feat(router): Add `relativeLinkResolution` migration to update default value (#38698)

The default value for `relativeLinkResolution` is changing from 'legacy' to 'corrected'.
This migration updates `RouterModule` configurations that use the default value to
now specifically use 'legacy' to prevent breakages when updating.

PR Close #38698

packages/core/schematics/BUILD.bazel

@@ -15,6 +15,7 @@ pkg_npm(
         "//packages/core/schematics/migrations/module-with-providers",
         "//packages/core/schematics/migrations/move-document",
         "//packages/core/schematics/migrations/navigation-extras-omissions",
+        "//packages/core/schematics/migrations/relative-link-resolution",
         "//packages/core/schematics/migrations/renderer-to-renderer2",
         "//packages/core/schematics/migrations/static-queries",
         "//packages/core/schematics/migrations/template-var-assignment",

packages/core/schematics/migrations.json

@@ -49,6 +49,11 @@
       "version": "11.0.0-beta",
       "description": "NavigationExtras omissions migration. In version 11, some unsupported properties were omitted from the `extras` parameter of the `Router.navigateByUrl` and `Router.createUrlTree` methods.",
       "factory": "./migrations/navigation-extras-omissions/index"
+    },
+    "migration-v11-router-relative-link-resolution-default": {
+      "version": "11.0.0-beta",
+      "description": "The default value for `relativeLinkResolution` is changing from 'legacy' to 'corrected'.\nThis migration updates `RouterModule` configurations that use the default value to \nnow specifically use 'legacy' to prevent breakages when updating.",
+      "factory": "./migrations/relative-link-resolution/index"
     }
   }
 }

packages/core/schematics/migrations/google3/BUILD.bazel

@@ -10,6 +10,8 @@ ts_library(
         "//packages/core/schematics/migrations/missing-injectable",
         "//packages/core/schematics/migrations/missing-injectable/google3",
         "//packages/core/schematics/migrations/navigation-extras-omissions",
+        "//packages/core/schematics/migrations/relative-link-resolution",
+        "//packages/core/schematics/migrations/relative-link-resolution/google3",
         "//packages/core/schematics/migrations/renderer-to-renderer2",
         "//packages/core/schematics/migrations/static-queries",
         "//packages/core/schematics/migrations/template-var-assignment",

packages/core/schematics/migrations/google3/relativeLinkResolutionDefaultRule.ts

@@ -0,0 +1,48 @@
+/**
+ * @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 {RuleFailure, Rules} from 'tslint';
+import * as ts from 'typescript';
+
+import {RelativeLinkResolutionCollector} from '../relative-link-resolution/collector';
+import {TslintUpdateRecorder} from '../relative-link-resolution/google3/tslint_update_recorder';
+import {RelativeLinkResolutionTransform} from '../relative-link-resolution/transform';
+
+export class Rule extends Rules.TypedRule {
+  applyWithProgram(sourceFile: ts.SourceFile, program: ts.Program): RuleFailure[] {
+    const typeChecker = program.getTypeChecker();
+    const ruleName = this.ruleName;
+    const sourceFiles = program.getSourceFiles().filter(
+        s => !s.isDeclarationFile && !program.isSourceFileFromExternalLibrary(s));
+    const updateRecorders = new Map<ts.SourceFile, TslintUpdateRecorder>();
+    const relativeLinkResolutionCollector = new RelativeLinkResolutionCollector(typeChecker);
+
+    // Analyze source files by detecting all modules.
+    sourceFiles.forEach(sourceFile => relativeLinkResolutionCollector.visitNode(sourceFile));
+
+    const {forRootCalls, extraOptionsLiterals} = relativeLinkResolutionCollector;
+    const transformer = new RelativeLinkResolutionTransform(getUpdateRecorder);
+    transformer.migrateRouterModuleForRootCalls(forRootCalls);
+    transformer.migrateObjectLiterals(extraOptionsLiterals);
+
+    if (updateRecorders.has(sourceFile)) {
+      return updateRecorders.get(sourceFile)!.failures;
+    }
+    return [];
+
+    /** Gets the update recorder for the specified source file. */
+    function getUpdateRecorder(sourceFile: ts.SourceFile): TslintUpdateRecorder {
+      if (updateRecorders.has(sourceFile)) {
+        return updateRecorders.get(sourceFile)!;
+      }
+      const recorder = new TslintUpdateRecorder(ruleName, sourceFile);
+      updateRecorders.set(sourceFile, recorder);
+      return recorder;
+    }
+  }
+}

