From dbaa8170bc71a53f0874cc9fce0e1ff0719219cf Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Thu, 10 Oct 2024 10:28:10 -0500
Subject: [PATCH 1/2] [3.11] Fix AsyncResolver query fallback swallowing the
 error message

Same change as #9451 but for the query fallback code for older
versions of aiodns
---
 aiohttp/resolver.py    |  4 ++--
 tests/test_resolver.py | 30 ++++++++++++++++++++++++++++++
 2 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/aiohttp/resolver.py b/aiohttp/resolver.py
index 5240bfbd8d..a988b0bf47 100644
--- a/aiohttp/resolver.py
+++ b/aiohttp/resolver.py
@@ -159,7 +159,7 @@ async def _resolve_with_query(
             resp = await self._resolver.query(host, qtype)
         except aiodns.error.DNSError as exc:
             msg = exc.args[1] if len(exc.args) >= 1 else "DNS lookup failed"
-            raise OSError(msg) from exc
+            raise OSError(None, msg) from exc
 
         hosts = []
         for rr in resp:
@@ -175,7 +175,7 @@ async def _resolve_with_query(
             )
 
         if not hosts:
-            raise OSError("DNS lookup failed")
+            raise OSError(None, "DNS lookup failed")
 
         return hosts
 
diff --git a/tests/test_resolver.py b/tests/test_resolver.py
index 842618c305..b460606707 100644
--- a/tests/test_resolver.py
+++ b/tests/test_resolver.py
@@ -332,6 +332,36 @@ async def test_async_resolver_query_ipv6_positive_lookup(loop) -> None:
         mock().query.assert_called_with("www.python.org", "AAAA")
 
 
+@pytest.mark.skipif(not getaddrinfo, reason="aiodns >=3.2.0 required")
+async def test_async_resolver_query_fallback_error_messages_passed(
+    loop: asyncio.AbstractEventLoop,
+) -> None:
+    """Ensure error messages are passed through from aiodns with query fallback."""
+    with patch("aiodns.DNSResolver", autospec=True, spec_set=True) as mock:
+        del mock().gethostbyname
+        mock().query.side_effect = aiodns.error.DNSError(1, "Test error message")
+        resolver = AsyncResolver()
+        with pytest.raises(OSError, match="Test error message") as excinfo:
+            await resolver.resolve("x.org")
+
+        assert excinfo.value.strerror == "Test error message"
+
+
+@pytest.mark.skipif(not getaddrinfo, reason="aiodns >=3.2.0 required")
+async def test_async_resolver_query_fallback_error_messages_passed_no_hosts(
+    loop: asyncio.AbstractEventLoop,
+) -> None:
+    """Ensure error messages are passed through from aiodns with query fallback."""
+    with patch("aiodns.DNSResolver", autospec=True, spec_set=True) as mock:
+        del mock().gethostbyname
+        mock().query.return_value = fake_query_result([])
+        resolver = AsyncResolver()
+        with pytest.raises(OSError, match="DNS lookup failed") as excinfo:
+            await resolver.resolve("x.org")
+
+        assert excinfo.value.strerror == "DNS lookup failed"
+
+
 @pytest.mark.skipif(not getaddrinfo, reason="aiodns >=3.2.0 required")
 async def test_async_resolver_error_messages_passed(
     loop: asyncio.AbstractEventLoop,

From fc8d676d5701002f1f3c8c4174075d1157564f52 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Thu, 10 Oct 2024 10:28:55 -0500
Subject: [PATCH 2/2] changelog

---
 CHANGES/9455.bugfix.rst | 1 +
 1 file changed, 1 insertion(+)
 create mode 120000 CHANGES/9455.bugfix.rst

diff --git a/CHANGES/9455.bugfix.rst b/CHANGES/9455.bugfix.rst
new file mode 120000
index 0000000000..da8457a1de
--- /dev/null
+++ b/CHANGES/9455.bugfix.rst
@@ -0,0 +1 @@
+9451.bugfix.rst
\ No newline at end of file