Reverting a merged pull request is a crucial skill for developers looking to undo changes that have been integrated into the main branch but later identified as problematic. This guide will cover the steps to revert pull requests using the command line for both Git and Bitbucket, including the use of the Graphite CLI to streamline these processes.
Reverting pull requests in Git
1. Identifying the merge commit
Before reverting a merge, you need to identify the commit SHA (a unique identifier for that commit) of the merge commit. You can find this using the git log command. Here's how you view the commit history:
git log --oneline --graph
This will display a simplified commit history. Look for a commit labeled as "Merge pull request #xx from some-branch."
2. Reverting the merge commit
To revert the merge commit, use the git revert command followed by the commit SHA. Here’s an example:
git revert -m 1 <commit-sha>
The -m 1 option tells Git to keep the parent side of the mainline, which is necessary for reverting a merge commit.
3. Solving conflicts and finalizing the revert
If the revert process introduces conflicts, Git will prompt you to resolve them manually. After resolving any conflicts, commit the changes:
git commit -am "Revert merge of PR #xx"
4. Pushing the changes to the repository
Once the revert is committed locally, push the changes to the remote repository:
git push origin main
This command updates the remote main branch with the reverted changes.
Reverting pull requests in Bitbucket
Bitbucket allows you to revert a merge through its UI, but you can also do this via command line using the same git revert command, as Bitbucket hosts Git repositories.
1. Find the merge commit
Identify the merge commit using the git log command, similar to the process in Git.
2. Execute the revert
Run the git revert command with the -m 1 option to revert the specific merge commit:
git revert -m 1 <commit-sha>
3. Resolve any conflicts
As with Git, you may need to resolve conflicts. Do this manually, then commit the changes:
git commit -am "Revert PR merge in Bitbucket"
4. Push the revert
Push the revert to the remote Bitbucket repository:
git push origin main
Using Graphite CLI to revert pull requests
Graphite CLI simplifies various Git operations, including reverting merges. Here’s how you can use Graphite to revert a merged pull request:
1. Install the Graphite CLI
First, ensure that the Graphite CLI is installed on your machine. You can install it using brew or npm.
brew:
brew install withgraphite/tap/graphitegt --version
npm:
npm install -g @withgraphite/graphite-cli@stablegt --version
2. Reverting a merge using Graphite
Once Graphite is installed, you can use it to revert a merge commit more efficiently. The CLI provides a streamlined command that can handle the revert operation, including conflict resolution guidance:
gt stack revert <stack-name>
Replace <stack-name> with the appropriate stack or branch name that you need to revert.
Summary
Reverting merged pull requests is an essential operation when dealing with errors in codebases. Using the command line provides a direct and controlled method to roll back changes, ensuring that developers can manage their code efficiently. With tools like Graphite CLI, the process becomes even more streamlined, offering additional functionality to handle complex scenarios involved in reverting code changes.