parsers: simplify error logic in compute_phases_map_sets Since Py_XDECREF and free both accept NULL pointers, we can get by with just two exit paths: one for success, and one for error. This considerably simplifies reasoning about the possible ways to exit from this function.

util: rename argument of isatty() In general, "fd" is a file descriptor, but isatty() expects a file object. We should call it "fp" or "fh".