try new tornado hotness

Author: bollwyvl

jupyter_server/pytest_plugin.py

@@ -1604,31 +1604,32 @@ def init_httpserver(self):
 
     @staticmethod
     def _init_asyncio_patch():
-        """set default asyncio policy to be compatible with tornado
-        Tornado 6 (at least) is not compatible with the default
-        asyncio implementation on Windows
-        Pick the older SelectorEventLoopPolicy on Windows
-        if the known-incompatible default policy is in use.
-        do this as early as possible to make it a low priority and overrideable
-        ref: https://github.com/tornadoweb/tornado/issues/2608
-        FIXME: if/when tornado supports the defaults in asyncio,
-               remove and bump tornado requirement for py38
-        """
-        if sys.platform.startswith("win") and sys.version_info >= (3, 8):
-            import asyncio
-            try:
-                from asyncio import (
-                    WindowsProactorEventLoopPolicy,
-                    WindowsSelectorEventLoopPolicy,
-                )
-            except ImportError:
-                pass
-                # not affected
-            else:
-                if type(asyncio.get_event_loop_policy()) is WindowsProactorEventLoopPolicy:
-                    # WindowsProactorEventLoopPolicy is not compatible with tornado 6
-                    # fallback to the pre-3.8 default of Selector
-                    asyncio.set_event_loop_policy(WindowsSelectorEventLoopPolicy())
+        return
+        # """set default asyncio policy to be compatible with tornado
+        # Tornado 6 (at least) is not compatible with the default
+        # asyncio implementation on Windows
+        # Pick the older SelectorEventLoopPolicy on Windows
+        # if the known-incompatible default policy is in use.
+        # do this as early as possible to make it a low priority and overrideable
+        # ref: https://github.com/tornadoweb/tornado/issues/2608
+        # FIXME: if/when tornado supports the defaults in asyncio,
+        #        remove and bump tornado requirement for py38
+        # """
+        # if sys.platform.startswith("win") and sys.version_info >= (3, 8):
+        #     import asyncio
+        #     try:
+        #         from asyncio import (
+        #             WindowsProactorEventLoopPolicy,
+        #             WindowsSelectorEventLoopPolicy,
+        #         )
+        #     except ImportError:
+        #         pass
+        #         # not affected
+        #     else:
+        #         if type(asyncio.get_event_loop_policy()) is WindowsProactorEventLoopPolicy:
+        #             # WindowsProactorEventLoopPolicy is not compatible with tornado 6
+        #             # fallback to the pre-3.8 default of Selector
+        #             asyncio.set_event_loop_policy(WindowsSelectorEventLoopPolicy())
 
     @catch_config_error
     def initialize(self, argv=None, find_extensions=True, new_httpserver=True):

jupyter_server/serverapp.py

@@ -37,7 +37,7 @@
     ],
     install_requires = [
         'jinja2',
-        'tornado>=5.0',
+        'tornado>=6.1.0',
         'pyzmq>=17',
         'ipython_genutils',
         'traitlets>=4.2.1',