The other day I had a bit more insomnia than usual. As such it seemed like a good idea to clean up my local repository’s branches using the immediate and seemingly permanent -D option:

git branch -D my_important_branch


With just one tiny statement on the command line, I managed to delete the very stuff I was working on. Apparently, git plans for this kind of stupidity, and it is quite easy to go back in time to a place free of grievous errors. Here is the fix:

git checkout -b my_important_branch HEAD@{1}


Some of this will look like very ordinary git stuff. Up until the “HEAD@{1}”, the above git command is just checking out a new branch. The HEAD@{1} specifies that the source for the new branch is … not the current branch. So what is this HEAD@{1}? It turns out that git keeps track of changes to the head of each branch using a tool ‘reflog’, with is short for reference log. You can look at what reflog is storing at any time:

git reflog


Here is an example of what I have on my current reflog at my wheel.js project:

121f1ea HEAD@{0}: commit: refactor EventManager drag events to be less aggressive about removing listeners from target
cbb109f HEAD@{1}: rebase -i (finish): returning to refs/heads/master
cbb109f HEAD@{2}: rebase -i (squash): Bug: swipes generated during drag
bacc417 HEAD@{3}: rebase -i (squash): updating HEAD
9e327e8 HEAD@{4}: rebase -i (squash): # This is a combination of 3 commits.
bacc417 HEAD@{5}: rebase -i (squash): updating HEAD
7b90379 HEAD@{6}: rebase -i (squash): # This is a combination of 2 commits.
bacc417 HEAD@{7}: rebase -i (squash): updating HEAD
fa11efd HEAD@{8}: checkout: moving from master to fa11efd
9a7d080 HEAD@{9}: commit: event managers no longer trigger swipe during drag


Reflog says that I did a normal commit. Before that I squashed some commits using an interactive rebase. Before that I switched branches.

So in the magic undelete code “HEAD@{1}” refers to reflog for the branch before it was deleted.

Of course, it is always wiser to use the -d option when deleting. That way git provides a nice warning if a branch is being deleted before it has been merged into master. Even better is advice is to get plenty of sleep. It will much improve the git workflow.