# fuckgit

A binary literally named `git` that, when run inside a [jj][] (Jujutsu) repo,
refuses to actually run git and instead tells you to use `jj`.

[jj]: https://github.com/jj-vcs/jj

## Why

AI coding agents (Claude Code, Cursor, et al.) keep running `git` inside
jj-managed repos despite being told to use `jj`. In a colocated jj+git
layout, that corrupts state. `fuckgit` shadows the real `git` on `PATH`
and traps these invocations, redirecting them with the equivalent `jj`
subcommand and inline `jj help <subcmd>` output.

It works on humans too, when they ask for it.

## Install

```sh
cargo install fuckgit
```

This installs a binary named **`git`** (yes, really) to `~/.cargo/bin/git`.
Make sure `~/.cargo/bin` is ahead of `/usr/bin` on `PATH`.

Linux and macOS only.

## Behavior

By default, `fuckgit` is a silent passthrough — every `git` invocation is
forwarded to the real `git` on `PATH`. The redirect *only* fires when
**all** of these are true:

1. You're inside a jj worktree (a `.jj` directory exists in the cwd or an
   ancestor — honoring `git -C <path>`).
2. The intercept gate is open — at least one of:
   - `FUCKGIT_INTERCEPT=1` is set, OR
   - an AI-agent marker env var is set (currently just `CLAUDECODE`).
3. The subcommand isn't on the plumbing allowlist (`rev-parse`, `cat-file`,
   `for-each-ref`, …).
4. None of the safety env vars are set: `GIT_DIR`, `GIT_EXEC_PATH`, `CARGO`.
5. No top-level `--git-dir=` or `--work-tree=` flag is present.

If any check fails, `git` behaves exactly as if `fuckgit` weren't installed.

When the redirect *does* fire, you'll see something like:

```
Don't use git. Use jj.

  git status  →  jj st
  jj has no staging area; `jj st` shows the working-copy commit's diff.

--- jj help status ---
Show high-level repo status [default alias: st]
…

Override with FUCKGIT_PASSTHROUGH=1  or  git --fucking-git <args...>
```

…and exit `2`.

## Escape hatches

When you need real `git` and the intercept is firing:

- `FUCKGIT_PASSTHROUGH=1 git <args>` — env var override
- `git --fucking-git <args>` — flag override (the flag is stripped before
  exec'ing real git)

## Configuration

| Variable                | Effect                                                           |
|-------------------------|------------------------------------------------------------------|
| `FUCKGIT_INTERCEPT=1`   | Open the intercept gate (opt in for your own jj repos).          |
| `FUCKGIT_PASSTHROUGH=1` | Force passthrough even with the gate open.                       |
| `CLAUDECODE`            | Set by Claude Code; opens the gate automatically.                |

To extend the AI-marker list, edit `AI_MARKERS` in `src/main.rs` and rebuild.

## Supported subcommands

`fuckgit` knows the `jj` equivalent for these `git` subcommands:

`status`, `log`, `commit`, `add`, `checkout`, `switch`, `restore`, `branch`,
`merge`, `rebase`, `pull`, `push`, `fetch`, `clone`, `init`, `diff`, `show`,
`reset`, `revert`, `cherry-pick`, `stash`, `tag`, `blame`, `remote`,
`bisect`, `config`, `reflog`.

Unknown subcommands fall through to a generic "use jj instead" + `jj help`
output.

## License

MIT — see [LICENSE](LICENSE).