packages/core/schematics/migrations/relative-link-resolution/BUILD.bazel

@@ -0,0 +1,23 @@
+load("//tools:defaults.bzl", "ts_library")
+
+ts_library(
+    name = "relative-link-resolution",
+    srcs = glob(["**/*.ts"]),
+    tsconfig = "//packages/core/schematics:tsconfig.json",
+    visibility = [
+        "//packages/core/schematics:__pkg__",
+        "//packages/core/schematics/migrations/google3:__pkg__",
+        "//packages/core/schematics/migrations/relative-link-resolution/google3:__pkg__",
+        "//packages/core/schematics/test:__pkg__",
+    ],
+    deps = [
+        "//packages/compiler-cli/src/ngtsc/annotations",
+        "//packages/compiler-cli/src/ngtsc/imports",
+        "//packages/compiler-cli/src/ngtsc/partial_evaluator",
+        "//packages/compiler-cli/src/ngtsc/reflection",
+        "//packages/core/schematics/utils",
+        "@npm//@angular-devkit/schematics",
+        "@npm//@types/node",
+        "@npm//typescript",
+    ],
+)

packages/core/schematics/migrations/relative-link-resolution/README.md

@@ -0,0 +1,33 @@
+## relativeLinkResolution migration
+
+The default value for `relativeLinkResolution` is changing from 'legacy' to 'corrected'.
+This migration updates `RouterModule` configurations that use the default value to 
+now specifically use 'legacy' to prevent breakages when updating.
+
+#### Before
+```ts
+import { NgModule } from '@angular/core';
+import { RouterModule } from '@angular/router';
+
+@NgModule({
+  imports: [
+    RouterModule.forRoot(ROUTES),
+  ]
+})
+export class AppModule {
+}
+```
+
+#### After
+```ts
+import { NgModule } from '@angular/core';
+import { RouterModule } from '@angular/router';
+
+@NgModule({
+  imports: [
+    RouterModule.forRoot(ROUTES, {relativeLinkResolution: 'legacy'}),
+  ]
+})
+export class AppModule {
+}
+```

