Re: purging unwanted history

From: Marcel M. Cary <marcel@oak.homeunix.org>
Date: Nov 18, 2008, 14:28 UTC
Message-ID: <4922D127.1020305@oak.homeunix.org>
In-Reply-To: <93c3eada0811161626h69929cd7va3fa4007a2341bae@mail.gmail.com>

Geoff,

I'm able to prune history with git filter-branch. For example, to throw away history on the current branch before commit 171d7661eda111d3e35f6e8097a1a3a07b30026c, I tried:

git filter-branch --parent-filter '
    if [ $GIT_COMMIT = 171d7661eda111d3e35f6e8097a1a3a07b30026c ]; then
        echo "";
    else
        read line;
        echo $line;
    fi'

I found the diff between that commit and it's rewritten version was empty, and diffs to subsequent commits looked sane. It took an hour on the git repository with about 16k commits. I probably should have excluded all the commits I didn't want to keep to reduce processing time.

However, after deleting all but the rewritten branch and cloning the repository, I didn't notice any decrease in the size of .git/, so I'm not sure why you'd want to do that. Also, all the remaining commitIDs changed so any previous clones would have a tough time merging with yours.

Another possibility whose results might be similar in runtime and repository size would be to run git rebase --interactive and squash all the commits together before the ones you want to keep.

Marcel

Geoff Russell wrote:

Show 20 quoted lines

> I have a repository with 5 years worth of history, I only want to keep
> 1 year, so I want to purge the
> first 4 years. As it happens, the repository only has a single branch
> which should
> simplify the problem.
> 
> Cheers,
> 
> Geoff Russell
> 
> P.S. Apologies, but I've asked this question before but didn't get an
> answer which
> I understood or which worked, so perhaps my description of the problem
> was faulty. This
> is a second attempt.
> --
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