Am I supposed to run BFG on the mirrored repo or the original?

Question

I want to delete two files from my git repo that aren't there anymore.

I put them in, committed, and tried to push but they were too large. So I took them out, and kept working, then committed, tried to push, but it still gave me the same error. I figured they're still in the history somewhere.

I think I made the problem worse because I kept working in that branch and made 1 more commit. Then I merged that branch back to the master branch.

So I searched for a solution and found bfg.

But the instructions on the page don't make sense to me.

First off,

$ git clone --mirror git://example.com/some-big-repo.git

Where am I supposed to clone from? My remote repo on github.com doesn't have the commits and the merge I did since I added the large files. But the instructions make it seem like I'm supposed to get it from there anyway. (I cloned from my local repo.)

Next,

$ java -jar bfg.jar --strip-blobs-bigger-than 100M some-big-repo.git

Is some-big-repo.git the mirrored repo or the normal local repo? (I used the mirrored repo for this.)

And then I checked that my history had been updated and tried,

$ cd some-big-repo.git
$ git reflog expire --expire=now --all && git gc --prune=now --aggressive

(I was in the mirrored clone for this) I got an error.

remote: error: refusing to update checked out branch: refs/heads/master
remote: error: By default, updating the current branch in a non-bare repository
remote: error: is denied, because it will make the index and work tree inconsistent
remote: error: with what you pushed, and will require 'git reset --hard' to match
remote: error: the work tree to HEAD.
remote: error: 
remote: error: You can set 'receive.denyCurrentBranch' configuration variable to
remote: error: 'ignore' or 'warn' in the remote repository to allow pushing into
remote: error: its current branch; however, this is not recommended unless you
remote: error: arranged to update its work tree to match what you pushed in some
remote: error: other way.
remote: error: 
remote: error: To squelch this message and still keep the default behaviour, set
remote: error: 'receive.denyCurrentBranch' configuration variable to 'refuse'.
To /home/cole/main_repo
 + 94b9a0d...c7c4317 work -> work (forced update)
 ! [remote rejected] master -> master (branch is currently checked out)
error: failed to push some refs to '/home/cole/main_repo'

This makes sense to me. Yeah I do currently have master checked out. But then, what else was I supposed to do? I can only see problems happening if I try it another way.

Answer 1

You should clone/mirror the repo that you eventually plan to replace the commits-in, but there's an underlying assumption that this repo is also a bare repo. This would usually be a remote repo, but you might also clone a local repo to save bandwidth.

The underlying assumption is that the repo where you will eventually store your cleaned repository is also a bare repo. Server-based repos e.g. GitHub are usually exactly that.

In your case it sounds like you have cloned a local, non-bare (contains a HEAD and working-copy) repo, either to save bandwidth, or because it is the repo that contains the commits you wish to clean. Either way, in order to push back into a non-bare repo, you need to make sure you don't have any refs you want to push checked-out, including master.

From your comment it looks like you found the solution, which is to push-back to the eventual origin repo, which will likely be a bare repo.

Answer 2

First 3 steps with BFG:

1. Download BFG using the following command in terminal: brew install bfg

2. Clone a fresh copy of your repo, using the --mirror flag.

   git clone --mirror git://example.com/some-big-repo.git
   

   The mirror flag allows you to make a full copy of the Git database without actually copying down the files of the repo.

3. bfg --the-options-you-want the-mirror-repo-you-just-cloned.git

Adapted from this manual by an IBM engineer. Don't cd into the repo as it says on step 3, otherwise you'll get an error "the-mirror-repo-you-just-cloned.git is not a valid Git repository."