Class _NamedTextIOWrapper

src/click/testing.py:156–208

A :class:`~io.TextIOWrapper` with custom ``name`` and ``mode`` that does not close its underlying buffer. When ``CliRunner`` runs in ``fd`` mode, ``_original_fd`` is patched to point at the saved (pre-redirection) ``fd``, so C-level consumers that call :meth:`fileno` (like ``faultha

class _NamedTextIOWrapper(io.TextIOWrapper):
    """A :class:`~io.TextIOWrapper` with custom ``name`` and ``mode``
    that does not close its underlying buffer.

    When ``CliRunner`` runs in ``fd`` mode, ``_original_fd`` is patched to
    point at the saved (pre-redirection) ``fd``, so C-level consumers that call
    :meth:`fileno` (like ``faulthandler`` or ``subprocess``) keep working. In
    the default ``sys`` mode ``_original_fd`` stays at ``-1`` and
    :meth:`fileno` raises :exc:`io.UnsupportedOperation`, matching the
    pre-``8.3.3`` behavior.
    """

    _name: str
    _mode: str
    _original_fd: int

    def __init__(
        self,
        buffer: t.BinaryIO,
        name: str,
        mode: str,
        **kwargs: t.Any,
    ) -> None:
        super().__init__(buffer, **kwargs)
        self._name = name
        self._mode = mode
        self._original_fd = -1

    def close(self) -> None:
        """The buffer this object contains belongs to some other object,
        so prevent the default ``__del__`` implementation from closing
        that buffer.

        .. versionadded:: 8.3.2
        """

    def fileno(self) -> int:
        """Return the file descriptor of the saved original stream when
        ``CliRunner`` runs in ``fd`` mode. Otherwise delegate to
        :class:`~io.TextIOWrapper`, which raises
        :exc:`io.UnsupportedOperation` for a ``BytesIO``-backed buffer.
        """
        if self._original_fd >= 0:
            return self._original_fd
        return super().fileno()

    @property
    def name(self) -> str:
        return self._name

    @property
    def mode(self) -> str:
        return self._mode


def make_input_stream(