gitk diff fails on merges

Hello,

I'm using the following:

[campedel@betelgeuse ~]$ git --version git version 0.99.9g [campedel@betelgeuse ~]$ cg --version cogito-0.16rc1

I think there's a bug in gitk diffing, both
	'Diff selected -> this'
and
	'Diff this -> selected'
fail when applied on the result of a merge.

To replicate the problem you can use the attached script and then try diffing against branch_1 head.

Thanks for your attention (and for your wonderful work!)

Lorenzo

cg init echo abc > a.file cg add a.file cg commit -m 'added a.file' cg tag tag_1 echo def >> a.file cg commit -m 'modified a.file' git checkout -b branch_1 tag_1 echo ghi > b.file cg add b.file cg commit -m 'added b.file' cg merge -c master cg commit -m 'merged with master' gitk --all

exit