Stuck on subtree merge

[Jed Brown]

So I finally got the go-ahead to switch our main repository over to Git,
but we want to publish an Hg mirror for a while. Along with the switch
to Git, we're starting to use git-subtree for a component that is
basically part of the main project, but that we want to also provide as
an independent package. Unfortunately, Hg seems to seg-fault on this
commit. (I haven't debugged seriously yet, but it's not surprising that
it's causing trouble.)

Any ideas about what would be the best thing to do here? I don't need Hg
to be able to make subtree merges, but I would like to be able to
publish Git subtree merges somehow. That is, subtree merge handling can
be one-way.