[git] How do I "commit" changes in a git submodule?

I have, in my naivety, set up a git submodule and treated it like a Subversion external - i.e. it's now full of changes that I've just realized haven't been committed or pushed anywhere.

Is there some easy way to commit/push the submodule changes back to the upstream repo? And what's the recommended technique in Git for doing simultaneous development on separate (but linked) repositories in this way?

Note that if you have committed a bunch of changes in various submodules, you can (or will be soon able to) push everything in one go (ie one push from the parent repo), with:

git push --recurse-submodules=on-demand

git1.7.11 ([ANNOUNCE] Git 1.7.11.rc1) mentions:

"git push --recurse-submodules" learned to optionally look into the histories of submodules bound to the superproject and push them out.

Probably done after this patch and the --on-demand option:

--recurse-submodules=<check|on-demand|no>::

Make sure all submodule commits used by the revisions to be pushed are available on a remote tracking branch.

• If check is used, it will be checked that all submodule commits that changed in the revisions to be pushed are available on a remote.
  Otherwise the push will be aborted and exit with non-zero status.
• If on-demand is used, all submodules that changed in the revisions to be pushed will be pushed.
  If on-demand was not able to push all necessary revisions it will also be aborted and exit with non-zero status.

This option only works for one level of nesting. Changes to the submodule inside of another submodule will not be pushed.

You can treat a submodule exactly like an ordinary repository. To propagate your changes upstream just commit and push as you would normally within that directory.

$ git submodule status --recursive

Is also a life saver in this situation. You can use it and gitk --all to keep track of your sha1's and verify your sub-modules are pointing at what you think they are.

Before you can commit and push, you need to init a working repository tree for a submodule. I am using tortoise and do following things:

First check if there exist .git file (not a directory)

• if there is such file it contains path to supermodule git directory
• delete this file
• do git init
• do git add remote path the one used for submodule
• follow instructions below

If there was .git file, there surly was .git directory which tracks local tree. You still need to a branch (you can create one) or switch to master (which sometimes does not work). Best to do is - git fetch - git pull. Do not omit fetch.

Now your commits and pulls will be synchronized with your origin/master