packages/core/schematics/migrations/relative-link-resolution/collector.ts

@@ -0,0 +1,87 @@
+/**
+ * @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 * as ts from 'typescript';
+
+import {isExtraOptions, isRouterModuleForRoot} from './util';
+
+
+/**
+ * Visitor that walks through specified TypeScript nodes and collects all
+ * found ExtraOptions#RelativeLinkResolution assignments.
+ */
+export class RelativeLinkResolutionCollector {
+  readonly forRootCalls: ts.CallExpression[] = [];
+  readonly extraOptionsLiterals: ts.ObjectLiteralExpression[] = [];
+
+  constructor(private readonly typeChecker: ts.TypeChecker) {}
+
+  visitNode(node: ts.Node) {
+    let forRootCall: ts.CallExpression|null = null;
+    let literal: ts.ObjectLiteralExpression|null = null;
+    if (isRouterModuleForRoot(this.typeChecker, node) && node.arguments.length > 0) {
+      if (node.arguments.length === 1) {
+        forRootCall = node;
+      } else if (ts.isObjectLiteralExpression(node.arguments[1])) {
+        literal = node.arguments[1] as ts.ObjectLiteralExpression;
+      } else if (ts.isIdentifier(node.arguments[1])) {
+        literal = this.getLiteralNeedingMigrationFromIdentifier(node.arguments[1] as ts.Identifier);
+      }
+    } else if (ts.isVariableDeclaration(node)) {
+      literal = this.getLiteralNeedingMigration(node);
+    }
+
+    if (literal !== null) {
+      this.extraOptionsLiterals.push(literal);
+    } else if (forRootCall !== null) {
+      this.forRootCalls.push(forRootCall);
+    } else {
+      // no match found, continue iteration
+      ts.forEachChild(node, n => this.visitNode(n));
+    }
+  }
+
+  private getLiteralNeedingMigrationFromIdentifier(id: ts.Identifier): ts.ObjectLiteralExpression
+      |null {
+    const symbolForIdentifier = this.typeChecker.getSymbolAtLocation(id);
+    if (symbolForIdentifier === undefined) {
+      return null;
+    }
+
+    if (symbolForIdentifier.declarations.length === 0) {
+      return null;
+    }
+
+    const declarationNode = symbolForIdentifier.declarations[0];
+    if (!ts.isVariableDeclaration(declarationNode) || declarationNode.initializer === undefined ||
+        !ts.isObjectLiteralExpression(declarationNode.initializer)) {
+      return null;
+    }
+
+    return declarationNode.initializer;
+  }
+
+  private getLiteralNeedingMigration(node: ts.VariableDeclaration): ts.ObjectLiteralExpression
+      |null {
+    if (node.initializer === undefined) {
+      return null;
+    }
+
+    // declaration could be `x: ExtraOptions = {}` or `x = {} as ExtraOptions`
+    if (ts.isAsExpression(node.initializer) &&
+        ts.isObjectLiteralExpression(node.initializer.expression) &&
+        isExtraOptions(this.typeChecker, node.initializer.type)) {
+      return node.initializer.expression;
+    } else if (
+        node.type !== undefined && ts.isObjectLiteralExpression(node.initializer) &&
+        isExtraOptions(this.typeChecker, node.type)) {
+      return node.initializer;
+    }
+
+    return null;
+  }
+}

packages/core/schematics/migrations/relative-link-resolution/google3/BUILD.bazel

@@ -0,0 +1,13 @@
+load("//tools:defaults.bzl", "ts_library")
+
+ts_library(
+    name = "google3",
+    srcs = glob(["**/*.ts"]),
+    tsconfig = "//packages/core/schematics:tsconfig.json",
+    visibility = ["//packages/core/schematics/migrations/google3:__pkg__"],
+    deps = [
+        "//packages/core/schematics/migrations/relative-link-resolution",
+        "@npm//tslint",
+        "@npm//typescript",
+    ],
+)

packages/core/schematics/migrations/relative-link-resolution/google3/tslint_update_recorder.ts

@@ -0,0 +1,28 @@
+/**
+ * @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 {Replacement, RuleFailure} from 'tslint';
+import * as ts from 'typescript';
+
+import {UpdateRecorder} from '../update_recorder';
+
+export class TslintUpdateRecorder implements UpdateRecorder {
+  failures: RuleFailure[] = [];
+
+  constructor(private ruleName: string, private sourceFile: ts.SourceFile) {}
+
+  updateNode(node: ts.Node, newText: string) {
+    this.failures.unshift(new RuleFailure(
+        this.sourceFile, node.getStart(), 0,
+        'The relativeLinkResolution default is changing from `legacy` to `corrected`. To keep behavior consistent' +
+            ' when the change is merged, specify `legacy` rather than using the default.',
+        this.ruleName, Replacement.replaceFromTo(node.getStart(), node.getEnd(), `${newText}`)));
+  }
+
+  commitUpdate() {}
+}

