Roll back code

Common Git commands

Git provides two commands for recovery: revert and reset. Because they have different effects, choose the command that best suits your needs based on the descriptions below.

git reset --hard HEAD^ # Roll back to the previous version
git reset --hard HEAD^^ # Roll back two versions
git reset --hard HEAD~3 # Roll back three commits. You can use ~n to roll back n commits.
git reset --hard <commitID> # Reset to a specific commit

When to use a force overwrite

Errors can occur when you push or merge a branch. For example:

• You accidentally use a force push when your local branch is behind the remote branch, causing the remote branch to roll back to an older version.

• You use a force push to overwrite the remote branch after your local branch has diverged from it.

• You merge an unapproved code review, adding unreviewed commits to the target branch.

In these cases, you typically need to force overwrite the target branch. This operation restores the target branch to a previous version and discards all the incorrectly merged commits.

Restore a branch to a newer version

Use this method when a remote branch is accidentally rolled back to an older version and you need to restore it to a more recent one.

This can happen when a developer's local branch falls behind the remote branch. If they perform a force push, their older local version overwrites the remote branch, causing other developers' commits to be lost.

The following example shows how to restore a corrupted main branch.

Step 1: Find the correct version

Find the most recent correct version in the activity feed: Go to the Activity page of your code repository. In the push history, find the last valid push to the branch you want to restore. For this example, we will use the main branch.

The activity feed usually flags force push events. You can use this record to see how the branch was changed. In this example, a force push overwrote the branch with commit add6fcd3. By looking further back in the activity history, you can find the most recent normal push. The commit ID from that push, 79b769, is the version you need to restore.

Step 2: Restore the branch with a force push

Once you have the target commit ID, you can restore the branch.

In the example above, we need to restore the main branch to commit 79b7691d3e3b6ca19bb8f4f6c76023443735362c.

• If a local repository still contains the commit, create a new branch from it and use that branch to force overwrite the remote branch. Run the following commands:

  # Create a new branch named main-recover from the target commit
  git checkout 79b7691d3e3b6ca19bb8f4f6c76023443735362c -b main-recover
  # Use the main-recover branch to overwrite the remote main branch
  git push --force origin main-recover:main

• If no local repository has the commit, but the server has not yet garbage-collected the object, you can create a new branch from that commit on the server and then recover it. Follow these steps:

  1. In Codeup, go to the Branches page and click New. In the branch name field, enter a custom name, such as main-recover. In the Source field, enter the target commit ID: 79b7691d3e3b6ca19bb8f4f6c76023443735362c.

  2. Pull the main-recover branch to your local machine and use it to force overwrite the remote main branch:

     # Fetch the remote main-recover branch to your local machine
     git fetch origin main-recover:main-recover
     # Locally, verify that main-recover is the version you want to restore
     git log main-recover
     # Overwrite the remote main branch with the main-recover branch
     git push --force origin main-recover:main

     After these steps, the main-recover branch overwrites the main branch, restoring it to the desired state. All incorrect commits added after the restored version are discarded.

Restore a branch to an older version

You may need to overwrite a branch to an older version when unexpected content is merged into a remote branch. For example, a developer might push commits directly to the main branch from their local machine if push rules are not configured. Another case is when a code review is mistakenly merged, requiring the target branch to be rolled back.

This process is relatively simple because you are typically rolling back newly added content. The commit you want to restore to is still part of the branch's history, so you just need to find the correct commit ID.

You can find the target commit ID by asking your team or by checking the Codeup Activity page.

For example, to roll back the main branch to commit add6fcd3efb163349cba4b4cc8fdfefe49befb6d, run the following commands:

# If your local branch is already synced with the corrupted remote, you can reset it directly
git reset --hard add6fcd3efb163349cba4b4cc8fdfefe49befb6d
# Use the corrected local main branch to overwrite the remote branch
git push --force origin main:main
# If your local branch contains your own work, create a new recovery branch instead
git checkout add6fcd3efb163349cba4b4cc8fdfefe49befb6d -b main-recover
# Then, use the recovery branch to overwrite the remote branch
git push --force origin main-recover:main

Restore a deleted branch

If a branch is accidentally deleted, you can restore it by finding its last commit ID. The recovery process is similar to previous scenarios because it relies on locating a specific commit.

1. On the Codeup Activity page, find the last commit ID of the deleted branch. For example, if the dev branch was deleted, its last commit was eba83265a7096d656f582161e4e42010bb4b89f7.

2. Recreate the branch from the commit ID eba83265a7096d656f582161e4e42010bb4b89f7:

   In the branch name field, enter dev, and then click OK to create the branch.