Hi,
I'm having the same problem in msysGit as already described here in the msysGit issue tracker:
http://code.google.com/p/msysgit/issues/detail?id=387
The problem seems to be that for some reason gitk is launching "git rev-list" (in $cmd) with a ton of IDs (in $ids), resulting in a command line that is too long. So the error message does not come from gitk / tk, but from git rev-list. I'm getting the same error (argument list too long) if I manually enter the command at the shell.
Is anyone else experiencing this and has a solution? Is the problem rather that the list of IDs is wrong (and thus too long), or do we need to find a work-around to pass auch long command lines to git rev-list?
Thanks.
-- Sebastian Schuberth