On Fri, Nov 4, 2011 at 2:22 PM, Junio C Hamano [off-list ref] wrote:

builtin/merge.c was updated to use want_commit() that uses peel_to_type()
to commit to make sure we do not get fed anything funky, and also uses
struct commit_list to pass around list of parents to be recorded, so we
should be OK in this department.

I'm pretty sure people have already done "git merge v3.1" kind of
things using local tags (where no peeling of FETCH_HEAD has been
done). See

    git log --merges --grep 'Merge.*v[23]\.[0-9]'

for a ton of examples of this (and there's something odd going on: we
have "Merge commit .." and "Merge tag ..", and I suspect the latter is
people editing it to be correct by hand, but I dunno).

So this has always worked, methinks.

However - exactly beause git apparently makes it do that "Merge commit
" message, I suspect we've peeled things too early and too much. We've
peeled it so early that once again something thinks it's a commit, not
a tag.

So if anything, I suspect "git merge" not only peels, but peels too
much (or at the wrong point). We should probably peel as late as
possible.

But it's a small detail.

                  Linus