build: use Bazel diff_test to compare file differences

Leverage the built-in `diff_test` feature from Bazel to check for file changes. For details, see: https://github.com/bazelbuild/bazel-skylib/blob/main/docs/diff_test_doc.md

Author: alan-agius4

package.json

@@ -92,7 +92,6 @@
     "@rollup/plugin-node-resolve": "^13.0.5",
     "@types/babel__core": "7.20.5",
     "@types/browser-sync": "^2.27.0",
-    "@types/diff": "^5.2.1",
     "@types/express": "^4.16.0",
     "@types/http-proxy": "^1.17.4",
     "@types/ini": "^4.0.0",
@@ -132,7 +131,6 @@
     "critters": "0.0.24",
     "css-loader": "7.1.2",
     "debug": "^4.1.1",
-    "diff": "^5.2.0",
     "esbuild": "0.23.1",
     "esbuild-wasm": "0.23.1",
     "eslint": "8.57.0",

packages/angular/ssr/package.json

@@ -29,7 +29,6 @@
     "@angular/platform-server": "19.0.0-next.1",
     "@angular/router": "19.0.0-next.1",
     "@bazel/runfiles": "^5.8.1",
-    "diff": "^5.2.0",
     "zone.js": "^0.15.0"
   },
   "schematics": "./schematics/collection.json",

packages/angular/ssr/test/npm_package/BUILD.bazel

@@ -1,4 +1,5 @@
-load("@build_bazel_rules_nodejs//:index.bzl", "nodejs_binary")
+load("@bazel_skylib//rules:diff_test.bzl", "diff_test")
+load("@bazel_skylib//rules:write_file.bzl", "write_file")
 load("@npm//@bazel/jasmine:index.bzl", "jasmine_node_test")
 load("//tools:defaults.bzl", "ts_library")
 
@@ -8,28 +9,50 @@ ts_library(
     srcs = glob(["**/*.ts"]),
     deps = [
         "@npm//@bazel/runfiles",
-        "@npm//@types/diff",
     ],
 )
 
 jasmine_node_test(
     name = "test",
     srcs = [":unit_test_lib"],
     data = [
-        "THIRD_PARTY_LICENSES.txt.golden",
         "//packages/angular/ssr:npm_package",
-        "@npm//diff",
     ],
 )
 
-nodejs_binary(
-    name = "test.accept",
-    testonly = True,
-    data = [
-        "THIRD_PARTY_LICENSES.txt.golden",
-        ":unit_test_lib",
+genrule(
+    name = "critters_license_file",
+    srcs = [
         "//packages/angular/ssr:npm_package",
-        "@npm//diff",
     ],
-    entry_point = ":update-package-golden.ts",
+    outs = [
+        "THIRD_PARTY_LICENSES.txt",
+    ],
+    cmd = """
+      cp $(location //packages/angular/ssr:npm_package)/third_party/critters/THIRD_PARTY_LICENSES.txt $(location :THIRD_PARTY_LICENSES.txt)
+    """,
+)
+
+diff_test(
+    name = "critters_license_test",
+    failure_message = """
+
+    To accept the new golden file, execute:
+    yarn bazel run //packages/angular/ssr/test/npm_package:critters_license_test.accept
+    """,
+    file1 = ":THIRD_PARTY_LICENSES.txt.golden",
+    file2 = ":critters_license_file",
+)
+
+write_file(
+    name = "critters_license_test.accept",
+    out = "critters_license_file_accept.sh",
+    content =
+        [
+            "#!/usr/bin/env bash",
+            "cd ${BUILD_WORKSPACE_DIRECTORY}",
+            "yarn bazel build //packages/angular/ssr:npm_package",
+            "cp -fv dist/bin/packages/angular/ssr/npm_package/third_party/critters/THIRD_PARTY_LICENSES.txt packages/angular/ssr/test/npm_package/THIRD_PARTY_LICENSES.txt.golden",
+        ],
+    is_executable = True,
 )

packages/angular/ssr/test/npm_package/package_spec.ts

@@ -6,15 +6,32 @@
  * found in the LICENSE file at https://angular.dev/license
  */
 
