Indeed, but it's also useless to add the check -- this function never returns `NULL` either.  And as @sardemff7 said, it's kinda weird to use `g_return_if_fail()` here, which is supposed to be used to check for programming errors like incorrect parameters -- ok, here it checks that `g_key_file_to_data()` isn't buggy, but huh.  IMHO, either leave it as is with the useless error checking, or remote the thing entirely.