New submission from INADA Naoki: In C implementation, write() calls underlaying flush() method when write_through=True.
https://github.com/python/cpython/blob/3.6/Modules/_io/textio.c if (self->write_through) text_needflush = 1; if (self->line_buffering && (haslf || PyUnicode_FindChar(text, '\r', 0, PyUnicode_GET_LENGTH(text), 1) != -1)) needflush = 1; But pure Python implementation doesn't care write_through option at all. https://github.com/python/cpython/blob/3.6/Lib/_pyio.py self.buffer.write(b) if self._line_buffering and (haslf or "\r" in s): self.flush() When PyPy 3.5 is released, this difference may affects PyPy users. (I hadn't checked how PyPy provide io module.) ---------- components: IO messages: 288282 nosy: inada.naoki priority: normal severity: normal status: open title: TextIOWrapper's write_through option behave differently between C and pure Python implementation. type: behavior versions: Python 3.5, Python 3.6, Python 3.7 _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue29611> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
