when revision not a number

[Bradley Giesbrecht]

It took me a while to find why "port outdated" was failing.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.

/opt/local/bin/port:912
            if { $comp_result == 0 } {
                set comp_result [expr $installed_revision - $latest_revision]
            }


Regards,
Bradley Giesbrecht (pixilla)