packages/core/schematics/migrations/relative-link-resolution/index.ts

@@ -0,0 +1,74 @@
+/**
+ * @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, SchematicsException, Tree} from '@angular-devkit/schematics';
+import {relative} from 'path';
+import * as ts from 'typescript';
+import {getProjectTsConfigPaths} from '../../utils/project_tsconfig_paths';
+import {createMigrationProgram} from '../../utils/typescript/compiler_host';
+import {RelativeLinkResolutionCollector} from './collector';
+import {RelativeLinkResolutionTransform} from './transform';
+import {UpdateRecorder} from './update_recorder';
+
+/** Entry point for the v11 "relativeLinkResolution RouterModule options" schematic. */
+export default function(): Rule {
+  return (tree: Tree) => {
+    const {buildPaths, testPaths} = getProjectTsConfigPaths(tree);
+    const basePath = process.cwd();
+
+    if (!buildPaths.length && !testPaths.length) {
+      throw new SchematicsException(
+          'Could not find any tsconfig file. Cannot update the "relativeLinkResolution" option for RouterModule');
+    }
+
+    for (const tsconfigPath of [...buildPaths, ...testPaths]) {
+      runRelativeLinkResolutionMigration(tree, tsconfigPath, basePath);
+    }
+  };
+}
+
+function runRelativeLinkResolutionMigration(tree: Tree, tsconfigPath: string, basePath: string) {
+  const {program} = createMigrationProgram(tree, tsconfigPath, basePath);
+  const typeChecker = program.getTypeChecker();
+  const relativeLinkResolutionCollector = new RelativeLinkResolutionCollector(typeChecker);
+  const sourceFiles = program.getSourceFiles().filter(
+      f => !f.isDeclarationFile && !program.isSourceFileFromExternalLibrary(f));
+
+  // Analyze source files by detecting all modules.
+  sourceFiles.forEach(sourceFile => relativeLinkResolutionCollector.visitNode(sourceFile));
+
+  const {forRootCalls, extraOptionsLiterals} = relativeLinkResolutionCollector;
+  const transformer = new RelativeLinkResolutionTransform(getUpdateRecorder);
+  const updateRecorders = new Map<ts.SourceFile, UpdateRecorder>();
+  transformer.migrateRouterModuleForRootCalls(forRootCalls);
+  transformer.migrateObjectLiterals(extraOptionsLiterals);
+
+  // Walk through each update recorder and commit the update. We need to commit the
+  // updates in batches per source file as there can be only one recorder per source
+  // file in order to avoid shift character offsets.
+  updateRecorders.forEach(recorder => recorder.commitUpdate());
+
+  /** Gets the update recorder for the specified source file. */
+  function getUpdateRecorder(sourceFile: ts.SourceFile): UpdateRecorder {
+    if (updateRecorders.has(sourceFile)) {
+      return updateRecorders.get(sourceFile)!;
+    }
+    const treeRecorder = tree.beginUpdate(relative(basePath, sourceFile.fileName));
+    const recorder: UpdateRecorder = {
+      updateNode(node: ts.Node, newText: string) {
+        treeRecorder.remove(node.getStart(), node.getWidth());
+        treeRecorder.insertRight(node.getStart(), newText);
+      },
+      commitUpdate() {
+        tree.commitUpdate(treeRecorder);
+      }
+    };
+    updateRecorders.set(sourceFile, recorder);
+    return recorder;
+  }
+}

packages/core/schematics/migrations/relative-link-resolution/transform.ts

@@ -0,0 +1,64 @@
+/**
+ * @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 * as ts from 'typescript';
+
+import {UpdateRecorder} from './update_recorder';
+
+
+const RELATIVE_LINK_RESOLUTION = 'relativeLinkResolution';
+
+export class RelativeLinkResolutionTransform {
+  private printer = ts.createPrinter();
+
+  constructor(private getUpdateRecorder: (sf: ts.SourceFile) => UpdateRecorder) {}
+
+  /** Migrate the ExtraOptions#RelativeLinkResolution property assignments. */
+  migrateRouterModuleForRootCalls(calls: ts.CallExpression[]) {
+    calls.forEach(c => {
+      this._updateCallExpressionWithoutExtraOptions(c);
+    });
+  }
+
+  migrateObjectLiterals(vars: ts.ObjectLiteralExpression[]) {
+    vars.forEach(v => this._maybeUpdateLiteral(v));
+  }
+
+  private _updateCallExpressionWithoutExtraOptions(callExpression: ts.CallExpression) {
+    const args = callExpression.arguments;
+    const emptyLiteral = ts.createObjectLiteral();
+    const newNode = ts.updateCall(
+        callExpression, callExpression.expression, callExpression.typeArguments,
+        [args[0], this._getMigratedLiteralExpression(emptyLiteral)]);
+    this._updateNode(callExpression, newNode);
+  }
+
+  private _getMigratedLiteralExpression(literal: ts.ObjectLiteralExpression) {
+    if (literal.properties.some(
+            prop => ts.isPropertyAssignment(prop) &&
+                prop.name.getText() === RELATIVE_LINK_RESOLUTION)) {
+      // literal already defines a value for relativeLinkResolution. Skip it
+      return literal;
+    }
+    const legacyExpression =
+        ts.createPropertyAssignment(RELATIVE_LINK_RESOLUTION, ts.createStringLiteral('legacy'));
+    return ts.updateObjectLiteral(literal, [...literal.properties, legacyExpression]);
+  }
+
+  private _maybeUpdateLiteral(literal: ts.ObjectLiteralExpression) {
+    const updatedLiteral = this._getMigratedLiteralExpression(literal);
+    if (updatedLiteral !== literal) {
+      this._updateNode(literal, updatedLiteral);
+    }
+  }
+
+  private _updateNode(node: ts.Node, newNode: ts.Node) {
+    const newText = this.printer.printNode(ts.EmitHint.Unspecified, newNode, node.getSourceFile());
+    const recorder = this.getUpdateRecorder(node.getSourceFile());
+    recorder.updateNode(node, newText);
+  }
+}

