The C function used by uuid.uuid4 is broken on

OSX 10.6 in that after os.fork() the parent and
child generate the same sequence of UUIDs.

This patch falls back to the the Python implementation
on OSX 10.6 or later.

Fixes issue #8621.

Lib/test/test_uuid.py

@@ -446,6 +446,34 @@ class TestUUID(TestCase):
             equal(u, uuid.UUID(v))
             equal(str(u), v)
 
+    def testIssue8621(self):
+        import os
+        import sys
+        if os.name != 'posix':
+            return
+
+        # On at least some versions of OSX uuid.uuid4 generates
+        # the same sequence of UUIDs in the parent and any
+        # children started using fork.
+        fds = os.pipe()
+        pid = os.fork()
+        if pid == 0:
+            os.close(fds[0])
+            value = uuid.uuid4()
+            os.write(fds[1], value.hex)
+            sys.exit(0)
+
+        else:
+            os.close(fds[1])
+            parent_value = uuid.uuid4().hex
+            os.waitpid(pid, 0)
+            child_value = os.read(fds[0], 100)
+
+            self.assertNotEqual(parent_value, child_value)
+
+
+
+
 
 def test_main():
     test_support.run_unittest(TestUUID)

Lib/uuid.py

@@ -406,6 +406,19 @@ try:
         if hasattr(lib, 'uuid_generate_time'):
             _uuid_generate_time = lib.uuid_generate_time
 
+    # The uuid_generate_* functions are broken on MacOS X 10.6, as noted
+    # in issue #8621 the function generates the same sequence of values
+    # in the parent process and all children created using fork (unless
+    # those children use exec as well).
+    #
+    # Assume that the uuid_generate functions are broken from 10.6 onward,
+    # the test can be adjusted when a later version is fixed.
+    import sys
+    if sys.platform == 'darwin':
+        import os
+        if int(os.uname()[2].split('.')[0]) >= 10:
+            _uuid_generate_random = _uuid_generate_time = None
+
     # On Windows prior to 2000, UuidCreate gives a UUID containing the
     # hardware address.  On Windows 2000 and later, UuidCreate makes a
     # random UUID and UuidCreateSequential gives a UUID containing the

Misc/NEWS

@@ -39,6 +39,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #8621: uuid.uuid4() returned the same sequence of values in the
+  parent and any children created using ``os.fork`` on MacOS X 10.6.
+
 - Issue #8313: traceback.format_exception_only() encodes unicode message to
   ASCII with backslashreplace error handler if str(value) failed