Solaris 9 and earlier fail to conform to POSIX, in that
stat("FILE/") succeeds even when FILE is not a directory.
POSIX says that in this case it should fail.  This problem causes os.path.exists("FILE/") to succeed when it should fail, which makes it harder to write portable Python code.  One of my students ran into this problem when doing a Django-based project: his code ran fine on his Linux box, but failed when he attempted to run it on the Solaris 8 server that is the standard platform for our students.

To reproduce the problem, on Solaris 8 (or 9):

$ touch file
$ ls -l file
-rw-rw-r-- 1 eggert csfac 0 Dec  7 14:19 file
$ python
Python 2.5 (r25:51908, Dec  7 2006, 13:14:10)
[GCC 4.1.1] on sunos5
Type "help", "copyright", "credits" or "license" for more information.
>>> import os
>>> os.path.exists("file/")
True

It should be False.

I'll attach a patch that works around the problem at
run-time.  If you prefer something that tests for it
at compile time please let me know.

I think it would be sufficient to put a #ifdef <solaris 9> ... #endif around the additional check. We don't want to make all platforms do extra system calls in order to avoid a Solaris 9 bug.  Or you could write a configure test to check for this bug, but that's more complicated a task.

OK, I'll attach a revised patch that uses a configure test to check for this bug.
File Added: python-stat-patch-2.diff

The patch need be revised for 3.3+.

Here's an updated version of the patch.  It at least compiles and runs on MacOS, but I don't have a Solaris installation to check whether it still fixes the problem on Solaris 9.

Note that, according to http://en.wikipedia.org/wiki/Solaris_(operating_system)#Version_history, Solaris 9 will only be supported until October 2014.

I don't like the idea of adding such a kludge to workaround an OS bug - especially since Solaris 9 won't be supported for too long.