Question

It’s possible this has been asked before, but it’s difficult to tell because submodules seem to cause lots of problems. Here’s what I’m doing.

# cd to parent repo
git submodule add git://example.com/myrepo
cd myrepo
# make some changes
git commit -am "made changes"
cd ..
git commit -am "modified submodule"
git clone --recursive . <path to cloned repo>

When I do this I get errors

fatal: reference is not a tree: 96fa64c0dd64684f86d17841f7c515446885eb33

followed by

Unable to checkout ’96fa64c0dd64684f86d17841f7c515446885eb33′ in submodule path ‘myrepo’

What am I doing wrong here? I just want to add a submodule, then make some changes to it, and then clone the entire parent source tree (including submodule) to a new repo.

Answer 1

You should call

git submodule init

after you add the submodule. git submodule add clones the repository and adds entries to .gitmodules. git submodule init initializes the submodules and copies the entries in .gitmodules to .git/config

EDIT

I suspect that you have missed some important step in using submodules. Here are the steps that I use to deal with submodules.

First clone the parent repo if applicable

git clone [e-mail]:test/test.git

Change to the cloned directory and add your submodule

#change to the parent repo directory
cd test

#add the submodule to test/submodules/mysubmodule
git add submodule [e-mail]/test/mysubmodule.git submodules/mysubmodule

Initialize all submodules and update all submodules including nested ones

git submodule update --init --recursive

Add all your changes and commit and push to remotes if applicable

git add .
git commit

This last part is really important as the repo does not really know about your submodule until you commit the changes.