"git-subtree add" fails to add the subtree into a repository with
submodules, reporting that the worktree is not clean, while `git status`
says that everything is clean (including submodules). I tracked the
problem down to the command "git index HEAD" returning all submodules as
having the M status:
$ git diff-index HEAD
:160000 160000 d3812c9318c4d0336897fd2d666be908fa1a7953
d3812c9318c4d0336897fd2d666be908fa1a7953 M ext/grpc
<snip more submodules>
$ git --version
git version 2.9.2.windows.1
I worked around the problem in my local copy of git-subtree shell script
by adding "--ignore-submodules=all" to the two invocations of `git
diff-index` in the ensure_clean() function (direct link
<https://github.com/git/git/blob/next/contrib/subtree/git-subtree.sh#L586>).
I am wondering, is this a defect in git-subtree? To my understanding,
the command should not care about submodules more than ensuring their
worktree is not in the way of new prefix, and that's a separate check.
So *even if* the submodule is modified, this should not be a show
stopper for "git-subtree add". Or am I missing some subtleties?
-kkm