dnspython+pypy fixups

docs/changes/1459.bugfix

 The c-ares and DNSPython resolvers now raise exceptions much more
-consistently with the standard resolver. Types and errnos are more
-likely to match. (Depending on the system and configuration, it may
-not match exactly, at least with DNSPython. There are still some rare
-cases where the system resolver can raise ``herror`` bun DNSPython
-will raise ``gaierror`` or vice versa. There doesn't seem to be a
-deterministic way to account for this.)
+consistently with the standard resolver. Types and errnos are
+substantially more likely to match what the standard library produces.
+
+Depending on the system and configuration, results may not match
+exactly, at least with DNSPython. There are still some rare cases
+where the system resolver can raise ``herror`` but DNSPython will
+raise ``gaierror`` or vice versa. There doesn't seem to be a
+deterministic way to account for this. On PyPy, ``getnameinfo`` can
+produce results when CPython raises ``socket.error``, and gevent's
+DNSPython resolver also raises ``socket.error``.
 
 In addition, several other small discrepancies were addressed,
 including handling of localhost and broadcast host names.

src/gevent/resolver/__init__.py

@@ -19,13 +19,14 @@ from _socket import gethostbyaddr as native_gethostbyaddr
 from _socket import gethostbyname as native_gethostbyname
 from _socket import gethostbyname_ex as native_gethostbyname_ex
 from _socket import getservbyname as native_getservbyname
-from _socket import herror
+
 
 from gevent._compat import string_types
 from gevent._compat import text_type
 from gevent._compat import hostname_types
 from gevent._compat import integer_types
 from gevent._compat import PY3
+from gevent._compat import PYPY
 from gevent._compat import MAC
 
 from gevent.resolver._addresses import is_ipv6_addr
@@ -245,14 +246,14 @@ class AbstractResolver(object):
         address = sockaddr[0]
         address = self._hostname_to_bytes(sockaddr[0])
 
-        if address in self._LOCAL_HOSTNAMES:
+        if address in self._LOCAL_AND_BROADCAST_HOSTNAMES:
             return native_getnameinfo(sockaddr, flags)
 
         port = sockaddr[1]
         if not isinstance(port, integer_types):
             raise TypeError('port must be an integer, not %s' % type(port))
 
-        if port >= 65536:
+        if not PYPY and port >= 65536:
             # System resolvers do different things with an
             # out-of-bound port; macOS CPython 3.8 raises ``gaierror: [Errno 8]
             # nodename nor servname provided, or not known``, while
@@ -260,8 +261,12 @@ class AbstractResolver(object):
             # sockaddr resolved to multiple addresses``. TravisCI, at least ot
             # one point, successfully resolved www.gevent.org to ``(readthedocs.org, '0')``.
             # But c-ares 1.16 would raise ``gaierror(25, 'ARES_ESERVICE: unknown')``.
-            # Doing this appears to get the expected results.
+            # Doing this appears to get the expected results on CPython
             port = 0
+        if PYPY and (port < 0 or port >= 65536):
+            # PyPy seems to always be strict about that and produce the same results
+            # on all platforms.
+            raise OverflowError("port must be 0-65535.")
 
         if len(sockaddr) > 2:
             # Must be IPv6: (host, port, [flowinfo, [scopeid]])

src/gevent/resolver/dnspython.py

@@ -351,6 +351,10 @@ class Resolver(AbstractResolver):
         symbolic scope IDs in IPv6 addresses passed to ``getaddrinfo`` exhibits
         some differences.
 
+        On PyPy, ``getnameinfo`` can produce results when CPython raises
+        ``socket.error``, and gevent's DNSPython resolver also
+        raises ``socket.error``.
+
     .. caution::
 
         This resolver is experimental. It may be removed or modified in

src/gevent/tests/test__socket_dns.py

@@ -32,6 +32,7 @@ from gevent.testing.sysinfo import RESOLVER_NOT_SYSTEM
 from gevent.testing.sysinfo import RESOLVER_DNSPYTHON
 from gevent.testing.sysinfo import RESOLVER_ARES
 from gevent.testing.sysinfo import PY2
+from gevent.testing.sysinfo import PYPY
 import gevent.testing.timing
 
 
@@ -398,6 +399,12 @@ class TestCase(greentest.TestCase):
         if isinstance(real_result, TypeError):
             return
 
+        if PYPY and isinstance(real_result, socket.herror):
+            # PyPy doesn't do errno or multiple arguments in herror;
+            # it just puts a string like 'host lookup failed: <thehost>';
+            # it must be doing that manually.
+            return
+
         self.assertEqual(real_result.args, gevent_result.args, msg)
         if hasattr(real_result, 'errno'):
             self.assertEqual(real_result.errno, gevent_result.errno)
@@ -420,7 +427,6 @@ class TestCase(greentest.TestCase):
 
         # If we're using a different resolver, allow the real resolver to generate an
         # error that the gevent resolver actually gets an answer to.
-
         if (
                 RESOLVER_NOT_SYSTEM
                 and isinstance(real_result, errors)
@@ -428,6 +434,19 @@ class TestCase(greentest.TestCase):
         ):
             return
 
+        # On PyPy, socket.getnameinfo() can produce results even when the hostname resolves to
+        # multiple addresses, like www.gevent.org does. DNSPython (and c-ares?) don't do that,
+        # they refuse to pick a name and raise ``socket.error``
+        if (
+                RESOLVER_NOT_SYSTEM
+                and PYPY
+                and func_name == 'getnameinfo'
+                and isinstance(gevent_result, socket.error)
+                and not isinstance(real_result, socket.error)
+        ):
+            return
+
+
         # From 2.7 on, assertEqual does a better job highlighting the results than we would
         # because it calls assertSequenceEqual, which highlights the exact
         # difference in the tuple
@@ -559,7 +578,8 @@ class TestBroadcast(TestCase):
     switch_expected = False
 
     if RESOLVER_DNSPYTHON:
-        # ares and dnspython raises errors for broadcasthost/255.255.255.255
+        # dnspython raises errors for broadcasthost/255.255.255.255, but the system
+        # can resolve it.
 
         @unittest.skip('ares raises errors for broadcasthost/255.255.255.255')
         def test__broadcast__gethostbyaddr(self):

src/gevent/tests/test__socket_dns6.py

@@ -11,7 +11,7 @@ from gevent.tests.test__socket_dns import TestCase, add
 from gevent.testing.sysinfo import OSX
 from gevent.testing.sysinfo import RESOLVER_NOT_SYSTEM
 from gevent.testing.sysinfo import RESOLVER_DNSPYTHON
-
+from gevent.testing.sysinfo import PYPY
 
 
 # We can't control the DNS servers on CI (or in general...)
@@ -73,12 +73,15 @@ class Test6(TestCase):
 class Test6_google(Test6):
     host = 'ipv6.google.com'
 
-    def _normalize_result_getnameinfo(self, result):
-        if greentest.RUNNING_ON_CI and RESOLVER_NOT_SYSTEM:
-            # Disabled, there are multiple possibilities
-            # and we can get different ones, rarely.
+    if greentest.RUNNING_ON_CI and RESOLVER_NOT_SYSTEM:
+        # Disabled, there are multiple possibilities
+        # and we can get different ones, rarely.
+        def _normalize_result_getnameinfo(self, result):
             return ()
-        return result
+
+        if PYPY:
+            # PyPy tends to be especially problematic in that area.
+            _normalize_result_getaddrinfo = _normalize_result_getnameinfo
 
 add(Test6, Test6.host)
 add(Test6_google, Test6_google.host)