build: support running compiler-cli tests on windows

In order to support running "compiler-cli" tests that use the "test_support.ts"
utilities on Windows with Bazel, we need to imporve the logic that resolves NPM
packages and symlinks them into a temporary directory.

A more Bazel idiomatic and windows compatible way of resolving Bazel runfiles
is to use the "RUNFILES_MANIFEST" if present. This ensures that the NPM
packages can be also symlinked on Windows, and tests can execute properly
on Windows. Read more about why this is needed here:

* bazelbuild/bazel#3726 (comment)

packages/compiler-cli/test/BUILD.bazel

@@ -7,6 +7,7 @@ ts_library(
     testonly = True,
     srcs = [
         "mocks.ts",
+        "runfile_helpers.ts",
         "test_support.ts",
     ],
     visibility = [

packages/compiler-cli/test/ngcc/ngcc_spec.ts

@@ -12,6 +12,7 @@ import {join} from 'path';
 const Module = require('module');
 
 import {mainNgcc} from '../../src/ngcc/src/main';
+import {getAngularPackagesFromRunfiles} from '../runfile_helpers';
 
 describe('ngcc main()', () => {
   beforeEach(createMockFileSystem);
@@ -40,8 +41,7 @@ describe('ngcc main()', () => {
 
 
 function createMockFileSystem() {
-  const packagesPath = join(process.env.TEST_SRCDIR !, 'angular/packages');
-  mockFs({'/node_modules/@angular': loadPackages(packagesPath)});
+  mockFs({'/node_modules/@angular': loadAngularPackages()});
   spyOn(Module, '_resolveFilename').and.callFake(mockResolve);
 }
 
@@ -50,27 +50,16 @@ function restoreRealFileSystem() {
 }
 
 
-/**
- * Load the built Angular packages into an in-memory structure.
- * @param packagesPath the path to the folder containing the built packages.
- */
-function loadPackages(packagesPath: string): Directory {
+/** Load the built Angular packages into an in-memory structure. */
+function loadAngularPackages(): Directory {
   const packagesDirectory: Directory = {};
-  readdirSync(packagesPath).forEach(name => {
-    const packagePath = join(packagesPath, name);
-    if (!statSync(packagePath).isDirectory()) {
-      return;
-    }
-    const npmPackagePath = join(packagePath, 'npm_package');
-    if (!existsSync(npmPackagePath)) {
-      return;
-    }
-    packagesDirectory[name] = loadDirectory(npmPackagePath);
-  });
+
+  getAngularPackagesFromRunfiles().forEach(
+      ({name, pkgPath}) => { packagesDirectory[name] = loadDirectory(pkgPath); });
+
   return packagesDirectory;
 }
 
-
 /**
  * Load real files from the filesystem into an "in-memory" structure,
  * which can be used with `mock-fs`.

packages/compiler-cli/test/runfile_helpers.ts

@@ -0,0 +1,48 @@
+/**
+ * @license
+ * Copyright Google Inc. 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
+ */
+
+import * as fs from 'fs';
+import * as path from 'path';
+
+/**
+ * Gets all built Angular NPM package artifacts by querying the Bazel runfiles.
+ * In case there is a runfiles manifest (e.g. on Windows), the packages are resolved
+ * through the manifest because the runfiles are not symlinked and cannot be searched
+ * within the real filesystem.
+ */
+export function getAngularPackagesFromRunfiles() {
+  // Path to the Bazel runfiles manifest if present. This file is present if runfiles are
+  // not symlinked into the runfiles directory.
+  const runfilesManifestPath = process.env.RUNFILES_MANIFEST_FILE;
+
+  if (!runfilesManifestPath) {
+    const packageRunfilesDir = path.join(process.env.RUNFILES !, 'angular/packages');
+
+    return fs.readdirSync(packageRunfilesDir)
+        .map(name => ({name, pkgPath: path.join(packageRunfilesDir, name, 'npm_package/')}))
+        .filter(({pkgPath}) => fs.existsSync(pkgPath));
+  }
+
+  return fs.readFileSync(runfilesManifestPath, 'utf8')
+      .split('\n')
+      .map(mapping => mapping.split(' '))
+      .filter(([runfilePath]) => runfilePath.match(/^angular\/packages\/[\w-]+\/npm_package$/))
+      .map(([runfilePath, realPath]) => ({
+             name: path.relative('angular/packages', runfilePath).split(path.sep)[0],
+             pkgPath: realPath,
+           }));
+}
+
+/**
+ * Resolves a NPM package from the Bazel runfiles. We need to resolve the Bazel tree
+ * artifacts using a "resolve file" because the NodeJS module resolution does not allow
+ * resolving to directory paths.
+ */
+export function resolveNpmTreeArtifact(manifestPath: string, resolveFile = 'package.json') {
+  return path.dirname(require.resolve(path.posix.join(manifestPath, resolveFile)));
+}

packages/compiler-cli/test/test_support.ts

@@ -10,9 +10,10 @@ import * as fs from 'fs';
 import * as path from 'path';
 import * as ts from 'typescript';
 import * as ng from '../index';
+import {getAngularPackagesFromRunfiles, resolveNpmTreeArtifact} from './runfile_helpers';
 
