From 25e09ab52b87e998ef098bcf747d1df5a8c65560 Mon Sep 17 00:00:00 2001
From: Eric Prestat <eric.prestat@gmail.com>
Date: Wed, 29 Jan 2020 12:50:42 +0000
Subject: [PATCH] Fix the consolewidget on windows with python 3.8, see
 https://github.com/ipython/ipykernel/pull/480.

---
 hyperspyui/widgets/consolewidget.py | 32 +++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/hyperspyui/widgets/consolewidget.py b/hyperspyui/widgets/consolewidget.py
index c5e25c91..feb7bd54 100644
--- a/hyperspyui/widgets/consolewidget.py
+++ b/hyperspyui/widgets/consolewidget.py
@@ -20,6 +20,7 @@
 
 @author: Vidar Tonaas Fauske
 """
+import sys
 
 try:
     from qtconsole.rich_jupyter_widget import RichJupyterWidget
@@ -31,11 +32,42 @@
 from IPython.lib import guisupport
 
 
+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())
+
+
 class ConsoleWidget(RichJupyterWidget):
 
     def __init__(self, *args, **kwargs):
         super(ConsoleWidget, self).__init__(*args, **kwargs)
 
+        _init_asyncio_patch()
         # Create an in-process kernel
         app = guisupport.get_app_qt4()
         kernel_manager = QtInProcessKernelManager()