Fix cancel logic during SessionPool.acquire()

tests/aio/test_session_pool.py

@@ -34,10 +34,15 @@ async def test_waiter_is_notified(driver):
 @pytest.mark.asyncio
 async def test_no_race_after_future_cancel(driver):
     pool = ydb.aio.SessionPool(driver, 1)
+
     s = await pool.acquire()
     waiter = asyncio.ensure_future(pool.acquire())
+    await asyncio.sleep(0)
     waiter.cancel()
     await pool.release(s)
+    await asyncio.wait([waiter])
+
+    assert pool._active_queue.qsize() == 1
     s = await pool.acquire()
     assert s.initialized()
     await pool.stop()

ydb/aio/table.py

@@ -563,7 +563,14 @@ async def _prepare_session(self, timeout, retry_num) -> ydb.ISession:
     async def _get_session_from_queue(self, timeout: float):
         task_wait = asyncio.ensure_future(asyncio.wait_for(self._active_queue.get(), timeout=timeout))
         task_should_stop = asyncio.ensure_future(self._should_stop.wait())
-        done, _ = await asyncio.wait((task_wait, task_should_stop), return_when=asyncio.FIRST_COMPLETED)
+        try:
+            done, _ = await asyncio.wait((task_wait, task_should_stop), return_when=asyncio.FIRST_COMPLETED)
+        except asyncio.CancelledError:
+            cancelled = task_wait.cancel()
+            if not cancelled:
+                priority, session = task_wait.result()
+                self._active_queue.put_nowait((priority, session))
+            raise
         if task_should_stop in done:
             task_wait.cancel()
             return self._create()