Introduction
To merge a new local project into an old GitHub repository while preserving both commit histories, follow these steps:
Clone our old repository
git clone <old-repo-url>
cd <old-repo-folder>
Add our local project as a remote repository
git remote add new-local-project <path-to-local-project>
Replace <path-to-local-project> with the absolute path to our new local project folder ( e.g., /path/to/new/local/project/.git )
Fetch the new local project's commit history
git fetch new-local-project
Merge the histories
git merge --allow-unrelated-histories new-local-project/main
This command merges the new project's main branch into the old repository's main branch. The --allow-unrelated-histories flag is necessary because the histories of the two repositories are unrelated.
Resolve any merge conflicts
git add <resolved-files>
git commit
git push origin main
Conclusion
After pushing the commit, both the commit histories should appear in the old repository.
Happy reading!