git-filter-repo/contrib/filter-repo-demos
Elijah Newren 320c85f941 filter-repo: improve support for partial history rewrites
Partial history rewrites were possible before with the (previously
hidden) --refs flag, but the defaults were wrong.  That could be worked
around with the --source or --target flags, but that disabled --no-data
for fast-export and thus slowed things down, and also would require
overridding --replace-refs.  And the defaults for --source and --target
may diverge further from what is wanted/needed for partial history
rewrites in the future.

So, add --partial as a first-class supported option with scary
documentation about how it permits mixing new and old history.  Make
--refs imply that flag.  Make the behavioral similarities (in regards to
which steps are skipped) between --source, --target, and --partial more
clear.  Add relevant documentation to round it out.

Signed-off-by: Elijah Newren <newren@gmail.com>
2019-10-17 18:55:09 -07:00
..
bfg-ish filter-repo: improve support for partial history rewrites 2019-10-17 18:55:09 -07:00
clean-ignore contrib: simple examples of tools based on filter-repo 2019-08-13 14:25:29 -07:00
filter-branch-ish contrib: new filter-repo demo named filter-lamely (or filter-branch-ish) 2019-08-20 23:58:47 -07:00
filter-lamely filter-repo: improve support for partial history rewrites 2019-10-17 18:55:09 -07:00
insert-beginning contrib: simple examples of tools based on filter-repo 2019-08-13 14:25:29 -07:00
lint-history contrib: simple examples of tools based on filter-repo 2019-08-13 14:25:29 -07:00
README.md contrib: new filter-repo demo named bfg-ish 2019-08-20 23:58:47 -07:00
signed-off-by filter-repo: improve support for partial history rewrites 2019-10-17 18:55:09 -07:00

Background

filter-repo is not merely a history rewriting tool, it also contains a library that can be used to write new history rewriting tools. This directory contains several examples showing the breadth of different things that could be done.

Quick overview

Command                         Description
insert-beginning Add a new file (e.g. LICENSE/COPYING) to the beginning of history.
signed-off-by Add a Signed-off-by tag to a range of commits
lint-history Run some lint command on all non-binary files in history.
clean-ignore Delete files from history which match current gitignore rules.
filter-lamely (or filterbranchish) A nearly bug compatible re-implementation of filter-branch (the git testsuite passes using it instead of filter-branch), with some performance tricks to make it several times faster (though it's still glacially slow compared to filter-repo).
bfg-ish A re-implementation of most of BFG Repo Cleaner, with new features and bug fixes.

Purpose

Please note that the point of these examples is not to provide new complete tools, but simply to demonstrate that extremely varied history rewriting tools can be created which automatically inherit lots of useful base functionality: rewriting hashes in commit messages, pruning commits that become empty, handling filenames with funny characters, non-standard encodings, handling of replace refs, etc. (Additional examples of using filter-repo as a library can also be found in the testsuite.) My sincerest hope is that these examples provide lots of useful functionality, but that each is missing at least one critical piece for your usecase. Go forth and extend and improve.

Usage

All the examples require a symlink to git-filter-repo in your PYTHONPATH named git_filter_repo.py in order to run; also, all have a --help flag to get a description of their usage and flags.