Revert "Recreate aiohttp session on connectivity check (#5332)" (#5851)

This reverts commit 1504278223a8d852d3b11de25f676fa8d6501a70.

It turns out that recreating the session can cause race conditions, e.g.
with API checks triggered by proxied requests running alongside. These
manifest in the following error:

AttributeError: 'NoneType' object has no attribute 'connect'
...
  File "supervisor/homeassistant/api.py", line 187, in check_api_state
    if state := await self.get_api_state():
  File "supervisor/homeassistant/api.py", line 171, in get_api_state
    data = await self.get_core_state()
  File "supervisor/homeassistant/api.py", line 145, in get_core_state
    return await self._get_json("api/core/state")
  File "supervisor/homeassistant/api.py", line 132, in _get_json
    async with self.make_request("get", path) as resp:
  File "contextlib.py", line 214, in __aenter__
    return await anext(self.gen)
  File "supervisor/homeassistant/api.py", line 106, in make_request
    async with getattr(self.sys_websession, method)(
  File "aiohttp/client.py", line 1425, in __aenter__
    self._resp: _RetType = await self._coro
  File "aiohttp/client.py", line 703, in _request
    conn = await self._connector.connect(

The only reason for the _connection in the aiohttp client to be None is
when close() gets called on the session. The only place this is being
done is the connectivity check.

So it seems that between fetching the session from the `sys_websession`
property) and actually using the connector, a connectivity check has been
run which then causes the above stack trace.

Let's not mess with the lifetime of the ClientSession object and simply
revert the change. Another solution for the original problem needs to be
found.

supervisor/coresys.py

@@ -68,7 +68,7 @@ class CoreSys:
 
         # External objects
         self._loop: asyncio.BaseEventLoop = asyncio.get_running_loop()
-        self._websession = None
+        self._websession: aiohttp.ClientSession = aiohttp.ClientSession()
 
         # Global objects
         self._config: CoreConfig = CoreConfig()
@@ -101,8 +101,10 @@ class CoreSys:
         self._bus: Bus | None = None
         self._mounts: MountManager | None = None
 
-        # Setup aiohttp session
-        self.create_websession()
+        # Set default header for aiohttp
+        self._websession._default_headers = MappingProxyType(
+            {aiohttp.hdrs.USER_AGENT: SERVER_SOFTWARE}
+        )
 
         # Task factory attributes
         self._set_task_context: list[Callable[[Context], Context]] = []
@@ -582,16 +584,6 @@ class CoreSys:
 
         return self.loop.run_in_executor(None, funct, *args)
 
-    def create_websession(self) -> None:
-        """Create a new aiohttp session."""
-        if self._websession:
-            self.create_task(self._websession.close())
-
-        # Create session and set default header for aiohttp
-        self._websession: aiohttp.ClientSession = aiohttp.ClientSession(
-            headers=MappingProxyType({aiohttp.hdrs.USER_AGENT: SERVER_SOFTWARE})
-        )
-
     def _create_context(self) -> Context:
         """Create a new context for a task."""
         context = copy_context()

supervisor/supervisor.py

@@ -292,8 +292,6 @@ class Supervisor(CoreSysAttributes):
                 "https://checkonline.home-assistant.io/online.txt", timeout=timeout
             )
         except (ClientError, TimeoutError):
-            # Need to recreate the websession to avoid stale connection checks
-            self.coresys.create_websession()
             self.connectivity = False
         else:
             self.connectivity = True