when revision not a number

[Joshua Root]

On 2013-6-7 02:16 , Bradley Giesbrecht wrote:
> It took me a while to find why "port outdated" was failing.
> 
> I had a port installed that had revision set to and empty string.
> 
> I doubt this is a common problem for developers but I mention it in the case that a test to verify that $installed_revision and $latest_revision are numbers would be worthwhile.

<https://trac.macports.org/ticket/26486>

- Josh