How to permanently delete a commit from Git's history?

Question

How can I permanently delete a commit from Git's history?

One of the developers on the team has accidentally committed a 200 MB file and pushed it to our Git server. It was deleted a few days later but the history is there. Our code files are only about 75 MB, and we have 4 branches. Due to the 200 MB file commit, the history is preserved and the size of our project folder (specifically the hidden .git folder) has ballooned to close to 700 MB. How do I permanently delete the two check-ins (commit of the huge file, delete of the huge file) from git as if it never happened? I'm using `TortoiseGit if that matters.

Answer 1

As forvaidya suggested, git filter-branch is the way to go. Specifically, in your case, you can execute the following command to remove that one file from the repo's history:

git filter-branch --tree-filter 'rm -f filename' HEAD

Substitute filename with the actual file name. Again, as forvaidya said, this rewrites the entire history of the repo so anyone who pulls after you make this change will get an error.

Edit: for performance reasons, it's actually better to use Git's rm command:

git filter-branch --index-filter 'git rm --cached --ignore-unmatch filename' HEAD