# The rename: zellij → sl0ppij

**Status: implemented.** See commit `sl0p: rename to sl0ppij behind a branding
seam`.

**Goal:** a machine can have stock zellij and sl0ppij installed at the same time,
running at the same time, without sharing a single byte of state.

## Isolation checklist

All disjoint from upstream as of the rename commit:

| surface | upstream | sl0ppij | done |
|---|---|---|---|
| binary name | `zellij` | `sl0ppij` | ✅ |
| config dir | `~/.config/zellij` | `~/.config/sl0ppij` | ✅ |
| cache/data dir | `ProjectDirs("org","Zellij Contributors","Zellij")` | `ProjectDirs("foo","sl0p","sl0ppij")` | ✅ |
| system config | `/etc/zellij` | `/etc/sl0ppij` | ✅ |
| system data | `/usr/share/zellij` | `/usr/share/sl0ppij` | ✅ |
| socket/tmp dir | `$TMPDIR/zellij-$UID` | `$TMPDIR/sl0ppij-$UID` | ✅ |
| log dir/file | `…/zellij-log/zellij.log` | `…/sl0ppij-log/sl0ppij.log` | ✅ |
| env vars | `ZELLIJ*` | `SL0PPIJ*` **and** `ZELLIJ*` (ours wins) | ✅ |
| plugin URL scheme | `zellij:about` | `sl0ppij:about` (accepts `zellij:`) | ✅ |
| help / CLI text | "zellij" | "sl0ppij" | ✅ |
| default-plugin text | "zellij" | — | ⬜ needs a wasm rebuild |
| desktop/shell assets | `assets/zellij.desktop`, `zellij.rc` | — | ⬜ packaging-only, unused so far |

## Where the work actually is

Encouragingly small and centralised:

- **`zellij-utils/src/consts.rs`** — the whole path story. Lines to touch:
  - `SYSTEM_DEFAULT_CONFIG_DIR` (`/etc/zellij`, and the Windows arm)
  - `ZELLIJ_PROJ_DIR` — `ProjectDirs::from("", "", "Zellij")` / `("org", "Zellij Contributors", "Zellij")`
  - `ZELLIJ_TMP_DIR` — `temp_dir().join(format!("zellij-{}", *UID))`
  - `ZELLIJ_TMP_LOG_DIR` / `ZELLIJ_TMP_LOG_FILE` — `zellij-log`, `zellij.log`
  - the non-unix arm's `tmp_dir.join("zellij")`
- **`zellij-utils/src/envs.rs`** — `ZELLIJ_ENV_KEY`, `SESSION_NAME_ENV_KEY`,
  `SOCKET_DIR_ENV_KEY`.
- **`zellij-utils/src/cli.rs:57`** — clap `name = "zellij"` (drives every usage
  string and `--help`).
- **`zellij-utils/src/input/plugins.rs:77`** — builtin plugin URL scheme.
- **`Cargo.toml`** — the root package `name = "zellij"` decides the binary name.
  *Renaming the package is the loudest possible change against upstream.* See
  "Strategy" below.
- **`assets/zellij.desktop`, `assets/zellij.rc`**, `wix/`, `.github/` packaging bits.
- **user-visible help strings** — `"zellij setup --check"`, `"zellij -l compact"`
  etc. inside `default-plugins/status-bar` tips and `about`.

## What was left out, on purpose

- **`default-plugins/*` strings** (the About screen, status-bar tips) still say
  "zellij". They live inside prebuilt `.wasm` blobs in
  `zellij-utils/assets/plugins/`, so changing them means rebuilding the plugins
  and committing new binaries — a separate, chunky commit.
- **`assets/zellij.desktop` / `zellij.rc`** are only used by distro packaging and
  the Windows build, neither of which we ship yet.
- **Crate names** (`zellij-utils`, `zellij-tile`, …) — see below.

