test_osutils fails because /dev/null may be a symlink

[Igor Pashev]

test_osutils.py check whether /dev/null is a character device, but /dev/null can be a symlink [to character device] as in Illumos (aka OpenSolaris).

http://bazaar.launchpad.net/~bzr-pqm/bzr/bzr.dev/view/head:/bzrlib/tests/test_osutils.py#L303

[Martin Pool (mbp)]

Thanks, I think that accounts for a previously known failure.

This test wants to examine something that is not a regular file, directory, or symlink. Of course we can't create device nodes from a non-root test.

What should we do?
 - skip this test if /dev/null is a symlink? the test is not super important but this report shows it's good to catch portability bugs.
 - assert there is at least one device file in /dev?
 - if /dev/null is a symlink, follow it, and check the ultimate target is a device

I think I like the last best. If you want to try a patch, please do.

[Igor Pashev (pashev-igor)]

Now I use this patch. It makes one more step it /dev/null is symlink.
Maybe make a loop "while symlink read target"?

[Igor Pashev (pashev-igor)]

But there two questions:

1. What if symlink is dangled
2. What if symlinks are cycled :-)

[Martin Pool (mbp)]

On 24 August 2011 19:09, ip1981 <email address hidden> wrote:
> But there two questions:
>
> 1. What if symlink is dangled
> 2. What if symlinks are cycled :-)

won't other unix things be sad if /dev/null doesn't exist at all?

os.path.realpath should cope with cycles safely.

m

[Igor Pashev (pashev-igor)]

Patch with realpath()