* std::string_view::data() does not necessarily have a NUL
    terminated string. So either convert to std::string() first
    or have function parameters use a const char* to begin with
    if that is what the caller provides.
  * subtle: the absl cleanup got a _copy_ of the initial allocated
    buffer pointer, but getline() will modify possibly that value as it
    might reallocate. So call the cleanup with a reference.

Not an access issue, just simplification:
  * in getting the env var, no need to convert to string_view first,
    then back to string just to have a nul-terminated string.
    We call that function with a const char* anyway.