Method FormatImpl

python/pyarrow/src/arrow/python/common.cc:141–175

 protected:
  Result<std::string> FormatImpl() const {
    PyAcquireGIL lock;

    // Use traceback.format_exception()
    OwnedRef traceback_module;
    RETURN_NOT_OK(internal::ImportModule("traceback", &traceback_module));

    OwnedRef fmt_exception;
    RETURN_NOT_OK(internal::ImportFromModule(traceback_module.obj(), "format_exception",
                                             &fmt_exception));

    OwnedRef formatted;
    formatted.reset(PyObject_CallFunctionObjArgs(fmt_exception.obj(), exc_type_.obj(),
                                                 exc_value_.obj(), exc_traceback_.obj(),
                                                 NULL));
    RETURN_IF_PYERROR();

    std::stringstream ss;
    ss << "Python exception: ";
    Py_ssize_t num_lines = PySequence_Length(formatted.obj());
    RETURN_IF_PYERROR();

    for (Py_ssize_t i = 0; i < num_lines; ++i) {
      Py_ssize_t line_size;

      PyObject* line = PySequence_GetItem(formatted.obj(), i);
      RETURN_IF_PYERROR();

      const char* data = PyUnicode_AsUTF8AndSize(line, &line_size);
      RETURN_IF_PYERROR();

      ss << std::string_view(data, line_size);
    }
    return ss.str();
  }

  PythonErrorDetail() = default;