diff --git a/Doc/library/multiprocessing.rst b/Doc/library/multiprocessing.rst index 5ff94eaea23..18e81a79385 100644 --- a/Doc/library/multiprocessing.rst +++ b/Doc/library/multiprocessing.rst @@ -710,7 +710,8 @@ Connection objects usually created using :func:`Pipe` -- see also Send an object to the other end of the connection which should be read using :meth:`recv`. - The object must be picklable. + The object must be picklable. Very large pickles (approximately 32 MB+, + though it depends on the OS) may raise a ValueError exception. .. method:: recv() @@ -742,7 +743,9 @@ Connection objects usually created using :func:`Pipe` -- see also complete message. If *offset* is given then data is read from that position in *buffer*. If - *size* is given then that many bytes will be read from buffer. + *size* is given then that many bytes will be read from buffer. Very large + buffers (approximately 32 MB+, though it depends on the OS) may raise a + ValueError exception .. method:: recv_bytes([maxlength]) diff --git a/Misc/NEWS b/Misc/NEWS index dd8c0ade99a..8a500597db9 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -202,6 +202,10 @@ Core and Builtins Library ------- +- Issue 3551: Patch multiprocessing to raise a proper exception if the size of the + object when writefile is called causes a ERROR_NO_SYSTEM_RESOURCES. Added docs + to note the limitation + - unittest.assertNotEqual() now uses the inequality operator (!=) instead of the equality operator. diff --git a/Modules/_multiprocessing/connection.h b/Modules/_multiprocessing/connection.h index 458d1d3cf30..c2f85635ad7 100644 --- a/Modules/_multiprocessing/connection.h +++ b/Modules/_multiprocessing/connection.h @@ -131,8 +131,12 @@ connection_sendbytes(ConnectionObject *self, PyObject *args) res = conn_send_string(self, buffer + offset, size); - if (res < 0) - return mp_SetError(PyExc_IOError, res); + if (res < 0) { + if (PyErr_Occurred()) + return NULL; + else + return mp_SetError(PyExc_IOError, res); + } Py_RETURN_NONE; } diff --git a/Modules/_multiprocessing/pipe_connection.c b/Modules/_multiprocessing/pipe_connection.c index 27e79dda7d4..66947c838f2 100644 --- a/Modules/_multiprocessing/pipe_connection.c +++ b/Modules/_multiprocessing/pipe_connection.c @@ -23,6 +23,12 @@ conn_send_string(ConnectionObject *conn, char *string, size_t length) Py_BEGIN_ALLOW_THREADS ret = WriteFile(conn->handle, string, length, &amount_written, NULL); Py_END_ALLOW_THREADS + + if (ret == 0 && GetLastError() == ERROR_NO_SYSTEM_RESOURCES) { + PyErr_Format(PyExc_ValueError, "Cannnot send %" PY_FORMAT_SIZE_T "d bytes over connection", length); + return MP_STANDARD_ERROR; + } + return ret ? MP_SUCCESS : MP_STANDARD_ERROR; }