Enums from other packages as path parameters is missing package name in front of enumValMap.

[kwonalbert]

Steps you follow to reproduce the error:

I have two packages package_a, and package_b which imports package_a. package_b defines a RPC that uses a message from package_a, and uses an enum from the said message in the path. E.g.,

// This file is in "/package_a/a.proto"
syntax = "proto3";
package package_a;

enum AEnum {
  ZERO = 0;
  ONE = 1;
  TWO = 2;
}

message AMessage {
  AEnum a = 1;
  string data = 2;
}

// This file is in "/package_b/b.proto"
syntax = "proto3";
package package_b;

import "google/api/annotations.proto";

import "package_a/a.proto";

service BRPC {
  rpc TestEnumFromAnotherPackageInPath(Request) returns (Response) {
    option (google.api.http) = {
      post: "/test/{messagea.a}"
      body: "*"
    };
  }
}

message Request {
  package_a.AMessage messagea = 1;
  string other_data = 2;
}

message Response {
  string some_data = 1;
}

The code that's generated for package_b looks like the following:

// Code generated by protoc-gen-grpc-gateway. DO NOT EDIT.
// source: package_b/b.proto

/*
Package package_b is a reverse proxy.

It translates gRPC into RESTful JSON APIs.
*/
package package_b

import (
	"context"
	"io"
	"net/http"
	"package_a"

	"github.com/golang/protobuf/descriptor"
	"github.com/golang/protobuf/proto"
	"github.com/grpc-ecosystem/grpc-gateway/runtime"
	"github.com/grpc-ecosystem/grpc-gateway/utilities"
	"google.golang.org/grpc"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/grpclog"
	"google.golang.org/grpc/status"
)

// Suppress "imported and not used" errors
var _ codes.Code
var _ io.Reader
var _ status.Status
var _ = runtime.String
var _ = utilities.NewDoubleArray
var _ = descriptor.ForMessage

func request_BRPC_TestEnumFromAnotherPackageInPath_0(ctx context.Context, marshaler runtime.Marshaler, client BRPCClient, req *http.Request, pathParams map[string]string) (proto.Message, runtime.ServerMetadata, error) {
	var protoReq Request
	var metadata runtime.ServerMetadata

	newReader, berr := utilities.IOReaderFactory(req.Body)
	if berr != nil {
		return nil, metadata, status.Errorf(codes.InvalidArgument, "%v", berr)
	}
	if err := marshaler.NewDecoder(newReader()).Decode(&protoReq); err != nil && err != io.EOF {
		return nil, metadata, status.Errorf(codes.InvalidArgument, "%v", err)
	}

	var (
		val string
		e   int32
		ok  bool
		err error
		_   = err
	)

	val, ok = pathParams["messagea.a"]
	if !ok {
		return nil, metadata, status.Errorf(codes.InvalidArgument, "missing parameter %s", "messagea.a")
	}

	err = runtime.PopulateFieldFromPath(&protoReq, "messagea.a", val)

	e, err = runtime.Enum(val, AEnum_value)

	if err != nil {
		return nil, metadata, status.Errorf(codes.InvalidArgument, "type mismatch, parameter: %s, error: %v", "messagea.a", err)
	}

	protoReq.Messagea.A = AEnum(e)

	msg, err := client.TestEnumFromAnotherPackageInPath(ctx, &protoReq, grpc.Header(&metadata.HeaderMD), grpc.Trailer(&metadata.TrailerMD))
	return msg, metadata, err

}

func local_request_BRPC_TestEnumFromAnotherPackageInPath_0(ctx context.Context, marshaler runtime.Marshaler, server BRPCServer, req *http.Request, pathParams map[string]string) (proto.Message, runtime.ServerMetadata, error) {
	var protoReq Request
	var metadata runtime.ServerMetadata

	newReader, berr := utilities.IOReaderFactory(req.Body)
	if berr != nil {
		return nil, metadata, status.Errorf(codes.InvalidArgument, "%v", berr)
	}
	if err := marshaler.NewDecoder(newReader()).Decode(&protoReq); err != nil && err != io.EOF {
		return nil, metadata, status.Errorf(codes.InvalidArgument, "%v", err)
	}

	var (
		val string
		e   int32
		ok  bool
		err error
		_   = err
	)

	val, ok = pathParams["messagea.a"]
	if !ok {
		return nil, metadata, status.Errorf(codes.InvalidArgument, "missing parameter %s", "messagea.a")
	}

	err = runtime.PopulateFieldFromPath(&protoReq, "messagea.a", val)

	e, err = runtime.Enum(val, AEnum_value)

	if err != nil {
		return nil, metadata, status.Errorf(codes.InvalidArgument, "type mismatch, parameter: %s, error: %v", "messagea.a", err)
	}

	protoReq.Messagea.A = AEnum(e)

	msg, err := server.TestEnumFromAnotherPackageInPath(ctx, &protoReq)
	return msg, metadata, err

