feat(@schematics/angular): add migration to update tslint to version 6

In tslint version 6, several recommanded rules have been removed in the following PRs:
palantir/tslint#4871 palantir/tslint#4312

With this migration we update the tslint depedency to 6+ and add back these rules in the user workspace `tslint.json` also we remove some deprecated rules.

Until version 10, this is an opt-in migration and users will need to run this manually with the below command:
```
ng update @angular/cli --migrate-only tslint-version-6
```

Closes: #17117
Reference: TOOL-1348

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

@@ -54,6 +54,11 @@
       "version": "9.0.2",
       "factory": "./update-9/schematic-options",
       "description": "Replace deprecated 'styleext' and 'spec' Angular schematic options."
+    },
+    "tslint-version-6": {
+      "version": "10.0.0-beta.0",
+      "factory": "./update-10/update-tslint",
+      "description": "Update tslint to version 6."
     }
   }
 }

packages/schematics/angular/migrations/update-10/update-tslint.ts

@@ -0,0 +1,156 @@
+/**
+ * @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 { JsonAstObject, JsonValue } from '@angular-devkit/core';
+import { Rule } from '@angular-devkit/schematics';
+import { addPackageJsonDependency, getPackageJsonDependency } from '../../utility/dependencies';
+import { findPropertyInAstObject, insertPropertyInAstObjectInOrder, removePropertyInAstObject } from '../../utility/json-utils';
+import { readJsonFileAsAstObject } from '../update-9/utils';
+
+export const TSLINT_VERSION = '~6.1.0';
+const TSLINT_CONFIG_PATH = '/tslint.json';
+
+const RULES_TO_DELETE: string[] = [
+  'no-use-before-declare',
+  'no-unused-variable',
+];
+
+const RULES_TO_ADD: Record<string, JsonValue> = {
+  align: {
+    options: ['parameters', 'statements'],
+  },
+  'arrow-return-shorthand': true,
+  curly: true,
+  eofline: true,
+  'import-spacing': true,
+  indent: {
+    options: ['spaces'],
+  },
+  'variable-name': {
+    options: ['ban-keywords', 'check-format', 'allow-pascal-case'],
+  },
+  semicolon: { options: ['always'] },
+  'space-before-function-paren': {
+    options: {
+      anonymous: 'never',
+      asyncArrow: 'always',
+      constructor: 'never',
+      method: 'never',
+      named: 'never',
+    },
+  },
+  'typedef-whitespace': {
+    options: [
+      {
+        'call-signature': 'nospace',
+        'index-signature': 'nospace',
+        parameter: 'nospace',
+        'property-declaration': 'nospace',
+        'variable-declaration': 'nospace',
+      },
+      {
+        'call-signature': 'onespace',
+        'index-signature': 'onespace',
+        parameter: 'onespace',
+        'property-declaration': 'onespace',
+        'variable-declaration': 'onespace',
+      },
+    ],
+  },
+  whitespace: {
+    options: [
+      'check-branch',
+      'check-decl',
+      'check-operator',
+      'check-separator',
+      'check-type',
+      'check-typecast',
+    ],
+  },
+};
+
+export default function (): Rule {
+  return (tree, context) => {
+    const logger = context.logger;
+
+    // Update tslint dependency
+    const current = getPackageJsonDependency(tree, 'tslint');
+
+    if (!current) {
+      logger.info('"tslint" in not a dependency of this workspace.');
+
+      return;
+    }
+
+    if (current.version !== TSLINT_VERSION) {
+      addPackageJsonDependency(tree, {
+        type: current.type,
+        name: 'tslint',
+        version: TSLINT_VERSION,
+        overwrite: true,
+      });
+    }
+
+    // Update tslint config.
+    const tslintJsonAst = readJsonFileAsAstObject(tree, TSLINT_CONFIG_PATH);
+    if (!tslintJsonAst) {
+      const config = ['tslint.js', 'tslint.yaml'].find(c => tree.exists(c));
+      if (config) {
+        logger.warn(`Expected a JSON configuration file but found "${config}".`);
+      } else {
+        logger.warn('Cannot find "tslint.json" configuration file.');
+      }
+
+      return;
+    }
+
+    // Remove old/deprecated rules.
+    for (const rule of RULES_TO_DELETE) {
+      const tslintJsonAst = readJsonFileAsAstObject(tree, TSLINT_CONFIG_PATH) as JsonAstObject;
+      const rulesAst = findPropertyInAstObject(tslintJsonAst, 'rules');
+      if (rulesAst?.kind !== 'object') {
+        break;
+      }
+
+      const recorder = tree.beginUpdate(TSLINT_CONFIG_PATH);
+      removePropertyInAstObject(recorder, rulesAst, rule);
+      tree.commitUpdate(recorder);
+    }
+
+    // Add new rules only iif the configuration extends 'tslint:recommended'.
+    // This is because some rules conflict with prettier or other tools.
+    const extendsAst = findPropertyInAstObject(tslintJsonAst, 'extends');
+    if (
+      !extendsAst ||
+      (extendsAst.kind === 'string' && extendsAst.value !== 'tslint:recommended') ||
+      (extendsAst.kind === 'array' && extendsAst.elements.some(e => e.value !== 'tslint:recommended'))
+    ) {
+      logger.warn(`tslint configuration does not extend "tslint:recommended".`
+        + '\nMigration will terminate as some rules might conflict.');
+
+      return;
+    }
+
+    for (const [name, value] of Object.entries(RULES_TO_ADD)) {
+      const tslintJsonAst = readJsonFileAsAstObject(tree, TSLINT_CONFIG_PATH) as JsonAstObject;
+      const rulesAst = findPropertyInAstObject(tslintJsonAst, 'rules');
+      if (rulesAst?.kind !== 'object') {
+        break;
+      }
+
+      if (findPropertyInAstObject(rulesAst, name)) {
+        // Skip as rule already exists.
+        continue;
+      }
+
+      const recorder = tree.beginUpdate(TSLINT_CONFIG_PATH);
+      insertPropertyInAstObjectInOrder(recorder, rulesAst, name, value, 4);
+      tree.commitUpdate(recorder);
+    }
+
+  };
+}

