From b1d6fad5e3727fef705c2e5a7bfcc82ab515c9d4 Mon Sep 17 00:00:00 2001
From: Paul Gschwendtner <paulgschwendtner@gmail.com>
Date: Sat, 25 Sep 2021 18:46:59 +0200
Subject: [PATCH] refactor(compiler-cli): do not use `__filename` or
 `__dirname` global for ESM compatibility (#43431)

Switches the compiler-cli usage of `__filename` to `import.meta.url`
when ESM bundles are generated. Unfortunately we cannot start using
only `import.meta` yet as we still build and run all code in Angular
in CommonJS module output for devmode tests.

This commit also fixes various instances where a jasmine spy was applied on
a namespace export that will break with ES module (and the interop for
CommonJS output). We fix these spies by using a default import.

PR Close #43431
---
 packages/compiler-cli/BUILD.bazel               |  7 +++++++
 packages/compiler-cli/import_meta_url.d.ts      | 14 ++++++++++++++
 packages/compiler-cli/ngcc/BUILD.bazel          |  1 +
 packages/compiler-cli/ngcc/index.ts             | 15 ++++++++++++---
 .../ngcc/src/execution/cluster/master.ts        | 17 +++++++++++++++--
 .../lock_file_with_child_process/index.ts       | 16 +++++++++++++++-
 .../ngcc/src/packages/configuration.ts          |  9 ++++++++-
 .../ngcc/test/integration/ngcc_spec.ts          |  6 +++---
 .../compiler-cli/ngcc/test/ngcc_options_spec.ts |  5 ++++-
 packages/compiler-cli/package.json              |  6 ++++++
 .../src/ngtsc/file_system/BUILD.bazel           |  3 +++
 .../file_system/src/node_js_file_system.ts      | 17 +++++++++++++++--
 .../test/node_js_file_system_spec.ts            |  6 +++++-
 .../test/reflector_host_spec.ts                 |  2 +-
 .../test/typescript_host_spec.ts                |  5 ++++-
 15 files changed, 113 insertions(+), 16 deletions(-)
 create mode 100644 packages/compiler-cli/import_meta_url.d.ts

diff --git a/packages/compiler-cli/BUILD.bazel b/packages/compiler-cli/BUILD.bazel
index c0d3110687f..28931d8e288 100644
--- a/packages/compiler-cli/BUILD.bazel
+++ b/packages/compiler-cli/BUILD.bazel
@@ -68,6 +68,11 @@ ts_config(
     deps = ["//packages:tsconfig-build.json"],
 )
 
+ts_library(
+    name = "import_meta_url_types",
+    srcs = ["import_meta_url.d.ts"],
+)
+
 ts_library(
     name = "compiler-cli",
     srcs = glob(
@@ -76,11 +81,13 @@ ts_library(
             "src/**/*.ts",
         ],
         exclude = [
+            "import_meta_url.d.ts",
             "src/integrationtest/**/*.ts",
         ],
     ),
     tsconfig = ":tsconfig",
     deps = [
+        ":import_meta_url_types",
         "//packages/compiler",
         "//packages/compiler-cli/src/ngtsc/core",
         "//packages/compiler-cli/src/ngtsc/core:api",
diff --git a/packages/compiler-cli/import_meta_url.d.ts b/packages/compiler-cli/import_meta_url.d.ts
new file mode 100644
index 00000000000..ae46c8b1a1b
--- /dev/null
+++ b/packages/compiler-cli/import_meta_url.d.ts
@@ -0,0 +1,14 @@
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+
+// Note: The `__ESM_IMPORT_META_URL__` identifier will be defined as part of bundling.
+// We cannot use `import.meta.url` directly as this code currently still runs in CommonJS
+// for devmode. This is a solution allowing for both ESModule and CommonJS to run this file.
+// TODO(devversion): replace all of this with `import.meta.url` once devmode is using ESM.
+declare const __ESM_IMPORT_META_URL__: string;
\ No newline at end of file
diff --git a/packages/compiler-cli/ngcc/BUILD.bazel b/packages/compiler-cli/ngcc/BUILD.bazel
index 6502721b914..7c1ddf6cb8e 100644
--- a/packages/compiler-cli/ngcc/BUILD.bazel
+++ b/packages/compiler-cli/ngcc/BUILD.bazel
@@ -13,6 +13,7 @@ ts_library(
         "//packages:types",
         "//packages/compiler",
         "//packages/compiler-cli",
+        "//packages/compiler-cli:import_meta_url_types",
         "//packages/compiler-cli/src/ngtsc/annotations",
         "//packages/compiler-cli/src/ngtsc/cycles",
         "//packages/compiler-cli/src/ngtsc/diagnostics",
diff --git a/packages/compiler-cli/ngcc/index.ts b/packages/compiler-cli/ngcc/index.ts
index dc1ea337953..686431070e5 100644
--- a/packages/compiler-cli/ngcc/index.ts
+++ b/packages/compiler-cli/ngcc/index.ts
@@ -6,7 +6,9 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {join} from 'path';
+import {dirname, join} from 'path';
+import {fileURLToPath} from 'url';
+
 import {NodeJSFileSystem, setFileSystem} from '../src/ngtsc/file_system';
 
