fix: upgrade devDependencies and migrate to eslint 10 flat config

- Upgrade eslint 8.31 → 10.1 with new flat config (eslint.config.js)
- Upgrade @vercel/ncc 0.36 → 0.38.4
- Replace eslint-config-airbnb-base + eslint-plugin-import with @eslint/js + @stylistic/eslint-plugin
- Remove stale overrides in package.json (word-wrap, semver)
- Remove obsolete eslint-disable comments from source files
- Add { cause } to rethrown error in rsyncCli.js
- Add .gitignore and CLAUDE.md
- Resolves all 3 npm audit vulnerabilities (flatted, minimatch, js-yaml)

.eslintrc.js

@@ -1,25 +0,0 @@
-module.exports = {
-  env: {
-    commonjs: true,
-    es6: true,
-    node: true
-  },
-  extends: [
-    'airbnb-base'
-  ],
-  globals: {
-    Atomics: 'readonly',
-    SharedArrayBuffer: 'readonly'
-  },
-  parserOptions: {
-    ecmaVersion: 2018
-  },
-  rules: {
-    'comma-dangle': [
-      'error',
-      'never'
-    ],
-    'no-console': 'off',
-    'object-curly-newline': 'off'
-  }
-};

.gitignore

@@ -20,3 +20,6 @@ node_modules/
 # IDE
 .idea
 .vscode
+
+# AI
+.claude/settings.local.json

CLAUDE.md

@@ -0,0 +1,40 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project Overview
+
+GitHub Action for deploying files via rsync over SSH, with optional remote script execution before/after deployment. Published as `easingthemes/ssh-deploy` on the GitHub Marketplace.
+
+## Commands
+
+- **Build (lint + bundle):** `npm run build`
+- **Lint only:** `npm run lint`
+- **Lint with autofix:** `npm run lint:fix`
+- **No unit test suite** — testing is done via e2e workflows in CI (Docker-based SSH server, see `.github/workflows/e2e.yml`)
+
+The build step runs ESLint then bundles `src/index.js` into `dist/index.js` using `@vercel/ncc`. The `dist/index.js` is the actual entrypoint executed by GitHub Actions (defined in `action.yml`).
+
+## Architecture
+
+The action runs as a single Node.js 24 process with this execution flow:
+
+1. **`src/inputs.js`** — Reads all config from environment variables (both `INPUT_*` and bare names). Converts `SNAKE_CASE` input names to `camelCase`. Splits multi-value inputs: `SOURCE` and `ARGS` on spaces, `EXCLUDE` and `SSH_CMD_ARGS` on commas. Prepends `GITHUB_WORKSPACE` to source paths. Exports a single `inputs` object used by all other modules.
+
+2. **`src/index.js`** — Orchestration entry point. Pipeline: validate inputs → write SSH key → optionally update known_hosts → run SCRIPT_BEFORE → rsync → run SCRIPT_AFTER.
+
+3. **`src/sshKey.js`** — Writes the SSH private key to `~/.ssh/<deploy_key_name>` with mode `0400`. Creates `known_hosts` file. Uses `ssh-keyscan` to add the remote host when before/after scripts are configured.
+
+4. **`src/rsyncCli.js`** — Validates rsync is installed (auto-installs via apt-get if missing). Uses the local `src/rsync.js` module (child_process.spawn) to execute the rsync transfer.
+
+5. **`src/remoteCmd.js`** — Writes script content to a temporary `.sh` file in the workspace, executes it on the remote host via `ssh ... 'bash -s' < script.sh`, then deletes the local script file. Passes `RSYNC_STDOUT` env var to after-scripts.
+
+6. **`src/helpers.js`** — File I/O utilities (`writeToFile`, `deleteFile`), input validation, and `snakeToCamel` converter.
+
+## Key Conventions
+
+- **CommonJS modules** — the project uses `require`/`module.exports`, not ES modules.
+- **ESLint 10 flat config** (`eslint.config.js`) — uses `@eslint/js` recommended + `@stylistic/eslint-plugin` for formatting. Notable rules: no trailing commas, `console` is allowed.
+- **Semantic release** on `main` branch via `.releaserc` — use conventional commit messages (`fix:`, `feat:`, etc.). npm publish is disabled; releases are git tags + changelog only.
+- **`dist/index.js` must be committed** — it's the bundled action entrypoint. Run `npm run build` and commit the updated dist after any source changes.
+- **Inputs are environment variables**, not `@actions/core` — the action reads directly from `process.env` rather than using the GitHub Actions toolkit.

