hashcommit

A tool to generate a Git commit with a specific hash part.

Prerequisites

Ensure you have Git installed on your system.

Installation

You can install the package using pip:

pip install hashcommit

Demo

This repository's history was rewritten using the rewrite_the_history.sh script and each new commit is added by using the hashcommit command. You can check the result here.

Usage

Creating a New Commit

To create a new commit with a specific hash part:

hashcommit --hash <desired_hash_part> --message "<commit_message>"

Overwriting the Last Commit

To overwrite the last commit with a specific hash part:

hashcommit --hash <desired_hash_part> --message "<commit_message>" --overwrite

Match Type

You can also specify if the hash must begin with, contain, or end with the desired string using the --match-type option. Regex matching is also supported. The default is to match the beginning of the hash:

hashcommit --hash <desired_hash_part> --message "<commit_message>" --match-type <begin|contain|end|regex>

Example Usage

To find and use a specific commit hash:

hashcommit --hash fff --match-type contain --message "foobar" ; git log -1 | cat

Example output:

Found matching commit hash: 93fffe4756192c250a7234c7c5fd81752c747091
commit 93fffe4756192c250a7234c7c5fd81752c747091
Author: Your Name <your-email@domain.com>
Date:   Thu May 23 17:06:24 2024 +0000

    foobar

Author Preservation

By default, the author is preserved when overwriting. To overwrite the author, use the --no-preserve-author option:

hashcommit --hash <desired_hash_part> --overwrite --no-preserve-author

Overwriting Commits in the Past

You can overwrite the existing commit that has other commits on top of it. To do this, use the --commit option:

hashcommit --hash <desired_hash_part> --overwrite --commit <commit_hash>

Rewriting the History

You can rewrite the history of the current branch using the rewrite_the_history.sh script. This script will recreate the commit history, ensuring that each commit's hash conforms to a sequence specified by the -d argument, which sets the number of digits for the sequence number.

For example, to rewrite the history with a two-digit sequence number at the beginning:

./scripts/rewrite_the_history.sh -d 2

Note: The default value for -d is 3. As the number of commits increases, consider adjusting the digit value accordingly to balance performance and the required hash length.

Development

To develop or contribute to this project, clone the repository and install the dependencies:

git clone https://github.com/wozniakpl/hashcommit.git
cd hashcommit
pip install -e .

Running Locally

You can run tests locally using tox or act:

# Using tox
tox

# Using act
act

You can use the following command for simplicity of development. It formats the code, runs the checks, and the tests on one Python version:

tox -e format && tox -e checks && tox -e py312 --

To run tox tests under docker (not using your git):

docker compose up

To set up an environment with hashcommit installed and a git repository initialized in the /repo directory, use Docker Compose:

docker compose run --rm --workdir /repo test bash

License

This project is licensed under the MIT License.