Git Submodules

A great summary about git submodules

Cloning a project which uses submodules

When freshly cloning a project which contains git submodules, run this command before doing anything else to load the file contents of all submodules inside the project:

git submodule update --init --recursive

Adding a submodule

Adds submodule foo into a folder foo.

git submodule add https://github.com/<user>/foo foo

Issue with detached state

This SO answer covers the topic well

tldr;

After you clone a repo which contains submodules for the first time, the submodule will not track a remote branch. You got to do it. Read the article for more information.

Committing with submodule changes

sourcetree will remind you when you didn’t yet commit the submodule content.

1. Commit the changes in the submnodule
2. Commit the changes in the main module which depend on the changes in the submodule by also commiting the changed hash of the submodule (sourcetree offers it for you)

git submodule got out of sync

In the main repo run git diff to see which submodule commit is expected by the current branch of the main repo.

Among other lines you’ll see something like this. Just copy the commit hash after -Subproject and checkout your submodule to that commit.

@@ -1 +1 @@
-Subproject commit d2e3affd9bfb0bb1e8c1a6c9440356d17d174fa1
+Subproject commit 35eda0228309bdd0d7f44dd1adbdb4b4565a5010