packages/core/schematics/migrations/relative-link-resolution/update_recorder.ts

@@ -0,0 +1,19 @@
+/**
+ * @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 * as ts from 'typescript';
+
+/**
+ * Update recorder interface that is used to transform source files in a non-colliding
+ * way. Also this indirection makes it possible to re-use logic for both TSLint rules
+ * and CLI devkit schematic updates.
+ */
+export interface UpdateRecorder {
+  updateNode(node: ts.Node, newText: string): void;
+  commitUpdate(): void;
+}

packages/core/schematics/migrations/relative-link-resolution/util.ts

@@ -0,0 +1,33 @@
+/**
+ * @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 * as ts from 'typescript';
+import {getImportOfIdentifier} from '../../utils/typescript/imports';
+
+/** Determine whether a node is a ModuleWithProviders type reference node without a generic type */
+export function isRouterModuleForRoot(
+    typeChecker: ts.TypeChecker, node: ts.Node): node is ts.CallExpression {
+  if (!ts.isCallExpression(node) || !ts.isPropertyAccessExpression(node.expression) ||
+      !ts.isIdentifier(node.expression.expression) || node.expression.name.text !== 'forRoot') {
+    return false;
+  }
+  const imp = getImportOfIdentifier(typeChecker, node.expression.expression);
+  return !!imp && imp.name === 'RouterModule' && imp.importModule === '@angular/router' &&
+      !node.typeArguments;
+}
+
+export function isExtraOptions(
+    typeChecker: ts.TypeChecker, node: ts.Node): node is ts.TypeReferenceNode {
+  if (!ts.isTypeReferenceNode(node) || !ts.isIdentifier(node.typeName)) {
+    return false;
+  }
+
+  const imp = getImportOfIdentifier(typeChecker, node.typeName);
+  return imp !== null && imp.name === 'ExtraOptions' && imp.importModule === '@angular/router' &&
+      !node.typeArguments;
+}

packages/core/schematics/test/BUILD.bazel

@@ -13,6 +13,7 @@ ts_library(
         "//packages/core/schematics/migrations/module-with-providers",
         "//packages/core/schematics/migrations/move-document",
         "//packages/core/schematics/migrations/navigation-extras-omissions",
+        "//packages/core/schematics/migrations/relative-link-resolution",
         "//packages/core/schematics/migrations/renderer-to-renderer2",
         "//packages/core/schematics/migrations/static-queries",
         "//packages/core/schematics/migrations/template-var-assignment",

