feat(lib): Add support for flat workspace layout

bin/cli.js

@@ -32,6 +32,7 @@ const {
   removeHuskyDefaultPreCommitIfPresent,
   mergePackageJsonForAiCommit,
   warnIfPrepareMissingHusky,
+  initWorkspaceFlat,
 } = require("../lib/init-workspace.js");
 
 function presetPath() {
@@ -195,6 +196,14 @@ function cmdInit(argv) {
     return;
   }
 
+  // --workspace (subdir layout): install the flat, husky-free CN layout at the git root —
+  // git-config core.hooksPath + committed normalized hooks + a root package.json (created if
+  // absent) carrying a commit delegator and a git-config prepare. No husky is needed at the root.
+  if (workspace && path.resolve(packageRoot) !== path.resolve(gitRoot)) {
+    initWorkspaceFlat({ cwd, gitRoot, packageRoot, force });
+    return;
+  }
+
   let { dir: huskyDir } = resolveGitHooksDir(gitRoot);
   let ranHuskyInit = false;
 

lib/init-workspace.js

@@ -143,16 +143,25 @@ function huskyRunnerSourceLine(hooksDirAbs) {
  * @returns {{ cdBlock: string, cmd: string }}
  */
 function userHookCommands(packageRoot, gitRoot, execPrefix, hook) {
-  const cmd =
-    hook === "prepare-commit-msg"
-      ? `${execPrefix} ai-commit prepare-commit-msg "$1" "$2"`
-      : `${execPrefix} ai-commit lint --edit "$1"`;
   const pkgNorm = path.resolve(packageRoot);
   const gitNorm = path.resolve(gitRoot);
+  const nested = pkgNorm !== gitNorm;
+  // Git passes the message-file path relative to the worktree root. When the hook cd's
+  // into a subdir (workspace layout) that relative path no longer resolves, so absolutize
+  // it first ($msg); at the git root the raw "$1" is already correct.
+  const msgArg = nested ? '"$msg"' : '"$1"';
+  const cmd =
+    hook === "prepare-commit-msg"
+      ? `${execPrefix} ai-commit prepare-commit-msg ${msgArg} "$2"`
+      : `${execPrefix} ai-commit lint --edit ${msgArg}`;
   let cdBlock = "";
-  if (pkgNorm !== gitNorm) {
+  if (nested) {
     const rel = path.relative(gitNorm, pkgNorm).split(path.sep).join("/");
-    cdBlock = `root="$(git rev-parse --show-toplevel)"\ncd "$root/${rel}"\n`;
+    cdBlock =
+      `root="$(git rev-parse --show-toplevel)"\n` +
+      `msg="$1"\n` +
+      `case "$msg" in\n  /*) ;;\n  *) msg="$root/$msg" ;;\nesac\n` +
+      `cd "$root/${rel}"\n`;
   }
   return { cdBlock, cmd };
 }
@@ -360,9 +369,156 @@ function warnIfPrepareMissingHusky(packageJsonPath) {
   }
 }
 
