fix(web.req): regression: IPV6_PRIOR|R_PROXY causes AssertionError

Happy eyeballs, available since aiohttp 3.10, cause AssertionError when
setting both proxy and socket family.

Make them mutually exclusive (proxy takes precedence) since it is always
meaningless to set them together.

TODO: Is it time to deprecate IPV6_PRIOR and completely rely on Happy
Eyeballs (RFC 8305)?

Fixes the regression introduced in
88fdb2c.

Signed-off-by: Rongrong <[email protected]>

src/web/req.py

@@ -155,16 +155,22 @@ async def _request(
     host = urlparse(url).hostname
     semaphore_to_use = locks.hostname_semaphore(host, parse=False) if semaphore in (None, True) \
         else (semaphore or nullcontext())
-    v6_rr_set = None
-    try:
-        v6_rr_set = (await asyncio.wait_for(resolve(host, 'AAAA', lifetime=1), 1.1)).rrset if env.IPV6_PRIOR else None
-    except DNSException:
-        pass
-    except asyncio.TimeoutError:
-        pass
-    except Exception as e:
-        logger.debug(f'Error occurred when querying {url} AAAA:', exc_info=e)
-    socket_family = AF_INET6 if v6_rr_set else 0
+
+    # Happy Eyeballs, available since aiohttp 3.10, cause AssertionError when setting both proxy and socket family.
+    # Make them mutually exclusive (proxy takes precedence) since it is always meaningless to set them together.
+    # TODO: Is it time to deprecate IPV6_PRIOR and completely rely on Happy Eyeballs (RFC 8305)?
+    use_proxy: bool = PROXY and proxy_filter(host, parse=False)
+    socket_family = 0
+    if env.IPV6_PRIOR and not use_proxy:
+        try:
+            if (
+                    await asyncio.wait_for(resolve(host, 'AAAA', lifetime=1), 1.1)
+            ).rrset:
+                socket_family = AF_INET6
+        except (DNSException, asyncio.TimeoutError):
+            pass
+        except Exception as e:
+            logger.debug(f'Error occurred when querying {url} AAAA:', exc_info=e)
 
     _headers = HEADER_TEMPLATE.copy()
     if headers:
@@ -215,7 +221,7 @@ async def _fetch():
             socket_family = AF_INET
         proxy_connector = (
             ProxyConnector.from_url(PROXY, family=socket_family, ssl=__SSL_CONTEXT)
-            if (PROXY and proxy_filter(host, parse=False))
+            if use_proxy
             else aiohttp.TCPConnector(family=socket_family, ssl=__SSL_CONTEXT)
         )