bpo-35682: Fix _ProactorBasePipeTransport._force_close() (GH-11462)

bpo-32622, bpo-35682: Fix asyncio.ProactorEventLoop.sendfile(): don't
attempt to set the result of an internal future if it's already done.

Fix asyncio _ProactorBasePipeTransport._force_close(): don't set the
result of _empty_waiter if it's already done.
(cherry picked from commit 80fda712c83f5dd9560d42bf2aa65a72b18b7759)

Co-authored-by: Victor Stinner <vstinner@redhat.com>

diff --git a/Lib/asyncio/proactor_events.py b/Lib/asyncio/proactor_events.py
index e350e8bc0c2485ccd30b40f0701078ae0dabdccc..782c86106bce00b39e2e0e6e657deea6a022b150 100644 (file)
--- a/Lib/asyncio/proactor_events.py
+++ b/Lib/asyncio/proactor_events.py
@@ -110,7 +110,7 @@ class _ProactorBasePipeTransport(transports._FlowControlMixin,
             self._force_close(exc)
 
     def _force_close(self, exc):
-        if self._empty_waiter is not None:
+        if self._empty_waiter is not None and not self._empty_waiter.done():
             if exc is None:
                 self._empty_waiter.set_result(None)
             else:

diff --git a/Misc/NEWS.d/next/Library/2019-01-08-01-54-02.bpo-35682.KDM9lk.rst b/Misc/NEWS.d/next/Library/2019-01-08-01-54-02.bpo-35682.KDM9lk.rst
new file mode 100644 (file)
index 0000000..8152bd7
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2019-01-08-01-54-02.bpo-35682.KDM9lk.rst
@@ -0,0 +1,2 @@
+Fix ``asyncio.ProactorEventLoop.sendfile()``: don't attempt to set the result
+of an internal future if it's already done.