+/**
+ * Root `prepare` for the flat (`core.hooksPath=.husky`) workspace layout: point Git at the
+ * committed hooks with plain git config — no husky is needed at the repo root, and a fresh
+ * clone re-activates hooks on install. The `git rev-parse` guard makes it a no-op outside a
+ * work tree (e.g. when installed as a dependency / in a tarball).
+ * @returns {string}
+ */
+function workspaceRootPrepareScript() {
+  return "git rev-parse --git-dir > /dev/null 2>&1 && git config core.hooksPath .husky || true";
+}
+
+/**
+ * `<pm> commit` delegator that runs the subdir's `commit` script from the repo root.
+ * @param {string} pm  pnpm | npm | yarn | bun
+ * @param {string} subdirRel  POSIX-relative subdir path
+ * @returns {string}
+ */
+function commitDelegator(pm, subdirRel) {
+  switch (pm) {
+    case "yarn":
+      return `yarn --cwd ${subdirRel} commit`;
+    case "npm":
+      return `npm --prefix ${subdirRel} run commit`;
+    case "bun":
+      return `bun --cwd ${subdirRel} run commit`;
+    default:
+      return `pnpm --dir ${subdirRel} commit`;
+  }
+}
+
+/**
+ * Add (missing-only) the flat-workspace root scripts — a `commit` delegator into the subdir and
+ * a git-config `prepare` — to the repo-root package.json, creating a minimal `{ private: true }`
+ * one if absent. Never clobbers an existing `commit`/`prepare`. @returns {{ changed: boolean }}
+ */
+function mergeWorkspaceRootPackageJson(rootPkgPath, subdirRel, pm) {
+  let pkg = {};
+  let existed = false;
+  try {
+    if (fs.statSync(rootPkgPath).isFile()) {
+      pkg = JSON.parse(fs.readFileSync(rootPkgPath, "utf8"));
+      existed = true;
+    }
+  } catch (_) {
+    /* absent — create a minimal private root */
+  }
+  if (pkg === null || typeof pkg !== "object" || Array.isArray(pkg)) {
+    throw new Error(`${rootPkgPath} is not a JSON object`);
+  }
+  let changed = !existed;
+  if (!existed && pkg.private === undefined) pkg.private = true;
+  pkg.scripts = pkg.scripts && typeof pkg.scripts === "object" ? pkg.scripts : {};
+  if (!pkg.scripts.commit) {
+    pkg.scripts.commit = commitDelegator(pm, subdirRel);
+    changed = true;
+  }
+  if (!pkg.scripts.prepare) {
+    pkg.scripts.prepare = workspaceRootPrepareScript();
+    changed = true;
+  }
+  if (changed) {
+    fs.writeFileSync(rootPkgPath, `${JSON.stringify(pkg, null, 2)}\n`, "utf8");
+  }
+  return { changed };
+}
+
+/**
+ * Install the flat, husky-free workspace hook layout (the "CN" pattern) at the git root:
+ *   - `core.hooksPath=.husky` via plain git config (no husky at the root; fresh clones
+ *     re-activate hooks from `prepare` alone);
+ *   - committed standalone hooks under `.husky/` that normalize the message path, cd into the
+ *     subdir, and run ai-commit;
+ *   - a root package.json (created `{ private: true }` if absent) with a `commit` delegator + a
+ *     git-config `prepare`;
+ *   - the subdir package.json wired for ai-commit (commit script + husky/dotenv devDeps).
+ * @param {{ cwd: string, gitRoot: string, packageRoot: string, force: boolean }} opts
+ */
+function initWorkspaceFlat({ cwd, gitRoot, packageRoot, force }) {
+  const huskyDir = path.join(gitRoot, ".husky");
+  const subdirRel = path
+    .relative(path.resolve(gitRoot), path.resolve(packageRoot))
+    .split(path.sep)
+    .join("/");
+  const execPrefix = detectPackageExec(packageRoot);
+  const pm = detectPackageInstallInfo(packageRoot, gitRoot).cmd.split(" ")[0];
+
+  const cfg = spawnSync("git", ["config", "core.hooksPath", ".husky"], { cwd: gitRoot });
+  if (cfg.status !== 0) {
+    process.stderr.write(
+      "warning: could not set core.hooksPath=.husky; run `git config core.hooksPath .husky` at the repo root.\n",
+    );
+  } else {
+    process.stdout.write("Set core.hooksPath=.husky (flat, husky-free layout).\n");
+  }
+
+  if (!fs.existsSync(huskyDir)) fs.mkdirSync(huskyDir, { recursive: true });
+  for (const abs of removeHuskyDefaultPreCommitIfPresent(gitRoot, huskyDir)) {
+    const rel = path.relative(cwd, abs) || path.basename(abs);
+    process.stdout.write(`Removed Husky default pre-commit (${rel}).\n`);
+  }
+
+  for (const hookKind of ["prepare-commit-msg", "commit-msg"]) {
+    const hookPath = path.join(huskyDir, hookKind);
+    if (fs.existsSync(hookPath) && !force) {
+      process.stderr.write(
+        `Skipped ${path.relative(cwd, hookPath)} (already exists). Use --force to overwrite.\n`,
+      );
+      continue;
+    }
+    fs.writeFileSync(hookPath, userHookScript(packageRoot, gitRoot, execPrefix, hookKind), {
+      encoding: "utf8",
+    });
+    try {
+      fs.chmodSync(hookPath, 0o755);
+    } catch {
+      /* ignore on platforms without chmod */
+    }
+    process.stdout.write(`Wrote ${path.relative(cwd, hookPath)}.\n`);
+  }
+
+  const subdirPkg = path.join(packageRoot, "package.json");
+  if (fs.existsSync(subdirPkg)) {
+    const { changed } = mergePackageJsonForAiCommit(subdirPkg);
+    if (changed) {
+      process.stdout.write(
+        "Updated subdir package.json (commit script + husky/dotenv devDependencies).\n",
+      );
+    }
+  } else {
+    process.stdout.write("No package.json in the subdir; skipped its merge (hooks still written).\n");
+  }
+
+  const rootPkg = path.join(gitRoot, "package.json");
+  const { changed: rootChanged } = mergeWorkspaceRootPackageJson(rootPkg, subdirRel, pm);
+  if (rootChanged) {
+    process.stdout.write(
+      `Wrote root package.json (commit delegator + git-config prepare) at ${path.relative(cwd, rootPkg) || "package.json"}.\n`,
+    );
+  }
+
+  process.stdout.write(`${formatPackageInstallLine(detectPackageInstallInfo(packageRoot, gitRoot), cwd)}\n`);
+}
+
 module.exports = {
   HUSKY_RANGE,
   DOTENV_RANGE,
+  initWorkspaceFlat,
+  mergeWorkspaceRootPackageJson,
+  workspaceRootPrepareScript,
+  commitDelegator,
   detectPackageExec,
   detectPackageInstallInfo,
   formatPackageInstallLine,