 // TEST_TMPDIR is always set by Bazel.
-const tmpdir = process.env.TEST_TMPDIR!;
+const tmpdir = process.env.TEST_TMPDIR !;
 
 export function makeTempDir(): string {
   let dir: string;
@@ -51,6 +52,7 @@ function createTestSupportFor(basePath: string) {
     'baseUrl': basePath,
     'declaration': true,
     'target': ts.ScriptTarget.ES5,
+    'newLine': ts.NewLineKind.LineFeed,
     'module': ts.ModuleKind.ES2015,
     'moduleResolution': ts.ModuleResolutionKind.NodeJs,
     'lib': Object.freeze([
@@ -62,7 +64,16 @@ function createTestSupportFor(basePath: string) {
   };
 
 
-  return {basePath, write, writeFiles, createCompilerOptions, shouldExist, shouldNotExist};
+  return {
+    // We normalize the basePath into a posix path, so that multiple assertions which compare
+    // paths don't need to normalize the path separators each time.
+    basePath: normalizeSeparators(basePath),
+    write,
+    writeFiles,
+    createCompilerOptions,
+    shouldExist,
+    shouldNotExist
+  };
 
   function write(fileName: string, content: string) {
     const dir = path.dirname(fileName);
@@ -95,37 +106,29 @@ function createTestSupportFor(basePath: string) {
   }
 }
 
-export function setupBazelTo(basePath: string) {
-  if (!process.env.TEST_SRCDIR) {
-    throw new Error('`setupBazelTo()` must only be called from in a Bazel job.');
-  }
-  const sources = process.env.TEST_SRCDIR;
-  const packages = path.join(sources, 'angular/packages');
-  const nodeModulesPath = path.join(basePath, 'node_modules');
+export function setupBazelTo(tmpDirPath: string) {
+  const nodeModulesPath = path.join(tmpDirPath, 'node_modules');
   const angularDirectory = path.join(nodeModulesPath, '@angular');
-  fs.mkdirSync(nodeModulesPath);
 
-  // Link the built angular packages
+  fs.mkdirSync(nodeModulesPath);
   fs.mkdirSync(angularDirectory);
-  const packageNames = fs.readdirSync(packages).filter(
-      name => fs.statSync(path.join(packages, name)).isDirectory() &&
-          fs.existsSync(path.join(packages, name, 'npm_package')));
-  for (const pkg of packageNames) {
-    fs.symlinkSync(path.join(packages, `${pkg}/npm_package`), path.join(angularDirectory, pkg));
-  }
 
-  // Link rxjs
-  const rxjsSource = path.join(sources, 'rxjs');
-  const rxjsDest = path.join(nodeModulesPath, 'rxjs');
-  if (fs.existsSync(rxjsSource)) {
-    fs.symlinkSync(rxjsSource, rxjsDest);
-  }
+  getAngularPackagesFromRunfiles().forEach(
+      ({pkgPath, name}) => { fs.symlinkSync(pkgPath, path.join(angularDirectory, name), 'dir'); });
 
   // Link typescript
-  const typescriptSource = path.join(sources, 'ngdeps/node_modules/typescript');
+  const typeScriptSource = resolveNpmTreeArtifact('ngdeps/node_modules/typescript');
   const typescriptDest = path.join(nodeModulesPath, 'typescript');
-  if (fs.existsSync(typescriptSource)) {
-    fs.symlinkSync(typescriptSource, typescriptDest);
+  fs.symlinkSync(typeScriptSource, typescriptDest, 'dir');
+
+  // Link "rxjs" if it has been set up as a runfile. "rxjs" is linked optionally because
+  // not all compiler-cli tests need "rxjs" set up.
+  try {
+    const rxjsSource = resolveNpmTreeArtifact('rxjs', 'index.js');
+    const rxjsDest = path.join(nodeModulesPath, 'rxjs');
+    fs.symlinkSync(rxjsSource, rxjsDest, 'dir');
+  } catch (e) {
+    if (e.code !== 'MODULE_NOT_FOUND') throw e;
   }
 }
 
@@ -148,3 +151,7 @@ export function expectNoDiagnosticsInProgram(options: ng.CompilerOptions, p: ng.
     ...p.getNgSemanticDiagnostics()
   ]);
 }
+
+export function normalizeSeparators(path: string): string {
+  return path.replace(/\\/g, '/');
+}