More SLOT related problems

[n0n]

(This post is highly related to this thread, so if you want more backstory, check there . . .)

Today Portage told me that I could upgrade Portage if I wished, and along with that change I'd also update bash. Everything worked fine, but I noticed when doing a clean that the old version of bash wasn't cleared out. Sure enough, checking in /var/db/pkg/sys-apps I found out that my previous version of bash (2.05a-r2), when originally installed, had a blank SLOT, whereas the new version of bash (2.05a-r3) had the correct "0" in its SLOT field. (The SLOT value has since been fixed in the -r2 ebuild, it seems.)

Obviously the extraneous bash isn't that big of a deal right now, but in a larger sense this could become an issue for other packages, too, if some file is left behind that shouldn't be. As I see it, I've got two options ((edit) if I want to get rid of the old version, that is):

1. Change the SLOT entry in /var/db/pkg on the old version to be "0"
   
2. Unmerge the old version manually by hand
   

In both situations, I'm worried about removing files that shouldn't be there. Are the files accounted for differently because they were originally in different SLOTs? If I unmerge the old version do I risk wiping away the old one? What, basically, is the risk that unmerging the old version (by whatever means) is going to screw things up?

I know that a lot of older ebuilds had the blank SLOT in there before the SLOT mechanism was either well-defined or included in the skeleton ebuild file, so potentially this could impact a number of packages on people's systems. Grepping through my /usr/portage tree, it seems that all packages have been fixed, though, so maybe it's not the problem I've made it out to be.

As always, thanks for any input in advance!

[n0n]

In case anyone was interested in hearing a followup to this, I've just posted a script to take care of some of this over here.