improvise/nix/ci.nix

# Everything CI *builds*, as Nix derivations (crane). The script-only checks
# (node tests, kb, the checkers, the comment and CI-graph gates, fmt) stay dev
# shell steps in ci.yml: they compile nothing, and their `#!/usr/bin/env bash`
# shebangs -- which scripts/checkers.sh itself enforces -- cannot run in the
# build sandbox, which has no /usr/bin/env.
#
# Why Nix: the self-hosted runners substitute from titan's harmonia first, and
# titan builds gh/main's outputs hourly. Dependencies are separate derivations
# (buildDepsOnly, keyed on the Cargo.lock), so a PR that leaves the lock alone
# rebuilds only the workspace.
{
  pkgs,
  craneLib,
  wasmBindgenCli,
  src,
  rev,
}: let
  inherit (pkgs) lib;

  # Two lockfiles: harness/opfs-contract is its own workspace root.
  cargoVendorDir = craneLib.vendorMultipleCargoDeps {
    cargoLockList = [../Cargo.lock ../harness/opfs-contract/Cargo.lock];
  };

  common = {
    inherit src cargoVendorDir;
    pname = "improvise";
    version = "0";
    strictDeps = true;
    # The `test` job ran the dev/test profiles, not crane's default release:
    # debug assertions and overflow checks are part of what it tested.
    CARGO_PROFILE = "";
  };

  wasmTarget = "wasm32-unknown-unknown";

  # The crates in the browser bundle, checked for wasm32 one at a time: a
  # single `cargo check -p a -p b` unifies features across them and can hide
  # a crate that only builds with a sibling's features (improvise-ywd).
  wasmCrates = [
    "improvise-core"
    "improvise-formula"
    "improvise-protocol"
    "improvise-io"
    "improvise-command"
    "improvise-wasm-client"
    "improvise-worker-server"
    "improvise-gp"
    # ADR 005 clause 14: nothing depends on it yet, and improvise-core will.
    "numtower"
    # ADR 009 clause 1: std-only; nothing depends on it yet.
    "zset"
    # ADR 009 clause 2: the Derived trait, Eager and the differential harness.
    "improvise-incremental"
  ];
  pFlags = crates: lib.concatMapStringsSep " " (c: "-p ${c}") crates;

  nativeDeps = craneLib.buildDepsOnly (common
    // {
      pname = "improvise-deps";
      cargoExtraArgs = "--locked --workspace";
    });

  wasmCheckDeps = craneLib.buildDepsOnly (common
    // {
      pname = "improvise-wasm-check-deps";
      cargoExtraArgs = "--locked --target ${wasmTarget} ${pFlags wasmCrates}";
      cargoCheckExtraArgs = "";
      doCheck = false;
    });

  # What wasm-pack's `cargo build --release --target wasm32` needs.
  bundleDeps = craneLib.buildDepsOnly (common
    // {
      pname = "improvise-bundle-deps";
      CARGO_PROFILE = "release";
      cargoExtraArgs = "--locked --target ${wasmTarget} ${pFlags ["improvise-wasm-client" "improvise-worker-server"]}";
      cargoCheckCommand = "true";
      doCheck = false;
    });

  # A derivation that runs cargo commands and only has to succeed.
  cargoCheck = name: args:
    craneLib.mkCargoDerivation (common
      // {
        pname = "improvise-${name}";
        doInstallCargoArtifacts = false;
        installPhaseCommand = "mkdir -p $out";
      }
      // args);
in rec {
  checks = {
    clippy = craneLib.cargoClippy (common
      // {
        pname = "improvise-clippy";
        cargoArtifacts = nativeDeps;
        cargoClippyExtraArgs = "--workspace --all-targets -- -D warnings";
      });

    # The evidence gate runs `cargo test --workspace -- --list`, so it runs
    # here, where the tests are already compiled, not as a separate step.
    test = craneLib.cargoTest (common
      // {
        pname = "improvise-test";
        cargoArtifacts = nativeDeps;
        cargoTestExtraArgs = "--workspace";
        nativeBuildInputs = [pkgs.python3 pkgs.git];
        # tests/shipped_documents_load.rs walks the git index (`git ls-files`)
        # and makes scratch repos. The flake source is exactly the tracked
        # files, so force-adding all of it (but crane's target/) rebuilds the
        # checkout's index, ignored-but-tracked documents included.
        preBuild = ''
          export HOME=$TMPDIR
          export GIT_AUTHOR_NAME=nix GIT_AUTHOR_EMAIL=nix@localhost
          export GIT_COMMITTER_NAME=nix GIT_COMMITTER_EMAIL=nix@localhost
          git init -q .
          git add --all --force -- . ':!target'
        '';
        postBuild = ''
          python3 scripts/check-comment-runs.py --check-evidence
        '';
      });

    wasm-check = cargoCheck "wasm-check" {
      cargoArtifacts = wasmCheckDeps;
      buildPhaseCargoCommand = lib.concatMapStringsSep "\n" (c: ''
        echo "== ${c}"
        cargo check --locked -p ${c} --target ${wasmTarget}
      '')
      wasmCrates;
    };

    # harness/opfs-contract is its own workspace, so the root clippy never
    # reaches it; `-p` keeps cargo fmt to this one crate (see ci.yml).
    harness-lint = cargoCheck "harness-lint" {
      cargoArtifacts = null;
      buildPhaseCargoCommand = ''
        cd harness/opfs-contract
        cargo fmt -p opfs-contract -- --check
        cargo clippy --locked --target ${wasmTarget} --all-targets -- -D warnings
      '';
    };
  };

  packages = {
    # The dependency builds on their own, for titan's cache timer to keep as a
    # GC root: the checks' outputs do not reference them, so rooting only the
    # checks would let the part a PR actually reuses be collected.
    ci-deps = pkgs.linkFarmFromDrvs "improvise-ci-deps" [nativeDeps wasmCheckDeps bundleDeps];

    # harness/build.sh, unchanged: the three wasm bundles and harness/serve.
    # No network: wasm-bindgen and wasm-opt come from PATH, so wasm-pack
    # downloads nothing (see wasmBindgenCli in flake.nix).
    web = craneLib.mkCargoDerivation (common
      // {
        pname = "improvise-web";
        cargoArtifacts = bundleDeps;
        doInstallCargoArtifacts = false;
        nativeBuildInputs = [pkgs.wasm-pack wasmBindgenCli pkgs.binaryen pkgs.nodejs_24];
        # web/assemble.sh calls scripts/assemble-stamp.sh, whose
        # `#!/usr/bin/env bash` has no interpreter in the sandbox. Patching
        # this private copy is harmless: no checker runs here.
        postPatch = "patchShebangs scripts web harness";
        buildPhaseCargoCommand = ''
          export HOME=$TMPDIR
          ./harness/build.sh
        '';
        installPhaseCommand = ''
          mkdir -p $out
          cp -r harness/serve $out/harness-serve
          cp -r web/pkg web/worker-pkg $out/
        '';
      });

    # The Pages tree, stamped with the commit it was built from. Separate from
    # `web` so the stamp changing every commit does not rebuild the bundles.
    site =
      pkgs.runCommand "improvise-site" {
        nativeBuildInputs = [pkgs.nodejs_24];
      } ''
        cp -r ${src} tree
        chmod -R u+w tree
        patchShebangs tree/scripts tree/web
        cp -r ${packages.web}/pkg ${packages.web}/worker-pkg tree/web/
        chmod -R u+w tree/web
        cd tree
        ./web/assemble.sh $out ${rev}
      '';
  };
}