Enforce resolution-mode=highest for pnpm versions 8.0.0 to 8.6.*

README.md

@@ -215,6 +215,9 @@ If you include `useYarn: true` in your `ember-try` config, all npm scenarios wil
 
 If you include `usePnpm: true` in your `ember-try` config, all npm scenarios will use `pnpm` for install with the `--no-lockfile` options. At cleanup, your dependencies will be restored to their prior state.
 
+> ⚠ pnpm versions from 8.0.0 to 8.6.x have the default value of [resolution-mode](https://pnpm.io/npmrc#resolution-mode) setting changed to `lowest-direct`. This violates `ember-try` expectations as `resolution-mode` is expected to be `highest`, like in `npm` and `pnpm` versions < 8.0.0 and >= 8.7.0.
+>
+> If you run into this issue, we recommend to upgrade pnpm to latest version. If you are unable to upgrade, you can set `resolution-mode = highest` in the `.npmrc` file.
 
 ##### A note on npm scenarios with lockfiles
 

lib/dependency-manager-adapters/pnpm.js

@@ -5,6 +5,8 @@ const fs = require('fs-extra');
 const path = require('path');
 const debug = require('debug')('ember-try:dependency-manager-adapter:pnpm');
 const Backup = require('../utils/backup');
+const semverLt = require('semver/functions/lt');
+const semverGte = require('semver/functions/gte');
 
 const PACKAGE_JSON = 'package.json';
 const PNPM_LOCKFILE = 'pnpm-lock.yaml';
@@ -21,12 +23,12 @@ module.exports = CoreObject.extend({
   },
 
   async setup() {
+    await this._throwOnResolutionMode();
     await this.backup.addFiles([PACKAGE_JSON, PNPM_LOCKFILE]);
   },
 
   async changeToDependencySet(depSet) {
     await this.applyDependencySet(depSet);
-
     await this._install(depSet);
 
     let deps = Object.assign({}, depSet.dependencies, depSet.devDependencies);
@@ -63,6 +65,49 @@ module.exports = CoreObject.extend({
     }
   },
 
+  /**
+   * pnpm versions 8.0.0 through 8.6.* have the `resolution-mode` setting inverted to
+   * `lowest-direct`, which breaks ember-try. This method throws a helpful error in the following
+   * case: pnpm version is within dangerous range and `pnpm config get resolution-mode` reports an
+   * empty value.
+   *
+   * @returns Promise<void>
+   */
+  async _throwOnResolutionMode() {
+    let version = await this._getPnpmVersion();
+    let resolutionMode = await this._getResolutionMode();
+
+    if (this._isResolutionModeWrong(version, resolutionMode)) {
+      throw new Error(
+        'You are using an old version of pnpm that uses wrong resolution mode that violates ember-try expectations. Please either upgrade pnpm or set `resolution-mode` to `highest` in `.npmrc`.'
+      );
+    }
+  },
+
+  async _getPnpmVersion() {
+    let result = await this.run('pnpm', ['--version'], { cwd: this.cwd, stdio: 'pipe' });
+    return result.stdout.split('\n')[0];
+  },
+
+  async _getResolutionMode() {
+    let result = await this.run('pnpm', ['config', 'get', 'resolution-mode'], {
+      cwd: this.cwd,
+      stdio: 'pipe',
+    });
+
+    return result.stdout.split('\n')[0];
+  },
+
+  _isResolutionModeWrong(versionStr, resolutionMode) {
+    // The `resolution-mode` is not set explicitly, and the current pnpm version makes it default
+    // to `lowest-direct`
+    if (!resolutionMode.length && semverGte(versionStr, '8.0.0') && semverLt(versionStr, '8.7.0')) {
+      return true;
+    }
+
+    return false;
+  },
+
   async _install(depSet) {
     let mgrOptions = this.managerOptions || [];
 

package.json

@@ -44,6 +44,7 @@
   },
   "devDependencies": {
     "chai": "^4.3.4",
+    "chai-as-promised": "^7.1.1",
     "codecov": "^3.8.3",
     "ember-cli": "~3.22.0",
     "eslint": "^7.31.0",
@@ -59,6 +60,7 @@
     "release-it": "^14.11.6",
     "release-it-lerna-changelog": "^3.1.0",
     "rsvp": "^4.7.0",
+    "sinon": "^15.2.0",
     "tmp-sync": "^1.1.0"
   },
   "engines": {