tests: change how sockets are closed

tests: change how sockets are closed

Python 3 uses a different type to represent a socket file object
than Python 2. We need to conditionalize how the socket is closed
accordingly.

While we're here, we switch to use socket.shutdown() to close the
socket. This is because socket.close() may not actually close
the socket until it is GCd. socket.shutdown() forces an immediate
shutdown.

I suspect Python 3 changed semantic behavior here, as I can't get
test-http-bad-server.t to work with socket.close(). socket.shutdown()
does appear to work, however.

Differential Revision: https://phab.mercurial-scm.org/D5751

--- a/tests/badserverext.py	Wed Jan 30 09:52:16 2019 -0800
+++ b/tests/badserverext.py	Wed Jan 30 13:08:59 2019 -0800
@@ -34,6 +34,7 @@
 import socket
 
 from mercurial import(
+    pycompat,
     registrar,
 )
 
@@ -115,7 +116,7 @@
         object.__setattr__(self, '_closeaftersendbytes', closeaftersendbytes)
 
     def __getattribute__(self, name):
-        if name in ('read', 'readline', 'write', '_writelog'):
+        if name in ('_close', 'read', 'readline', 'write', '_writelog'):
             return object.__getattribute__(self, name)
 
         return getattr(object.__getattribute__(self, '_orig'), name)
@@ -133,6 +134,19 @@
         object.__getattribute__(self, '_logfp').write(b'\n')
         object.__getattribute__(self, '_logfp').flush()
 
+    def _close(self):
+        # Python 3 uses an io.BufferedIO instance. Python 2 uses some file
+        # object wrapper.
+        if pycompat.ispy3:
+            orig = object.__getattribute__(self, '_orig')
+
+            if hasattr(orig, 'raw'):
+                orig.raw._sock.shutdown(socket.SHUT_RDWR)
+            else:
+                self.close()
+        else:
+            self._sock.shutdown(socket.SHUT_RDWR)
+
     def read(self, size=-1):
         remaining = object.__getattribute__(self, '_closeafterrecvbytes')
 
@@ -161,7 +175,8 @@
 
         if remaining <= 0:
             self._writelog(b'read limit reached, closing socket')
-            self._sock.close()
+            self._close()
+
             # This is the easiest way to abort the current request.
             raise Exception('connection closed after receiving N bytes')
 
@@ -194,7 +209,8 @@
 
         if remaining <= 0:
             self._writelog(b'read limit reached; closing socket')
-            self._sock.close()
+            self._close()
+
             # This is the easiest way to abort the current request.
             raise Exception('connection closed after receiving N bytes')
 
@@ -225,7 +241,8 @@
 
         if remaining <= 0:
             self._writelog(b'write limit reached; closing socket')
-            self._sock.close()
+            self._close()
+
             raise Exception('connection closed after sending N bytes')
 
         return result