Add support for proto2 default values

.github/workflows/build.yml

@@ -6,13 +6,13 @@ jobs:
     steps:
       - uses: actions/checkout@v3
       - name: Set up Go
-        uses: actions/setup-go@v3
+        uses: actions/setup-go@v4
         with:
-          go-version: 1.19
+          go-version: '1.20'
       - name: Install Protoc
         run: |
           sudo apt install -y protobuf-compiler
-          go install google.golang.org/protobuf/cmd/protoc-gen-go@v1.28
+          go install google.golang.org/protobuf/cmd/protoc-gen-go@latest
       - name: Test
         run: make test
       - name: Build

pkg/protodump/fixtures/test.proto2

@@ -0,0 +1,19 @@
+syntax = "proto2";
+
+package hello.world;
+
+option go_package = "./;helloworld";
+
+message SearchRequest {
+  optional string query = 1 [default = "hello"];
+  optional int32 page_number = 2;
+  optional int32 result_per_page = 3 [default = 10];
+  optional .hello.world.Corpus corpus = 4 [default = CORPUS_UNIVERSAL];
+  optional bool field = 5 [default = true];
+}
+
+enum Corpus {
+  CORPUS_UNSPECIFIED = 0;
+  CORPUS_UNIVERSAL = 1;
+}
+

pkg/protodump/proto.go

@@ -135,6 +135,19 @@ func (pd *ProtoDefinition) writeField(field protoreflect.FieldDescriptor) {
 	pd.write(string(field.Name()))
 	pd.write(" = ")
 	pd.write(strconv.Itoa(int(field.Number())))
+	if field.HasDefault() {
+		pd.write(" [default = ")
+		kind := field.Kind().String()
+		if kind == "string" {
+			pd.write(fmt.Sprintf("\"%s\"", field.Default().String()))
+		} else if kind == "enum" {
+			pd.write(string(field.Enum().Values().ByNumber(field.Default().Enum()).Name()))
+		} else {
+			pd.write(field.Default().String())
+		}
+
+		pd.write("]")
+	}
 	pd.write(";\n")
 }
 

pkg/protodump/proto_test.go

@@ -5,7 +5,6 @@ import (
 	"os"
 	"os/exec"
 	"path"
-	"regexp"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -15,8 +14,6 @@ import (
 
 const FIXTURES = "fixtures"
 
-var regex = regexp.MustCompile("(?m)var .* = \\[\\]byte{([^}]*)}")
-
 func convertProtoToFileDescriptor(filePath string) (*descriptorpb.FileDescriptorProto, error) {
 	dir, err := os.MkdirTemp("", "")
 	if err != nil {