? Git Submodules

? Quick Overview

Git submodules allow you to embed one Git repository inside another while keeping both repositories independent. The main repository is called the superproject, and the embedded repository is called a submodule. This approach is commonly used for managing external libraries or shared components without merging their entire commit history into your project.

? Key Concepts

• Superproject: The main Git repository that contains submodules.
• Submodule: An embedded Git repository with its own history.
• Commit Reference: The superproject stores a pointer to a specific commit of the submodule.
• Independent History: Submodules maintain their own commits and branches.

? Syntax & Theory

Submodules are stored as references to specific commits of another repository. Git does not automatically update submodules unless explicitly told to do so. This ensures controlled dependency versions.

? Code Examples

// Add a new submodule to the repository
git submodule add <repository-url> <path-to-submodule>

// Example: Adding a library as a submodule
git submodule add https://github.com/example/library.git libs/library

? Cloning with Submodules

// Clone repository and automatically initialize submodules
git clone --recurse-submodules <repository-url>

// Initialize submodules after cloning
git submodule update --init --recursive

⚙️ Working with Submodules

Checking Status

// Show current commit and status of submodules
git submodule status

Updating Submodules

// Update submodule to latest remote commit
git submodule update --remote <submodule-name>

Committing Submodule Changes

// Commit changes inside submodule and update reference
cd libs/library
git commit -am "Update submodule content"
cd ../../
git add libs/library
git commit -m "Updated submodule reference"

?️ Removing a Submodule

// Deinitialize submodule
git submodule deinit <submodule-path>

// Remove submodule from index
git rm <submodule-path>

// Commit submodule removal
git commit -m "Remove submodule"

// Delete remaining submodule files
rm -rf <submodule-path>

? Use Cases

• Including third-party libraries
• Sharing common components across projects
• Maintaining strict dependency versions
• Separating large codebases into manageable units