feat(@schematics/angular): add /.angular/cache to .gitignore

With this change we add `/.angular/cache` to `.gitignore`. This folder will primary be used to store the build disk cache artifacts.

packages/angular_devkit/build_angular/test/hello-world-lib/.gitignore

@@ -25,6 +25,7 @@
 !.vscode/extensions.json
 
 # misc
+/.angular/cache
 /.sass-cache
 /connect.lock
 /coverage

packages/angular_devkit/build_webpack/test/basic-app/.gitignore

@@ -25,6 +25,7 @@
 !.vscode/extensions.json
 
 # misc
+/.angular/cache
 /.sass-cache
 /connect.lock
 /coverage

packages/schematics/angular/migrations/migration-collection.json

@@ -139,6 +139,11 @@
       "version": "13.0.0",
       "factory": "./update-13/drop-ie-polyfills",
       "description": "Remove polyfills required only for Internet Explorer which is no longer supported."
+    },
+    "update-gitignore": {
+      "version": "13.0.0",
+      "factory": "./update-13/update-gitignore",
+      "description": "Updating '.gitignore' to include '.angular/cache'."
     }
   }
 }

packages/schematics/angular/migrations/update-13/update-gitignore.ts

@@ -0,0 +1,51 @@
+/**
+ * @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
+ */
+
+import { Rule } from '@angular-devkit/schematics';
+
+export default function (): Rule {
+  return (tree, context) => {
+    const gitIgnoreEntry = '/.angular/cache';
+    const gitIgnorePath = '.gitignore';
+
+    const contents = tree.read(gitIgnorePath)?.toString();
+    if (!contents) {
+      context.logger.warn(`Could not find '${gitIgnorePath}'.`);
+
+      return;
+    }
+
+    if (contents.includes(gitIgnoreEntry)) {
+      // The migration has run already.
+      return;
+    }
+
+    // Try to insert the new entry in the misc section.
+    const recorder = tree.beginUpdate(gitIgnorePath);
+    let idx = contents.indexOf('# misc');
+    if (idx < 0) {
+      idx = 0;
+    } else {
+      switch (contents[idx + 6]) {
+        case '\n':
+          idx += 7;
+          break;
+        case '\r':
+          idx += 8;
+          break;
+        default:
+          // the word is something else.
+          idx = 0;
+          break;
+      }
+    }
+
+    recorder.insertLeft(idx, `${gitIgnoreEntry}\n`);
+    tree.commitUpdate(recorder);
+  };
+}

packages/schematics/angular/migrations/update-13/update-gitignore_spec.ts

@@ -0,0 +1,128 @@
+/**
+ * @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
+ */
+
+import { tags } from '@angular-devkit/core';
+import { EmptyTree } from '@angular-devkit/schematics';
+import { SchematicTestRunner, UnitTestTree } from '@angular-devkit/schematics/testing';
+
+describe('Migration to update "gitignore".', () => {
+  const schematicName = 'update-gitignore';
+  const schematicRunner = new SchematicTestRunner(
+    'migrations',
+    require.resolve('../migration-collection.json'),
+  );
+
+  let tree: UnitTestTree;
+  beforeEach(() => {
+    tree = new UnitTestTree(new EmptyTree());
+  });
+
+  it(`should not modify '.gitignore' if '.angular/cache' is already present.`, async () => {
+    const input = tags.stripIndents`
+        # dependencies
+        /node_modules
+
+        # profiling files
+        chrome-profiler-events*.json
+
+        # misc
+        /.angular/cache
+        /.sass-cache
+        /connect.lock
+        /coverage
+
+        # System Files
+        .DS_Store
+        Thumbs.db
+    `;
+
+    tree.create('.gitignore', input);
+    const newTree = await schematicRunner.runSchematicAsync(schematicName, {}, tree).toPromise();
+    expect(newTree.readContent('.gitignore')).toBe(input);
+  });
+
+  it(`should insert '.angular/cache' in '# misc' section when it exists.`, async () => {
+    const input = tags.stripIndents`
+        # dependencies
+        /node_modules
+
+        # profiling files
+        chrome-profiler-events*.json
+
+        # misc
+        /.sass-cache
+        /connect.lock
+        /coverage
+
+        # System Files
+        .DS_Store
+        Thumbs.db
+    `;
+
+    const output = tags.stripIndents`
+        # dependencies
+        /node_modules
+
+        # profiling files
+        chrome-profiler-events*.json
+
+        # misc
+        /.angular/cache
+        /.sass-cache
+        /connect.lock
+        /coverage
+
+        # System Files
+        .DS_Store
+        Thumbs.db
+    `;
+
+    tree.create('.gitignore', input);
+    const newTree = await schematicRunner.runSchematicAsync(schematicName, {}, tree).toPromise();
+    expect(newTree.readContent('.gitignore')).toBe(output);
+  });
+
+  it(`should insert '.angular/cache' at the top when '# misc' section does not exist.`, async () => {
+    const input = tags.stripIndents`
+        # dependencies
+        /node_modules
+
+        # profiling files
+        chrome-profiler-events*.json
+
+        # miscs
+        /connect.lock
+        /coverage
+
+        # System Files
+        .DS_Store
+        Thumbs.db
+    `;
+
+    const output = tags.stripIndents`
+        /.angular/cache
+        # dependencies
+        /node_modules
+
+        # profiling files
+        chrome-profiler-events*.json
+
+        # miscs
+        /connect.lock
+        /coverage
+
+        # System Files
+        .DS_Store
+        Thumbs.db
+    `;
+
+    tree.create('.gitignore', input);
+    const newTree = await schematicRunner.runSchematicAsync(schematicName, {}, tree).toPromise();
+    expect(newTree.readContent('.gitignore')).toBe(output);
+  });
+});

packages/schematics/angular/workspace/files/__dot__gitignore.template

@@ -31,6 +31,7 @@ chrome-profiler-events*.json
 .history/*
 
 # misc
+/.angular/cache
 /.sass-cache
 /connect.lock
 /coverage