attempt to detect errors during file writing

embed/embed.go

@@ -124,13 +124,7 @@ func Run(conf *Config) error {
 		}
 	}
 	sort.Strings(fnames)
-	w := os.Stdout
-	if conf.OutputFile != "" {
-		if w, err = os.Create(conf.OutputFile); err != nil {
-			return err
-		}
-		defer w.Close()
-	}
+	w := new(bytes.Buffer)
 	headerText, err := header(conf.Package, !(conf.Private))
 	if nil != err {
 		return fmt.Errorf("failed to expand autogenerated code: %s", err)
@@ -191,7 +185,19 @@ func Run(conf *Config) error {
 		local: %q,
 	},%s`, dir, local, "\n")
 	}
-	fmt.Fprint(w, footer)
+	w.WriteString(footer)
+	out := os.Stdout
+	if conf.OutputFile != "" {
+		if out, err = os.Create(conf.OutputFile); err != nil {
+			return err
+		}
+	}
+	if _, err := w.WriteTo(out); err != nil {
+		return err
+	}
+	if conf.OutputFile != "" {
+		return out.Close()
+	}
 	return nil
 }