[rush] Avoid unnecessary package manager install lock

common/changes/@microsoft/rush/package-manager-install-lock_2026-06-23-13-27.json

@@ -0,0 +1,11 @@
+{
+  "changes": [
+    {
+      "packageName": "@microsoft/rush",
+      "comment": "Avoid acquiring the global package manager install lock when the requested package manager is already installed and no install lock file exists.",
+      "type": "patch"
+    }
+  ],
+  "packageName": "@microsoft/rush",
+  "email": "EscapeB@users.noreply.github.com"
+}

libraries/rush-lib/src/logic/installManager/InstallHelpers.ts

@@ -298,47 +298,81 @@ export class InstallHelpers {
       node: process.versions.node
     });
 
+    if (
+      (await packageManagerMarker.isValidAsync()) &&
+      !InstallHelpers._doesPackageManagerInstallLockFileExist(rushUserFolder, packageManagerAndVersion)
+    ) {
+      logIfConsoleOutputIsNotRestricted(
+        `Found ${packageManager} version ${packageManagerVersion} in ${packageManagerToolFolder}`
+      );
+      InstallHelpers._ensureLocalPackageManagerSymlink(
+        rushConfiguration,
+        packageManager,
+        packageManagerToolFolder,
+        logIfConsoleOutputIsNotRestricted
+      );
+      return;
+    }
+
     logIfConsoleOutputIsNotRestricted(`Trying to acquire lock for ${packageManagerAndVersion}`);
 
     const lock: LockFile = await LockFile.acquireAsync(rushUserFolder, packageManagerAndVersion);
 
     logIfConsoleOutputIsNotRestricted(`Acquired lock for ${packageManagerAndVersion}`);
 
-    if (!(await packageManagerMarker.isValidAsync()) || lock.dirtyWhenAcquired) {
-      logIfConsoleOutputIsNotRestricted(
-        Colorize.bold(`Installing ${packageManager} version ${packageManagerVersion}\n`)
-      );
+    try {
+      if (!(await packageManagerMarker.isValidAsync()) || lock.dirtyWhenAcquired) {
+        logIfConsoleOutputIsNotRestricted(
+          Colorize.bold(`Installing ${packageManager} version ${packageManagerVersion}\n`)
+        );
+
+        // note that this will remove the last-install flag from the directory
+        await Utilities.installPackageInDirectoryAsync({
+          directory: packageManagerToolFolder,
+          packageName: packageManager,
+          version: rushConfiguration.packageManagerToolVersion,
+          tempPackageTitle: `${packageManager}-local-install`,
+          maxInstallAttempts: maxInstallAttempts,
+          // This is using a local configuration to install a package in a shared global location.
+          // Generally that's a bad practice, but in this case if we can successfully install
+          // the package at all, we can reasonably assume it's good for all the repositories.
+          // In particular, we'll assume that two different NPM registries cannot have two
+          // different implementations of the same version of the same package.
+          // This was needed for: https://github.com/microsoft/rushstack/issues/691
+          commonRushConfigFolder: rushConfiguration.commonRushConfigFolder,
+          // Only filter npm-incompatible properties when the repo uses pnpm or yarn.
+          // If the repo uses npm, the .npmrc is already configured for npm, so don't filter.
+          filterNpmIncompatibleProperties: rushConfiguration.packageManager !== 'npm'
+        });
+
+        logIfConsoleOutputIsNotRestricted(
+          `Successfully installed ${packageManager} version ${packageManagerVersion}`
+        );
+      } else {
+        logIfConsoleOutputIsNotRestricted(
+          `Found ${packageManager} version ${packageManagerVersion} in ${packageManagerToolFolder}`
+        );
+      }
 
