moonwell-client-core/docs/METHOD.md

METHOD — how benilla is built

benilla is a from-scratch World of Warcraft 1.12.1 client in Rust and Bevy. It reads the game's data from the player's own install, speaks the original protocol to any 1.12.1 server, and does not build a server or simulate the game. The reference client is the spec: benilla does what 1.12.1 does, as a modern, idiomatic client.

The rule for every change

A change is right when it makes benilla more like 1.12.1 or fixes a bug, with evidence from the reference, in one small piece, with the gates green. A deviation from the reference is the maintainer's call alone, and each one is written down where it lives: a CVar's Deviates row, a comment naming the reference fact and why we differ. Anything else lives on top of benilla, in a crate of its own or a fork, and benilla opens a piece of itself to such a crate only when its own 1.12.1 work creates that piece (docs/CONTRIBUTING.md, "Building on top").

The loop

1. The reference first. For anything fidelity-defining, get the mechanism from the real client before building: its code as benilla-re documents it by address, its behaviour, a DBC field, a FrameXML line, a packet capture. The names and shapes under reference/ are the surface benilla tracks. A fact benilla-re lacks, or gets wrong, is settled there, as an issue or a finding, and cited here by its client address.
2. Build it idiomatically. Modern Bevy and Rust, performance woven in from the start. Implement the mechanism well; do not ape a quirk that is a bug.
3. Measure, never eyeball. Timing, delay, ordering and feel are settled with instruments: trace timestamps, byte-derived numbers, a numeric probe. A capture confirms an existence fact; it cannot measure time. Never search for a viewpoint: take the one simplest shot, and if it does not settle the question, hand over a precise script ("log in, look at X, does Y?").
4. Close the loop on the symptom. A bug reported as seen is closed by reproducing it at the reported spot first, fixing, and showing the same instrument clean there plus one adjacent state. Green gates and an existing mechanism are never that evidence.
5. Prove the run before reading the result. A live result is evidence once the run is valid from numbers: preflight banner clean, camera and body where intended, the subject in frame, the window long enough. A negative from an unproven run is not evidence.
6. Commit small and often; land by pull request. Atomic commits, explicit paths, on a branch; main moves only by a squash-merged pull request, one commit per piece of work. No "done" and no commit without saying what was verified and how the result was judged.

Hard rules

• Never commit anything from the install. Art, models, sounds, maps, data: the install is read at runtime from a gitignored path, and everyone provides their own. Interface code is no exception: FrameXML and GlueXML run off the player's own patch chain, and assets/ui holds only benilla's own files.
• The install is read-only. benilla never writes into the WoW folder: no screenshot, log, cache or scratch file. scripts/smoke.sh fails a run that leaves the install changed.
• Local state lives in one folder, benilla-config/, at the repo root in a dev build and beside the binary in the player build; every path to it resolves through crate::local_state. Player settings are CVars persisted as a diff in benilla-config/config.toml.
• The core UI is the stock UI; benilla's own is one layer on top. The core loads the stock 1.12 FrameXML off the player's own chain, byte for byte, and builds the engine verbs those files call, never stubbing one to make a file load. benilla's own interface (its options window, its game-menu look, its fixes to the stock Lua) is one layer that loads after the stock files and before third-party addons, the way an addon does: written against the 1.12 API alone, listed in no addon list and always on, and offering nothing another addon can build on. Anything that changes what the stock UI does or shows lives in the layer, and the layer does not grow: a test names its files and fails on a new one.
• A setting's default is the reference's default. Every option boots at the stock 1.12 value. Shipping another value costs an explicit Deviates row with the reason, and a test fails a row that drifts either way.
• Our code is MIT OR Apache-2.0, which is a claim about provenance: no original client code, no bundled assets.

Where things live

• docs/METHOD.md, this file: rules and method. Never state, never a log.
• docs/MAP.md: what is built, generated from the code by scripts/genmap.sh at every land. Read it to orient; never edit or commit it by hand.
• docs/DEVIATIONS.md: every place benilla differs from 1.12.1, its Deviates rows and Deviation: comments, generated from the code by scripts/genmap.sh at every land; never edited by hand.
• git: the history. No changelogs, no status docs, no "what we did" narratives.
• The code: a comment says what the code does and the 1.12 fact behind it, in a line. No history, no stories.

Gates

• The land gates: cargo fmt --all -- --check, cargo clippy --workspace --all-targets -- -D warnings, the workspace tests (scripts/unit-tests.sh: cargo-nextest where it is installed, else cargo test) and their doctests, the doc-link lint (a full cargo doc of the workspace) and the render-pass lint, the vendored-reference and message-catalog checks, the player build without the dev feature, linted and with its own tests, and the engine boot checks, as scripts/gates.sh. It runs on the tree that lands, before it lands; it is memoized on the tree. The tests that read the install or the addon corpus skip where the data is absent, and the gate prints the count; where the data is, a skip is a failure (BENILLA_REQUIRE_DATA=1). The workspace tests then run a second time with WOW_DATA= (no install), so a test that reads the install without opening with wow_data_or_skip! fails here and not on a clone.
• Per round: scripts/check.sh, scoped to the changed crates and their dependents. Run each gate once per round; tee the output to a file and grep the file.
• A clean run is the fourth gate: scripts/smoke.sh, a live login and logout against the local server. For wire work the gate is a live run with a trace (WOW_MOVE_TRACE=<path>, tags filtered), never a capture: capture mode has no network.
• Platform seams: a cfg(target_os), a [target.'cfg(…)'] dependency, a #[link] or an extern "system" is invisible to the gates of the platform you are on. Say in the commit which platforms you built.

The local server

benilla talks to any 1.12.1 server: WOW_HOST names it (default localhost), WOW_USER and WOW_PASS together log in without typing, WOW_CHAR picks the character. There is no default account. These bind every session and every agent:

• A scripted run logs in as the account its checkout declares in .probe-identity (the three variables, one per line, never committed), or as the three variables name; never as a player's, because a login kicks whoever holds the account, and the client refuses a scripted login from a checkout on any account but the declared one.
• Every unattended run says so: WOW_UNATTENDED=1. An agent's run is silent: WOW_NOSOUND=1.
• No unattended combat probes.
• Anything about hostility, reaction colour, nameplates, threat, damage or breath runs with WOW_GM=off.
• Read the preflight banner before debugging anything else.

The switches for such a run are docs/CONTRIBUTING.md, "Running it unattended".