If I pass in the same commit multiple times (possibly under different names) to gitk, it will echo the warning from git-rev-list (sort_list_in_merge_order: duplicate commit 82e3583b9426c193659a4c1315d6a3b3cee11dce ignored) and then simply stop.
Surely this can be handled more gracefully.
Note that I do want to be able to pass the same commit multiple times. At least, I don't want to check whether two "branches" happen to refer to the same commit.
skimo