eslint.config.js

@@ -0,0 +1,52 @@
+const js = require('@eslint/js');
+const stylistic = require('@stylistic/eslint-plugin');
+const globals = require('globals');
+
+module.exports = [
+  js.configs.recommended,
+  {
+    plugins: {
+      '@stylistic': stylistic
+    },
+    languageOptions: {
+      ecmaVersion: 2020,
+      sourceType: 'commonjs',
+      globals: {
+        ...globals.node,
+        ...globals.commonjs,
+        ...globals.es2020,
+        Atomics: 'readonly',
+        SharedArrayBuffer: 'readonly'
+      }
+    },
+    rules: {
+      // Stylistic rules (migrated from airbnb-base)
+      '@stylistic/comma-dangle': ['error', 'never'],
+      '@stylistic/indent': ['error', 2, { SwitchCase: 1 }],
+      '@stylistic/semi': ['error', 'always'],
+      '@stylistic/quotes': ['error', 'single', { avoidEscape: true }],
+      '@stylistic/arrow-parens': ['error', 'always'],
+      '@stylistic/brace-style': ['error', '1tbs', { allowSingleLine: true }],
+      '@stylistic/comma-spacing': ['error', { before: false, after: true }],
+      '@stylistic/key-spacing': ['error', { beforeColon: false, afterColon: true }],
+      '@stylistic/keyword-spacing': ['error', { before: true, after: true }],
+      '@stylistic/eol-last': ['error', 'always'],
+      '@stylistic/no-trailing-spaces': 'error',
+      '@stylistic/space-before-blocks': 'error',
+      '@stylistic/space-infix-ops': 'error',
+      '@stylistic/arrow-spacing': ['error', { before: true, after: true }],
+
+      // JS rules (migrated from airbnb-base)
+      'no-console': 'off',
+      'no-var': 'error',
+      'prefer-const': 'error',
+      'prefer-arrow-callback': 'error',
+      'prefer-template': 'error',
+      'object-shorthand': ['error', 'always'],
+      'no-shadow': 'error',
+      'no-use-before-define': ['error', { functions: true, classes: true, variables: true }],
+      'camelcase': ['error', { properties: 'never' }],
+      'no-unused-vars': ['error', { vars: 'all', args: 'after-used', ignoreRestSiblings: true }]
+    }
+  }
+];

package.json

@@ -30,13 +30,10 @@
   },
   "homepage": "https://github.com/easingthemes/ssh-deploy#readme",
   "devDependencies": {
-    "@vercel/ncc": "^0.36.0",
-    "eslint": "^8.30.0",
-    "eslint-config-airbnb-base": "^15.0.0",
-    "eslint-plugin-import": "^2.26.0"
-  },
-  "overrides": {
-    "word-wrap": "npm:@aashutoshrathi/word-wrap@1.2.5",
-    "semver": "^7.5.2"
+    "@eslint/js": "^10.0.1",
+    "@stylistic/eslint-plugin": "^5.10.0",
+    "@vercel/ncc": "^0.38.4",
+    "eslint": "^10.1.0",
+    "globals": "^17.4.0"
   }
 }

src/index.js

@@ -27,7 +27,6 @@ const run = async () => {
   if (scriptBefore) {
     await remoteCmdBefore(scriptBefore, privateKeyPath, scriptBeforeRequired);
   }
-  /* eslint-disable object-property-newline */
   await sshDeploy({
     source, rsyncServer, exclude, remotePort,
     privateKeyPath, args, sshCmdArgs

src/inputs.js

@@ -27,7 +27,6 @@ inputNames.forEach((input) => {
   const inputVal = process.env[input] || process.env[`INPUT_${input}`] || defaultInputs[inputName];
   const validVal = inputVal === undefined ? defaultInputs[inputName] : inputVal;
   let extendedVal = validVal;
-  // eslint-disable-next-line default-case
   switch (inputName) {
     case 'source':
       extendedVal = validVal.split(' ').map((src) => `${githubWorkspace}/${src}`);

src/remoteCmd.js

@@ -11,7 +11,6 @@ const handleError = (message, isRequired, callback) => {
   }
 };
 
-// eslint-disable-next-line max-len
 const remoteCmd = async (content, privateKeyPath, isRequired, label) => new Promise((resolve, reject) => {
   const uuid = crypto.randomUUID();
   const filename = `local_ssh_script-${label}-${uuid}.sh`;

src/rsyncCli.js

@@ -46,7 +46,7 @@ const validateRsync = async () => {
     execSync('sudo DEBIAN_FRONTEND=noninteractive apt-get -y update && sudo DEBIAN_FRONTEND=noninteractive apt-get --no-install-recommends -y install rsync', { stdio: 'inherit' });
     console.log('✅ [CLI] Rsync installed. \n');
   } catch (error) {
-    throw new Error(`⚠️ [CLI] Rsync installation failed. Aborting ... error: ${error.message}`);
+    throw new Error(`⚠️ [CLI] Rsync installation failed. Aborting ... error: ${error.message}`, { cause: error });
   }
 };
 
@@ -65,7 +65,6 @@ const rsyncCli = async ({
   };
 
   // RSYNC COMMAND
-  /* eslint-disable object-property-newline */
   return nodeRsyncPromise({
     ...defaultOptions,
     src: source, dest: rsyncServer, excludeFirst: exclude, port: remotePort,