Improve _mythread checks (#7403)

* Improve _mythread checks

* Create get_running_loop util

electrum/lnrater.py

@@ -14,13 +14,8 @@ from typing import TYPE_CHECKING, Dict, NamedTuple, Tuple, List, Optional
 import sys
 import time
 
-if sys.version_info[:2] >= (3, 7):
-    from asyncio import get_running_loop
-else:
-    from asyncio import _get_running_loop as get_running_loop  # noqa: F401
-
 from .logging import Logger
-from .util import profiler
+from .util import profiler, get_running_loop
 from .lnrouter import fee_for_edge_msat
 from .lnutil import LnFeatures, ln_compare_features, IncompatibleLightningFeatures
 

electrum/network.py

@@ -275,11 +275,6 @@ class Network(Logger, NetworkRetryManager[ServerAddr]):
 
         self.asyncio_loop = asyncio.get_event_loop()
         assert self.asyncio_loop.is_running(), "event loop not running"
-        try:
-            self._loop_thread = self.asyncio_loop._mythread  # type: threading.Thread  # only used for sanity checks
-        except AttributeError as e:
-            self.logger.warning(f"asyncio loop does not have _mythread set: {e!r}")
-            self._loop_thread = None
 
         assert isinstance(config, SimpleConfig), f"config should be a SimpleConfig instead of {type(config)}"
         self.config = config
@@ -387,7 +382,7 @@ class Network(Logger, NetworkRetryManager[ServerAddr]):
             self.path_finder = None
 
     def run_from_another_thread(self, coro, *, timeout=None):
-        assert self._loop_thread != threading.current_thread(), 'must not be called from network thread'
+        assert util.get_running_loop() != self.asyncio_loop, 'must not be called from network thread'
         fut = asyncio.run_coroutine_threadsafe(coro, self.asyncio_loop)
         return fut.result(timeout)
 
@@ -1318,7 +1313,7 @@ class Network(Logger, NetworkRetryManager[ServerAddr]):
     def send_http_on_proxy(cls, method, url, **kwargs):
         network = cls.get_instance()
         if network:
-            assert network._loop_thread is not threading.currentThread()
+            assert util.get_running_loop() != network.asyncio_loop
             loop = network.asyncio_loop
         else:
             loop = asyncio.get_event_loop()

electrum/util.py

@@ -1279,7 +1279,6 @@ def create_and_start_event_loop() -> Tuple[asyncio.AbstractEventLoop,
                                          args=(stopping_fut,),
                                          name='EventLoop')
     loop_thread.start()
-    loop._mythread = loop_thread
     return loop, stopping_fut, loop_thread
 
 
@@ -1626,3 +1625,12 @@ class nullcontext:
 
     async def __aexit__(self, *excinfo):
         pass
+
+def get_running_loop():
+    """Mimics _get_running_loop convenient functionality for sanity checks on all python versions"""
+    if sys.version_info < (3, 7):
+        return asyncio._get_running_loop()
+    try:
+        return asyncio.get_running_loop()
+    except RuntimeError:
+        return None