fix tag for nested messages

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

ast.go

@@ -15,20 +15,9 @@ import (
 	"google.golang.org/protobuf/proto"
 )
 
-var (
-	astFields = make(map[string]map[string]map[string]*structtag.Tags) // map proto file with proto message ast struct
-)
+var astFields = make(map[string]map[string]map[string]*structtag.Tags) // map proto file with proto message ast struct
 
-func (g *Generator) astGenerate(plugin *protogen.Plugin) error {
-	if g.tagPath == "" {
-		return nil
-	}
-	for _, file := range plugin.Files {
-		if !file.Generate {
-			continue
-		}
-
-		for _, message := range file.Messages {
+func (g *Generator) astFill(file *protogen.File, message *protogen.Message) error {
 	for _, field := range message.Fields {
 		if field.Desc.Options() == nil {
 			continue
@@ -57,6 +46,28 @@ func (g *Generator) astGenerate(plugin *protogen.Plugin) error {
 			astFields[fpath] = mp
 		}
 	}
+	for _, nmessage := range message.Messages {
+		if err := g.astFill(file, nmessage); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (g *Generator) astGenerate(plugin *protogen.Plugin) error {
+	if g.tagPath == "" {
+		return nil
+	}
+
+	for _, file := range plugin.Files {
+		if !file.Generate {
+			continue
+		}
+		for _, message := range file.Messages {
+			if err := g.astFill(file, message); err != nil {
+				return err
+			}
 		}
 	}