From 500bd858293a29d21b311e500c30343ab22b4e06 Mon Sep 17 00:00:00 2001
From: Adam Lehechka <42357034+alehechka@users.noreply.github.com>
Date: Wed, 27 Jul 2022 16:15:08 -0500
Subject: [PATCH] Generate GraphQL types for empty proto messages (#2)

---
 protoc-gen-graphql/generator/generator.go |  4 ----
 protoc-gen-graphql/template.go            | 16 ++++++++++++++--
 2 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/protoc-gen-graphql/generator/generator.go b/protoc-gen-graphql/generator/generator.go
index a244a43..2902002 100644
--- a/protoc-gen-graphql/generator/generator.go
+++ b/protoc-gen-graphql/generator/generator.go
@@ -111,10 +111,6 @@ func (g *Generator) generateFile(file *spec.File, tmpl string, services []*spec.
 	var packages []*spec.Package
 
 	for _, m := range g.messages {
-		// skip empty field message, otherwise graphql-go raise error
-		if len(m.Fields()) == 0 {
-			continue
-		}
 		if m.IsDepended(spec.DependTypeMessage, file.Package()) {
 			switch {
 			case file.Package() == m.Package():
diff --git a/protoc-gen-graphql/template.go b/protoc-gen-graphql/template.go
index 8461363..cebe057 100644
--- a/protoc-gen-graphql/template.go
+++ b/protoc-gen-graphql/template.go
@@ -95,7 +95,8 @@ func Gql__type_{{ .TypeName }}() *graphql.Object {
 			Description: ` + "`" + `{{ .Comment }}` + "`" + `,
 			{{- end }}
 			Fields: graphql.Fields {
-{{- range .Fields }}
+{{- if .Fields }}
+	{{- range .Fields }}
 				{{- if .IsResolve }}
 				{{ $query := .ResolveSubField $.Services }}
 				"{{ .FieldName }}": &graphql.Field{
@@ -158,6 +159,11 @@ func Gql__type_{{ .TypeName }}() *graphql.Object {
 					{{- end }}
 				},
 				{{- end }}
+	{{- end }}
+{{- else }}
+	"_": &graphql.Field{
+		Type: graphql.Boolean,
+	},			
 {{- end }}
 			},
 			{{- if .Interfaces }}
@@ -180,13 +186,19 @@ func Gql__input_{{ .TypeName }}() *graphql.InputObject {
 		gql__input_{{ .TypeName }} =  graphql.NewInputObject(graphql.InputObjectConfig{
 			Name: "{{ $.RootPackage.CamelName }}_Input_{{ .TypeName }}",
 			Fields: graphql.InputObjectConfigFieldMap{
-{{- range .Fields }}
+{{- if .Fields}}
+	{{- range .Fields }}
 				"{{ .FieldName }}": &graphql.InputObjectFieldConfig{
 					{{- if .Comment }}
 					Description: ` + "`" + `{{ .Comment }}` + "`" + `,
 					{{- end }}
 					Type: {{ .FieldTypeInput $.RootPackage.Name }},
 				},
+	{{- end }}
+{{- else }}
+	"_": &graphql.InputObjectFieldConfig{
+		Type: graphql.Boolean,
+	},
 {{- end }}
 			},
 		})