git - switching between branches where a subdirectory was in the main repo vs. submodularized -

we've made subdirectory s separate repo , re-added submodule in branch b. when want switch original branch a, subdirectory checked original repo, git complains stuff submodule untracked , has moved away first. can switch @ without manually dragging s away , moving in b?

update: comments below indicate may deficiency of old branch , git not willing smart thing here. so, , kind of rebasing, if any, of original branch s in main repo can let coexist , checkout-able @ time vs. submodularized version?

your history looks this:

---x         \      y   b 

git ls-tree a shows (e.g.):

040000 tree 48770cdc854cc14fecc71029180be7a979f4baa1    s 100644 blob beac6e189b7c69b249271b52cd2db5e418c05a50    file 

git ls-tree a:s shows (e.g.):

100644 blob 6357df9903460c9e8b43311aff3c7a6fd7fe6aa1    somefile 

git ls-tree b shows (e.g.):

100644 blob 1f8556335163a2bcbcc366a17d08d1f8e0540e6f    .gitmodules 160000 commit 234871cd6f0c1f9109e483383d7712dd8a1986e5  s 100644 blob beac6e189b7c69b249271b52cd2db5e418c05a50    file 

(cd s; git ls-tree head) shows (e.g.):

100644 blob abccc3958be33be4b93f56efae1b60820545aad2    somefile 

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you want move commit y (or later) commit x (or earlier) or vice versa.

if active branch b, git checkout a says (e.g.):

error: following untracked working tree files overwritten checkout:         s/somefile please move or remove them before can switch branches. aborting 

git tries hard never lose data unless tell (e.g. “force” options). problem git finds , reports here branch has different content s/somefile working tree. because s/somefile not tracked (from perspective of superproject), git refuses replace file , refuses switch branches/commits.

git arguably smarter (by noticing file tracked in submodule, should not considered untracked when switching branches in superproject), limitation of current implementation. there google summer of code 2011 project git aims address areas of submodule support, not clear me whether exact problem covered.

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you could, suggest, rewrite history s appeared have been submodule. present smoothest surface future commit switches, complicated fact need make sure have commits in submodule’s origin repository reflect each historical state of s directory in original commits. if have many different s trees (i.e. had made local changes under s before converting submodule), may complicated process/script.

a simpler workaround might temporarily checkout “empty branch” in submodule before switching commit has directory.

• create “empty branch” in submodule.

  git checkout --orphan empty git rm -r --cached . git commit --allow-empty -mempty 

  you publish “branch” in submodule’s origin repository no 1 else need recreate form themselves.

• when need switch commit s submodule commit s directory, checkout “empty branch” in submodule first:

  (cd s && git checkout empty) git checkout 

  you see warning because git leave behind s/.git:

  warning: unable rmdir s: directory not empty 

  because s/.git still present, should careful issue git commands outside s when working on commit has s directory; git commands issued under s operate on s/.git (in state, “subrepository”, not full submodule) instead of top level .git repository.

• when need switch commit s directory commit s submodule, need check out appropriate branch/commit in submodule after switching superproject’s commit.
  can use git submodule update restore commit recorded in superproject. or, if working on branch in submodule, check out.

  git checkout b  #  git submodule update  #   or checkout specific branch  (cd s && git checkout master)  #   or checkout previous branch  (cd s && git checkout -)