-      // note that this will remove the last-install flag from the directory
-      await Utilities.installPackageInDirectoryAsync({
-        directory: packageManagerToolFolder,
-        packageName: packageManager,
-        version: rushConfiguration.packageManagerToolVersion,
-        tempPackageTitle: `${packageManager}-local-install`,
-        maxInstallAttempts: maxInstallAttempts,
-        // This is using a local configuration to install a package in a shared global location.
-        // Generally that's a bad practice, but in this case if we can successfully install
-        // the package at all, we can reasonably assume it's good for all the repositories.
-        // In particular, we'll assume that two different NPM registries cannot have two
-        // different implementations of the same version of the same package.
-        // This was needed for: https://github.com/microsoft/rushstack/issues/691
-        commonRushConfigFolder: rushConfiguration.commonRushConfigFolder,
-        // Only filter npm-incompatible properties when the repo uses pnpm or yarn.
-        // If the repo uses npm, the .npmrc is already configured for npm, so don't filter.
-        filterNpmIncompatibleProperties: rushConfiguration.packageManager !== 'npm'
-      });
+      await packageManagerMarker.createAsync();
 
-      logIfConsoleOutputIsNotRestricted(
-        `Successfully installed ${packageManager} version ${packageManagerVersion}`
-      );
-    } else {
-      logIfConsoleOutputIsNotRestricted(
-        `Found ${packageManager} version ${packageManagerVersion} in ${packageManagerToolFolder}`
+      InstallHelpers._ensureLocalPackageManagerSymlink(
+        rushConfiguration,
+        packageManager,
+        packageManagerToolFolder,
+        logIfConsoleOutputIsNotRestricted
       );
+    } finally {
+      lock.release();
     }
+  }
 
-    await packageManagerMarker.createAsync();
-
+  private static _ensureLocalPackageManagerSymlink(
+    rushConfiguration: RushConfiguration,
+    packageManager: PackageManagerName,
+    packageManagerToolFolder: string,
+    logIfConsoleOutputIsNotRestricted: (message?: string) => void
+  ): void {
     // Example: "C:\MyRepo\common\temp"
     FileSystem.ensureFolder(rushConfiguration.commonTempFolder);
 
@@ -365,8 +399,23 @@ export class InstallHelpers {
       linkTargetPath: packageManagerToolFolder,
       newLinkPath: localPackageManagerToolFolder
     });
+  }
+
+  private static _doesPackageManagerInstallLockFileExist(
+    rushUserFolder: string,
+    packageManagerAndVersion: string
+  ): boolean {
+    for (const itemName of FileSystem.readFolderItemNames(rushUserFolder)) {
+      if (itemName === `${packageManagerAndVersion}.lock`) {
+        return true;
+      }
+
+      if (itemName.startsWith(`${packageManagerAndVersion}#`) && itemName.endsWith('.lock')) {
+        return true;
+      }
+    }
 
-    lock.release();
+    return false;
   }
 
   // Helper for getPackageManagerEnvironment

libraries/rush-lib/src/logic/test/InstallHelpers.test.ts

@@ -1,12 +1,17 @@
 // Copyright (c) Microsoft Corporation. All rights reserved. Licensed under the MIT license.
 // See LICENSE in the project root for license information.
 
-import { type IPackageJson, JsonFile } from '@rushstack/node-core-library';
+import * as path from 'node:path';
+
+import { FileSystem, type IPackageJson, JsonFile, LockFile } from '@rushstack/node-core-library';
 import { StringBufferTerminalProvider, Terminal } from '@rushstack/terminal';
 import { TestUtilities } from '@rushstack/heft-config-file';
 
 import { InstallHelpers } from '../installManager/InstallHelpers';
 import { RushConfiguration } from '../../api/RushConfiguration';
+import { LastInstallFlag } from '../../api/LastInstallFlag';
+import type { RushGlobalFolder } from '../../api/RushGlobalFolder';
+import { Utilities } from '../../utilities/Utilities';
 
