nixpkgs/overlays/mods/n8n.nix

{prev}: let
  # n8n >= 2.32 replaced the sheetjs-CDN `xlsx@0.20.2` tarball (which lacked an
  # integrity checksum and had to be patched into pnpm-lock.yaml) with the
  # regular npm package `@e965/xlsx@0.20.3`, which already carries an integrity
  # field. The old lockfile-integrity workaround is therefore obsolete and has
  # been removed.
  #
  # n8n >= 2.37.0 demands pnpm >= 11.22.0 via `engines.pnpm`, but the pinned
  # nixpkgs only ships pnpm_10 (10.34.5) and pnpm_11 (11.17.0) — both too old.
  # pnpm enforces that gate for ITSELF regardless of `engine-strict`, so both
  # fetchPnpmDeps and the main build die with ERR_PNPM_UNSUPPORTED_ENGINE
  # before any hash mismatch is even reached. Additionally n8n's lockfile,
  # while still declaring lockfileVersion '9.0', now serialises
  # patchedDependencies as plain `name@version: hash` scalars (no `path:`
  # mapping), which pnpm 10 cannot parse (ERR_PNPM_LOCKFILE_CONFIG_MISMATCH).
  # We therefore build with pnpm_11 + fetcherVersion 4 and relax the engine
  # gate in package.json. Drop the sed once nixpkgs ships pnpm >= 11.22 and
  # this overlay's nixpkgs pin has caught up.
  relaxPnpmEngine = ''
    sed -i -E 's/"pnpm": *"[^"]*"/"pnpm": "*"/' package.json
  '';
in
  prev.n8n.overrideAttrs (finalAttrs: previousAttrs: {
    version = "2.38.7";

    src = prev.fetchFromGitHub {
      owner = "n8n-io";
      repo = "n8n";
      tag = "n8n@${finalAttrs.version}";
      hash = "sha256-APKju7+jHw2fET+1FDFi8EhAQ3ZJRVzy8LwPgLm3Bbc=";
    };

    pnpmDeps = prev.fetchPnpmDeps {
      inherit (finalAttrs) pname version src;
      pnpm = prev.pnpm_11;
      fetcherVersion = 4;
      postPatch = relaxPnpmEngine;
      hash = "sha256-0k3h5dcVPzLpZoYstJkFrXrcP4kmB0A2Q0YdAdmfOGs=";
    };

    postPatch = (previousAttrs.postPatch or "") + relaxPnpmEngine;

    # Swap pnpm_10 -> pnpm_11 from the inherited nativeBuildInputs: upstream
    # n8n calls pnpm directly during the build (install/build/prune) and pnpm 10
    # cannot parse the pnpm-11 lockfile. The top-level pnpmConfigHook stays as
    # is — it discovers the fetcher version from pnpmDeps' .fetcher-version.
    nativeBuildInputs = builtins.map (x:
      if (x.outPath or null) == prev.pnpm_10.outPath
      then prev.pnpm_11
      else x)
    previousAttrs.nativeBuildInputs;

    preBuild =
      (previousAttrs.preBuild or "")
      + ''
        if [ ! -e node_modules/sass-embedded ] && [ -e node_modules/.pnpm/node_modules/sass-embedded ]; then
          ln -s .pnpm/node_modules/sass-embedded node_modules/sass-embedded
        fi
        if [ ! -e node_modules/sqlite3 ] && [ -e node_modules/.pnpm/node_modules/sqlite3 ]; then
          ln -s .pnpm/node_modules/sqlite3 node_modules/sqlite3
        fi
      '';

    # Self-contained update script (./update.sh) — fetches latest stable
    # release from n8n-io/n8n, recomputes both src and pnpmDeps hashes.
    # The CI workflow in .gitea/workflows/nix-update.yml discovers and runs it.
    passthru = (previousAttrs.passthru or {}) // {updateScript = ./update.sh;};

    meta =
      previousAttrs.meta
      // {
        changelog = "https://github.com/n8n-io/n8n/releases/tag/n8n@${finalAttrs.version}";
      };
  })