Question

Yesterday I did my first fork on github.

I modified something and then made a pull request to the original repo.

Then I’ve discovered that i did something wrong, now I want to sync my fork to the original repo so that all the changes i did (creating new files, modified some..) will be deleted.

I tried with

git fetch upstream
git merge upstream/master

and the changes made on the original repo in the meantime get synced to my fork but the changes i did remained in my fork!

I want my repo to be the same as the original one.

Answer 1

You can fix your fork by adding a remote to the original repo, fetch from there, reset your branches to match the ones pulled, then force push the branches to your fork.

Assuming your forked repo is represented by origin, here is an example with master as the only branch you have:

git remote add upstream http://github.com/original.git
git fetch upstream
git reset --hard upstream/master
git push -f origin master

now master will be in the same place in both repos. When you do a merge, you either move the reference forward (called a fast-forward merge) because nothing existed on your side, or you make a new commit as there are changes to both. Reset is the answer here if you want to throw away your commits – not merge.

If you have other branches that you want to reset back to where they are on the initial repo you can do it without checking them out with:

git push -f . upstream/feature1:feature1
git push -f origin feature1

the . says push within the same repo. It’s a clever way to move a branch pointer without having to checkout the branch. The colon syntax in push means <source>:<destination>. If :<destination> is omitted, it implies the same name which is why you don’t often see the syntax with push examples. A more common example is when you push a local branch to a remote one that has a different name: git push origin myexperiment:dev would update the dev branch on the remote to what myexperiment points to.