feat(core): add support for pnpm as package manager (#3802)

Add `pnpm` as package manager option to the `stryker init` command. When selecting `pnpm`, the installed plugins will be explicitly listed inside your stryker.conf.json file.

Co-authored-by: Nico Jansen <jansennico@gmail.com>

CONTRIBUTING.md

@@ -63,7 +63,7 @@ To run local changes you made in StrykerJS in an actual project you have two opt
 
 ## VSCode environment configuration
 
-We've chosen to **check in in our vscode configuration**. This makes development unified amongst stryker developers. VSCode is an open source code editor maintained by Microsoft. For more info and the download link, please visit https://code.visualstudio.com/.
+We've chosen to **check in our vscode configuration**. This makes development unified amongst stryker developers. VSCode is an open source code editor maintained by Microsoft. For more info and the download link, please visit https://code.visualstudio.com/.
 
 We recommend you to install the following plugins:
 
@@ -98,7 +98,7 @@ New features are welcome! Either as requests or proposals.
 1. Create a fork on your github account.
 1. When writing your code, please conform to the existing coding style.
    See [.editorconfig](https://github.com/stryker-mutator/stryker-js/blob/master/.editorconfig), the [typescript guidelines](https://github.com/Microsoft/TypeScript/wiki/Coding-guidelines) and our tslint.json
-    * You can check if there are lint issues using `npm run lint:log`. Output will be in root folder in `lint.log` file.
+    * You can check if there are lint issues using `npm run lint`.
     * You can automatically fix a lot of lint issues using `npm run lint:fix`
 1. Please create or edit unit tests or integration tests.
 1. Run the tests using `npm test`