packages/core/schematics/test/google3/relative_link_resolution_default_spec.ts

@@ -0,0 +1,202 @@
+/**
+ * @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 {readFileSync, writeFileSync} from 'fs';
+import {dirname, join} from 'path';
+import * as shx from 'shelljs';
+import {Configuration, Linter} from 'tslint';
+
+describe('Google3 relativeLinkResolution TSLint rule', () => {
+  const rulesDirectory =
+      dirname(require.resolve('../../migrations/google3/relativeLinkResolutionDefaultRule'));
+
+  let tmpDir: string;
+
+  beforeEach(() => {
+    tmpDir = join(process.env['TEST_TMPDIR']!, 'google3-test');
+    shx.mkdir('-p', tmpDir);
+    writeFile('tsconfig.json', JSON.stringify({compilerOptions: {module: 'es2015'}}));
+  });
+
+  afterEach(() => shx.rm('-r', tmpDir));
+
+  function runTSLint(fix: boolean) {
+    const program = Linter.createProgram(join(tmpDir, 'tsconfig.json'));
+    const linter = new Linter({fix, rulesDirectory: [rulesDirectory]}, program);
+    const config = Configuration.parseConfigFile({
+      rules: {'relative-link-resolution-default': true},
+    });
+
+    program.getRootFileNames().forEach(fileName => {
+      linter.lint(fileName, program.getSourceFile(fileName)!.getFullText(), config);
+    });
+
+    return linter;
+  }
+
+  function writeFile(fileName: string, content: string) {
+    writeFileSync(join(tmpDir, fileName), content);
+  }
+
+  function getFile(fileName: string) {
+    return readFileSync(join(tmpDir, fileName), 'utf8');
+  }
+
+  it('should flag forRoot with no options', () => {
+    writeFile('/index.ts', `
+        import { NgModule } from '@angular/core';
+        import { RouterModule } from '@angular/router';
+        @NgModule({
+          imports: [
+            RouterModule.forRoot([]),
+          ]
+        })
+        export class AppModule {
+        }
+    `);
+
+    const linter = runTSLint(false);
+    const failures = linter.getResult().failures.map(failure => failure.getFailure());
+
+    expect(failures.length).toBe(1);
+    expect(failures[0])
+        .toBe(
+            'The relativeLinkResolution default is changing from `legacy` to `corrected`. To keep' +
+            ' behavior consistent when the change is merged, specify `legacy` rather than using the default.');
+  });
+
+  it('should migrate forRoot with no options', () => {
+    writeFile('/index.ts', `
+        import { NgModule } from '@angular/core';
+        import { RouterModule } from '@angular/router';
+        @NgModule({
+          imports: [
+            RouterModule.forRoot([]),
+          ]
+        })
+        export class AppModule {
+        }
+      `);
+
+    runTSLint(true);
+    expect(getFile('/index.ts'))
+        .toContain(`RouterModule.forRoot([], { relativeLinkResolution: "legacy" })`);
+  });
+
+  it('should migrate options without relativeLinkResolution', () => {
+    writeFile('/index.ts', `
+        import { NgModule } from '@angular/core';
+        import { RouterModule } from '@angular/router';
+        @NgModule({
+          imports: [
+            RouterModule.forRoot([], {useHash: true}),
+          ]
+        })
+        export class AppModule {
+        }
+      `);
+
+    runTSLint(true);
