expandPath bug in CF8

I've just encountered a very annoying bug with the expandPath function in CF8.

Take the following code:

<cfset MyDir = "."/>

<cfloop index="i" from="1" to="5">
    <cfset MyDir = expandPath(MyDir)/>
    <cfoutput><br/>#MyDir#</cfoutput>
</cfloop>

Run the code through Railo and you will get exactly the right behaviour, with the current directory output five times:

C:\dev\scratch
C:\dev\scratch
C:\dev\scratch
C:\dev\scratch
C:\dev\scratch

Now go run the same code with CF8 - and this is what you get:

F:\ColdFusion8\wwwroot\scratch
F:\ColdFusion8\wwwroot\scratch\F:\ColdFusion8\wwwroot\scratch
F:\ColdFusion8\wwwroot\scratch\F:\ColdFusion8\wwwroot\scratch\F:\ColdFusion8\wwwroot\scratch
F:\ColdFusion8\wwwroot\scratch\F:\ColdFusion8\wwwroot\scratch\F:\ColdFusion8\wwwroot\scratch\F:\ColdFusion8\wwwroot\scratch
F:\ColdFusion8\wwwroot\scratch\F:\ColdFusion8\wwwroot\scratch\F:\ColdFusion8\wwwroot\scratch\F:\ColdFusion8\wwwroot\scratch\F:\ColdFusion8\wwwroot\scratch

It simply stacks the current directory onto the front each time. Very frustrating.

In order to get round this, I created a regular expression to pull off the last value of any directory containing more than one colon - this will work for Windows machines, but may need to be changed for Linux or MacOSX machines (if the bug affects these).

<cfif isDefined('Server.ColdFusion.ProductName')
    AND Server.ColdFusion.ProductName EQ 'ColdFusion Server'
    AND ListLen( MyDir ,':') GT 2>
    <cfset MyDir = REreplace( MyDir , "^.*([A-Z]:[^:]+)$" , "\1" )/>
</cfif>