docs/troubleshooting.md

@@ -276,4 +276,36 @@ The solution is to include all files that are mutated in your project's tsconfig
 }
 ```
 
-This shouldn't change anything about your Angular project. Your just being a bit more explicit in which files you want to include.
+This shouldn't change anything about your Angular project. You're just being a bit more explicit in which files you want to include.
+
+### Plugins can't be found when using pnpm as package manager
+
+**Symptom**
+
+Stryker is unable to load plugins (like `@stryker-mutator/typescript-checker`) when using pnpm as package manager.
+You might run into errors like:
+
+```
+Cannot find TestRunner plugin "mocha". No TestRunner plugins were loaded.
+```
+
+**Problem**
+
+When using npm or yarn as package manager, Stryker can automagically load plugins by scanning your `node_modules`.
+Because _pnpm_ uses a special directory structure to store dependencies, Stryker can't auto-detect plugins like the `@stryker-mutator/typescript-checker` plugin.
+
+**Solution**
+
+Explicitly specify the plugins to load in your Stryker configuration file. 
+
+```diff
+{
+  "packageManager": "pnpm",
+  "testRunner": "jest",
+  "checkers": ["typescript"],
++  "plugins": [
++    "@stryker-mutator/jest-runner",
++    "@stryker-mutator/typescript-checker"
++  ]
+}
+```

packages/api/schema/stryker-core.json

@@ -367,7 +367,8 @@
     "packageManager": {
       "enum": [
         "npm",
-        "yarn"
+        "yarn",
+        "pnpm"
       ],
       "description": "The package manager Stryker can use to install missing dependencies."
     },

packages/core/src/initializer/stryker-config-writer.ts

@@ -43,13 +43,14 @@ export class StrykerConfigWriter {
     buildCommand: PromptOption,
     selectedReporters: PromptOption[],
     selectedPackageManager: PromptOption,
+    requiredPlugins: string[],
     additionalPiecesOfConfig: Array<Partial<StrykerOptions>>,
     exportAsJson: boolean
   ): Promise<string> {
     const configObject: Partial<StrykerOptions> & { _comment: string } = {
       _comment:
         "This config was generated using 'stryker init'. Please take a look at: https://stryker-mutator.io/docs/stryker-js/configuration/ for more information",
-      packageManager: selectedPackageManager.name as 'npm' | 'yarn',
+      packageManager: selectedPackageManager.name as 'npm' | 'pnpm' | 'yarn',
       reporters: selectedReporters.map((rep) => rep.name),
       testRunner: selectedTestRunner.name,
       coverageAnalysis: CommandTestRunner.is(selectedTestRunner.name) ? 'off' : 'perTest',
@@ -58,6 +59,9 @@ export class StrykerConfigWriter {
     // Only write buildCommand to config file if non-empty
     if (buildCommand.name) configObject.buildCommand = buildCommand.name;
 
+    // Automatic plugin discovery doesn't work with pnpm, so explicitly specify the required plugins in the config file
+    if (selectedPackageManager.name === 'pnpm') configObject.plugins = requiredPlugins;
+
     Object.assign(configObject, ...additionalPiecesOfConfig);
     return this.writeStrykerConfig(configObject, exportAsJson);
   }

packages/core/src/initializer/stryker-initializer.ts

@@ -18,6 +18,7 @@ import { initializerTokens } from './index.js';
 const enum PackageManager {
   Npm = 'npm',
   Yarn = 'yarn',
+  Pnpm = 'pnpm',
 }
 
 export class StrykerInitializer {
@@ -108,6 +109,7 @@ export class StrykerInitializer {
       buildCommand,
       selectedReporters,
       selectedPackageManager,
+      npmDependencies.map((pkg) => pkg.name),
       await this.fetchAdditionalConfig(npmDependencies),
       isJsonSelected
     );
@@ -162,6 +164,10 @@ export class StrykerInitializer {
         name: PackageManager.Yarn,
         pkg: null,
       },
+      {
+        name: PackageManager.Pnpm,
+        pkg: null,
+      },
     ]);
   }
 
@@ -187,7 +193,7 @@ export class StrykerInitializer {
 
     const dependencyArg = dependencies.join(' ');
     this.out('Installing NPM dependencies...');
-    const cmd = selectedOption.name === PackageManager.Npm ? `npm i --save-dev ${dependencyArg}` : `yarn add ${dependencyArg} --dev`;
+    const cmd = this.getInstallCommand(selectedOption.name as PackageManager, dependencyArg);
     this.out(cmd);
     try {
       childProcess.execSync(cmd, { stdio: [0, 1, 2] });
@@ -196,6 +202,17 @@ export class StrykerInitializer {
     }
   }
 
+  private getInstallCommand(packageManager: PackageManager, dependencyArg: string): string {
+    switch (packageManager) {
+      case PackageManager.Yarn:
+        return `yarn add ${dependencyArg} --dev`;
+      case PackageManager.Pnpm:
+        return `pnpm add -D ${dependencyArg}`;
+      case PackageManager.Npm:
+        return `npm i --save-dev ${dependencyArg}`;
+    }
+  }
+
   private async fetchAdditionalConfig(dependencies: PackageInfo[]): Promise<Array<Record<string, unknown>>> {
     return (await Promise.all(dependencies.map((dep) => this.client.getAdditionalConfig(dep)))).filter(notEmpty);
   }

packages/core/test/unit/initializer/stryker-initializer.spec.ts

@@ -123,7 +123,7 @@ describe(StrykerInitializer.name, () => {
       expect(promptReporters.type).to.eq('checkbox');
       expect(promptReporters.choices).to.deep.eq(['dimension', 'mars', 'html', 'clear-text', 'progress', 'dashboard']);
       expect(promptPackageManagers.type).to.eq('list');
-      expect(promptPackageManagers.choices).to.deep.eq(['npm', 'yarn']);
+      expect(promptPackageManagers.choices).to.deep.eq(['npm', 'yarn', 'pnpm']);
       expect(promptConfigTypes.type).to.eq('list');
       expect(promptConfigTypes.choices).to.deep.eq(['JSON', 'JavaScript']);
     });
@@ -217,7 +217,7 @@ describe(StrykerInitializer.name, () => {
       expect(promptConfigType.type).to.eq('list');
       expect(promptConfigType.choices).to.deep.eq(['JSON', 'JavaScript']);
       expect(promptPackageManager.type).to.eq('list');
-      expect(promptPackageManager.choices).to.deep.eq(['npm', 'yarn']);
+      expect(promptPackageManager.choices).to.deep.eq(['npm', 'yarn', 'pnpm']);
     });
 
     it('should install any additional dependencies', async () => {
@@ -234,6 +234,41 @@ describe(StrykerInitializer.name, () => {
       });
     });
 
+    it('should install additional dependencies with pnpm', async () => {
+      inquirerPrompt.resolves({
+        packageManager: 'pnpm',
+        reporters: [],
+        testRunner: 'awesome',
+      });
+      await sut.initialize();
+      expect(childExecSync).calledWith('pnpm add -D @stryker-mutator/awesome-runner', {
+        stdio: [0, 1, 2],
+      });
+    });
+
+    it('should explicitly specify plugins when using pnpm', async () => {
+      childExec.resolves();
+      const expectedOutput = `// @ts-check
+          /** @type {import('@stryker-mutator/api/core').PartialStrykerOptions} */  
+          const config =  {
+            "_comment": "This config was generated using 'stryker init'. Please take a look at: https://stryker-mutator.io/docs/stryker-js/configuration/ for more information",
+            "packageManager": "pnpm",
+            "reporters": [],
+            "testRunner": "awesome",
+            "coverageAnalysis": "perTest",
+            "plugins": [ "@stryker-mutator/awesome-runner" ]
+          };
+          export default config;`;
+      inquirerPrompt.resolves({
+        packageManager: 'pnpm',
+        reporters: [],
+        testRunner: 'awesome',
+        configType: 'JavaScript',
+      });
+      await sut.initialize();
+      expectStrykerConfWritten(expectedOutput);
+    });
+
     it('should configure testRunner, reporters, and packageManager', async () => {
       inquirerPrompt.resolves({
         packageManager: 'npm',