+    expect(getFile('/index.ts'))
+        .toContain(`RouterModule.forRoot([], { useHash: true, relativeLinkResolution: "legacy" })`);
+  });
+
+  it('should not migrate options containing relativeLinkResolution', () => {
+    writeFile('/index.ts', `
+        import { NgModule } from '@angular/core';
+        import { RouterModule } from '@angular/router';
+        @NgModule({
+          imports: [
+            RouterModule.forRoot([], {relativeLinkResolution: 'corrected'}),
+          ]
+        })
+        export class AppModule {
+        }
+      `);
+
+    runTSLint(true);
+    expect(getFile('/index.ts'))
+        .toContain(`RouterModule.forRoot([], {relativeLinkResolution: 'corrected'})`);
+  });
+
+  it('should migrate when options is a variable with AsExpression', () => {
+    writeFile('/index.ts', `
+        import { ExtraOptions } from '@angular/router';
+        const options = {useHash: true} as ExtraOptions;
+      `);
+
+    runTSLint(true);
+    expect(getFile('/index.ts'))
+        .toContain(
+            `const options = { useHash: true, relativeLinkResolution: "legacy" } as ExtraOptions;`);
+  });
+
+  it('should migrate when options is a variable', () => {
+    writeFile('/index.ts', `
+        import { ExtraOptions } from '@angular/router';
+        const options: ExtraOptions = {useHash: true};
+      `);
+
+    runTSLint(true);
+    expect(getFile('/index.ts'))
+        .toContain(
+            `const options: ExtraOptions = { useHash: true, relativeLinkResolution: "legacy" };`);
+  });
+
+  it('should migrate when options is a variable with no type', () => {
+    writeFile('/index.ts', `
+        import { NgModule } from '@angular/core';
+        import { ExtraOptions, RouterModule } from '@angular/router';
+
+        const options = {useHash: true};
+
+        @NgModule({
+          imports: [
+            RouterModule.forRoot([], options),
+          ]
+        })
+        export class AppModule {
+        }
+      `);
+
+    runTSLint(true);
+    expect(getFile('/index.ts'))
+        .toContain(`const options = { useHash: true, relativeLinkResolution: "legacy" };`);
+    expect(getFile('/index.ts')).toContain(`RouterModule.forRoot([], options)`);
+  });
+
+  it('should migrate when aliased options is a variable', () => {
+    writeFile('/index.ts', `
+        import { ExtraOptions as RouterExtraOptions } from '@angular/router';
+        const options: RouterExtraOptions = {useHash: true};
+      `);
+
+    runTSLint(true);
+    expect(getFile('/index.ts'))
+        .toContain(
+            `const options: RouterExtraOptions = { useHash: true, relativeLinkResolution: "legacy" };`);
+  });
+
+  it('should migrate aliased RouterModule.forRoot', () => {
+    writeFile('/index.ts', `
+        import { NgModule } from '@angular/core';
+        import { RouterModule as AngularRouterModule} from '@angular/router';
+        @NgModule({
+          imports: [
+            AngularRouterModule.forRoot([]),
+          ]
+        })
+        export class AppModule {
+        }
+      `);
+
+    runTSLint(true);
+    expect(getFile('/index.ts'))
+        .toContain(`AngularRouterModule.forRoot([], { relativeLinkResolution: "legacy" }),`);
+  });
+});

