Live with that "the hardware address" is an ill-defined

concept, and that different ways of trying to find "the
hardware address" may return different results.  Certainly
true on both of my Windows boxes, and in different ways
(see whining on python-dev).

2 files changed, 23 insertions, 8 deletions

diff --git a/Lib/test/test_uuid.py b/Lib/test/test_uuid.py
index 3842bb9..36266e1 100644
--- a/Lib/test/test_uuid.py
+++ b/Lib/test/test_uuid.py
@@ -284,7 +284,11 @@ class TestUUID(TestCase):
                 msg = "different sources disagree on node:\n"
                 for s, n in TestUUID.source2node.iteritems():
                     msg += "    from source %r, node was %012x\n" % (s, n)
-                self.fail(msg)
+                # There's actually no reason to expect the MAC addresses
+                # to agree across various methods -- e.g., a box may have
+                # multiple network interfaces, and different ways of getting
+                # a MAC address may favor different HW.
+                ##self.fail(msg)
         else:
             TestUUID.last_node = node
 
@@ -309,7 +313,7 @@ class TestUUID(TestCase):
     def test_random_getnode(self):
         node = uuid._random_getnode()
         self.assert_(0 <= node)
-        self.assert_(node < 1<<48L)
+        self.assert_(node < (1L <<48))
 
     def test_unixdll_getnode(self):
         import os
@@ -322,10 +326,14 @@ class TestUUID(TestCase):
             self.check_node(uuid._windll_getnode(), 'windll')
 
     def test_getnode(self):
-        self.check_node(uuid.getnode(), "getnode1")
+        node1 = uuid.getnode()
+        self.check_node(node1, "getnode1")
 
         # Test it again to ensure consistency.
-        self.check_node(uuid.getnode(), "getnode2")
+        node2 = uuid.getnode()
+        self.check_node(node2, "getnode2")
+
+        self.assertEqual(node1, node2)
 
     def test_uuid1(self):
         equal = self.assertEqual
diff --git a/Lib/uuid.py b/Lib/uuid.py
index 11e0da3..dabe22e 100644
--- a/Lib/uuid.py
+++ b/Lib/uuid.py
@@ -362,6 +362,10 @@ try:
     # hardware address.  On Windows 2000 and later, UuidCreate makes a
     # random UUID and UuidCreateSequential gives a UUID containing the
     # hardware address.  These routines are provided by the RPC runtime.
+    # NOTE:  at least on Tim's WinXP Pro SP2 desktop box, while the last
+    # 6 bytes returned by UuidCreateSequential are fixed, they don't appear
+    # to bear any relationship to the MAC address of any network device
+    # on the box.
     try:
         lib = ctypes.windll.rpcrt4
     except:
@@ -389,10 +393,13 @@ def _random_getnode():
 _node = None
 
 def getnode():
-    """Get the hardware address as a 48-bit integer.  The first time this
-    runs, it may launch a separate program, which could be quite slow.  If
-    all attempts to obtain the hardware address fail, we choose a random
-    48-bit number with its eighth bit set to 1 as recommended in RFC 4122."""
+    """Get the hardware address as a 48-bit positive integer.
+
+    The first time this runs, it may launch a separate program, which could
+    be quite slow.  If all attempts to obtain the hardware address fail, we
+    choose a random 48-bit number with its eighth bit set to 1 as recommended
+    in RFC 4122.
+    """
 
     global _node
     if _node is not None: