Restore fnm availability after suitup rewrites shell config (#23)

- [x] Re-check the reviewer comment and confirm the remaining requested
changes
- [x] Re-inspect the setup, frontend installer, and install.sh flows
before editing
- [x] Fix fnm installation success/failure handling and add Homebrew
fallback when available
- [x] Detect existing suitup-managed state and avoid preselecting
already-completed setup steps
- [x] Add an init vs append choice to install.sh and cover it with
focused tests
- [x] Run targeted tests for the touched areas, review the final diff,
and update the PR title/comment reply

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Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: ChangeHow <23733347+ChangeHow@users.noreply.github.com>

Author: Copilot

README.md

@@ -36,6 +36,7 @@ Suitup can bootstrap Zsh and Homebrew for you, but the most reliable path is to
 - Recommended: install Homebrew first so later package/tool steps run in a known-good environment
 - Optional: if you skip either one, keep the `Bootstrap` step selected and let suitup set them up for you
 - If your setup stopped halfway, run `node src/cli.js append` to add missing blocks or switch the prompt preset without replacing your whole `.zshrc`
+- When suitup detects existing suitup-managed config or already-installed frontend prerequisites, setup now deselects those completed steps by default so reruns stay focused
 
 ### Install and run
 
@@ -47,14 +48,20 @@ Suitup now assumes zsh is already installed and that you are running the command
 curl -fsSL https://raw.githubusercontent.com/ChangeHow/suitup/main/install.sh | bash
 ```
 
-The installer downloads a temporary copy of the repo, runs `npm ci`, and then launches `node src/cli.js` inside `zsh`.
+The installer first asks whether you want `init` (full setup) or `append` (incremental updates to an existing `.zshrc`), then downloads a temporary copy of the repo, runs `npm ci`, and launches the matching `node src/cli.js` command inside `zsh`.
 
 You can also pass a specific command to the installer:
 
 ```bash
 curl -fsSL https://raw.githubusercontent.com/ChangeHow/suitup/main/install.sh | bash -s -- clean
 ```
 
+If you want append mode directly without the prompt:
+
+```bash
+curl -fsSL https://raw.githubusercontent.com/ChangeHow/suitup/main/install.sh | bash -s -- append
+```
+
 ### Clone locally
 
 ```bash
@@ -104,7 +111,7 @@ Bootstrap details:
 - Linux: choose `apt-get`, `dnf`, `yum`, `brew`, or skip
 - If Homebrew is already installed in a non-default location, suitup now tries common shellenv paths automatically during Zsh startup
 - Suitup now also writes a minimal `~/.zshenv` so non-interactive shells can still load shared env vars and PATH setup
-- When fnm installs Node.js, suitup sets the installed version as the fnm default so `node`, `npm`, and globally installed CLIs resolve from the fnm-managed location in both interactive and non-interactive shells
+- When fnm installs Node.js, suitup keeps both the `fnm` binary and the installed default Node version on PATH so `fnm`, `node`, `npm`, and globally installed CLIs resolve correctly in both interactive and non-interactive shells
 
 ### Append
 

README.zh-CN.md

@@ -36,6 +36,7 @@ Suitup 可以帮你初始化 Zsh 和 Homebrew，但更稳妥的路径仍然是
 - 推荐：先安装 Homebrew，这样后续包管理和工具安装会更稳定
 - 可选：如果你不想手动准备，也可以保留 `Bootstrap` 步骤，让 suitup 代为安装
 - 如果初始化做到一半中断了，可以运行 `node src/cli.js append` 继续补齐缺失配置，或者切换 prompt 预设，而不必整体重写 `.zshrc`
+- 如果 suitup 检测到本地已经存在 suitup 管理的配置，或者前端工具链已经装好，setup 现在会默认把这些已完成步骤反选掉，方便你只补剩余内容
 
 ### 安装并运行
 
@@ -47,14 +48,20 @@ suitup 现在默认你已经安装好 zsh，并且当前就在 zsh 会话里运
 curl -fsSL https://raw.githubusercontent.com/ChangeHow/suitup/main/install.sh | bash
 ```
 
-这个安装脚本会临时下载仓库、执行 `npm ci`，然后在 `zsh` 中启动 `node src/cli.js`。
+这个安装脚本会先询问你要走 `init`（完整 setup）还是 `append`（给现有 `.zshrc` 做增量补充），然后临时下载仓库、执行 `npm ci`，最后在 `zsh` 中启动对应的 `node src/cli.js` 命令。
 
 如果你想直接执行某个命令，也可以这样传参：
 
 ```bash
 curl -fsSL https://raw.githubusercontent.com/ChangeHow/suitup/main/install.sh | bash -s -- clean
 ```
 
+如果你想跳过提示、直接进入 append 模式，也可以这样运行：
+
+```bash
+curl -fsSL https://raw.githubusercontent.com/ChangeHow/suitup/main/install.sh | bash -s -- append
+```
+
 ### 本地 clone 运行
 
 ```bash
@@ -104,7 +111,7 @@ Bootstrap 细节：
 - Linux：可选 `apt-get`、`dnf`、`yum`、`brew`，或直接跳过
 - 如果 Homebrew 已经安装在非默认位置，suitup 现在会在 Zsh 启动时自动尝试常见 `shellenv` 路径
 - suitup 现在也会生成一个精简的 `~/.zshenv`，保证非交互式 shell 也能加载共享环境变量和 PATH
-- 当 fnm 安装 Node.js 后，suitup 会把该版本设置为 fnm 默认版本，确保交互式/非交互式 shell 下的 `node`、`npm` 和全局 CLI 都优先指向 fnm 管理的路径
+- 当 fnm 安装 Node.js 后，suitup 会把 `fnm` 自身和该默认 Node 版本一起放进 PATH，确保交互式/非交互式 shell 下的 `fnm`、`node`、`npm` 和全局 CLI 都优先指向 fnm 管理的路径
 
 ### Append（追加）
 

configs/core/paths.zsh

@@ -16,14 +16,20 @@ do
 done
 unset _suitup_brew_bin
 
-# fnm (Fast Node Manager) — expose the default Node installation to all
-# shells so that globally-installed CLIs (pnpm, git-cz …) work in
-# non-interactive contexts such as scripts, editors, agents, and git hooks.
-# Interactive shells get the full fnm env from shared/tools.zsh instead.
-_suitup_fnm_default_bin="${FNM_DIR:-${XDG_DATA_HOME:-$HOME/.local/share}/fnm}/aliases/default/bin"
+# fnm (Fast Node Manager) — keep the fnm binary itself on PATH after suitup
+# rewrites ~/.zshrc, then expose the default Node installation to all shells
+# so globally-installed CLIs (pnpm, git-cz …) work in non-interactive
+# contexts such as scripts, editors, agents, and git hooks. Interactive
+# shells get the full fnm env from shared/tools.zsh instead.
+_suitup_fnm_dir="${FNM_DIR:-${XDG_DATA_HOME:-$HOME/.local/share}/fnm}"
+if [[ -d "$_suitup_fnm_dir" && ":${PATH}:" != *":${_suitup_fnm_dir}:"* ]]; then
+  export PATH="${_suitup_fnm_dir}:${PATH}"
+fi
+
+_suitup_fnm_default_bin="${_suitup_fnm_dir}/aliases/default/bin"
 if [[ -d "$_suitup_fnm_default_bin" && ":${PATH}:" != *":${_suitup_fnm_default_bin}:"* ]]; then
   export PATH="${_suitup_fnm_default_bin}:${PATH}"
 fi
-unset _suitup_fnm_default_bin
+unset _suitup_fnm_dir _suitup_fnm_default_bin
 
 # Keep this file for user PATH overrides if needed.

install.sh

@@ -37,6 +37,31 @@ if (major < 18) {
 }
 '
 
+CLI_COMMAND="${1:-}"
+if [[ -n "${CLI_COMMAND}" ]]; then
+  shift
+  if [[ "${CLI_COMMAND}" == "init" ]]; then
+    CLI_COMMAND="setup"
+  fi
+else
+  echo "Choose install mode:"
+  echo "  1) init   - full interactive setup"
+  echo "  2) append - incremental config updates for an existing ~/.zshrc"
+  read -r -p "Select [1-2] (default 1): " INSTALL_MODE < /dev/tty
+  case "${INSTALL_MODE:-1}" in
+    1)
+      CLI_COMMAND="setup"
+      ;;
+    2)
+      CLI_COMMAND="append"
+      ;;
+    *)
+      echo "Invalid selection: ${INSTALL_MODE}. Please enter 1 for init or 2 for append." >&2
+      exit 1
+      ;;
+  esac
+fi
+
 echo "Downloading ${REPO_SLUG}@${SUITUP_REF}..."
 curl --fail --show-error --silent --location "${ARCHIVE_URL}" --output "${ARCHIVE_PATH}"
 
@@ -49,4 +74,4 @@ cd "${WORK_DIR}/repo"
 npm ci --no-fund --no-audit
 
 echo "Launching suitup inside zsh..."
-zsh -lc 'cd "$1" && shift && node src/cli.js "$@"' -- "${WORK_DIR}/repo" "$@" < /dev/tty
+zsh -lc 'cd "$1" && shift && node src/cli.js "$@"' -- "${WORK_DIR}/repo" "${CLI_COMMAND}" "$@" < /dev/tty

src/setup.js

@@ -13,6 +13,8 @@ import { setupVim } from "./steps/vim.js";
 import { setupAliases } from "./steps/aliases.js";
 import { cleanDock } from "./steps/dock.js";
 import { setupZshConfig, writeZshrc, writeZshenv } from "./steps/zsh-config.js";
+import { readFileSafe } from "./utils/fs.js";
+import { commandExists } from "./utils/shell.js";
 import { isZshShell } from "./utils/shell-context.js";
 export { isZshShell } from "./utils/shell-context.js";
 
@@ -31,6 +33,87 @@ export function getDefaultSteps(platform = process.platform) {
   ];
 }
 
+function hasCompletedBootstrap(platform, commandExistsFn) {
+  if (!commandExistsFn("zsh")) {
+    return false;
+  }
+
+  if (platform === "darwin") {
+    return commandExistsFn("brew");
+  }
+
+  if (platform === "linux") {
+    return ["apt-get", "dnf", "yum", "brew"].some((manager) => commandExistsFn(manager));
+  }
+
+  return false;
+}
+
+export function detectCompletedSteps({
+  home = homedir(),
+  platform = process.platform,
+  commandExistsFn = commandExists,
+} = {}) {
+  const completed = new Set();
+  const zshConfigDir = join(home, ".config", "zsh");
+  const suitupDir = join(home, ".config", "suitup");
+  const xdgDataHome = process.env.XDG_DATA_HOME || join(home, ".local", "share");
+  const zinitHome = join(xdgDataHome, "zinit", "zinit.git");
+  const zshrc = readFileSafe(join(home, ".zshrc"));
+  const zshenv = readFileSafe(join(home, ".zshenv"));
+  const vimrc = readFileSafe(join(home, ".vimrc"));
+
+  if (hasCompletedBootstrap(platform, commandExistsFn)) {
+    completed.add("bootstrap");
+  }
+
+  if (
+    zshrc.includes("Generated by suitup") &&
+    zshenv.includes("Generated by suitup") &&
+    existsSync(join(zshConfigDir, "core", "perf.zsh")) &&
+    existsSync(join(zshConfigDir, "core", "env.zsh")) &&
+    existsSync(join(zshConfigDir, "core", "paths.zsh")) &&
+    existsSync(join(zshConfigDir, "core", "options.zsh")) &&
+    existsSync(join(zshConfigDir, "shared", "tools.zsh")) &&
+    existsSync(join(zshConfigDir, "shared", "prompt.zsh")) &&
+    existsSync(join(zshConfigDir, "local", "machine.zsh"))
+  ) {
+    completed.add("zsh-config");
+  }
+
+  if (existsSync(join(suitupDir, "zinit-plugins")) || existsSync(zinitHome)) {
+    completed.add("plugins");
+  }
+
+  if (existsSync(join(suitupDir, "aliases"))) {
+    completed.add("aliases");
+  }
+
+  if (
+    commandExistsFn("fnm") &&
+    commandExistsFn("node") &&
+    commandExistsFn("pnpm") &&
+    commandExistsFn("git-cz")
+  ) {
+    completed.add("frontend");
+  }
+
+  if (existsSync(join(home, ".ssh", "github_rsa"))) {
+    completed.add("ssh");
+  }
+
+  if (existsSync(join(suitupDir, "config.vim")) && vimrc.includes("config.vim")) {
+    completed.add("vim");
+  }
+
+  return [...completed];
+}
+
+export function getInitialStepValues(opts = {}) {
+  const completed = new Set(detectCompletedSteps(opts));
+  return getDefaultSteps(opts.platform).filter((step) => !completed.has(step));
+}
+
 export async function runSetup() {
   p.intro(pc.bgCyan(pc.black(" Suit up! ")));
 
@@ -42,6 +125,12 @@ export async function runSetup() {
   }
 
   // --- Step 1: Select setup steps ---
+  const completedSteps = detectCompletedSteps();
+  const initialValues = getInitialStepValues();
+  if (completedSteps.length > 0) {
+    p.log.info(`Deselected already configured steps: ${completedSteps.join(", ")}`);
+  }
+
   const steps = await p.multiselect({
     message: "Select setup steps:",
     required: true,
@@ -57,7 +146,7 @@ export async function runSetup() {
       { value: "vim", label: "Vim Config", hint: "basic vim setup" },
       { value: "dock", label: "Dock Cleanup", hint: "clean macOS Dock" },
     ],
-    initialValues: getDefaultSteps(),
+    initialValues,
   });
 
   if (p.isCancel(steps)) {

src/steps/frontend.js

@@ -1,17 +1,41 @@
 import * as p from "@clack/prompts";
-import { commandExists, run, runStream } from "../utils/shell.js";
+import { brewInstall, commandExists, run, runStream } from "../utils/shell.js";
+
+async function runStreamChecked(cmd) {
+  const exitCode = await runStream(cmd);
+  if (exitCode !== 0) {
+    throw new Error(`Command failed with exit code ${exitCode}: ${cmd}`);
+  }
+}
 
 /**
  * Install fnm (Fast Node Manager) and set up Node.js + pnpm.
  */
 export async function installFrontendTools() {
+  let fnmReady = commandExists("fnm");
+
   // fnm
-  if (commandExists("fnm")) {
+  if (fnmReady) {
     p.log.success("fnm is already installed");
   } else {
     p.log.step("Installing fnm...");
-    await runStream("curl -fsSL https://fnm.vercel.app/install | bash");
-    p.log.success("fnm installed");
+    try {
+      await runStreamChecked("curl -fsSL https://fnm.vercel.app/install | bash");
+      p.log.success("fnm installed");
+      fnmReady = true;
+    } catch {
+      if (commandExists("brew")) {
+        p.log.warn("Could not install fnm via curl, trying Homebrew...");
+        if (brewInstall("fnm")) {
+          p.log.success("fnm installed via Homebrew");
+          fnmReady = true;
+        } else {
+          p.log.warn("Could not install fnm via curl or Homebrew");
+        }
+      } else {
+        p.log.warn("Could not install fnm via curl, and Homebrew is not available");
+      }
+    }
   }
 
   // Fetch latest LTS version
@@ -27,12 +51,16 @@ export async function installFrontendTools() {
   }
 
