "generated".
option go_package = "v1alpha1";

// ArchiveStrategy describes how to archive files/directory when saving artifacts
message ArchiveStrategy {
  optional TarStrategy tar = 1;

  optional NoneStrategy none = 2;
}

When I tried to compile:

protoc -I /usr/local/include -I . -I ./vendor -I /root/go/src \
       -I /root/go/pkg/mod/github.com/gogo/protobuf@v1.3.1/gogoproto \
       -I /root/go/pkg/mod/github.com/grpc-ecosystem/grpc-gateway@v1.12.2/third_party/googleapis \
       --include_imports --gogofast_out=plugins=grpc:/root/go/src \
       --grpc-gateway_out=logtostderr=true:/root/go/src \
       --swagger_out=logtostderr=true,fqn_for_swagger_name=true:. \ 
       pkg/apis/workflow/v1alpha1/generated.proto

it reminds me that:

pkg/apis/workflow/v1alpha1/generated.proto:6:11: Expected ";"

It's a compile error which means the package name should not contain -.

Are there any methods to use - in package name or any workaround?

Thanks!

Answer 1

Protobuf

It's not allowed, neither by proto2 specs (as in your example code) nor by proto3 specs.

As shown in the specs (either of above mentioned), a package declaration follows the pattern:

package = "package" fullIdent ";"

i.e. the keyword package followed by a fullIdent followed by one ; semicolon, where fullIdent is defined as:

fullIdent = ident { "." ident }

i.e. at least one ident followed by zero or more other ident's preceded by ., where ident is defined as:

ident = letter { letter | decimalDigit | "_" }

i.e. at least one letter, followed by zero or more letters ([A-Z], [a-z]), digits ([0-9]), or the underscore _ character.

So in conclusion, you can't have a minus (dash) - character in your protobuf package name.

---

Go

Additionally, as @colm.anseo pointed out, Go package names also don't allow dash - characters either:

PackageName = identifier . where identifier = letter { letter | unicode_digit } .

(The underscore character is considered a letter.)