Contributing to wolf-lsp

The engine is not here

The language server is wolf lsp, the wolf compiler itself, serving LSP from the same code that compiles (D34: one process, one truth). This repo contains no server code, and none is accepted here.

No fallback. No "temporary" diagnostic parser. No formatting shim. No client-side approximation of a capability that has not shipped. A second implementation of anything server-side is the exact failure this track exists to avoid: the moment the editor layer can answer a question itself, it stops proving that the compiler can.

Concretely:

• A capability an editor wants is a wolf-lang sprint, not a shim here. Semantic tokens, inlay hints, rename, refactoring are all compiler-track post-v1. Their tests get written when the server ships them.
• No cargo dependency on any wolf_* crate, and no vendored wolf-lang source. This repo talks to a wolf process over stdio or it does not talk.
• CI never builds the compiler. It downloads the artifact wolf-lang publishes, keyed by vendor/upstream/PIN, or it skips loudly.

cargo xtask independence enforces all three, on every PR.

Commits

Mirroring the compiler and interpreter tracks:

• Commit in chunks. One logical change per commit. A refactor and the feature it enables are two commits. A toolchain bump or a pin bump is always its own commit. Never git add -A.
• Terse, imperative subjects, under ~250 characters unless the change genuinely needs elaboration: matcher: default ServerCapabilities to subset, not Added some logic so that capabilities can grow without....
• Never git checkout files that were just written but not yet committed. Stage or stash first. This has eaten work before.

Tests are first class

• Every behaviour worth having is worth a test, and every bug fix arrives with the test that would have caught it. Tests land in the same commit as the code.
• CI is first class too. A red CI is a stop-the-line event, never a thing to merge around.
• cargo xtask ci is the local gate: fmt-check, clippy -D warnings, tests, sync-pin, independence, and the lspconf doctor report.

The two halves

Everything in this repo is either server-free or server-dependent, and the split is load-bearing:

• Server-free (transcript parsing, matchers, normalization, profile validation, pin integrity) must be green on a fresh clone with no wolf on PATH. That is why the matcher engine is a pure function of two JSON values.
• Server-dependent (record, replay, bench) must skip loudly: print SKIP: <reason> and exit 77. Never exit 0 for work that did not happen. A lane that reports success for doing nothing is a lane nobody notices is dark. --require-server turns the skip into a failure, for jobs that are supposed to have a binary.

The snapshot ritual (insta)

Snapshots live in crates/*/tests/snapshots/. When one legitimately changes:

INSTA_UPDATE=always cargo test        # rewrite the .snap files
git diff '**/snapshots/'              # READ the diff — this is the review
cargo test                            # verify-clean run against the new snaps

The middle step is the whole point. INSTA_UPDATE=always makes any diff disappear, including the one that was a real regression. Reviewing the diff is what turns that hazard into a workflow. Never commit a .snap.new or a .pending-snap.

Snapshots hold the normalized view of a transcript and never the raw one, so a diff means a behavior change and not a different run.

Corpus samples are read-only

vendor/upstream/samples/ is the only source of .lu in this repo, and its bytes are canonical wolf fmt output at a STYLE_VERSION. Never reformat a sample, never fork one into a local fixture, and never "fix" one that looks wrong. That is a finding to report upstream. A sample whose bytes change is a pin bump, in its own commit (vendor/README.md).

Platform lessons

These were paid for once already, upstream. Do not re-derive them.

• Line endings are protocol surface. .gitattributes pins * text=auto eol=lf and it stays that way. LSP positions are derived from byte offsets, and a CRLF checkout silently shifts every column in every transcript. CI proves it held.
• Capture, then grep. Never pipe a program's stdout into grep -q. grep -q exits at the first match and closes the read end. The producer's exit-time flush then hits EPIPE, and Rust's default SIGPIPE-ignore turns that into a panic, nondeterministically, and it surfaced on macOS first. Write out=$(cmd) then printf '%s' "$out" | grep -q ….
• Sort read_dir output before it can influence any generated artifact or any message a human reads. Directory order is platform noise.
• Never seed an RNG from a raw file path. Normalize separators first. A Windows \ explored an unvetted seed space compiler-side. ls01's edit fuzzer takes explicit seeds. More generally, no raw platform path reaches a transcript, a report key, or a hash: use lsp_harness::slash_path.
• Pin CI toolchains explicitly. rust-toolchain.toml names the toolchain. CI installs it with an explicit rustup step, then adds components. An implicit proxy-install races the first cargo invocation and picks up neither rustfmt nor clippy.
• Content-Length counts bytes, not characters. The most common framing bug in hand-written clients, which is most of the clients this track integrates with.

Toolchain

Pinned in rust-toolchain.toml (rustup and CI) and rust-version (everyone). Bump deliberately, in a dedicated commit, CI-green on all three platforms.

Model policy

Track agents run Opus. The work is integration against hand-rolled LSP clients in three languages, where the failure modes are subtle (framing, position encoding, unanswered server requests) and a wrong patch lands in someone's daily driver. Agent guidance itself stays untracked: AGENTS.md and CLAUDE.md are gitignored, as on the compiler and interpreter tracks.

Before you push

cargo xtask ci

Green, on a clean tree. wolf lsp exists upstream as of s52, so the server-dependent lanes light up as soon as a binary at the pinned version resolves. Without one, lspconf doctor reports SERVER UNAVAILABLE, which is a skip and not a failure, and xtask ci treats it as one.

Where the plan lives

The sprint plan is the lsp track (lsNN) in the wolf metarepo. Sprint files are the implementation contract, and the decision log is the design authority.