ioloop,asyncio: Be more careful to restore old asyncio loop

Any asyncio event loop that was created but neither closed nor set as
current for some thread will log a warning at the end of the test (in
a way that doesn't cause the test to fail). Fix a bug in
make_current() (in which multiple calls would clobber
self.old_asyncio) and use it more consistently when "current" status
changes.

diff --git a/tornado/ioloop.py b/tornado/ioloop.py
index c829afcf53f838dcaee1bc1a131da1d42a509474..b17f24bd9db09d858baf008dad4fa4ef823cc87e 100644 (file)
--- a/tornado/ioloop.py
+++ b/tornado/ioloop.py
@@ -310,6 +310,9 @@ class IOLoop(Configurable):
         .. versionchanged:: 5.0
            This method also sets the current `asyncio` event loop.
         """
+        old = getattr(IOLoop._current, "instance", None)
+        if old is not None:
+            old.clear_current()
         IOLoop._current.instance = self
 
     @staticmethod
@@ -924,8 +927,9 @@ class PollIOLoop(IOLoop):
         if self._stopped:
             self._stopped = False
             return
-        old_current = getattr(IOLoop._current, "instance", None)
-        IOLoop._current.instance = self
+        old_current = IOLoop.current(instance=False)
+        if old_current is not self:
+            self.make_current()
         self._thread_ident = thread.get_ident()
         self._running = True
 
@@ -1068,7 +1072,10 @@ class PollIOLoop(IOLoop):
             self._stopped = False
             if self._blocking_signal_threshold is not None:
                 signal.setitimer(signal.ITIMER_REAL, 0, 0)
-            IOLoop._current.instance = old_current
+            if old_current is None:
+                IOLoop.clear_current()
+            elif old_current is not self:
+                old_current.make_current()
             if old_wakeup_fd is not None:
                 signal.set_wakeup_fd(old_wakeup_fd)
 

diff --git a/tornado/platform/asyncio.py b/tornado/platform/asyncio.py
index ac0946cd7be14b2378633a416483ce3766092ad9..d28a491db9486a3b2dfb98cc84c984a8ee7dfae6 100644 (file)
--- a/tornado/platform/asyncio.py
+++ b/tornado/platform/asyncio.py
@@ -186,6 +186,7 @@ class AsyncIOLoop(BaseAsyncIOLoop):
        to refer to this class directly.
     """
     def initialize(self, **kwargs):
+        self.is_current = False
         loop = asyncio.new_event_loop()
         try:
             super(AsyncIOLoop, self).initialize(loop, **kwargs)
@@ -195,16 +196,25 @@ class AsyncIOLoop(BaseAsyncIOLoop):
             loop.close()
             raise
 
+    def close(self, all_fds=False):
+        if self.is_current:
+            self.clear_current()
+        super(AsyncIOLoop, self).close(all_fds=all_fds)
+
     def make_current(self):
-        super(AsyncIOLoop, self).make_current()
-        try:
-            self.old_asyncio = asyncio.get_event_loop()
-        except RuntimeError:
-            self.old_asyncio = None
+        if not self.is_current:
+            super(AsyncIOLoop, self).make_current()
+            try:
+                self.old_asyncio = asyncio.get_event_loop()
+            except RuntimeError:
+                self.old_asyncio = None
+            self.is_current = True
         asyncio.set_event_loop(self.asyncio_loop)
 
     def _clear_current_hook(self):
-        asyncio.set_event_loop(self.old_asyncio)
+        if self.is_current:
+            asyncio.set_event_loop(self.old_asyncio)
+            self.is_current = False
 
 
 def to_tornado_future(asyncio_future):