netutil: Update docs for OverrideResolver and release notes

diff --git a/docs/releases/v5.0.0.rst b/docs/releases/v5.0.0.rst
index 0ef227a980e038489d7a690ec38726919d61be95..33d42b67178ac7dfac3cfe862d46bc3580e6cfad 100644 (file)
--- a/docs/releases/v5.0.0.rst
+++ b/docs/releases/v5.0.0.rst
@@ -16,7 +16,7 @@ Highlights
   this change, code changes may be required for compatibility with
   Tornado 5.0, as detailed in the following section.
 - Support for Python 2.7 and 3.4 are deprecated; Tornado 6.0 will
-  require Python 3.5+. TODO(bdarnell): decide whether to drop py2 in 5.0
+  require Python 3.5+.
 
 Backwards-compatibility notes
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -213,6 +213,7 @@ Other notes
   `.ExecutorResolver`, and `.ThreadedResolver` have been removed.
 - `.add_accept_handler` returns a callable which can be used to remove
   all handlers that were added.
+- `.OverrideResolver` now accepts per-family overrides.
 
 `tornado.options`
 ~~~~~~~~~~~~~~~~~

diff --git a/tornado/netutil.py b/tornado/netutil.py
index 45d9e36c0a8e019e20b271bb268541d3e4a151a2..5f52e2dea4a8a53a521761442e7460bd974747ff 100644 (file)
--- a/tornado/netutil.py
+++ b/tornado/netutil.py
@@ -464,8 +464,21 @@ class OverrideResolver(Resolver):
     This can be used to make local DNS changes (e.g. for testing)
     without modifying system-wide settings.
 
-    The mapping can contain either host strings or host-port pairs or
-    host-port-family triplets.
+    The mapping can be in three formats::
+
+        {
+            # Hostname to host or ip
+            "example.com": "127.0.1.1",
+
+            # Host+port to host+port
+            ("login.example.com", 443): ("localhost", 1443),
+
+            # Host+port+address family to host+port
+            ("login.example.com", 443, socket.AF_INET6): ("::1", 1443),
+        }
+
+    .. versionchanged:: 5.0
+       Added support for host-port-family triplets.
     """
     def initialize(self, resolver, mapping):
         self.resolver = resolver