}

// RegisterBRPCHandlerServer registers the http handlers for service BRPC to "mux".
// UnaryRPC     :call BRPCServer directly.
// StreamingRPC :currently unsupported pending https://github.com/grpc/grpc-go/issues/906.
func RegisterBRPCHandlerServer(ctx context.Context, mux *runtime.ServeMux, server BRPCServer) error {

	mux.Handle("POST", pattern_BRPC_TestEnumFromAnotherPackageInPath_0, func(w http.ResponseWriter, req *http.Request, pathParams map[string]string) {
		ctx, cancel := context.WithCancel(req.Context())
		defer cancel()
		inboundMarshaler, outboundMarshaler := runtime.MarshalerForRequest(mux, req)
		rctx, err := runtime.AnnotateIncomingContext(ctx, mux, req)
		if err != nil {
			runtime.HTTPError(ctx, mux, outboundMarshaler, w, req, err)
			return
		}
		resp, md, err := local_request_BRPC_TestEnumFromAnotherPackageInPath_0(rctx, inboundMarshaler, server, req, pathParams)
		ctx = runtime.NewServerMetadataContext(ctx, md)
		if err != nil {
			runtime.HTTPError(ctx, mux, outboundMarshaler, w, req, err)
			return
		}

		forward_BRPC_TestEnumFromAnotherPackageInPath_0(ctx, mux, outboundMarshaler, w, req, resp, mux.GetForwardResponseOptions()...)

	})

	return nil
}

// RegisterBRPCHandlerFromEndpoint is same as RegisterBRPCHandler but
// automatically dials to "endpoint" and closes the connection when "ctx" gets done.
func RegisterBRPCHandlerFromEndpoint(ctx context.Context, mux *runtime.ServeMux, endpoint string, opts []grpc.DialOption) (err error) {
	conn, err := grpc.Dial(endpoint, opts...)
	if err != nil {
		return err
	}
	defer func() {
		if err != nil {
			if cerr := conn.Close(); cerr != nil {
				grpclog.Infof("Failed to close conn to %s: %v", endpoint, cerr)
			}
			return
		}
		go func() {
			<-ctx.Done()
			if cerr := conn.Close(); cerr != nil {
				grpclog.Infof("Failed to close conn to %s: %v", endpoint, cerr)
			}
		}()
	}()

	return RegisterBRPCHandler(ctx, mux, conn)
}

// RegisterBRPCHandler registers the http handlers for service BRPC to "mux".
// The handlers forward requests to the grpc endpoint over "conn".
func RegisterBRPCHandler(ctx context.Context, mux *runtime.ServeMux, conn *grpc.ClientConn) error {
	return RegisterBRPCHandlerClient(ctx, mux, NewBRPCClient(conn))
}

// RegisterBRPCHandlerClient registers the http handlers for service BRPC
// to "mux". The handlers forward requests to the grpc endpoint over the given implementation of "BRPCClient".
// Note: the gRPC framework executes interceptors within the gRPC handler. If the passed in "BRPCClient"
// doesn't go through the normal gRPC flow (creating a gRPC client etc.) then it will be up to the passed in
// "BRPCClient" to call the correct interceptors.
func RegisterBRPCHandlerClient(ctx context.Context, mux *runtime.ServeMux, client BRPCClient) error {

	mux.Handle("POST", pattern_BRPC_TestEnumFromAnotherPackageInPath_0, func(w http.ResponseWriter, req *http.Request, pathParams map[string]string) {
		ctx, cancel := context.WithCancel(req.Context())
		defer cancel()
		inboundMarshaler, outboundMarshaler := runtime.MarshalerForRequest(mux, req)
		rctx, err := runtime.AnnotateContext(ctx, mux, req)
		if err != nil {
			runtime.HTTPError(ctx, mux, outboundMarshaler, w, req, err)
			return
		}
		resp, md, err := request_BRPC_TestEnumFromAnotherPackageInPath_0(rctx, inboundMarshaler, client, req, pathParams)
		ctx = runtime.NewServerMetadataContext(ctx, md)
		if err != nil {
			runtime.HTTPError(ctx, mux, outboundMarshaler, w, req, err)
			return
		}

		forward_BRPC_TestEnumFromAnotherPackageInPath_0(ctx, mux, outboundMarshaler, w, req, resp, mux.GetForwardResponseOptions()...)

	})

	return nil
}

var (
	pattern_BRPC_TestEnumFromAnotherPackageInPath_0 = runtime.MustPattern(runtime.NewPattern(1, []int{2, 0, 1, 0, 4, 1, 5, 1}, []string{"test", "messagea.a"}, "", runtime.AssumeColonVerbOpt(true)))
)

var (
	forward_BRPC_TestEnumFromAnotherPackageInPath_0 = runtime.ForwardResponseMessage
)

This causes compile time error due to AEnum_value and AEnum being undefined (they are defined in package_a).

What did you expect to happen instead:

It should have package_a. in front of AEnum_value and AEnum, which seems to make it compile okay.

What's your theory on why it isn't working:

It seems that when the code for an enum that is part of a message from another package is generated for path parameters, it's omitting the package name in the front, and assumes the enum is part of the current package.

[johanbrandhorst]

Nice find! Would you be interested in submitting a fix for this?

[kwonalbert]

Sure, I'd be happy to, though it might take me a bit of time to get started on it (the earliest I can start is probably next weekend).

[kwonalbert]

I'm waiting on my company to hear back about the CLA. Meanwhile, my fix is at https://github.com/kwonalbert/grpc-gateway. It was just some small updates to the template for codegen.

[johanbrandhorst]

Great work, looking forward to the PR!

[carvalhorr]

Really nice find, @kwonalbert . I run into this problem in my first attempt to use grpc-gateway. Looking forward to seeing the fix merged.

[sgtsquiggs]

Bump; I have this same issue and would love this merged into the 1.x branch

[sgtsquiggs]

This change does not work: kwonalbert@14e42a6

You end up with:

	e, err = runtime.Enum(val, path/to/specific/package.Table_value)

	if err != nil {
		return nil, metadata, status.Errorf(codes.InvalidArgument, "type mismatch, parameter: %s, error: %v", "table", err)
	}

	protoReq.Table = path / to / specific / package.Table(e)

[sgtsquiggs]

This change worked for me:

diff --git a/protoc-gen-grpc-gateway/internal/gengateway/template.go b/protoc-gen-grpc-gateway/internal/gengateway/template.go
index 392110a..22952f1 100644
--- a/protoc-gen-grpc-gateway/internal/gengateway/template.go
+++ b/protoc-gen-grpc-gateway/internal/gengateway/template.go
@@ -359,10 +359,10 @@ var (
 {{if $param.IsNestedProto3}}
 	err = runtime.PopulateFieldFromPath(&protoReq, {{$param | printf "%q"}}, val)
 	{{if $enum}}
-		e{{if $param.IsRepeated}}s{{end}}, err = {{$param.ConvertFuncExpr}}(val{{if $param.IsRepeated}}, {{$binding.Registry.GetRepeatedPathParamSeparator | printf "%c" | printf "%q"}}{{end}}, {{$enum.GoType $param.Target.Message.File.GoPkg.Path}}_value)
+		e{{if $param.IsRepeated}}s{{end}}, err = {{$param.ConvertFuncExpr}}(val{{if $param.IsRepeated}}, {{$binding.Registry.GetRepeatedPathParamSeparator | printf "%c" | printf "%q"}}{{end}}, {{$enum.GoType $param.Method.Service.File.GoPkg.Path}}_value)
 	{{end}}
 {{else if $enum}}
-	e{{if $param.IsRepeated}}s{{end}}, err = {{$param.ConvertFuncExpr}}(val{{if $param.IsRepeated}}, {{$binding.Registry.GetRepeatedPathParamSeparator | printf "%c" | printf "%q"}}{{end}}, {{$enum.GoType $param.Target.Message.File.GoPkg.Path}}_value)
+	e{{if $param.IsRepeated}}s{{end}}, err = {{$param.ConvertFuncExpr}}(val{{if $param.IsRepeated}}, {{$binding.Registry.GetRepeatedPathParamSeparator | printf "%c" | printf "%q"}}{{end}}, {{$enum.GoType $param.Method.Service.File.GoPkg.Path}}_value)
 {{else}}
 	{{$param.AssignableExpr "protoReq"}}, err = {{$param.ConvertFuncExpr}}(val{{if $param.IsRepeated}}, {{$binding.Registry.GetRepeatedPathParamSeparator | printf "%c" | printf "%q"}}{{end}})
 {{end}}
@@ -370,13 +370,13 @@ var (
 		return nil, metadata, status.Errorf(codes.InvalidArgument, "type mismatch, parameter: %s, error: %v", {{$param | printf "%q"}}, err)
 	}
 {{if and $enum $param.IsRepeated}}
-	s := make([]{{$enum.GoType $param.Target.Message.File.GoPkg.Path}}, len(es))
+	s := make([]{{$enum.GoType $param.Method.Service.File.GoPkg.Path}}, len(es))
 	for i, v := range es {
-		s[i] = {{$enum.GoType $param.Target.Message.File.GoPkg.Path}}(v)
+		s[i] = {{$enum.GoType $param.Method.Service.File.GoPkg.Path}}(v)
 	}
 	{{$param.AssignableExpr "protoReq"}} = s
 {{else if $enum}}
-	{{$param.AssignableExpr "protoReq"}} = {{$enum.GoType $param.Target.Message.File.GoPkg.Path}}(e)
+	{{$param.AssignableExpr "protoReq"}} = {{$enum.GoType $param.Method.Service.File.GoPkg.Path}}(e)
 {{end}}
 	{{end}}
 {{end}}
@@ -521,10 +521,10 @@ func local_request_{{.Method.Service.GetName}}_{{.Method.GetName}}_{{.Index}}(ct
 {{if $param.IsNestedProto3}}
 	err = runtime.PopulateFieldFromPath(&protoReq, {{$param | printf "%q"}}, val)
 	{{if $enum}}
-		e{{if $param.IsRepeated}}s{{end}}, err = {{$param.ConvertFuncExpr}}(val{{if $param.IsRepeated}}, {{$binding.Registry.GetRepeatedPathParamSeparator | printf "%c" | printf "%q"}}{{end}}, {{$enum.GoType $param.Target.Message.File.GoPkg.Path}}_value)
+		e{{if $param.IsRepeated}}s{{end}}, err = {{$param.ConvertFuncExpr}}(val{{if $param.IsRepeated}}, {{$binding.Registry.GetRepeatedPathParamSeparator | printf "%c" | printf "%q"}}{{end}}, {{$enum.GoType $param.Method.Service.File.GoPkg.Path}}_value)
 	{{end}}
 {{else if $enum}}
-	e{{if $param.IsRepeated}}s{{end}}, err = {{$param.ConvertFuncExpr}}(val{{if $param.IsRepeated}}, {{$binding.Registry.GetRepeatedPathParamSeparator | printf "%c" | printf "%q"}}{{end}}, {{$enum.GoType $param.Target.Message.File.GoPkg.Path}}_value)
+	e{{if $param.IsRepeated}}s{{end}}, err = {{$param.ConvertFuncExpr}}(val{{if $param.IsRepeated}}, {{$binding.Registry.GetRepeatedPathParamSeparator | printf "%c" | printf "%q"}}{{end}}, {{$enum.GoType $param.Method.Service.File.GoPkg.Path}}_value)
 {{else}}
 	{{$param.AssignableExpr "protoReq"}}, err = {{$param.ConvertFuncExpr}}(val{{if $param.IsRepeated}}, {{$binding.Registry.GetRepeatedPathParamSeparator | printf "%c" | printf "%q"}}{{end}})
 {{end}}
@@ -532,13 +532,13 @@ func local_request_{{.Method.Service.GetName}}_{{.Method.GetName}}_{{.Index}}(ct
 		return nil, metadata, status.Errorf(codes.InvalidArgument, "type mismatch, parameter: %s, error: %v", {{$param | printf "%q"}}, err)
 	}
 {{if and $enum $param.IsRepeated}}
-	s := make([]{{$enum.GoType $param.Target.Message.File.GoPkg.Path}}, len(es))
+	s := make([]{{$enum.GoType $param.Method.Service.File.GoPkg.Path}}, len(es))
 	for i, v := range es {
-		s[i] = {{$enum.GoType $param.Target.Message.File.GoPkg.Path}}(v)
+		s[i] = {{$enum.GoType $param.Method.Service.File.GoPkg.Path}}(v)
 	}
 	{{$param.AssignableExpr "protoReq"}} = s
 {{else if $enum}}
-	{{$param.AssignableExpr "protoReq"}} = {{$enum.GoType $param.Target.Message.File.GoPkg.Path}}(e)
+	{{$param.AssignableExpr "protoReq"}} = {{$enum.GoType $param.Method.Service.File.GoPkg.Path}}(e)
 {{end}}
 	{{end}}
 {{end}}

[kwonalbert]

That change seems better than what I was doing. I still haven't heard back about the CLA from my company, so feel free to file a PR with your change for this instead..

[johanbrandhorst]

Thanks Matthew, would you like to contribute a PR with this fix?