How can a revert commit also be a merge commit?

Question

Recently at work, we lost some code on a project under version control using git (and a private github repository).

I used git bisect to find the culprit commit, and I got really surprised discovering it was looking like a revert commit, but also had two parents like merge commits :

commit b5f97311eea2905baf8a96fddec22321d952f05c
Merge: 8cc7371 131d463
Author: Bob <[email protected]>
Date:   Fri May 22 19:42:25 2015 +0200

    Revert "ISB-CPW-3627 - Mise en place du calage des filtres DS1/DS2/DS3/DS4"

    This reverts commit 8cc7371e7133b68db95ac8e9aeb730d7889a1166.

This issue has been resolved by creating a new branch from an ancestor commit, and applying some patches on top of that new branch.

So I don't need help to fix that, I just want to understand how can a revert commit could also be a merge commit, what happened, and how to reproduce this weird behavior.

I tried to reproduce it like this :

• create a new branch at 8cc7371
• git revert 8cc7371

It creates a revert commit with a single parent (8cc7371) as expected.

The culprit commit author uses Atlassian SourceTree instead of the native command line interface, so I also tried using the revert feature within SourceTree and got the same result as above (single parent).

After running some git commands on b5f9731, I noticed that git diff and git show are not reporting the same file set :

$ git diff b5f9731..8cc7371 --name-only
=> 2 files :
   application/sites/frontend/views/scripts/Layout/Foobar/PointsDeVente/index.tpl
   public/media/design/frontend/css/main-dev.css
$ git show --oneline --name-only  b5f9731
=> 1 file :
   public/media/design/frontend/css/main-dev.css

SourceTree and Github are showing 2 files.

You can find how the graph looks like here : graph.html, and some git commands results there : misc.html.

Could anybody explain what happened with b5f9731 ?

Answer 1

What comes to my mind:

git revert ...
# new commit abcdef
git merge ...
# new commit fedcba
git rebase -i HEAD~2

pick abcdef - the original revert commit
squash fedcba - the merge commit

Message is taken from abcdef.

This all results in the new b5f9731. It has two parents from a merge commit and the message from the revert commit.

Answer 2

Steps to revert the commit from local branch are as following:-

1) Execute the "git log -1" command on git bash 2) Get the "committed GUID" from above command 3) Execute the "Git reset --hard committed GUID" command on git bash