Introduction

git filter-branch is a really nice git feature. For instance, it allows fancy stuff like subtree-splitting.

Problems may arise when the repository contains a lot of commits: this operation can take a lot of time.

Luckily recent versions of git allow us to perform this operation in an incremental way: the first time filter-branch still requires some time, but following calls can be very fast.

Requirements

• git 2.16.0 or newer
• common commands (sed, grep, md5sum, cut, ...)
• sufficient space in /dev/shm or a different location specified with --tempdir to run filters

Usage

Get the script and read the syntax using the --help option.

Examples

./bin/incremental-git-filterbranch \
    --branch-whitelist 'develop master rx:release\/.*' \
    --tag-blacklist 'rx:5\..*' \
    --tags-plan all --tags-max-history-lookup 10 \
    https://github.com/concrete5/concrete5.git \
    '--prune-empty --subdirectory-filter concrete' \
    git@github.com:concrete5/concrete5-core.git

Legal stuff

Use at your own risk. MIT License.

Credits

Special thanks to Ian Campbell for the implementation of the --state-branch option of git, and his hints about how it can be used. This script works only thanks to him (and if it doesn't work I'm the only person to blame).