   // Install Node via fnm
-  p.log.step(`Installing Node.js v${ltsVersion} via fnm...`);
-  try {
-    await runStream(`fnm install ${ltsVersion} && fnm use ${ltsVersion} && fnm default ${ltsVersion}`);
-    p.log.success(`Node.js v${ltsVersion} installed`);
-  } catch {
-    p.log.warn("Could not install Node.js — fnm may need a shell restart first");
+  if (fnmReady) {
+    p.log.step(`Installing Node.js v${ltsVersion} via fnm...`);
+    try {
+      await runStreamChecked(`fnm install ${ltsVersion} && fnm use ${ltsVersion} && fnm default ${ltsVersion}`);
+      p.log.success(`Node.js v${ltsVersion} installed`);
+    } catch {
+      p.log.warn("Could not install Node.js — fnm may need a shell restart first");
+    }
+  } else {
+    p.log.warn("Skipping Node.js install because fnm is unavailable");
   }
 
   // pnpm

tests/configs.test.js

@@ -122,9 +122,11 @@ describe("Static config templates", () => {
     expect(content).toContain("shellenv zsh");
   });
 
-  test("core/paths.zsh exposes fnm default node for non-interactive shells", () => {
+  test("core/paths.zsh keeps fnm and its default node on PATH for non-interactive shells", () => {
     const content = readFileSync(join(CONFIGS_DIR, "core", "paths.zsh"), "utf-8");
     expect(content).toContain("fnm");
+    expect(content).toContain("_suitup_fnm_dir");
+    expect(content).toContain(".local/share}/fnm");
     expect(content).toContain("aliases/default/bin");
     // Should check for PATH deduplication
     expect(content).toContain(":${PATH}:");

tests/frontend.test.js

@@ -14,7 +14,10 @@ vi.mock("../src/utils/shell.js", () => ({
 }));
 
 import { installFrontendTools } from "../src/steps/frontend.js";
-import { commandExists, run, runStream } from "../src/utils/shell.js";
+import { brewInstall, commandExists, run, runStream } from "../src/utils/shell.js";
+import * as p from "@clack/prompts";
+
+const CURL_HTTP_ERROR_CODE = 22;
 
 describe("frontend step", () => {
   beforeEach(() => {
@@ -48,6 +51,38 @@ describe("frontend step", () => {
     expect(calls.some((c) => c.includes("fnm.vercel.app"))).toBe(true);
   });
 
+  test("falls back to Homebrew when fnm curl install fails", async () => {
+    commandExists.mockImplementation((name) => {
+      if (name === "fnm") return false;
+      if (name === "brew") return true;
+      return true;
+    });
+    runStream.mockImplementationOnce(() => Promise.resolve(CURL_HTTP_ERROR_CODE));
+    brewInstall.mockReturnValue(true);
+
+    await installFrontendTools();
+
+    expect(brewInstall).toHaveBeenCalledWith("fnm");
+    expect(p.log.success).not.toHaveBeenCalledWith("fnm installed");
+    expect(p.log.warn).toHaveBeenCalledWith("Could not install fnm via curl, trying Homebrew...");
+    expect(p.log.success).toHaveBeenCalledWith("fnm installed via Homebrew");
+  });
+
+  test("warns when fnm curl install fails and Homebrew is unavailable", async () => {
+    commandExists.mockImplementation((name) => {
+      if (name === "fnm" || name === "brew") return false;
+      return true;
+    });
+    runStream.mockImplementationOnce(() => Promise.resolve(CURL_HTTP_ERROR_CODE));
+
+    await installFrontendTools();
+
+    expect(brewInstall).not.toHaveBeenCalled();
+    expect(p.log.success).not.toHaveBeenCalledWith("fnm installed");
+    expect(p.log.warn).toHaveBeenCalledWith("Could not install fnm via curl, and Homebrew is not available");
+    expect(p.log.warn).toHaveBeenCalledWith("Skipping Node.js install because fnm is unavailable");
+  });
+
   test("sets fnm default after installing node", async () => {
     commandExists.mockReturnValue(true);