-import { createPatch } from 'diff';
+import { runfiles } from '@bazel/runfiles';
 import { existsSync } from 'node:fs';
 import { readFile } from 'node:fs/promises';
-import { join } from 'node:path';
-import {
+import { dirname, join } from 'node:path';
+
+/**
+ * Resolve paths for the Critters license file and the golden reference file.
+ */
+const ANGULAR_SSR_PACKAGE_PATH = dirname(
+  runfiles.resolve('angular_cli/packages/angular/ssr/npm_package/package.json'),
+);
+
+/**
+ * Path to the actual license file for the Critters library.
+ * This file is located in the `third_party/critters` directory of the Angular CLI npm package.
+ */
+const CRITTERS_ACTUAL_LICENSE_FILE_PATH = join(
   ANGULAR_SSR_PACKAGE_PATH,
-  CRITTERS_ACTUAL_LICENSE_FILE_PATH,
-  CRITTERS_GOLDEN_LICENSE_FILE_PATH,
-} from './utils';
+  'third_party/critters/THIRD_PARTY_LICENSES.txt',
+);
+
+/**
+ * Path to the golden reference license file for the Critters library.
+ * This file is used as a reference for comparison and is located in the same directory as this script.
+ */
+const CRITTERS_GOLDEN_LICENSE_FILE_PATH = join(__dirname, 'THIRD_PARTY_LICENSES.txt.golden');
 
 describe('NPM Package Tests', () => {
   it('should not include the contents of third_party/critters/index.js in the FESM bundle', async () => {
@@ -27,36 +44,5 @@ describe('NPM Package Tests', () => {
     it('should exist', () => {
       expect(existsSync(CRITTERS_ACTUAL_LICENSE_FILE_PATH)).toBe(true);
     });
-
-    it('should match the expected golden file', async () => {
-      const [expectedContent, actualContent] = await Promise.all([
-        readFile(CRITTERS_GOLDEN_LICENSE_FILE_PATH, 'utf-8'),
-        readFile(CRITTERS_ACTUAL_LICENSE_FILE_PATH, 'utf-8'),
-      ]);
-
-      if (expectedContent.trim() === actualContent.trim()) {
-        return;
-      }
-
-      const patch = createPatch(
-        CRITTERS_GOLDEN_LICENSE_FILE_PATH,
-        expectedContent,
-        actualContent,
-        'Golden License File',
-        'Current License File',
-        { context: 5 },
-      );
-
-      const errorMessage = `The content of the actual license file differs from the expected golden reference.
-      Diff:
-      ${patch}
-      To accept the new golden file, execute:
-        yarn bazel run ${process.env['BAZEL_TARGET']}.accept
-    `;
-
-      const error = new Error(errorMessage);
-      error.stack = error.stack?.replace(`      Diff:\n      ${patch}`, '');
-      throw error;
-    });
   });
 });

packages/angular/ssr/test/npm_package/update-package-golden.ts

@@ -668,7 +668,6 @@ __metadata:
     "@rollup/plugin-node-resolve": "npm:^13.0.5"
     "@types/babel__core": "npm:7.20.5"
     "@types/browser-sync": "npm:^2.27.0"
-    "@types/diff": "npm:^5.2.1"
     "@types/express": "npm:^4.16.0"
     "@types/http-proxy": "npm:^1.17.4"
     "@types/ini": "npm:^4.0.0"
@@ -708,7 +707,6 @@ __metadata:
     critters: "npm:0.0.24"
     css-loader: "npm:7.1.2"
     debug: "npm:^4.1.1"
-    diff: "npm:^5.2.0"
     esbuild: "npm:0.23.1"
     esbuild-wasm: "npm:0.23.1"
     eslint: "npm:8.57.0"
@@ -969,7 +967,6 @@ __metadata:
     "@angular/platform-server": "npm:19.0.0-next.1"
     "@angular/router": "npm:19.0.0-next.1"
     "@bazel/runfiles": "npm:^5.8.1"
-    diff: "npm:^5.2.0"
     tslib: "npm:^2.3.0"
     zone.js: "npm:^0.15.0"
   peerDependencies:
@@ -4871,13 +4868,6 @@ __metadata:
   languageName: node
   linkType: hard
 
-"@types/diff@npm:^5.2.1":
-  version: 5.2.1
-  resolution: "@types/diff@npm:5.2.1"
-  checksum: 10c0/62dcab32197ac67f212939cdd79aa3953327a482bec55c6a38ad9de8a0662a9f920b59504609a322fc242593bd9afb3d2704702f4bc98087a13171234b952361
-  languageName: node
-  linkType: hard
-
 "@types/estree@npm:*, @types/estree@npm:1.0.5, @types/estree@npm:^1.0.0, @types/estree@npm:^1.0.5":
   version: 1.0.5
   resolution: "@types/estree@npm:1.0.5"
@@ -8561,7 +8551,7 @@ __metadata:
   languageName: node
   linkType: hard
 
-"diff@npm:^5.0.0, diff@npm:^5.1.0, diff@npm:^5.2.0":
+"diff@npm:^5.0.0, diff@npm:^5.1.0":
   version: 5.2.0
   resolution: "diff@npm:5.2.0"
   checksum: 10c0/aed0941f206fe261ecb258dc8d0ceea8abbde3ace5827518ff8d302f0fc9cc81ce116c4d8f379151171336caf0516b79e01abdc1ed1201b6440d895a66689eb4