Use alternative methods to get homedir that do not require cgo.

Fix arduino#133

Author: cmaglie

configs/directories.go

@@ -20,12 +20,11 @@ package configs
 import (
 	"fmt"
 	"os"
-	"os/user"
 	"runtime"
 
-	"github.com/arduino/go-paths-helper"
-
-	"github.com/arduino/go-win32-utils"
+	paths "github.com/arduino/go-paths-helper"
+	win32 "github.com/arduino/go-win32-utils"
+	homedir "github.com/mitchellh/go-homedir"
 )
 
 // getDefaultConfigFilePath returns the default path for .cli-config.yml,
@@ -39,11 +38,11 @@ func getDefaultConfigFilePath() *paths.Path {
 }
 
 func getDefaultArduinoDataDir() (*paths.Path, error) {
-	usr, err := user.Current()
+	homedir, err := homedir.Dir()
 	if err != nil {
 		return nil, fmt.Errorf("retrieving user home dir: %s", err)
 	}
-	arduinoDataDir := paths.New(usr.HomeDir)
+	arduinoDataDir := paths.New(homedir)
 
 	switch runtime.GOOS {
 	case "linux":
@@ -63,16 +62,16 @@ func getDefaultArduinoDataDir() (*paths.Path, error) {
 }
 
 func getDefaultSketchbookDir() (*paths.Path, error) {
-	usr, err := user.Current()
+	homedir, err := homedir.Dir()
 	if err != nil {
 		return nil, fmt.Errorf("retrieving home dir: %s", err)
 	}
 
 	switch runtime.GOOS {
 	case "linux":
-		return paths.New(usr.HomeDir).Join("Arduino"), nil
+		return paths.New(homedir).Join("Arduino"), nil
 	case "darwin":
-		return paths.New(usr.HomeDir).Join("Documents", "Arduino"), nil
+		return paths.New(homedir).Join("Documents", "Arduino"), nil
 	case "windows":
 		documentsPath, err := win32.GetDocumentsFolder()
 		if err != nil {

configs/directories_test.go

@@ -0,0 +1,16 @@
+package configs
+
+import (
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestGetDefaultDirs(t *testing.T) {
+	// This should fail if cross-compiled for linux/amd64 or compiled natively without CGO enable
+	// See: https://github.com/arduino/arduino-cli/issues/133
+	os.Setenv("USER", "")
+	_, err := getDefaultArduinoDataDir()
+	require.NoError(t, err)
+}