qa: Fix "RuntimeError: Event loop is closed" on Windows

[hebasto]

On master (2161a05), running functional tests that use the P2P interface ends with an error:

RuntimeError: Event loop is closed

This PR fixes this bug, and enables more functional tests on Windows MSVC CI task.

More details about bugfix:

• What’s New In Python 3.7
• https://bugs.python.org/issue33792
• actual change done in Python 3.8

Excluded tests, that are listed in the EXCLUDE_TESTS environment variable, need more thorough investigation to be enabled.

[fanquake]

In master we still require a minimum Python version of 3.6. From what I can see, WindowsSelectorEventLoopPolicy didn't exist until Python 3.8.

[hebasto]

In master we still require a minimum Python version of 3.6. From what I can see, WindowsSelectorEventLoopPolicy didn't exist until Python 3.8.

Right. Would it be sufficient to update our docs and specifically for Windows users mention that they are required to install Python 3.8+ ?

Or add a version check?

[maflcko]

This should be fine. Python doesn't care about unexecuted code.

I am running python3.6 on my machine with the following diff and everything passed:

diff --git a/test/functional/test_framework/p2p.py b/test/functional/test_framework/p2p.py
index ec563cc290..1cf23ef191 100755
--- a/test/functional/test_framework/p2p.py
+++ b/test/functional/test_framework/p2p.py
@@ -578,7 +578,7 @@ class NetworkThread(threading.Thread):
         NetworkThread.listeners = {}
         NetworkThread.protos = {}
         if sys.platform == 'win32':
-            asyncio.set_event_loop_policy(asyncio.WindowsSelectorEventLoopPolicy())
+            asyncio.foo_bar(asyncio.FooBar())
         NetworkThread.network_event_loop = asyncio.new_event_loop()
 
     def run(self):

Again, I don't think anyone of our users is running the functional tests on windows, so it seems odd to even think about spending time to support running them on older versions of python.

[maflcko]

review ACK 357f0c7 🌆

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review ACK 357f0c723308b296c6250946c26cf476d9ecfda2 🌆
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Timestamp of file with hash 81344abdd7d21141fc132bf636bb4c3a9b6e24b5ef0ed9a189290709b209a0d8 -

[maflcko]

I reset the ci run 4 times, all times it did pass.

Would be good to merge this before the std::fs refactor, so that it has better test coverage.

[fanquake]

This should be fine. Python doesn't care about unexecuted code.

Sure. However I do care about implicit / undocumented dependency changes. At a minimum the commit / PR description should mention the change in requirements.

[maflcko]

The PR description links to "what is new in Python 3.7". Is there anything else it can say?

[fanquake]

Is there anything else it can say?

Link to / mention the actual minimum requirement, which is 3.8?

[hebasto]

Is there anything else it can say?

Link to / mention the actual minimum requirement, which is 3.8?

Added.

[fanquake]

This has been merged.