How to Revert to a Previous Commit in Git without Modifying History
What is a safe way to rollback to a previous state in our Git repository without destroying or altering the history?
git revert --no-commit
Suppose we want to revert back to a commit with the hash
git revert --no-commit 521dd125..HEAD git commit -m "revert all in one"
This will revert everything from the
HEAD back to the commit hash. We are restoring the state of the repository to that of the commit with hash
521dd125 by creating one single commit that is “undoing” all the changes in this commit tree.
--no-commitflag allows us to revert all the commits in this tree at once. Without it, we’ll create commits for every commit we want to revert.
no -m option was given
We might end up with an error like this:
fatal: Commit <SHA1> is a merge but no -m option was given.
We might get this error because we are trying to revert a merge commit.
When resetting or reverting a commit, it will try to figure out what changed in that commit by comparing it to its parent commit. However, in a merge commit, there will be multiple parent commits.
If this is the case, we have to specify which parent of the merge to revert to using the
-m flag followed by an ordinal number representing where the parent commit ID resides in the merge commit.
git revert --no-commit 521dd125..HEAD -m 1
-m flag with
We can use
cat-file to display the parent branches in order and determine which parent to choose.
git cat-file -p merge_commit_id
The first one listed would be
-m 1, the second would be
-m 2, and so on.
-m flag with
We can also use
git log to search for the merge commit.
commit 121d31d2a4da5d315da2345d35d435d2345dad2 Merge: da12195 1a87d98 Author: Author <firstname.lastname@example.org> Date: Date Merge branch 'feature' into 'develop'
In this case,
da12195 would be
-m 1 and
1a87d98 would be
In most cases, we want to use
-m 1, but this may not be true all the time.