Issue 3551: Raise ValueError if the size causes ERROR_NO_SYSTEM_RESOURCES
diff --git a/Doc/library/multiprocessing.rst b/Doc/library/multiprocessing.rst
index 5ff94ea..18e81a7 100644
--- a/Doc/library/multiprocessing.rst
+++ b/Doc/library/multiprocessing.rst
@@ -710,7 +710,8 @@
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 @@
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 dd8c0ad..8a50059 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -202,6 +202,10 @@
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 458d1d3..c2f8563 100644
--- a/Modules/_multiprocessing/connection.h
+++ b/Modules/_multiprocessing/connection.h
@@ -131,8 +131,12 @@
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 27e79dd..66947c8 100644
--- a/Modules/_multiprocessing/pipe_connection.c
+++ b/Modules/_multiprocessing/pipe_connection.c
@@ -23,6 +23,12 @@
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;
}