Re: Removing data from repository

[Jeff King <peff@peff.net>]

On Thu, Jan 24, 2019 at 02:51:50PM +0000, Naum Derzhi wrote:

> I have this problem: years ago one of our developers committed a large
> (Gigabytes) piece of binary data into our project repository. This
> should not have been done, but it happened. (Honest, it was not me).
> We never needed this data in the repository.
> 
> Using git rm removes these files from the working tree, but they are
> still somewhere in the repository, so when we clone, we transfer
> gigabytes of unneeded data. 
> 
> Is it possible to fix this problem?

You'll have to rewrite the offending history. You can use
git-filter-branch. See especially these sections of the manpage:

  https://git-scm.com/docs/git-filter-branch#_examples

  https://git-scm.com/docs/git-filter-branch#_checklist_for_shrinking_a_repository

as well as the warning in the DESCRIPTION section:

  WARNING! The rewritten history will have different object names for
  all the objects and will not converge with the original branch. You
  will not be able to easily push and distribute the rewritten branch on
  top of the original branch. Please do not use this command if you do
  not know the full implications, and avoid using it anyway, if a simple
  single commit would suffice to fix your problem. (See the "RECOVERING
  FROM UPSTREAM REBASE" section in git-rebase(1) for further information
  about rewriting published history.)

You may also want to check out the BFG repo cleaner[1], as separate
project that handles this case a little more simply (it doesn't save you
from dealing with rewritten history, but it does avoid having to learn
filter-branch's flexible but confusing syntax).

-Peff

[1] https://rtyley.github.io/bfg-repo-cleaner/