Revert to json.Encoder

Add tiny test for ldflags
Fix err declaration

import_obfuscation.go

@@ -6,7 +6,7 @@ package main
 import (
 	"bufio"
 	"bytes"
-	"encoding/gob"
+	"encoding/json"
 	"errors"
 	"fmt"
 	"os"
@@ -55,16 +55,9 @@ func appendPrivateNameMap(nameMap map[string]string, packageDirectory string) er
 	if err != nil {
 		return err
 	}
-
-	var localMap map[string]string
-	if err = gob.NewDecoder(file).Decode(&localMap); err != nil {
+	if err := json.NewDecoder(file).Decode(&nameMap); err != nil {
 		return err
 	}
-
-	for oldName, newName := range localMap {
-		nameMap[oldName] = newName
-	}
-
 	return nil
 }
 
@@ -93,7 +86,7 @@ func obfuscateImports(objPath, importCfgPath string) (garbledImports, privateNam
 			pkgs = append(pkgs, pkgInfo{pkg, info.Path, private})
 
 			packageDir := filepath.Dir(info.Path)
-			if err = appendPrivateNameMap(nameMap, packageDir); err != nil {
+			if err := appendPrivateNameMap(nameMap, packageDir); err != nil {
 				return nil, nil, fmt.Errorf("error parsing name map %s at %s: %v", pkgPath, info.Path, err)
 			}
 		}

main.go

@@ -607,7 +607,7 @@ func transformCompile(args []string) ([]string, error) {
 		}
 		defer file.Close()
 
-		if err := gob.NewEncoder(file).Encode(privateNameMap); err != nil {
+		if err := json.NewEncoder(file).Encode(privateNameMap); err != nil {
 			return nil, err
 		}
 	}

testdata/scripts/ldflags.txt

@@ -1,13 +1,18 @@
 # Note the proper domain, since the dot adds an edge case.
 env GOPRIVATE=domain.test/main
 
-garble -tiny build -ldflags='-X=main.unexportedVersion=v1.0.0 -X=domain.test/main/imported.ExportedVar=replaced'
+garble build -ldflags='-X=main.unexportedVersion=v1.0.0 -X=domain.test/main/imported.ExportedVar=replaced'
 exec ./main
 cmp stderr main.stderr
 ! binsubstr main$exe 'unexportedVersion'
 
 [short] stop # no need to verify this with -short
 
+garble -tiny build -ldflags='-X=main.unexportedVersion=v1.0.0 -X=domain.test/main/imported.ExportedVar=replaced'
+exec ./main
+cmp stderr main.stderr
+! binsubstr main$exe 'unexportedVersion'
+
 exec go build -ldflags='-X=main.unexportedVersion=v1.0.0 -X=domain.test/main/imported.ExportedVar=replaced'
 exec ./main
 cmp stderr main.stderr