# Changelog

All notable changes to cargoxx will be documented in this file.

## [Unreleased]

### Added
- M0 repo skeleton: hand-written `CMakeLists.txt`, bootstrap `flake.nix`,
  empty C++23 module units for every component listed in `TECH_SPEC.md` §1
  (`util`, `exec`, `manifest`, `lockfile`, `layout`, `linkdb`, `resolver`,
  `codegen`, `cli`), root module `cargoxx`, and a stub `main.cpp` that
  builds an empty `cargoxx` binary.
- `.clang-format` (LLVM, 100-column) and `.gitignore`.
- `SPEC.md`, `TECH_SPEC.md`.
- M1 foundation in `cargoxx.util`: `ErrorCode` (numbers per `TECH_SPEC.md` §4),
  `Error`, `Result<T> = std::expected<T, Error>`, and `format(Error)` rendering
  `error[Ennnn]: ...` with optional `--> path:line:col` and `hint:` lines.
  `format` lives in `src/util/error.cpp` as a module implementation unit.
- `Catch2 v3` wired through `flake.nix` (libc++-built override) and registered
  in CMake; `tests/util_error.cpp` covers six format cases via
  `catch_discover_tests`.
- `cargoxx.manifest` public types (`Package`, `Dependency`, `BuildSettings`,
  `Edition`, `Manifest`) and `parse(path)` returning `Result<Manifest>`,
  backed by toml++ vendored as `third_party/toml.hpp`. Unknown keys in
  `[package]` / `[build]` and unknown top-level keys are rejected; reserved
  fields (`description`, `repository`, `[dev-dependencies]`, `[features]`,
  `[workspace]`) are accepted. `tests/manifest_parse.cpp` covers 17 cases.
- `manifest::write(m, path)` serializes a `Manifest` as TOML using toml++.
  Dependencies are emitted alphabetically (matches Cargo). Round-trip
  property is exercised by `tests/manifest_write.cpp` (9 cases).
  Defaulted `operator==` on the manifest structs supports comparison.
- `cargoxx.layout` public types (`Target`, `TargetKind`, `DiscoveredLayout`)
  and `discover(project_root, package_name)`. Walks `src/` recursively
  for the library (excluding the `src/bin/` subtree), enumerates
  `src/main.cpp`, `src/bin/*.cpp`, `tests/*.cpp`, `examples/*.cpp` flat,
  sorts results for deterministic output, and returns `LayoutNoTarget`
  when neither a library nor any binary is present.
  `tests/layout_discovery.cpp` covers 12 cases.
- `cargoxx new <name>` and `cargoxx new --lib <name>` scaffold a project
  directory with `Cargoxx.toml`, `src/main.cpp` or `src/lib.cppm`, and a
  minimal `.gitignore`. Hyphens in the package name are mapped to
  underscores when generating the module/namespace identifier.
  Codegen of `flake.nix` / `CMakeLists.txt` is intentionally deferred to M3.
  CLI11 v2.6.2 vendored at `third_party/CLI11.hpp`; entry point is now
  `cargoxx::cli::run(argc, argv)`. `tests/cmd_new.cpp` covers 9 cases.
- `util::satisfies(version, range)` — minimal semver range matcher
  supporting `*`, `==/>=/<=/>/<` operators, and comma-separated AND
  clauses. Versions are zero-padded to three components.
  `tests/semver_satisfies.cpp` covers 7 cases.
- `cargoxx.linkdb`: `Recipe`, `Database::open()`, `Database::resolve(...)`
  for curated lookups. The curated database ships at `data/linkdb.json`
  with all 25 packages from `SPEC.md` §11. Component-substitution helpers
  expand `{{components}}` (space-joined) in `find_package` and fan out
  `{{component}}` per-target. Path is injected via the
  `CARGOXX_LINKDB_DEFAULT_PATH` compile definition. nlohmann/json 3.12.0
  vendored at `third_party/json.hpp`. SQLite overlay and `add_manual`
  are deferred to the M2 follow-up commit.
  `tests/linkdb_lookup.cpp` covers 13 cases including a smoke test that
  resolves all 25 curated packages.
- `cargoxx.lockfile`: `Lockfile`, `LockfilePackage` types and `parse(path)` /
  `write(lock, path)` matching the format in `SPEC.md` §5. Also
  `Lockfile::nixpkgs_rev()` returns the shared revision (codegen will
  consume this in M3). `tests/lockfile_round_trip.cpp` covers 9 cases.
- `cargoxx.codegen`: `GenerateInputs` plus the pure function
  `flake_nix(in) -> std::string`. Substitutes the package name, the
  resolved nixpkgs revision (defaulting to `nixos-unstable` when the
  lockfile pins none), and a deduplicated list of dep `nixpkgs_attr`
  entries into `buildInputs`. Output is byte-deterministic.
  `tests/codegen_flake.cpp` covers 7 cases. Note: SPEC §7's template did
  not show `buildInputs`; we add one between `nativeBuildInputs` and the
  `env.NIX_CFLAGS_COMPILE` block as the natural slot for the deps that
  TECH_SPEC §10 says we splice in.
- SQLite overlay: `Database::open(overlay_path)` now opens (and creates,
  if missing) a per-user `linkdb.sqlite` cache, applying the schema from
  `SPEC.md` §9 idempotently. Default path is
  `$XDG_CACHE_HOME/cargoxx/linkdb.sqlite` (falling back to
  `$HOME/.cache/cargoxx/...`); tests pass an explicit temp path so they
  never touch the user cache. `Database::add_manual(pkg, range, recipe)`
  inserts a row with `source = 'manual'` and `verified_at = now()`;
  `resolve()` consults the overlay first and falls back to curated when
  no overlay row matches the requested version range. Manual entries
  never expire; `nix-probe` (v0.2) entries respect a 30-day freshness
  window. `tests/linkdb_overlay.cpp` covers 7 cases (insert/persist,
  override-curated, version-range gating, components rejection,
  move semantics).