pool: Untrack connection if it's closed in pool.release

Author: 1st1

asyncpg/pool.py

@@ -120,7 +120,10 @@ async def acquire(self, *, timeout=None):
 
     async def release(self, connection):
         self._check_init()
-        if connection._protocol.queries_count >= self._max_queries:
+        if connection.is_closed():
+            self._con_count -= 1
+            self._connections.remove(connection)
+        elif connection._protocol.queries_count >= self._max_queries:
             self._con_count -= 1
             self._connections.remove(connection)
             await connection.close()

tests/test_pool.py

@@ -61,3 +61,19 @@ async def test_pool_03(self):
 
         pool.terminate()
         del con
+
+    async def test_pool_04(self):
+        addr = self.cluster.get_connection_addr()
+        pool = await asyncpg.create_pool(host=addr[0], port=addr[1],
+                                         database='postgres',
+                                         loop=self.loop, min_size=1,
+                                         max_size=1)
+
+        con = await pool.acquire(timeout=0.1)
+        con.terminate()
+        await pool.release(con)
+
+        con = await pool.acquire(timeout=0.1)
+        self.assertEqual(await con.fetchval('SELECT 1'), 1)
+
+        await pool.close()