Fix DNS error re-write on Windows

On windows only, the driver would re-write the DNS error when resolving
`Address(None, None)` to be retryable, which it shouldn't.

Author: robsdedude

src/neo4j/_async_compat/network/_util.py

@@ -14,6 +14,8 @@
 # limitations under the License.
 
 
+from __future__ import annotations
+
 import asyncio
 import contextlib
 import logging
@@ -88,14 +90,17 @@ async def _dns_resolver(address, family=0):
                 type=socket.SOCK_STREAM,
             )
         except OSError as e:
-            if e.errno in _RETRYABLE_DNS_ERRNOS or (
-                e.errno in _EAI_NONAME
-                and (address.host is not None or address.port is not None)
+            # note: on some systems like Windows, EAI_NONAME and EAI_NODATA
+            #       have the same error-code.
+            if e.errno in _EAI_NONAME and (
+                address.host is None and address.port is None
             ):
-                raise ServiceUnavailable(
-                    f"Failed to DNS resolve address {address}: {e}"
-                ) from e
-            raise ValueError(
+                err_cls = ValueError
+            elif e.errno in _RETRYABLE_DNS_ERRNOS or e.errno in _EAI_NONAME:
+                err_cls = ServiceUnavailable
+            else:
+                err_cls = ValueError
+            raise err_cls(
                 f"Failed to DNS resolve address {address}: {e}"
             ) from e
         return list(_resolved_addresses_from_info(info, address._host_name))
@@ -179,14 +184,17 @@ def _dns_resolver(address, family=0):
                 type=socket.SOCK_STREAM,
             )
         except OSError as e:
-            if e.errno in _RETRYABLE_DNS_ERRNOS or (
-                e.errno in _EAI_NONAME
-                and (address.host is not None or address.port is not None)
+            # note: on some systems like Windows, EAI_NONAME and EAI_NODATA
+            #       have the same error-code.
+            if e.errno in _EAI_NONAME and (
+                address.host is None and address.port is None
             ):
-                raise ServiceUnavailable(
-                    f"Failed to DNS resolve address {address}: {e}"
-                ) from e
-            raise ValueError(
+                err_cls = ValueError
+            elif e.errno in _RETRYABLE_DNS_ERRNOS or e.errno in _EAI_NONAME:
+                err_cls = ServiceUnavailable
+            else:
+                err_cls = ValueError
+            raise err_cls(
                 f"Failed to DNS resolve address {address}: {e}"
             ) from e
         return _resolved_addresses_from_info(info, address._host_name)

tests/unit/async_/test_addressing.py

@@ -56,6 +56,7 @@ async def test_address_resolve_with_custom_resolver_none() -> None:
     [
         (Address(("example.invalid", "7687")), ServiceUnavailable),
         (Address(("example.invalid", 7687)), ServiceUnavailable),
+        (Address(("example.invalid", None)), ServiceUnavailable),
         (Address(("127.0.0.1", "abcd")), ValueError),
         (Address((None, None)), ValueError),
         (Address((1234, "7687")), TypeError),
@@ -65,14 +66,27 @@ async def test_address_resolve_with_custom_resolver_none() -> None:
 async def test_address_resolve_with_unresolvable_address(
     test_input, expected
 ) -> None:
-    # import contextlib
-    # with contextlib.suppress(Exception):
     with pytest.raises(expected):
         await AsyncUtil.list(
             AsyncNetworkUtil.resolve_address(test_input, resolver=None)
         )
 
 
+@pytest.mark.parametrize(
+    "test_input",
+    [
+        Address((None, 7687)),
+        Address(("example.com", None)),
+    ],
+)
+@mark_async_test
+async def test_address_resolves_with_none(test_input) -> None:
+    resolved = await AsyncUtil.list(
+        AsyncNetworkUtil.resolve_address(test_input, resolver=None)
+    )
+    assert resolved
+
+
 @mark_async_test
 @pytest.mark.parametrize("resolver_type", ("sync", "async"))
 async def test_address_resolve_with_custom_resolver(resolver_type) -> None: