From d95912703bc9e1d64ec42ad8d3fd61a78fec9f86 Mon Sep 17 00:00:00 2001
From: Charles Lyding <19598772+clydin@users.noreply.github.com>
Date: Thu, 17 Jun 2021 19:50:24 -0400
Subject: [PATCH] fix(@angular-devkit/build-angular): control linker template
 sourcemapping via builder sourcemap options

This change allows the linker sourcemap behavior to be controlled by the Webpack sourcemap configuration. For example, if a vendor file is being processed and vendor sourcemaps are disabled, the linker will now skip its internal sourcemap loading and processing steps.

(cherry picked from commit d4c5f8518d4801b9fd76de289a015dcbb8d8f69b)
---
 .../build_angular/src/babel/presets/application.ts     | 10 ++++++----
 .../build_angular/src/babel/webpack-loader.ts          | 10 ++++++++++
 2 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/packages/angular_devkit/build_angular/src/babel/presets/application.ts b/packages/angular_devkit/build_angular/src/babel/presets/application.ts
index a04bb848534b..6d5d2b728235 100644
--- a/packages/angular_devkit/build_angular/src/babel/presets/application.ts
+++ b/packages/angular_devkit/build_angular/src/babel/presets/application.ts
@@ -20,6 +20,7 @@ export interface ApplicationPresetOptions {
   angularLinker?: {
     shouldLink: boolean;
     jitMode: boolean;
+    sourcemap: boolean;
   };
 
   forceES5?: boolean;
@@ -31,7 +32,8 @@ export interface ApplicationPresetOptions {
 type I18nDiagnostics = import('@angular/localize/src/tools/src/diagnostics').Diagnostics;
 function createI18nDiagnostics(reporter: DiagnosticReporter | undefined): I18nDiagnostics {
   // Babel currently is synchronous so import cannot be used
-  const diagnostics: I18nDiagnostics = new (require('@angular/localize/src/tools/src/diagnostics').Diagnostics)();
+  const diagnostics: I18nDiagnostics =
+    new (require('@angular/localize/src/tools/src/diagnostics').Diagnostics)();
 
   if (!reporter) {
     return diagnostics;
@@ -130,13 +132,13 @@ export default function (api: unknown, options: ApplicationPresetOptions) {
 
   if (options.angularLinker?.shouldLink) {
     // Babel currently is synchronous so import cannot be used
-    const {
-      createEs2015LinkerPlugin,
-    } = require('@angular/compiler-cli/linker/babel') as typeof import('@angular/compiler-cli/linker/babel');
+    const { createEs2015LinkerPlugin } =
+      require('@angular/compiler-cli/linker/babel') as typeof import('@angular/compiler-cli/linker/babel');
 
     plugins.push(
       createEs2015LinkerPlugin({
         linkerJitMode: options.angularLinker.jitMode,
+        sourceMapping: options.angularLinker.sourcemap,
         logger: createNgtscLogger(options.diagnosticReporter),
         fileSystem: {
           resolve: path.resolve,
diff --git a/packages/angular_devkit/build_angular/src/babel/webpack-loader.ts b/packages/angular_devkit/build_angular/src/babel/webpack-loader.ts
index 3b818fe5acd7..42e159f24a2f 100644
--- a/packages/angular_devkit/build_angular/src/babel/webpack-loader.ts
+++ b/packages/angular_devkit/build_angular/src/babel/webpack-loader.ts
@@ -53,6 +53,7 @@ export default custom<AngularCustomOptions>(() => {
         customOptions.angularLinker = {
           shouldLink: true,
           jitMode: aot !== true,
+          sourcemap: false,
         };
         shouldProcess = true;
       }
@@ -101,6 +102,15 @@ export default custom<AngularCustomOptions>(() => {
       return { custom: customOptions, loader: loaderOptions };
     },
     config(configuration, { customOptions }) {
+      // Only enable linker template sourcemapping if linker is enabled and Webpack provides
+      // a sourcemap. This logic allows the linker sourcemap behavior to be controlled by the
+      // Webpack sourcemap configuration. For example, if a vendor file is being processed
+      // and vendor sourcemaps are disabled, the `inputSourceMap` property will be `undefined`
+      // which will effectively disable linker sourcemapping for vendor files.
+      if (customOptions.angularLinker && configuration.options.inputSourceMap) {
+        customOptions.angularLinker.sourcemap = true;
+      }
+
       return {
         ...configuration.options,
         // Workaround for https://github.com/babel/babel-loader/pull/896 is available