git fatal "in submodule" - Shell/Bash

Introduction

When working on a Git repository containing submodules, you may encounter the error message "git fatal in submodule". This error indicates that there is an issue with one of the submodules in your repository. In this guide, we'll explore what causes this error and how to resolve it.

Causes of the Error

There are several reasons why you might encounter this error:

1. Missing submodule: If the submodule directory is missing or empty, Git will not be able to execute submodule commands.

2. Outdated submodule: If you're working with an outdated submodule, you may run into compatibility issues that cause the "git fatal in submodule" error.

3. Permissions mismatch: Another possible cause of this error is a permissions mismatch between the submodule directory and the parent repository.

Resolving the Issue

Verify Submodule Status

The first step in resolving "git fatal in submodule" errors is to verify the submodule status:

git submodule status

This command will display the status of all submodules in your repository in the following format:

-<commit> <submodule path>

If any of the submodules have an empty value for the commit field, it means that the submodule directory is missing or empty.

Update Submodule

If the submodule is outdated, you'll need to update it before you can continue working on your parent repository. To update the submodule, execute the following commands:

git submodule update --init --recursive

This will update all submodules in your repository. If you only want to update a specific submodule, navigate to the submodule directory and execute the following commands:

git fetch
git checkout <branch>

Where branch is the name of the branch you want to update the submodule to.

Check Permissions

If the submodule directory has the wrong permissions, you might not be able to execute submodule commands. To fix this, navigate to the submodule directory and run:

chmod 755 .git

This will update the directory permissions to 755.

Push to Submodule

If you've recently added a submodule to your repository, you might need to push changes to the submodule before you can continue working on your parent repository. To push changes to a submodule, navigate to the submodule directory and execute the following commands:

git add .
git commit -m "Commit Message"
git push

Once you've pushed changes to the submodule, you should be able to continue working on your parent repository.

Conclusion

Resolving "git fatal in submodule" errors can be frustrating, but by following the steps in this guide, you should be able to resolve the issue quickly. Remember to always verify submodule status, update outdated submodules, check permissions, and push changes to submodules when necessary.