Use filename instead of file handler to scan file for null byte

kg/helpers.go

@@ -32,13 +32,21 @@ func genRange[T character](start, end T) []T {
 }
 
 // Returns whether or not the given file contains a NULL character
-func fileContainsNullChar(file *os.File) bool {
+func fileContainsNullChar(filename string) (bool, error) {
+	file, err := os.Open(filename)
+	if err != nil {
+		return true, err
+	}
+	defer file.Close()
 	scanner := bufio.NewScanner(file)
 	for scanner.Scan() {
 		line := scanner.Text()
 		if strings.Contains(line, "\000") {
-			return true
+			return true, nil
 		}
 	}
-	return false
+	if err := scanner.Err(); err != nil {
+		return true, err
+	}
+	return false, nil
 }