packages/schematics/angular/migrations/update-10/update-tslint_spec.ts

@@ -0,0 +1,114 @@
+/**
+ * @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 { EmptyTree } from '@angular-devkit/schematics';
+import { SchematicTestRunner, UnitTestTree } from '@angular-devkit/schematics/testing';
+import { TSLINT_VERSION } from './update-tslint';
+
+describe('Migration of tslint to version 6', () => {
+  const schematicRunner = new SchematicTestRunner(
+    'migrations',
+    require.resolve('../migration-collection.json'),
+  );
+
+  let tree: UnitTestTree;
+  const TSLINT_PATH = '/tslint.json';
+  const PACKAGE_JSON_PATH = '/package.json';
+
+  const TSLINT_CONFIG = {
+    extends: 'tslint:recommended',
+    rules: {
+      'no-use-before-declare': true,
+      'arrow-return-shorthand': false,
+      'label-position': true,
+    },
+  };
+
+  const PACKAGE_JSON = {
+    devDependencies: {
+      tslint: '~5.1.0',
+    },
+  };
+
+  beforeEach(() => {
+    tree = new UnitTestTree(new EmptyTree());
+    tree.create(PACKAGE_JSON_PATH, JSON.stringify(PACKAGE_JSON, null, 2));
+    tree.create(TSLINT_PATH, JSON.stringify(TSLINT_CONFIG, null, 2));
+  });
+
+  it('should update tslint dependency', async () => {
+    const newTree = await schematicRunner.runSchematicAsync('tslint-version-6', {}, tree).toPromise();
+    const packageJson = JSON.parse(newTree.readContent(PACKAGE_JSON_PATH));
+    expect(packageJson.devDependencies.tslint).toBe(TSLINT_VERSION);
+  });
+
+  it('should remove old/deprecated rules', async () => {
+    const newTree = await schematicRunner.runSchematicAsync('tslint-version-6', {}, tree).toPromise();
+    const { rules } = JSON.parse(newTree.readContent(TSLINT_PATH));
+    expect(rules['no-use-before-declare']).toBeUndefined();
+  });
+
+  it('should add new rules', async () => {
+    const newTree = await schematicRunner.runSchematicAsync('tslint-version-6', {}, tree).toPromise();
+    const { rules } = JSON.parse(newTree.readContent(TSLINT_PATH));
+    expect(rules['eofline']).toBe(true);
+  });
+
+  it('should not update already present rules', async () => {
+    const newTree = await schematicRunner.runSchematicAsync('tslint-version-6', {}, tree).toPromise();
+    const { rules } = JSON.parse(newTree.readContent(TSLINT_PATH));
+    expect(rules['arrow-return-shorthand']).toBe(false);
+  });
+
+  it(`should not add new rules when not extending 'tslint:recommended'`, async () => {
+    tree.overwrite(
+      TSLINT_PATH,
+      JSON.stringify({
+        ...TSLINT_CONFIG,
+        extends: 'tslint-config-prettier',
+      }, null, 2),
+    );
+
+    const newTree = await schematicRunner.runSchematicAsync('tslint-version-6', {}, tree).toPromise();
+    const { rules } = JSON.parse(newTree.readContent(TSLINT_PATH));
+    expect(rules['eofline']).toBeUndefined();
+  });
+
+  it(`should not add new rules when extending multiple configs`, async () => {
+    tree.overwrite(
+      TSLINT_PATH,
+      JSON.stringify({
+        ...TSLINT_CONFIG,
+        extends: [
+          'tslint:recommended',
+          'tslint-config-prettier',
+        ],
+      }, null, 2),
+    );
+
+    const newTree = await schematicRunner.runSchematicAsync('tslint-version-6', {}, tree).toPromise();
+    const { rules } = JSON.parse(newTree.readContent(TSLINT_PATH));
+    expect(rules['eofline']).toBeUndefined();
+  });
+
+  it(`should remove old/deprecated rules when extending multiple configs`, async () => {
+    tree.overwrite(
+      TSLINT_PATH,
+      JSON.stringify({
+        ...TSLINT_CONFIG,
+        extends: [
+          'tslint:recommended',
+          'tslint-config-prettier',
+        ],
+      }, null, 2),
+    );
+
+    const newTree = await schematicRunner.runSchematicAsync('tslint-version-6', {}, tree).toPromise();
+    const { rules } = JSON.parse(newTree.readContent(TSLINT_PATH));
+    expect(rules['no-use-before-declare']).toBeUndefined();
+  });
+});