# Oxygen

Oxygen (`oxy`) is a distributed, commutative version control system written in Rust for large repositories. See [docs/spec.md](docs/spec.md) for the specification, [docs/guide.md](docs/guide.md) for a user guide by task, and [docs/protocol.md](docs/protocol.md) if you are implementing a client or server.

It is self-hosting: this directory is an Oxygen repository, and the project's own history is kept with `oxy`, not with Git.

## What is different

- **History is a set of changes, not a chain of snapshots.** A change records what it did to identified lines and tree nodes and which earlier changes it depends on. Changes that do not depend on each other commute, so there are no merge commits and rebasing independent work rewrites nothing.

- **Conflicts are data.** A conflicted state can be committed, pushed and pulled. Resolving one is an ordinary edit followed by a commit.

- **Every change has a stable ID and a content hash.** The ID survives rewrites; the hash makes history tamper-evident.

- **Everything is signed.** Composite Ed25519 + ML-DSA-65 signatures on changes and on every bookmark update, verified against a trust policy that lives in the repository.

- **Every operation is undoable** through an operation log.

- **Large files are chunked** with content-defined chunking into a BLAKE3-addressed store.

## Status

Early, but usable for its own development. Implemented: the object model, the change graph with conflict detection and resolution, the working copy (`status`, `commit`, `checkout`, `diff`, `undo`), identities and signatures, remotes over local paths and HTTP(S) with `clone`, `fetch`, `pull`, `push`, the reference server `oxy serve`, the trust policy, and packed storage.

Not yet: checkpoints for very long histories, history editing (`rebase`, `split`, `edit`), multiple workspaces, garbage collection with retention, and the Thin client profile for constrained machines.

## Install

Builds for Linux, macOS and Windows are on the [releases page](https://oxygenhub.io/andymccall/oxygen/releases). These are early releases: the macOS and Windows builds are not signed and have had little testing.

- **Debian, Ubuntu and other Linux with apt** (x86_64 or arm64): download `oxy_VERSION_amd64.deb` (or `_arm64.deb`) and run `sudo apt install ./oxy_VERSION_amd64.deb`. It needs glibc 2.28 or later (Debian 10, Ubuntu 20.04 and newer).

- **Other Linux:** unpack `oxy-VERSION-linux-x86_64.tar.gz` (or `-linux-arm64`) and put `oxy` on your `PATH`.

- **macOS** (Apple Silicon or Intel): unpack `oxy-VERSION-macos-arm64.tar.gz` (or `-macos-x86_64`), then `xattr -d com.apple.quarantine oxy`, since the build is not notarised, and put it on your `PATH`.

- **Windows:** unzip `oxy-VERSION-windows-x86_64.zip` and put the folder on your `PATH`. SmartScreen may warn on first run, since the build is not signed.

`oh`, the OxygenHub command line, is released the same way from [OxygenHub's releases](https://oxygenhub.io/andymccall/oxygenhub/releases).

Check a download against the release's `SHA256SUMS` with `sha256sum -c SHA256SUMS --ignore-missing`.

## Building

```

cargo build --release

cargo test --workspace

```

The binary is `target/release/oxy`.

**Changelog:** a commit that changes code adds a line under `## Unreleased` in CHANGELOG.md (Added, Changed, Fixed or Security, with the issue number); versions change only at release. `scripts/changelog-check.sh [PATH...]` checks it for the paths a commit takes (the working copy's changes without any) and runs in the gate; `NO_CHANGELOG=1` for code changes users won't notice.

## Quick start

```

oxy identity create --name "Your Name" --email [email protected]

oxy config --user core.sign change      # sign every commit

oxy init                                 # in a project directory

oxy status

oxy commit -m "First change"

oxy log                                  # -n 10 for the latest ten, -v for full messages

oxy log -r 'v0.3.1..main & author(me)'   # a revset: set algebra over history

```

Output uses colour, glyphs, and relative times on a UTF-8 terminal, and

falls back to plain ASCII when piped, with `--plain`, or with `NO_COLOR` set.

Collaborating through a hub such as OxygenHub: sign in once, in the

browser, and every repository on that hub clones, fetches and pushes with it.

```

oxy auth login https://oxygenhub.io

oxy clone https://oxygenhub.io/owner/project

oxy push

oxy pull

```

Or with your own server:

```

oxy serve --root /srv/oxy --bind 0.0.0.0:8890 --tls-cert cert.pem --tls-key key.pem --token SECRET

echo SECRET | oxy auth login https://host:8890 --with-token

oxy clone https://host:8890/project

```

A repository kept on your own storage, with no server in between (Oxygen

Strata, see `docs/strata.md`): a bucket in your cloud account, in your

region, under your keys, or a directory on a shared drive.

```

oxy remote add cloud s3://my-bucket/repos/project --profile work   # or gs://, az://, dir://

oxy remote check cloud                   # reachable, what it holds, and that it behaves

oxy push cloud

oxy clone s3://my-bucket/repos/project?profile=work

```

Trust policy, so a server accepts only changes from keys you have granted:

```

oxy policy init                          # your key becomes the root

oxy identity export                      # a contributor sends you this file

oxy policy grant alice.identity

oxy push                                 # publishes the policy

```

Bookmarks (`oxy bookmark create|switch`, `oxy merge`), submodules (`oxy submodule add|update`),

partial commits (`oxy commit PATH..`, `oxy commit -i`), `oxy blame`, `oxy bisect`, `oxy squash` and

`oxy rebase` cover the everyday Git toolbox; see the guide.

Working alongside Git: `oxy git import <repo> <dest>` converts a Git history, `oxy git fetch <url>`

brings new commits of a Git remote into the bookmark, `oxy git push <url>` publishes the bookmark as

commits on top of them, and `oxy git export <dir>` writes a plain Git mirror.

Keys have a lifecycle: `oxy identity rotate` moves to a fresh key pair (the policy follows),

`oxy identity renew --expires 365` sets an expiry, `oxy identity delegate add agent.identity --scope changes --expires 8h`

lets another key sign changes for you (an AI agent, say) for a while without ever being able

to move a bookmark, and `oxy identity revoke` retires a key. With several root

keys, `oxy policy root add|remove|threshold` and `oxy policy sign` gather the required signatures

through proposal files.

## Layout

| Path | Contents |

|---|---|

| `crates/oxy-core` | Library: encoding, hashing, objects, the change graph, storage, identities, policy, protocol, repository operations |

| `crates/oxy-server` | Reference HTTP(S) server for the wire protocol |

| `crates/oxy-strata` | The S3, Google Cloud Storage and Azure stores a repository can be kept on |

| `src/cli` | The `oxy` command-line interface |

| `docs/spec.md` | The specification |

| `docs/guide.md` | User guide, organised by task |

| `docs/strata.md` | Keeping a repository on your own storage: S3, GCS, Azure, a directory |

| `docs/protocol.md` | Wire protocol for other implementers |

| `docs/prompt.md` | Shell prompt integration |

## Licence

MIT or Apache-2.0, at your option (see `LICENSE`).