Introduction
Git is a distributed version control system popular among programmers for its ability to track changes in source code during software development. However, there might be occasions when you need to commit and push files that haven’t changed to trigger certain actions like a Continuous Integration (CI) or Continuous Deployment (CD) pipeline. This article covers several ways to force Git into accepting and pushing an unchanged commit.
Prerequisites
- Basic understanding of Git commands.
- A configured and initialized Git repository.
Basic Commit without Any Changes
If you try to commit without changes, Git will not permit it, because there are no changes to commit.
$ git commit -m 'Trigger CI'
on branch main
Your branch is up-to-date with 'origin/main'.
nothing to commit, working directory clean
Using touch Command
This method involves updating the timestamp of a file without changing its contents. The touch command is used to update the file modification time, which Git sees as a change.
$ touch trigger.txt
$ git add trigger.txt
$ git commit -m 'Trigger empty commit'
[master 0e4db9b] Trigger empty commit
1 file changed, 0 insertions(+), 0 deletions(-)
$ git push origin master
Empty Commit
A straightforward approach is to create an empty commit with the --allow-empty option. This makes Git generate a commit that has no content changes.
$ git commit --allow-empty -m 'Trigger CI with empty commit'
[master 123a456] Trigger CI with empty commit
$ git push origin master
Advanced Tactics to Trigger Actions
For more complex situations, additional steps may be required.
Forcing a Non-changes Commit with --amend
A commonly used trick is to amend the last commit without actually changing it and then force push to the remote.
$ git commit --amend --no-edit
$ git push --force-with-lease origin master
Changing and Reverting a File
Sometimes two commits are used: one that introduces a change and one that reverts it.
$ echo 'temporary change' >> file.txt
$ git add file.txt
$ git commit -m 'Temporary change to trigger CI'
$ git revert HEAD --no-edit
$ git push origin master
Creating a Git Alias for Empty Commits
You can create an alias in Git to simplify running the command each time.
$ git config --global alias.empty '!git commit --allow-empty -m'
$ git empty 'CI trigger commit'
$ git push origin master
Working with Tags
Sometimes triggering an action is not about changes in the files but changes in tags.
Adding and Pushing Tags
You can create a new tag and push that tag to trigger a CI/CD process.
$ git tag -a v1.2.3 -m 'Trigger deploy with tag'
$ git push origin v1.2.3
Handling Potential Pitfalls
A thorough approach also addresses the potential problems of using these tactics.
Being Conscious of CI/CD Costs
Every time a CI/CD pipeline runs, it consumes resources. Frequent triggering without code changes should be done considering the costs.
Maintaining the Repository’s Integrity
Pushing empty commits or using –force commands might cause confusion or conflict within the team. Clear communication on the use case is essential.
Security Implications of --force Push
Overwriting commit history can sometimes lead to security implications or loss of work and must be done with care.
Conclusion
In summary, there are various methods to commit and push unchanged files in Git, from simple commands like touch to more complex strategies involving empty commits or tag manipulation. When using these methods, be mindful of the impact on CI/CD workflows and communicate effectively with your team to maintain repository integrity.