## Strategy: one seam, not a sed

Do **not** `sed -i s/zellij/sl0ppij/g` the tree. Every touched upstream line is a
rebase conflict forever, and there are ~3300 upstream commits of future rebases.

Instead:

1. **Introduce a single branding module** (`zellij-utils/src/branding.rs`) with
   `pub const APP: &str = "sl0ppij";` plus derived consts (config dir name, tmp
   prefix, log names, env prefix, plugin scheme).
2. **Point the ~15 sites above at it.** Each becomes a one-line diff that reads
   `branding::APP` instead of a literal — small, stable, easy to re-apply.
3. **Keep the crate/package names as `zellij*`.** The *binary* name is set with
   `[[bin]] name = "sl0ppij"` instead of renaming the package, so all the
   intra-workspace `zellij-utils`/`zellij-tile` deps, plugin APIs and the
   `0.45.0+sl0p1` version trick keep working untouched. Nothing user-facing says
   "zellij" and nothing internal has to move.
4. **`ZELLIJ_EXECUTABLE_LOCATION` / self-exec**: the client re-execs itself to
   spawn the server. Verify it resolves via `current_exe()` and not a hardcoded
   `"zellij"` on `$PATH`, or a sl0ppij client will start a zellij server.

## Decided: env vars keep both spellings

Renaming `ZELLIJ=0` → `SL0PPIJ=0` outright would break every third-party thing
that detects "am I in a multiplexer" (shell prompts, starship, nested-session
guards, and our own `pi-ext`).

So **both are exported**, and `SL0PPIJ*` takes precedence on read:

| variable | ours | upstream's |
|---|---|---|
| marker | `SL0PPIJ` | `ZELLIJ` |
| session | `SL0PPIJ_SESSION_NAME` | `ZELLIJ_SESSION_NAME` |
| pane | `SL0PPIJ_PANE_ID` | `ZELLIJ_PANE_ID` |
| socket dir | `SL0PPIJ_SOCKET_DIR` | `ZELLIJ_SOCKET_DIR` |
| config file/dir, layout dir | `SL0PPIJ_CONFIG_*`, `SL0PPIJ_LAYOUT_DIR` | `ZELLIJ_CONFIG_*`, `ZELLIJ_LAYOUT_DIR` |

`branding::import_compat_env()` runs first thing in `main()` and folds an
inherited `ZELLIJ_*` into its `SL0PPIJ_*` spelling, which is what makes the
clap-derived arguments honour both (clap accepts only one env name per arg).

Note the spelling is `SL0PPIJ` (zero), matching the binary name.

> Because both spellings are exported, a pi running inside sl0ppij still sees
> `$ZELLIJ`, so **pi-ext needed no changes**.

## Verification (all performed)

**Unit tests** in `branding.rs`: no shipped default path contains the string
`zellij`; env precedence is ours-then-upstream; `set_env_var` writes both
spellings; every pair differs only by prefix.

**Suites:** `zellij-utils` 471 passed, `zellij-server` 1499 passed.

**Live, against a box already running stock zellij:**

```
$ sl0ppij --version              -> sl0ppij 0.45.0+sl0p1
$ sl0ppij setup --check          -> ~/.config/sl0ppij, ~/.cache/sl0ppij,
                                    /usr/share/sl0ppij
$ ls -d /tmp/sl0ppij-1000 /tmp/zellij-1000   -> both exist, disjoint
$ zellij  list-sessions          -> 3 sessions
$ sl0ppij list-sessions          -> "No active sl0ppij sessions found."
```

**Env precedence, end to end:**

| set | resulting CONFIG DIR |
|---|---|
| `ZELLIJ_CONFIG_DIR=/tmp/cfg-upstream` | `/tmp/cfg-upstream` |
| `SL0PPIJ_CONFIG_DIR=/tmp/cfg-ours` | `/tmp/cfg-ours` |
| both | `/tmp/cfg-ours` |

**Config:** the rebranded `config/config.kdl` loads under the renamed binary
(`[CONFIG FILE]: Well defined.`).