asyncio: sync with Tulip

* Cleanup gather(): use cancelled() method instead of using private Future
  attribute
* Fix _UnixReadPipeTransport and _UnixWritePipeTransport. Only start reading
  when connection_made() has been called.
* Issue #23333: Fix BaseSelectorEventLoop._accept_connection(). Close the
  transport on error. In debug mode, log errors using call_exception_handler()

3 files changed, 50 insertions, 13 deletions

diff --git a/Lib/asyncio/selector_events.py b/Lib/asyncio/selector_events.py
index 3195f62..9147832 100644
--- a/Lib/asyncio/selector_events.py
+++ b/Lib/asyncio/selector_events.py
@@ -22,6 +22,7 @@ from . import futures
 from . import selectors
 from . import transports
 from . import sslproto
+from .coroutines import coroutine
 from .log import logger
 
 
@@ -181,16 +182,47 @@ class BaseSelectorEventLoop(base_events.BaseEventLoop):
             else:
                 raise  # The event loop will catch, log and ignore it.
         else:
+            extra = {'peername': addr}
+            accept = self._accept_connection2(protocol_factory, conn, extra,
+                                              sslcontext, server)
+            self.create_task(accept)
+
+    @coroutine
+    def _accept_connection2(self, protocol_factory, conn, extra,
+                            sslcontext=None, server=None):
+        protocol = None
+        transport = None
+        try:
             protocol = protocol_factory()
+            waiter = futures.Future(loop=self)
             if sslcontext:
-                self._make_ssl_transport(
-                    conn, protocol, sslcontext,
-                    server_side=True, extra={'peername': addr}, server=server)
+                transport = self._make_ssl_transport(
+                    conn, protocol, sslcontext, waiter=waiter,
+                    server_side=True, extra=extra, server=server)
             else:
-                self._make_socket_transport(
-                    conn, protocol , extra={'peername': addr},
+                transport = self._make_socket_transport(
+                    conn, protocol, waiter=waiter, extra=extra,
                     server=server)
-        # It's now up to the protocol to handle the connection.
+
+            try:
+                yield from waiter
+            except:
+                transport.close()
+                raise
+
+            # It's now up to the protocol to handle the connection.
+        except Exception as exc:
+            if self.get_debug():
+                context = {
+                    'message': ('Error on transport creation '
+                                'for incoming connection'),
+                    'exception': exc,
+                }
+                if protocol is not None:
+                    context['protocol'] = protocol
+                if transport is not None:
+                    context['transport'] = transport
+                self.call_exception_handler(context)
 
     def add_reader(self, fd, callback, *args):
         """Add a reader callback."""
diff --git a/Lib/asyncio/tasks.py b/Lib/asyncio/tasks.py
index 63412a9..4f19a25 100644
--- a/Lib/asyncio/tasks.py
+++ b/Lib/asyncio/tasks.py
@@ -592,7 +592,7 @@ def gather(*coros_or_futures, loop=None, return_exceptions=False):
                 fut.exception()
             return
 
-        if fut._state == futures._CANCELLED:
+        if fut.cancelled():
             res = futures.CancelledError()
             if not return_exceptions:
                 outer.set_exception(res)
diff --git a/Lib/asyncio/unix_events.py b/Lib/asyncio/unix_events.py
index 67973f1..7e1265a 100644
--- a/Lib/asyncio/unix_events.py
+++ b/Lib/asyncio/unix_events.py
@@ -298,8 +298,10 @@ class _UnixReadPipeTransport(transports.ReadTransport):
         _set_nonblocking(self._fileno)
         self._protocol = protocol
         self._closing = False
-        self._loop.add_reader(self._fileno, self._read_ready)
         self._loop.call_soon(self._protocol.connection_made, self)
+        # only start reading when connection_made() has been called
+        self._loop.call_soon(self._loop.add_reader,
+                             self._fileno, self._read_ready)
         if waiter is not None:
             # only wake up the waiter when connection_made() has been called
             self._loop.call_soon(waiter._set_result_unless_cancelled, None)
@@ -401,13 +403,16 @@ class _UnixWritePipeTransport(transports._FlowControlMixin,
         self._conn_lost = 0
         self._closing = False  # Set when close() or write_eof() called.
 
-        # On AIX, the reader trick only works for sockets.
-        # On other platforms it works for pipes and sockets.
-        # (Exception: OS X 10.4?  Issue #19294.)
+        self._loop.call_soon(self._protocol.connection_made, self)
+
+        # On AIX, the reader trick (to be notified when the read end of the
+        # socket is closed) only works for sockets. On other platforms it
+        # works for pipes and sockets. (Exception: OS X 10.4?  Issue #19294.)
         if is_socket or not sys.platform.startswith("aix"):
-            self._loop.add_reader(self._fileno, self._read_ready)
+            # only start reading when connection_made() has been called
+            self._loop.call_soon(self._loop.add_reader,
+                                 self._fileno, self._read_ready)
 
-        self._loop.call_soon(self._protocol.connection_made, self)
         if waiter is not None:
             # only wake up the waiter when connection_made() has been called
             self._loop.call_soon(waiter._set_result_unless_cancelled, None)