fix(@angular-devkit/build-angular): use istanbul-lib-instrument directly for karma code coverage

The `istanbul-lib-instrument` package provides the required functionality needed
to instrument code for test coverage within the context of the Angular CLI.
Since the build pipeline already contains a customized babel preset, this package
can be integrated directly into the pipeline.
This reduces the number of dependencies required for `@angular-devkit/build-angular`
including the deprecated `inflight` package.

(cherry picked from commit fb2981d)

Author: clydin

package.json

@@ -122,7 +122,6 @@
     "ansi-colors": "4.1.3",
     "autoprefixer": "10.4.19",
     "babel-loader": "9.1.3",
-    "babel-plugin-istanbul": "6.1.1",
     "browser-sync": "3.0.2",
     "browserslist": "^4.21.5",
     "buffer": "6.0.3",
@@ -145,6 +144,7 @@
     "husky": "9.0.11",
     "ini": "4.1.2",
     "inquirer": "9.2.22",
+    "istanbul-lib-instrument": "6.0.2",
     "jasmine": "^5.0.0",
     "jasmine-core": "~5.1.0",
     "jasmine-spec-reporter": "~7.0.0",

packages/angular_devkit/build_angular/BUILD.bazel

@@ -162,7 +162,6 @@ ts_library(
         "@npm//ansi-colors",
         "@npm//autoprefixer",
         "@npm//babel-loader",
-        "@npm//babel-plugin-istanbul",
         "@npm//browserslist",
         "@npm//copy-webpack-plugin",
         "@npm//critters",
@@ -173,6 +172,7 @@ ts_library(
         "@npm//http-proxy-middleware",
         "@npm//https-proxy-agent",
         "@npm//inquirer",
+        "@npm//istanbul-lib-instrument",
         "@npm//jsonc-parser",
         "@npm//karma",
         "@npm//karma-source-map-support",

packages/angular_devkit/build_angular/package.json

@@ -26,7 +26,6 @@
     "ansi-colors": "4.1.3",
     "autoprefixer": "10.4.19",
     "babel-loader": "9.1.3",
-    "babel-plugin-istanbul": "6.1.1",
     "browserslist": "^4.21.5",
     "copy-webpack-plugin": "11.0.0",
     "critters": "0.0.22",
@@ -36,6 +35,7 @@
     "https-proxy-agent": "7.0.4",
     "http-proxy-middleware": "3.0.0",
     "inquirer": "9.2.22",
+    "istanbul-lib-instrument": "6.0.2",
     "jsonc-parser": "3.2.1",
     "karma-source-map-support": "1.4.0",
     "less": "4.2.0",

packages/angular_devkit/build_angular/src/tools/babel/plugins/add-code-coverage.ts

@@ -0,0 +1,43 @@
+/**
+ * @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.dev/license
+ */
+
+import { NodePath, PluginObj, types } from '@babel/core';
+import { Visitor, programVisitor } from 'istanbul-lib-instrument';
+import assert from 'node:assert';
+
+/**
+ * A babel plugin factory function for adding istanbul instrumentation.
+ *
+ * @returns A babel plugin object instance.
+ */
+export default function (): PluginObj {
+  const visitors = new WeakMap<NodePath, Visitor>();
+
+  return {
+    visitor: {
+      Program: {
+        enter(path, state) {
+          const visitor = programVisitor(types, state.filename, {
+            // Babel returns a Converter object from the `convert-source-map` package
+            inputSourceMap: (state.file.inputMap as undefined | { toObject(): object })?.toObject(),
+          });
+          visitors.set(path, visitor);
+
+          visitor.enter(path);
+        },
+        exit(path) {
+          const visitor = visitors.get(path);
+          assert(visitor, 'Instrumentation visitor should always be present for program path.');
+
+          visitor.exit(path);
+          visitors.delete(path);
+        },
+      },
+    },
+  };
+}

packages/angular_devkit/build_angular/src/tools/babel/plugins/types.d.ts

@@ -0,0 +1,20 @@
+/**
+ * @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.dev/license
+ */
+
+declare module 'istanbul-lib-instrument' {
+  export interface Visitor {
+    enter(path: import('@babel/core').NodePath<types.Program>): void;
+    exit(path: import('@babel/core').NodePath<types.Program>): void;
+  }
+
+  export function programVisitor(
+    types: typeof import('@babel/core').types,
+    filePath?: string,
+    options?: { inputSourceMap?: object | null },
+  ): Visitor;
+}

packages/angular_devkit/build_angular/src/tools/babel/presets/application.ts

@@ -265,13 +265,7 @@ export default function (api: unknown, options: ApplicationPresetOptions) {
   }
 
   if (options.instrumentCode) {
-    plugins.push([
-      require('babel-plugin-istanbul').default,
-      {
-        inputSourceMap: options.instrumentCode.inputSourceMap ?? false,
-        cwd: options.instrumentCode.includedBasePath,
-      },
-    ]);
+    plugins.push(require('../plugins/add-code-coverage').default);
   }
 
   if (needRuntimeTransform) {