# HG changeset patch
# User Matt Mackall <mpm@selenic.com>
# Date 1293643107 21600
# Node ID 86a218df3c2beb4689646bb110798c27cb707c6a
# Parent  501f979d26b6517508a5e60abb4a36a26e3112fa# Parent  650314ed845d9fb1940d93beb465ddd738f252ff
merge with stable

diff -r 501f979d26b6 -r 86a218df3c2b mercurial/windows.py
--- a/mercurial/windows.py	Sun Dec 26 12:08:20 2010 +0100
+++ b/mercurial/windows.py	Wed Dec 29 11:18:27 2010 -0600
@@ -299,20 +299,18 @@
         # rename is safe to do.
         # The temporary name is chosen at random to avoid the situation
         # where a file is left lying around from a previous aborted run.
-        # The usual race condition this introduces can't be avoided as
-        # we need the name to rename into, and not the file itself. Due
-        # to the nature of the operation however, any races will at worst
-        # lead to the rename failing and the current operation aborting.
 
-        def tempname(prefix):
-            for tries in xrange(10):
-                temp = '%s-%08x' % (prefix, random.randint(0, 0xffffffff))
-                if not os.path.exists(temp):
-                    return temp
+        for tries in xrange(10):
+            temp = '%s-%08x' % (dst, random.randint(0, 0xffffffff))
+            try:
+                os.rename(dst, temp)  # raises OSError EEXIST if temp exists
+                break
+            except OSError, e:
+                if e.errno != errno.EEXIST:
+                    raise
+        else:
             raise IOError, (errno.EEXIST, "No usable temporary filename found")
 
-        temp = tempname(dst)
-        os.rename(dst, temp)
         try:
             os.unlink(temp)
         except: