Enabling http2 in HassHttpXAsyncClient breaks aiohttp clients #160074
Description
The problem
I have an integration that wants to use http2. I create a client for it using
create_async_httpx_client(hass, http2=True)
But after doing so, I get errors in my logs shaped like:
2025-12-31 12:18:06.120 ERROR (MainThread) [metno] Access to https://aa015h6buqvih86i1.api.met.no/weatherapi/locationforecast/2.0/complete returned error 'ClientResponseError'
2025-12-31 12:17:54.682 ERROR (MainThread) [homeassistant.components.homeassistant_alerts.coordinator] Error requesting homeassistant_alerts data: 400, message="Expected HTTP/, RTSP/ or ICE/:\n\n b''\n ^", url='https://alerts.home-assistant.io/alerts.json'
2025-12-31 12:17:55.109 ERROR (MainThread) [metno] Access to https://aa015h6buqvih86i1.api.met.no/weatherapi/locationforecast/2.0/complete returned error 'ClientResponseError'
I have tried a little to diagnose what's going on here without a ton of luck, homeassistant_alerts.coordinator uses aiohttp as near as I can tell which makes me very puzzled about why enabling http2 in my integration is breaking it.
What version of Home Assistant Core has the issue?
core-2025.12.5
What was the last working version of Home Assistant Core?
No response
What type of installation are you running?
Home Assistant OS
Integration causing the issue
custom (In my case, franklinwh)
Link to integration documentation on our website
No response
Diagnostics information
No response
Example YAML snippet
Anything in the logs that might be useful for us?
Additional information
No response