fix: PowerShell fallback when wmic is unavailable on Windows (0.6.1)

.github/workflows/lint.yml

@@ -14,7 +14,11 @@ jobs:
       - name: Setup repo
         uses: actions/checkout@v2
       - name: Setup node
-        uses: actions/setup-node@v1
+        uses: actions/setup-node@v4
+        with:
+          # Pinned: the legacy xo@0.20 toolchain crashes on modern Node
+          # (util.isDate was removed). Revisit when the toolchain is updated.
+          node-version: 14
       - name: Install dev dependencies
         run: |
           npm install --only=dev

.github/workflows/test-macos.yml

@@ -13,7 +13,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        node: [current, 16, 14, 12, 10, 8, 6, 4]
+        node: [current, 22, 20, 18]
     steps:
       - name: Setup repo
         uses: actions/checkout@v3

.github/workflows/test-ubuntu.yml

@@ -13,7 +13,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        node: [current, 16, 14, 12, 10, 8, 6, 4]
+        node: [current, 22, 20, 18]
     steps:
       - name: Setup repo
         uses: actions/checkout@v3

.github/workflows/test-windows.yml

@@ -8,12 +8,14 @@ on:
 
 jobs:
   test:
+    # windows-latest is Windows Server 2025, which ships without wmic, so the
+    # integration tests here run against the PowerShell fallback in lib/get.js.
     runs-on: windows-latest
     name: AVA & TSD & Benchmark & Codecov
     strategy:
       fail-fast: false
       matrix:
-        node: [current, 16, 14, 12, 10, 8, 6, 4]
+        node: [current, 22, 20, 18]
     steps:
       - name: Setup repo
         uses: actions/checkout@v3

lib/bin.js

@@ -42,7 +42,9 @@ function run(cmd, args, options, done) {
   ch.on('error', function(err) {
     if (executed) return;
     executed = true;
-    done(new Error(err));
+    // Pass the original error through so callers can inspect err.code
+    // (e.g. 'ENOENT' when the binary is missing) to decide on a fallback.
+    done(err);
   });
 
   ch.on('close', function(code) {

lib/get.js

@@ -15,6 +15,7 @@ var platformToMethod = {
 var methodToRequireFn = {
   ps: () => require('./ps'),
   wmic: () => require('./wmic'),
+  powershell: () => require('./powershell'),
 };
 
 var platform = os.platform();
@@ -36,6 +37,24 @@ function get(callback) {
           ' is not supported yet, please open an issue (https://github.com/simonepri/pidtree)'
       )
     );
+    return;
+  }
+
+  // On Windows wmic has been removed from recent versions (e.g. Windows 11
+  // 24H2 and Windows Server 2025). Try it first since it is faster when
+  // present, and fall back to PowerShell when the binary cannot be found.
+  if (method === 'wmic') {
+    var wmic = methodToRequireFn.wmic();
+    wmic(function(err, list) {
+      if (err && err.code === 'ENOENT') {
+        var powershell = methodToRequireFn.powershell();
+        powershell(callback);
+        return;
+      }
+
+      callback(err, list);
+    });
+    return;
   }
 
   var list = methodToRequireFn[method]();

lib/powershell.js

@@ -0,0 +1,70 @@
+'use strict';
+
+var os = require('os');
+var bin = require('./bin');
+
+// PowerShell command used to list every process as "<ppid> <pid>" lines.
+// Get-CimInstance is the supported replacement for the removed wmic utility
+// (see https://github.com/simonepri/pidtree/issues/20).
+// $ProgressPreference is silenced so PowerShell does not serialize its
+// progress stream (e.g. "Preparing modules for first use.") to stderr as
+// CLIXML, which would otherwise be treated as an error.
+var COMMAND =
+  "$ProgressPreference = 'SilentlyContinue'; " +
+  'Get-CimInstance -ClassName Win32_Process | ' +
+  'ForEach-Object { "$($_.ParentProcessId) $($_.ProcessId)" }';
+
+// The command is passed through -EncodedCommand (Base64 of the UTF-16LE
+// string) to avoid any cross-shell argument quoting issues on Windows.
+var ENCODED = Buffer.from(COMMAND, 'utf16le').toString('base64');
+
+/**
+ * Gets the list of all the pids of the system through PowerShell.
+ * Used as a fallback on Windows installations where wmic is not available
+ * (e.g. Windows 11 24H2 and Windows Server 2025).
+ * @param  {Function} callback(err, list)
+ */
+function powershell(callback) {
+  var args = ['-NoProfile', '-NonInteractive', '-EncodedCommand', ENCODED];
+  var options = {windowsHide: true};
+  bin('powershell', args, options, function(err, stdout, code) {
+    if (err) {
+      callback(err);
+      return;
+    }
+
+    if (code !== 0) {
+      callback(
+        new Error('pidtree powershell command exited with code ' + code)
+      );
+      return;
+    }
+
+    // Example of stdout
+    //
+    // 0 777
+    // 777 778
+    // 0 779
+
+    try {
+      stdout = stdout.split(os.EOL);
+
+      var list = [];
+      for (var i = 0; i < stdout.length; i++) {
+        stdout[i] = stdout[i].trim();
+        if (!stdout[i]) continue;
+        var parts = stdout[i].split(/\s+/);
+        var ppid = parseInt(parts[0], 10); // PPID
+        var pid = parseInt(parts[1], 10); // PID
+        if (isNaN(ppid) || isNaN(pid)) continue;
+        list.push([ppid, pid]);
+      }
+
+      callback(null, list);
+    } catch (error) {
+      callback(error);
+    }
+  });
+}
+
+module.exports = powershell;