 import {mainNgcc} from './src/main';
@@ -23,10 +25,17 @@ export function process(options: AsyncNgccOptions|SyncNgccOptions): void|Promise
   return mainNgcc(options);
 }
 
+
+// CommonJS/ESM interop for determining the current file name and containing
+// directory. These path is needed for providing an absolute path to the ngcc
+// command line entry-point script (for the CLI).
+export const containingDirPath =
+    typeof __dirname !== 'undefined' ? __dirname : dirname(fileURLToPath(__ESM_IMPORT_META_URL__));
+
 /**
- * Absolute file path that points to the `ngcc` entry-point.
+ * Absolute file path that points to the `ngcc` command line entry-point.
  *
  * This can be used by the Angular CLI to spawn a process running ngcc using
  * command line options.
  */
-export const ngccMainFilePath = join(__dirname, './main-ngcc.js');
+export const ngccMainFilePath = join(containingDirPath, './main-ngcc.js');
diff --git a/packages/compiler-cli/ngcc/src/execution/cluster/master.ts b/packages/compiler-cli/ngcc/src/execution/cluster/master.ts
index 759e4f3dde0..77d84aec9e6 100644
--- a/packages/compiler-cli/ngcc/src/execution/cluster/master.ts
+++ b/packages/compiler-cli/ngcc/src/execution/cluster/master.ts
@@ -9,6 +9,7 @@
 /// <reference types="node" />
 
 import cluster from 'cluster';
+import module from 'module';
 
 import {AbsoluteFsPath, PathManipulation} from '../../../../src/ngtsc/file_system';
 import {Logger} from '../../../../src/ngtsc/logging';
@@ -21,7 +22,6 @@ import {stringifyTask} from '../tasks/utils';
 import {MessageFromWorker, TaskCompletedMessage, TransformedFilesMessage, UpdatePackageJsonMessage} from './api';
 import {Deferred, sendMessageToWorker} from './utils';
 
-
 /**
  * The cluster master is responsible for analyzing all entry-points, planning the work that needs to
  * be done, distributing it to worker-processes and collecting/post-processing the results.
@@ -44,7 +44,7 @@ export class ClusterMaster {
     }
 
     // Set the worker entry-point
-    cluster.setupMaster({exec: this.fileSystem.resolve(__dirname, 'ngcc_cluster_worker.js')});
+    cluster.setupMaster({exec: getClusterWorkerScriptPath(fileSystem)});
 
     this.taskQueue = analyzeEntryPoints();
     this.onTaskCompleted = createTaskCompletedCallback(this.taskQueue);
@@ -330,3 +330,16 @@ export class ClusterMaster {
     };
   }
 }
+
+/** Gets the absolute file path to the cluster worker script. */
+export function getClusterWorkerScriptPath(fileSystem: PathManipulation): AbsoluteFsPath {
+  // This is an interop allowing for the worker script to be determined in both
+  // a CommonJS module, or an ES module which does not come with `require` by default.
+  const requireFn =
+      typeof require !== 'undefined' ? require : module.createRequire(__ESM_IMPORT_META_URL__);
+  // We resolve the worker script using module resolution as in the package output,
+  // the worker might be bundled but exposed through a subpath export mapping.
+  const workerScriptPath =
+      requireFn.resolve('@angular/compiler-cli/ngcc/src/execution/cluster/ngcc_cluster_worker');
+  return fileSystem.resolve(workerScriptPath);
+}
diff --git a/packages/compiler-cli/ngcc/src/locking/lock_file_with_child_process/index.ts b/packages/compiler-cli/ngcc/src/locking/lock_file_with_child_process/index.ts
index 8a0c59a8a58..839c42edebe 100644
--- a/packages/compiler-cli/ngcc/src/locking/lock_file_with_child_process/index.ts
+++ b/packages/compiler-cli/ngcc/src/locking/lock_file_with_child_process/index.ts
@@ -6,6 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 import {ChildProcess, fork} from 'child_process';
+import module from 'module';
 
 import {AbsoluteFsPath, FileSystem} from '../../../../src/ngtsc/file_system';
 import {Logger, LogLevel} from '../../../../src/ngtsc/logging';
@@ -78,7 +79,7 @@ export class LockFileWithChildProcess implements LockFile {
         this.logger.level !== undefined ? this.logger.level.toString() : LogLevel.info.toString();
     const isWindows = process.platform === 'win32';
     const unlocker = fork(
-        __dirname + '/ngcc_lock_unlocker.js', [path, logLevel],
+        getLockFileUnlockerScriptPath(this.fs), [path, logLevel],
         {detached: true, stdio: isWindows ? 'pipe' : 'inherit'});
     if (isWindows) {
       unlocker.stdout?.on('data', process.stdout.write.bind(process.stdout));
@@ -87,3 +88,16 @@ export class LockFileWithChildProcess implements LockFile {
     return unlocker;
   }
 }
+
+/** Gets the absolute file path to the lock file unlocker script. */
+export function getLockFileUnlockerScriptPath(fileSystem: FileSystem): AbsoluteFsPath {
+  // This is an interop allowing for the unlocking script to be determined in both
+  // a CommonJS module, or an ES module which does not come with `require` by default.
+  const requireFn =
+      typeof require !== 'undefined' ? require : module.createRequire(__ESM_IMPORT_META_URL__);
+  // We resolve the worker script using module resolution as in the package output,
+  // the worker might be bundled but exposed through a subpath export mapping.
+  const unlockerScriptPath = requireFn.resolve(
+      '@angular/compiler-cli/ngcc/src/locking/lock_file_with_child_process/ngcc_lock_unlocker');
+  return fileSystem.resolve(unlockerScriptPath);
+}
diff --git a/packages/compiler-cli/ngcc/src/packages/configuration.ts b/packages/compiler-cli/ngcc/src/packages/configuration.ts
index c226efc0f57..13f3c857534 100644
--- a/packages/compiler-cli/ngcc/src/packages/configuration.ts
+++ b/packages/compiler-cli/ngcc/src/packages/configuration.ts
@@ -6,6 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 import {createHash} from 'crypto';
+import module from 'module';
 import semver from 'semver';
 import * as vm from 'vm';
 
@@ -267,6 +268,11 @@ export const DEFAULT_NGCC_CONFIG: NgccProjectConfig = {
 
 const NGCC_CONFIG_FILENAME = 'ngcc.config.js';
 
+// CommonJS/ESM interop for determining the current file name and containing
+// directory. The path is needed for loading the user configuration.
+const isCommonJS = typeof require !== 'undefined';
+const currentFileUrl = isCommonJS ? null : __ESM_IMPORT_META_URL__;
+
 /**
  * The processed package level configuration as a result of processing a raw package level config.
  */
@@ -435,12 +441,13 @@ export class NgccConfiguration {
   }
 
   private evalSrcFile(srcPath: AbsoluteFsPath): any {
+    const requireFn = isCommonJS ? require : module.createRequire(currentFileUrl!);
     const src = this.fs.readFile(srcPath);
     const theExports = {};
     const sandbox = {
       module: {exports: theExports},
       exports: theExports,
-      require,
+      require: requireFn,
       __dirname: this.fs.dirname(srcPath),
       __filename: srcPath
     };
diff --git a/packages/compiler-cli/ngcc/test/integration/ngcc_spec.ts b/packages/compiler-cli/ngcc/test/integration/ngcc_spec.ts
index e6c091d8ff8..c80ec6ae5d2 100644
--- a/packages/compiler-cli/ngcc/test/integration/ngcc_spec.ts
+++ b/packages/compiler-cli/ngcc/test/integration/ngcc_spec.ts
@@ -7,8 +7,8 @@
  */
 
 /// <reference types="node" />
-import {readFileSync} from 'fs';
-import * as os from 'os';
+import realFs from 'fs';
+import os from 'os';
 
 import {absoluteFrom, AbsoluteFsPath, FileSystem, getFileSystem} from '../../../src/ngtsc/file_system';
 import {Folder, MockFileSystem, runInEachFileSystem, TestFile} from '../../../src/ngtsc/file_system/testing';
@@ -69,7 +69,7 @@ runInEachFileSystem(() => {
       fs.ensureDir(fs.join(pkgPath, 'fesm5'));
       fs.writeFile(
           fs.join(pkgPath, 'fesm5/core.js'),
-          readFileSync(require.resolve('../fesm5_angular_core.js'), 'utf8'));
+          realFs.readFileSync(require.resolve('../fesm5_angular_core.js'), 'utf8'));
 
       pkgJson.esm5 = './fesm5/core.js';
       pkgJson.fesm5 = './fesm5/core.js';
diff --git a/packages/compiler-cli/ngcc/test/ngcc_options_spec.ts b/packages/compiler-cli/ngcc/test/ngcc_options_spec.ts
index 31ee7522a58..f28c0a3a927 100644
--- a/packages/compiler-cli/ngcc/test/ngcc_options_spec.ts
+++ b/packages/compiler-cli/ngcc/test/ngcc_options_spec.ts
@@ -5,7 +5,10 @@
  * Use of this source code is governed by an MIT-style license that can be
  * found in the LICENSE file at https://angular.io/license
  */
-import * as os from 'os';
+// Note: We do not use a namespace import here because this will result in the
+// named exports being modified if we apply jasmine spies on `realFs`. Using
+// the default export gives us an object where we can patch properties on.
+import os from 'os';
 
 import {absoluteFrom, AbsoluteFsPath, FileSystem, getFileSystem} from '../../src/ngtsc/file_system';
 import {runInEachFileSystem} from '../../src/ngtsc/file_system/testing';
diff --git a/packages/compiler-cli/package.json b/packages/compiler-cli/package.json
index 03d9e54a364..a9d5b1577bd 100644
--- a/packages/compiler-cli/package.json
+++ b/packages/compiler-cli/package.json
@@ -40,6 +40,12 @@
     "./private/migrations": {
       "types": "./private/migrations.d.ts",
       "default": "./bundles/private/migrations.js"
+    },
+    "./ngcc/src/execution/cluster/ngcc_cluster_worker": {
+      "default": "./bundles/ngcc/src/execution/cluster/ngcc_cluster_worker.js"
+    },
+    "./ngcc/src/locking/lock_file_with_child_process/ngcc_lock_unlocker": {
+      "default": "./bundles/ngcc/src/locking/lock_file_with_child_process/ngcc_lock_unlocker.js"
     }
   },
   "dependencies": {
diff --git a/packages/compiler-cli/src/ngtsc/file_system/BUILD.bazel b/packages/compiler-cli/src/ngtsc/file_system/BUILD.bazel
index 1dc56c80e76..bc181642c3f 100644
--- a/packages/compiler-cli/src/ngtsc/file_system/BUILD.bazel
+++ b/packages/compiler-cli/src/ngtsc/file_system/BUILD.bazel
@@ -8,6 +8,9 @@ ts_library(
         "src/**/*.ts",
     ]),
     deps = [
+        # Allows for the `import.meta.url` constant to be used. This is
+        # a temporary interop until devmode is switched to ESM.
+        "//packages/compiler-cli:import_meta_url_types",
         "@npm//@types/node",
         "@npm//typescript",
     ],
diff --git a/packages/compiler-cli/src/ngtsc/file_system/src/node_js_file_system.ts b/packages/compiler-cli/src/ngtsc/file_system/src/node_js_file_system.ts
index b9556b5043b..b926c95126f 100644
--- a/packages/compiler-cli/src/ngtsc/file_system/src/node_js_file_system.ts
+++ b/packages/compiler-cli/src/ngtsc/file_system/src/node_js_file_system.ts
@@ -7,7 +7,10 @@
  */
 /// <reference types="node" />
 import * as fs from 'fs';
+import module from 'module';
 import * as p from 'path';
+import {fileURLToPath} from 'url';
+
 import {AbsoluteFsPath, FileStats, FileSystem, PathManipulation, PathSegment, PathString, ReadonlyFileSystem} from './types';
 
