Guard with RELEASE_BUILD_FLAGS_IN_PROTOBUF

If false, then we output an empty file, which will cause
release_config.mk to do the old process.

Bug: 328495189
Test: manual
Change-Id: I4aa82301f3bbb29633a275a801431a6667feb48d

cmd/release_config/crunch_flags/main.go

@@ -21,6 +21,7 @@ var (
 	manualFlagNamePrefixes []string = []string{
 		"RELEASE_ACONFIG_",
 		"RELEASE_PLATFORM_",
+		"RELEASE_BUILD_FLAGS_",
 	}
 
 	// Set `aconfig_flags_only: true` in these release configs.

cmd/release_config/release_config/main.go

@@ -35,6 +35,7 @@ func main() {
 	var product string
 	var allMake bool
 	var useBuildVar bool
+	var guard bool
 
 	defaultRelease := os.Getenv("TARGET_RELEASE")
 	if defaultRelease == "" {
@@ -52,6 +53,7 @@ func main() {
 	flag.BoolVar(&pb, "pb", true, "write artifacts as binary protobuf")
 	flag.BoolVar(&allMake, "all_make", true, "write makefiles for all release configs")
 	flag.BoolVar(&useBuildVar, "use_get_build_var", false, "use get_build_var PRODUCT_RELEASE_CONFIG_MAPS")
+	flag.BoolVar(&guard, "guard", true, "whether to guard with RELEASE_BUILD_FLAGS_IN_PROTOBUF")
 
 	flag.Parse()
 
@@ -76,20 +78,21 @@ func main() {
 		panic(err)
 	}
 
-	if err = config.WritePartitionBuildFlags(outputDir, product, targetRelease); err != nil {
-		panic(err)
-	}
-
-	if allMake {
+	makefilePath := filepath.Join(outputDir, fmt.Sprintf("release_config-%s-%s.mk", product, releaseName))
+	useProto, ok := config.FlagArtifacts["RELEASE_BUILD_FLAGS_IN_PROTOBUF"]
+	if guard && (!ok || rc_lib.MarshalValue(useProto.Value) == "") {
+		// We were told to guard operation and either we have no build flag, or it is False.
+		// Write an empty file so that release_config.mk will use the old process.
+		os.WriteFile(makefilePath, []byte{}, 0644)
+	} else if allMake {
 		for k, _ := range configs.ReleaseConfigs {
-			makefilePath := filepath.Join(outputDir, fmt.Sprintf("release_config-%s-%s.mk", product, k))
+			makefilePath = filepath.Join(outputDir, fmt.Sprintf("release_config-%s-%s.mk", product, k))
 			err = configs.WriteMakefile(makefilePath, k)
 			if err != nil {
 				panic(err)
 			}
 		}
 	} else {
-		makefilePath := filepath.Join(outputDir, fmt.Sprintf("release_config-%s-%s.mk", product, releaseName))
 		err = configs.WriteMakefile(makefilePath, targetRelease)
 		if err != nil {
 			panic(err)
@@ -113,4 +116,8 @@ func main() {
 			panic(err)
 		}
 	}
+	if err = config.WritePartitionBuildFlags(outputDir, product, targetRelease); err != nil {
+		panic(err)
+	}
+
 }

cmd/release_config/release_config_lib/flag_value.go

@@ -52,6 +52,9 @@ func UnmarshalValue(str string) *rc_proto.Value {
 }
 
 func MarshalValue(value *rc_proto.Value) string {
+	if value == nil {
+		return ""
+	}
 	switch val := value.Val.(type) {
 	case *rc_proto.Value_UnspecifiedValue:
 		// Value was never set.

cmd/release_config/release_config_lib/flag_value_test.go

@@ -24,7 +24,7 @@ import (
 	"google.golang.org/protobuf/proto"
 )
 
-type testCaseFlagValue struct {
+type testCaseFlagValueFactory struct {
 	protoPath string
 	name      string
 	data      []byte
@@ -32,14 +32,14 @@ type testCaseFlagValue struct {
 	err       error
 }
 
-func (tc testCaseFlagValue) assertProtoEqual(t *testing.T, expected, actual proto.Message) {
+func (tc testCaseFlagValueFactory) assertProtoEqual(t *testing.T, expected, actual proto.Message) {
 	if !proto.Equal(expected, actual) {
 		t.Errorf("Expected %q found %q", expected, actual)
 	}
 }
 
-func TestFlagValue(t *testing.T) {
-	testCases := []testCaseFlagValue{
+func TestFlagValueFactory(t *testing.T) {
+	testCases := []testCaseFlagValueFactory{
 		{
 			name:      "stringVal",
 			protoPath: "build/release/flag_values/test/RELEASE_FOO.textproto",
@@ -65,3 +65,50 @@ func TestFlagValue(t *testing.T) {
 		tc.assertProtoEqual(t, &tc.expected, &actual.proto)
 	}
 }
+
+type testCaseMarshalValue struct {
+	name     string
+	value    *rc_proto.Value
+	expected string
+}
+
+func TestMarshalValue(t *testing.T) {
+	testCases := []testCaseMarshalValue{
+		{
+			name:     "nil",
+			value:    nil,
+			expected: "",
+		},
+		{
+			name:     "unspecified",
+			value:    &rc_proto.Value{},
+			expected: "",
+		},
+		{
+			name:     "false",
+			value:    &rc_proto.Value{Val: &rc_proto.Value_BoolValue{false}},
+			expected: "",
+		},
+		{
+			name:     "true",
+			value:    &rc_proto.Value{Val: &rc_proto.Value_BoolValue{true}},
+			expected: "true",
+		},
+		{
+			name:     "string",
+			value:    &rc_proto.Value{Val: &rc_proto.Value_StringValue{"BAR"}},
+			expected: "BAR",
+		},
+		{
+			name:     "obsolete",
+			value:    &rc_proto.Value{Val: &rc_proto.Value_Obsolete{true}},
+			expected: " #OBSOLETE",
+		},
+	}
+	for _, tc := range testCases {
+		actual := MarshalValue(tc.value)
+		if actual != tc.expected {
+			t.Errorf("Expected %q found %q", tc.expected, actual)
+		}
+	}
+}