package.json

@@ -1,6 +1,6 @@
 {
   "name": "pidtree",
-  "version": "0.6.0",
+  "version": "0.6.1",
   "description": "Cross platform children list of a PID",
   "license": "MIT",
   "homepage": "http://github.com/simonepri/pidtree#readme",

test/get.js

@@ -0,0 +1,83 @@
+import test from 'ava';
+import mockery from 'mockery';
+
+import pify from 'pify';
+
+test.before(() => {
+  mockery.enable({
+    warnOnReplace: false,
+    warnOnUnregistered: false,
+    useCleanCache: true,
+  });
+});
+
+test.beforeEach(() => {
+  mockery.resetCache();
+});
+
+test.after(() => {
+  mockery.disable();
+});
+
+function osMock(platform) {
+  return {
+    EOL: '\n',
+    platform: () => platform,
+    type: () => 'type',
+    release: () => 'release',
+  };
+}
+
+test('should use wmic on Windows when it is available', async t => {
+  mockery.registerMock('os', osMock('win32'));
+  mockery.registerMock('./wmic', cb => cb(null, [[0, 100], [100, 101]]));
+  mockery.registerMock('./powershell', () => {
+    t.fail('powershell should not be used when wmic succeeds');
+  });
+
+  const get = require('../lib/get');
+
+  const result = await pify(get)();
+  t.deepEqual(result, [[0, 100], [100, 101]]);
+
+  mockery.deregisterMock('os');
+  mockery.deregisterMock('./wmic');
+  mockery.deregisterMock('./powershell');
+});
+
+test('should fall back to powershell when wmic is missing on Windows', async t => {
+  const enoent = new Error('spawn wmic ENOENT');
+  enoent.code = 'ENOENT';
+
+  mockery.registerMock('os', osMock('win32'));
+  mockery.registerMock('./wmic', cb => cb(enoent));
+  mockery.registerMock('./powershell', cb => cb(null, [[0, 777], [777, 778]]));
+
+  const get = require('../lib/get');
+
+  const result = await pify(get)();
+  t.deepEqual(result, [[0, 777], [777, 778]]);
+
+  mockery.deregisterMock('os');
+  mockery.deregisterMock('./wmic');
+  mockery.deregisterMock('./powershell');
+});
+
+test('should not fall back to powershell on a non ENOENT wmic error', async t => {
+  const boom = new Error('wmic exploded');
+
+  mockery.registerMock('os', osMock('win32'));
+  mockery.registerMock('./wmic', cb => cb(boom));
+  mockery.registerMock('./powershell', () => {
+    t.fail('powershell should not be used on a generic wmic error');
+  });
+
+  const get = require('../lib/get');
+
+  const err = await t.throws(pify(get)());
+  t.is(err.message, 'wmic exploded');
+
+  mockery.deregisterMock('os');
+  mockery.deregisterMock('./wmic');
+  mockery.deregisterMock('./powershell');
+});

test/powershell.js

@@ -0,0 +1,66 @@
+import test from 'ava';
+import mockery from 'mockery';
+
+import pify from 'pify';
+
+import mocks from './helpers/mocks';
+
+test.before(() => {
+  mockery.enable({
+    warnOnReplace: false,
+    warnOnUnregistered: false,
+    useCleanCache: true,
+  });
+});
+
+test.beforeEach(() => {
+  mockery.resetCache();
+});
+
+test.after(() => {
+  mockery.disable();
+});
+
+test('should parse powershell output on Windows', async t => {
+  const stdout = '0 777\r\n777 778\r\n0 779\r\n';
+
+  mockery.registerMock('child_process', {
+    spawn: () => mocks.spawn(stdout, '', null, 0, null),
+  });
+  mockery.registerMock('os', {
+    EOL: '\n',
+    platform: () => 'win32',
+    type: () => 'type',
+    release: () => 'release',
+  });
+
+  const powershell = require('../lib/powershell');
+
+  const result = await pify(powershell)();
+  t.deepEqual(result, [[0, 777], [777, 778], [0, 779]]);
+
+  mockery.deregisterMock('child_process');
+  mockery.deregisterMock('os');
+});
+
+test('should ignore non numeric lines in powershell output', async t => {
+  const stdout = '\r\n0 777\r\nsome banner line\r\n777 778\r\n';
+
+  mockery.registerMock('child_process', {
+    spawn: () => mocks.spawn(stdout, '', null, 0, null),
+  });
+  mockery.registerMock('os', {
+    EOL: '\n',
+    platform: () => 'win32',
+    type: () => 'type',
+    release: () => 'release',
+  });
+
+  const powershell = require('../lib/powershell');
+
+  const result = await pify(powershell)();
+  t.deepEqual(result, [[0, 777], [777, 778]]);
+
+  mockery.deregisterMock('child_process');
+  mockery.deregisterMock('os');
+});