As opposed to using TestCaseForTestnet class, this allows having a single class
of many related unit tests, some using testnet and some using mainnet constants.
asyncio.get_event_loop() became deprecated in python3.10. (see https://github.com/python/cpython/issues/83710)
```
.../electrum/electrum/daemon.py:470: DeprecationWarning: There is no current event loop
self.asyncio_loop = asyncio.get_event_loop()
.../electrum/electrum/network.py:276: DeprecationWarning: There is no current event loop
self.asyncio_loop = asyncio.get_event_loop()
```
Also, according to that thread, "set_event_loop() [... is] not deprecated by oversight".
So, we stop using get_event_loop() and set_event_loop() in our own code.
Note that libraries we use (such as the stdlib for python <3.10), might call get_event_loop,
which then relies on us having called set_event_loop e.g. for the GUI thread. To work around
this, a custom event loop policy providing a get_event_loop implementation is used.
Previously, we have been using a single asyncio event loop, created with
util.create_and_start_event_loop, and code in many places got a reference to this loop
using asyncio.get_event_loop().
Now, we still use a single asyncio event loop, but it is now stored as a global in
util._asyncio_event_loop (access with util.get_asyncio_loop()).
I believe these changes also fix https://github.com/spesmilo/electrum/issues/5376
from travis logs:
--- Logging error ---
Traceback (most recent call last):
File "/opt/python/3.7.6/lib/python3.7/logging/__init__.py", line 1028, in emit
stream.write(msg + self.terminator)
ValueError: I/O operation on closed file.
Call stack:
File "/opt/python/3.7.6/lib/python3.7/threading.py", line 890, in _bootstrap
self._bootstrap_inner()
File "/opt/python/3.7.6/lib/python3.7/threading.py", line 926, in _bootstrap_inner
self.run()
File "/home/travis/build/spesmilo/electrum/electrum/plugin.py", line 213, in run
self.run_jobs()
File "/home/travis/build/spesmilo/electrum/electrum/util.py", line 359, in on_stop
self.logger.info("stopped")
Message: 'stopped'
The few other cases that used SimpleConfig.get_instance() now
either get passed a config instance, or they try to get a reference
to something else that has a reference to a config.
(see lnsweep, qt/qrcodewidget, qt/qrtextedit)
previously load_transactions() had to be called before upgrade();
now we reverse this order.
to reproduce/illustrate issue, before this commit:
try running convert_version_17 and convert_version_18
(e.g. see testcase test_upgrade_from_client_2_9_3_old_seeded_with_realistic_history)
and then in qt console:
>> wallet.storage.db.get_data_ref('spent_outpoints') == wallet.storage.db.spent_outpoints
False
>> wallet.storage.db.get_data_ref('verified_tx3') == wallet.storage.db.verified_tx
False