 describe('InstallHelpers', () => {
   describe('generateCommonPackageJson', () => {
@@ -73,4 +78,71 @@ describe('InstallHelpers', () => {
       );
     });
   });
+
+  describe(InstallHelpers.ensureLocalPackageManagerAsync.name, () => {
+    const tempFolderPath: string = `${__dirname}/temp/${InstallHelpers.name}`;
+
+    beforeEach(() => {
+      FileSystem.ensureEmptyFolder(tempFolderPath);
+    });
+
+    afterEach(() => {
+      FileSystem.deleteFolder(tempFolderPath);
+      jest.restoreAllMocks();
+    });
+
+    it('does not acquire the global lock when the package manager is already installed', async () => {
+      const rushGlobalFolder: RushGlobalFolder = {
+        path: `${tempFolderPath}/rush-global`,
+        nodeSpecificPath: `${tempFolderPath}/rush-global/node-${process.version}`
+      } as RushGlobalFolder;
+      const packageManagerToolFolder: string = path.join(rushGlobalFolder.nodeSpecificPath, 'pnpm-10.27.0');
+      await new LastInstallFlag(packageManagerToolFolder, { node: process.versions.node }).createAsync();
+
+      const lockAcquireSpy: jest.SpyInstance = jest.spyOn(LockFile, 'acquireAsync');
+      const rushConfiguration: RushConfiguration = {
+        commonRushConfigFolder: `${tempFolderPath}/common/config/rush`,
+        commonTempFolder: `${tempFolderPath}/common/temp`,
+        packageManager: 'pnpm',
+        packageManagerToolVersion: '10.27.0'
+      } as RushConfiguration;
+
+      await InstallHelpers.ensureLocalPackageManagerAsync(rushConfiguration, rushGlobalFolder, 1, true);
+
+      expect(lockAcquireSpy).not.toHaveBeenCalled();
+      expect(FileSystem.exists(`${rushConfiguration.commonTempFolder}/pnpm-local`)).toEqual(true);
+    });
+
+    it('acquires the global lock if an install lock file is present', async () => {
+      const rushGlobalFolder: RushGlobalFolder = {
+        path: `${tempFolderPath}/rush-global`,
+        nodeSpecificPath: `${tempFolderPath}/rush-global/node-${process.version}`
+      } as RushGlobalFolder;
+      const packageManagerToolFolder: string = path.join(rushGlobalFolder.nodeSpecificPath, 'pnpm-10.27.0');
+      await new LastInstallFlag(packageManagerToolFolder, { node: process.versions.node }).createAsync();
+      FileSystem.writeFile(`${rushGlobalFolder.nodeSpecificPath}/pnpm-10.27.0#123.lock`, '');
+
+      const releaseAsync: jest.Mock = jest.fn();
+      const lockAcquireSpy: jest.SpyInstance = jest.spyOn(LockFile, 'acquireAsync').mockResolvedValue({
+        dirtyWhenAcquired: true,
+        release: releaseAsync
+      } as unknown as LockFile);
+      const installSpy: jest.SpyInstance = jest
+        .spyOn(Utilities, 'installPackageInDirectoryAsync')
+        .mockResolvedValue();
+      const rushConfiguration: RushConfiguration = {
+        commonRushConfigFolder: `${tempFolderPath}/common/config/rush`,
+        commonTempFolder: `${tempFolderPath}/common/temp`,
+        packageManager: 'pnpm',
+        packageManagerToolVersion: '10.27.0'
+      } as RushConfiguration;
+
+      await InstallHelpers.ensureLocalPackageManagerAsync(rushConfiguration, rushGlobalFolder, 1, true);
+
+      expect(lockAcquireSpy).toHaveBeenCalledTimes(1);
+      expect(installSpy).toHaveBeenCalledTimes(1);
+      expect(releaseAsync).toHaveBeenCalledTimes(1);
+      expect(FileSystem.exists(`${rushConfiguration.commonTempFolder}/pnpm-local`)).toEqual(true);
+    });
+  });
 });