interface.got_disconnected: change from Future to Event

Events are far easier to reason about.

electrum/interface.py

@@ -351,7 +351,7 @@ class Interface(Logger):
 
     def __init__(self, *, network: 'Network', server: ServerAddr, proxy: Optional[dict]):
         self.ready = asyncio.Future()
-        self.got_disconnected = asyncio.Future()
+        self.got_disconnected = asyncio.Event()
         self.server = server
         Logger.__init__(self)
         assert network.config.path
@@ -486,8 +486,7 @@ class Interface(Logger):
                 self.logger.debug(f"(disconnect) trace for {repr(e)}", exc_info=True)
             finally:
                 await self.network.connection_down(self)
-                if not self.got_disconnected.done():
-                    self.got_disconnected.set_result(1)
+                self.got_disconnected.set()
                 # if was not 'ready' yet, schedule waiting coroutines:
                 self.ready.cancel()
         return wrapper_func

electrum/network.py

@@ -820,20 +820,20 @@ class Network(Logger, NetworkRetryManager[ServerAddr]):
                 assert iface.ready.done(), "interface not ready yet"
                 # try actual request
                 success_fut = asyncio.ensure_future(func(self, *args, **kwargs))
-                await asyncio.wait([success_fut, iface.got_disconnected], return_when=asyncio.FIRST_COMPLETED)
+                await asyncio.wait([success_fut, iface.got_disconnected.wait()], return_when=asyncio.FIRST_COMPLETED)
                 if success_fut.done() and not success_fut.cancelled():
                     if success_fut.exception():
                         try:
                             raise success_fut.exception()
                         except RequestTimedOut:
                             await iface.close()
-                            await iface.got_disconnected
+                            await iface.got_disconnected.wait()
                             continue  # try again
                         except RequestCorrupted as e:
                             # TODO ban server?
                             iface.logger.exception(f"RequestCorrupted: {e}")
                             await iface.close()
-                            await iface.got_disconnected
+                            await iface.got_disconnected.wait()
                             continue  # try again
                     return success_fut.result()
                 # otherwise; try again