Use fmt.Errorf to be able to unwrap error

Author: johejo

shellwords_test.go

@@ -1,8 +1,10 @@
 package shellwords
 
 import (
+	"errors"
 	"go/build"
 	"os"
+	"os/exec"
 	"path"
 	"reflect"
 	"testing"
@@ -183,9 +185,9 @@ func TestBacktickError(t *testing.T) {
 	if err == nil {
 		t.Fatal("Should be an error")
 	}
-	expected := "exit status 2:go Version: unknown command\nRun 'go help' for usage.\n"
-	if expected != err.Error() {
-		t.Fatalf("Expected %q, but %q", expected, err.Error())
+	var eerr *exec.ExitError
+	if !errors.As(err, &eerr) {
+		t.Fatal("Should be able to unwrap to *exec.ExitError")
 	}
 	_, err = parser.Parse(`echo $(echo1)`)
 	if err == nil {

util_posix.go

@@ -3,7 +3,7 @@
 package shellwords
 
 import (
-	"errors"
+	"fmt"
 	"os"
 	"os/exec"
 	"strings"
@@ -23,7 +23,7 @@ func shellRun(line, dir string) (string, error) {
 		if eerr, ok := err.(*exec.ExitError); ok {
 			b = eerr.Stderr
 		}
-		return "", errors.New(err.Error() + ":" + string(b))
+		return "", fmt.Errorf("%s: %w", string(b), err)
 	}
 	return strings.TrimSpace(string(b)), nil
 }

util_windows.go

@@ -3,7 +3,7 @@
 package shellwords
 
 import (
-	"errors"
+	"fmt"
 	"os"
 	"os/exec"
 	"strings"
@@ -23,7 +23,7 @@ func shellRun(line, dir string) (string, error) {
 		if eerr, ok := err.(*exec.ExitError); ok {
 			b = eerr.Stderr
 		}
-		return "", errors.New(err.Error() + ":" + string(b))
+		return "", fmt.Errorf("%s: %w", string(b), err)
 	}
 	return strings.TrimSpace(string(b)), nil
 }