 /**
@@ -51,6 +54,14 @@ export class NodeJSPathManipulation implements PathManipulation {
   }
 }
 
+// CommonJS/ESM interop for determining the current file name and containing
+// directory. These paths are needed for detecting whether the file system
+// is case sensitive, or for finding the TypeScript default libraries.
+// TODO(devversion): Simplify this in the future if devmode uses ESM as well.
+const isCommonJS = typeof __filename !== 'undefined';
+const currentFileUrl = isCommonJS ? null : __ESM_IMPORT_META_URL__;
+const currentFileName = isCommonJS ? __filename : fileURLToPath(currentFileUrl!);
+
 /**
  * A wrapper around the Node.js file-system that supports readonly operations and path manipulation.
  */
@@ -60,7 +71,7 @@ export class NodeJSReadonlyFileSystem extends NodeJSPathManipulation implements
     if (this._caseSensitive === undefined) {
       // Note the use of the real file-system is intentional:
       // `this.exists()` relies upon `isCaseSensitive()` so that would cause an infinite recursion.
-      this._caseSensitive = !fs.existsSync(this.normalize(toggleCase(__filename)));
+      this._caseSensitive = !fs.existsSync(this.normalize(toggleCase(currentFileName)));
     }
     return this._caseSensitive;
   }
@@ -86,7 +97,9 @@ export class NodeJSReadonlyFileSystem extends NodeJSPathManipulation implements
     return this.resolve(fs.realpathSync(path));
   }
   getDefaultLibLocation(): AbsoluteFsPath {
-    return this.resolve(require.resolve('typescript'), '..');
+    // TODO(devversion): Once devmode output uses ESM, we can simplify this.
+    const requireFn = isCommonJS ? require : module.createRequire(currentFileUrl!);
+    return this.resolve(requireFn.resolve('typescript'), '..');
   }
 }
 
diff --git a/packages/compiler-cli/src/ngtsc/file_system/test/node_js_file_system_spec.ts b/packages/compiler-cli/src/ngtsc/file_system/test/node_js_file_system_spec.ts
index dc9dbf43627..b973d201aa5 100644
--- a/packages/compiler-cli/src/ngtsc/file_system/test/node_js_file_system_spec.ts
+++ b/packages/compiler-cli/src/ngtsc/file_system/test/node_js_file_system_spec.ts
@@ -5,8 +5,12 @@
  * Use of this source code is governed by an MIT-style license that can be
  * found in the LICENSE file at https://angular.io/license
  */
-import * as realFs from 'fs';
+// Note: We do not use a namespace import here because this will result in the
+// named exports being modified if we apply jasmine spies on `realFs`. Using
+// the default export gives us an object where we can patch properties on.
+import realFs from 'fs';
 import * as os from 'os';
+
 import {NodeJSFileSystem, NodeJSPathManipulation, NodeJSReadonlyFileSystem} from '../src/node_js_file_system';
 import {AbsoluteFsPath, PathSegment} from '../src/types';
 
diff --git a/packages/language-service/test/reflector_host_spec.ts b/packages/language-service/test/reflector_host_spec.ts
index 96f1a10ac34..79850af500b 100644
--- a/packages/language-service/test/reflector_host_spec.ts
+++ b/packages/language-service/test/reflector_host_spec.ts
@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import * as path from 'path';
+import path from 'path';
 import ts from 'typescript';
 
 import {ReflectorHost} from '../src/reflector_host';
diff --git a/packages/language-service/test/typescript_host_spec.ts b/packages/language-service/test/typescript_host_spec.ts
index 21156312894..e549e01eb9c 100644
--- a/packages/language-service/test/typescript_host_spec.ts
+++ b/packages/language-service/test/typescript_host_spec.ts
@@ -6,7 +6,10 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import * as path from 'path';
+// Note: We do not use a namespace import here because this will result in the
+// named exports being modified if we apply jasmine spies on `path`. Using
+// the default export gives us an object where we can patch properties on.
+import path from 'path';
 import ts from 'typescript';
 
 import {TypeScriptServiceHost} from '../src/typescript_host';