Implement module.parent (#4614)

* Implement module.parent.require

* Implement module.parent.filename

* Implement module.parent.id

* Try to set parent to actual parent module

* Fix tests

* styel nit to minimize diff

* Fix failing test

* Make module.parent a lazy getter

* make `parent` enumerable

* Share type definition for ModuleRegistry

* module.parent should be null not undefined for entrypoints

packages/jest-cli/src/__tests__/search_source.test.js

@@ -373,12 +373,14 @@ describe('SearchSource', () => {
 
     it('finds tests that depend directly on the path', () => {
       const filePath = path.join(rootDir, 'RegularModule.js');
+      const file2Path = path.join(rootDir, 'RequireRegularModule.js');
       const loggingDep = path.join(rootDir, 'logging.js');
       const parentDep = path.join(rootDir, 'ModuleWithSideEffects.js');
       const data = searchSource.findRelatedTests(new Set([filePath]));
       expect(toPaths(data.tests).sort()).toEqual([
         parentDep,
         filePath,
+        file2Path,
         loggingDep,
         rootPath,
       ]);

packages/jest-runtime/src/__tests__/runtime_require_module.test.js

@@ -8,7 +8,8 @@
 
 'use strict';
 
-const path = require('path');
+import path from 'path';
+import slash from 'slash';
 
 let createRuntime;
 
@@ -27,16 +28,50 @@ describe('Runtime requireModule', () => {
     }));
 
   it('provides `module.parent` to modules', () =>
+    createRuntime(__filename).then(runtime => {
+      const exports = runtime.requireModule(
+        runtime.__mockRootPath,
+        'RequireRegularModule',
+      );
+      expect(Object.keys(exports.parent)).toEqual([
+        'exports',
+        'filename',
+        'id',
+        'children',
+        'parent',
+        'paths',
+        'require',
+      ]);
+    }));
+
+  it('`module.parent` should be undefined for entrypoints', () =>
     createRuntime(__filename).then(runtime => {
       const exports = runtime.requireModule(
         runtime.__mockRootPath,
         'RegularModule',
       );
-      expect(exports.parent).toEqual({
-        exports: {},
-        filename: 'mock.js',
-        id: 'mockParent',
-      });
+      expect(exports.parent).toBeNull();
+    }));
+
+  it('resolve module.parent.require correctly', () =>
+    createRuntime(__filename).then(runtime => {
+      const exports = runtime.requireModule(
+        runtime.__mockRootPath,
+        'inner_parent_module',
+      );
+      expect(exports.outputString).toEqual('This should happen');
+    }));
+
+  it('resolve module.parent.filename correctly', () =>
+    createRuntime(__filename).then(runtime => {
+      const exports = runtime.requireModule(
+        runtime.__mockRootPath,
+        'inner_parent_module',
+      );
+
+      expect(slash(exports.parentFileName.replace(__dirname, ''))).toEqual(
+        '/test_root/inner_parent_module.js',
+      );
     }));
 
   it('provides `module.filename` to modules', () =>

packages/jest-runtime/src/__tests__/test_root/RequireRegularModule.js

@@ -0,0 +1,12 @@
+/**
+ * Copyright (c) 2014-present, Facebook, Inc. All rights reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @providesModule RequireRegularModule
+ */
+
+'use strict';
+
+module.exports.parent = require('RegularModule').parent;

packages/jest-runtime/src/__tests__/test_root/inner_parent_module.js

@@ -0,0 +1,14 @@
+/**
+ * Copyright (c) 2014-present, Facebook, Inc. All rights reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @providesModule inner_parent_module
+ */
+
+'use strict';
+
+const impl = require('module-needing-parent');
+
+module.exports = impl;

packages/jest-runtime/src/index.js

@@ -57,6 +57,8 @@ type CoverageOptions = {
   mapCoverage: boolean,
 };
 
+type ModuleRegistry = {[key: string]: Module};
+
 type BooleanObject = {[key: string]: boolean};
 type CacheFS = {[path: Path]: string};
 
@@ -75,12 +77,6 @@ const getModuleNameMapper = (config: ProjectConfig) => {
   return null;
 };
 
-const mockParentModule = {
-  exports: {},
-  filename: 'mock.js',
-  id: 'mockParent',
-};
-
 const unmockRegExpCache = new WeakMap();
 
 class Runtime {
@@ -92,13 +88,13 @@ class Runtime {
   _currentlyExecutingModulePath: string;
   _environment: Environment;
   _explicitShouldMock: BooleanObject;
-  _internalModuleRegistry: {[key: string]: Module};
+  _internalModuleRegistry: ModuleRegistry;
   _isCurrentlyExecutingManualMock: ?string;
   _mockFactories: {[key: string]: () => any};
   _mockMetaDataCache: {[key: string]: MockFunctionMetadata};
   _mockRegistry: {[key: string]: any};
   _moduleMocker: ModuleMocker;
-  _moduleRegistry: {[key: string]: Module};
+  _moduleRegistry: ModuleRegistry;
   _resolver: Resolver;
   _shouldAutoMock: boolean;
   _shouldMockModuleCache: BooleanObject;
@@ -329,7 +325,7 @@ class Runtime {
         // $FlowFixMe
         localModule.exports = require(modulePath);
       } else {
-        this._execModule(localModule, options);
+        this._execModule(localModule, options, moduleRegistry, from);
       }
     }
     return moduleRegistry[modulePath].exports;
@@ -390,7 +386,7 @@ class Runtime {
         filename: modulePath,
         id: modulePath,
       };
-      this._execModule(localModule);
+      this._execModule(localModule, undefined, this._mockRegistry, from);
       this._mockRegistry[moduleID] = localModule.exports;
     } else {
       // Look for a real module to generate an automock from
@@ -478,7 +474,12 @@ class Runtime {
     return to ? this._resolver.resolveModule(from, to) : from;
   }
 
-  _execModule(localModule: Module, options: ?InternalModuleOptions) {
+  _execModule(
+    localModule: Module,
+    options: ?InternalModuleOptions,
+    moduleRegistry: ModuleRegistry,
+    from: Path,
+  ) {
     // If the environment was disposed, prevent this module from being executed.
     if (!this._environment.global) {
       return;
@@ -493,7 +494,19 @@ class Runtime {
 
     const dirname = path.dirname(filename);
     localModule.children = [];
-    localModule.parent = mockParentModule;
+
+    Object.defineProperty(
+      localModule,
+      'parent',
+      // https://github.com/facebook/flow/issues/285#issuecomment-270810619
+      ({
+        enumerable: true,
+        get() {
+          return moduleRegistry[from] || null;
+        },
+      }: Object),
+    );
+
     localModule.paths = this._resolver.getModulePaths(dirname);
     localModule.require = this._createRequireImplementation(filename, options);