Migrate Submodules

Git migrations tools like GitHub Importer and even ghe-migrator are not able to update submodule urls. This small script solves that problem by updating all your .gitmodules files recursively with a simple sed command.

Install

You can run this script in any git repository and it will recursively itterate submodules and perform the following operations:

1. Executes the sed command provided via -s on .gitmodules
2. Synchronizes submodules' remote URL configuration setting to the value specified in .gitmodules
3. Updates(pulls) all submodules.
4. Commits the changes to the branch provided via -b with the message provided via -m

NOTES

• You must have read/write permission on the repositories you are modifying
• This script will not import repositories for you and assumes all required repositories have already been imported to your target. This means if you are replacing the url of a submodule, the new URL must be pointing to a valid repository.

Usage 🏃‍♂️

This example is migrating the url from bitbucket.org to github.com.

Clone your repo that contains submodules and cd inside:

git clone https://austenstone@bitbucket.org/austenstone/main-test1.git
cd main-test1

Run the script:

migrate-submodules.sh -s 's/bitbucket.org/github.com/g' -b 'master'

Congratulations. Your submodules have been updated! 🎉

Check them out 👀

cat .gitmodules && git submodule foreach --recursive '[ -f .gitmodules ] && cat .gitmodules || true'

If you are happy with the results, push your changes to remote:

git submodule foreach --recursive git push origin master
git push origin master

TIP: You can automatically sync all branches with master by running the following command:

for BRANCH in `ls .git/refs/heads`; do git rebase master $BRANCH; done
git push --all origin

To see this example in action read the GitHub Actions workflow and also checkout the previous runs.

Install ⬇️

Simply add the script to your PATH.

cd /usr/local/bin
curl https://raw.githubusercontent.com/austenstone/migrate-submodules/main/migrate-submodules.sh > migrate-submodules.sh
chmod +x migrate-submodules.sh

Script tested on Ubuntu and MacOS.

Test Repo Hierarchy

bitbucket.org/austenstone/main-test1 is the root of a small set of repos and is used to test the functionality.

github.com/austenstone/main-test1 is the migrated repo.

graph TD;
    main-test1-->child-test1;
    child-test1-->child-test1-child ;
    main-test1-->child-test2;

Loading

Possible Improvements 🚧

• Use set-url [--] <path> <newurl> instead of sed.
• Sync all branches in the script
• Dynamically get the default branch using git remote show origin | sed -n '/HEAD branch/s/.*: //p'

Inspiration ✨

• Enteee/git-submodule-url-rewrite