packages/core/schematics/test/relative_link_resolution_spec.ts

@@ -0,0 +1,188 @@
+/**
+ * @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 {getSystemPath, normalize, virtualFs} from '@angular-devkit/core';
+import {TempScopedNodeJsSyncHost} from '@angular-devkit/core/node/testing';
+import {HostTree} from '@angular-devkit/schematics';
+import {SchematicTestRunner, UnitTestTree} from '@angular-devkit/schematics/testing';
+import * as shx from 'shelljs';
+
+describe('initial navigation migration', () => {
+  let runner: SchematicTestRunner;
+  let host: TempScopedNodeJsSyncHost;
+  let tree: UnitTestTree;
+  let tmpDirPath: string;
+  let previousWorkingDir: string;
+
+  beforeEach(() => {
+    runner = new SchematicTestRunner('test', require.resolve('../migrations.json'));
+    host = new TempScopedNodeJsSyncHost();
+    tree = new UnitTestTree(new HostTree(host));
+
+    writeFile('/tsconfig.json', JSON.stringify({
+      compilerOptions: {
+        lib: ['es2015'],
+      }
+    }));
+    writeFile('/angular.json', JSON.stringify({
+      projects: {t: {architect: {build: {options: {tsConfig: './tsconfig.json'}}}}}
+    }));
+
+    previousWorkingDir = shx.pwd();
+    tmpDirPath = getSystemPath(host.root);
+
+    // Switch into the temporary directory path. This allows us to run
+    // the schematic against our custom unit test tree.
+    shx.cd(tmpDirPath);
+  });
+
+  afterEach(() => {
+    shx.cd(previousWorkingDir);
+    shx.rm('-r', tmpDirPath);
+  });
+
+  it('should migrate forRoot with no options', async () => {
+    writeFile('/index.ts', `
+        import { NgModule } from '@angular/core';
+        import { RouterModule } from '@angular/router';
+        @NgModule({
+          imports: [
+            RouterModule.forRoot([]),
+          ]
+        })
+        export class AppModule {
+        }
+      `);
+
+    await runMigration();
+    expect(tree.readContent('/index.ts'))
+        .toContain(`RouterModule.forRoot([], { relativeLinkResolution: "legacy" })`);
+  });
+
+  it('should migrate options without relativeLinkResolution', async () => {
+    writeFile('/index.ts', `
+        import { NgModule } from '@angular/core';
+        import { RouterModule } from '@angular/router';
+        @NgModule({
+          imports: [
+            RouterModule.forRoot([], {useHash: true}),
+          ]
+        })
+        export class AppModule {
+        }
+      `);
+
+    await runMigration();
+    expect(tree.readContent('/index.ts'))
+        .toContain(`RouterModule.forRoot([], { useHash: true, relativeLinkResolution: "legacy" })`);
+  });
+
+  it('should not migrate options containing relativeLinkResolution', async () => {
+    writeFile('/index.ts', `
+        import { NgModule } from '@angular/core';
+        import { RouterModule } from '@angular/router';
+        @NgModule({
+          imports: [
+            RouterModule.forRoot([], {relativeLinkResolution: 'corrected'}),
+          ]
+        })
+        export class AppModule {
+        }
+      `);
+
+    await runMigration();
+    expect(tree.readContent('/index.ts'))
+        .toContain(`RouterModule.forRoot([], {relativeLinkResolution: 'corrected'})`);
+  });
+
+  it('should migrate when options is a variable with AsExpression', async () => {
+    writeFile('/index.ts', `
+        import { ExtraOptions } from '@angular/router';
+        const options = {useHash: true} as ExtraOptions;
+      `);
+
+    await runMigration();
+    expect(tree.readContent('/index.ts'))
+        .toContain(
+            `const options = { useHash: true, relativeLinkResolution: "legacy" } as ExtraOptions;`);
+  });
+
+  it('should migrate when options is a variable', async () => {
+    writeFile('/index.ts', `
+        import { ExtraOptions } from '@angular/router';
+        const options: ExtraOptions = {useHash: true};
+      `);
+
+    await runMigration();
+    expect(tree.readContent('/index.ts'))
+        .toContain(
+            `const options: ExtraOptions = { useHash: true, relativeLinkResolution: "legacy" };`);
+  });
+
+  it('should migrate when options is a variable with no type', async () => {
+    writeFile('/index.ts', `
+        import { NgModule } from '@angular/core';
+        import { ExtraOptions, RouterModule } from '@angular/router';
+
+        const options = {useHash: true};
+
+        @NgModule({
+          imports: [
+            RouterModule.forRoot([], options),
+          ]
+        })
+        export class AppModule {
+        }
+      `);
+
+    await runMigration();
+    expect(tree.readContent('/index.ts'))
+        .toContain(`const options = { useHash: true, relativeLinkResolution: "legacy" };`);
+    expect(tree.readContent('/index.ts')).toContain(`RouterModule.forRoot([], options)`);
+  });
+
+  it('should migrate when aliased options is a variable', async () => {
+    writeFile('/index.ts', `
+        import { ExtraOptions as RouterExtraOptions } from '@angular/router';
+        const options: RouterExtraOptions = {useHash: true};
+      `);
+
+    await runMigration();
+    expect(tree.readContent('/index.ts'))
+        .toContain(
+            `const options: RouterExtraOptions = { useHash: true, relativeLinkResolution: "legacy" };`);
+  });
+
+  it('should migrate aliased RouterModule.forRoot', async () => {
+    writeFile('/index.ts', `
+        import { NgModule } from '@angular/core';
+        import { RouterModule as AngularRouterModule} from '@angular/router';
+        @NgModule({
+          imports: [
+            AngularRouterModule.forRoot([]),
+          ]
+        })
+        export class AppModule {
+        }
+      `);
+
+    await runMigration();
+    expect(tree.readContent('/index.ts'))
+        .toContain(`AngularRouterModule.forRoot([], { relativeLinkResolution: "legacy" }),`);
+  });
+
+  function writeFile(filePath: string, contents: string) {
+    host.sync.write(normalize(filePath), virtualFs.stringToFileBuffer(contents));
+  }
+
+  function runMigration() {
+    return runner
+        .runSchematicAsync('migration-v11-router-relative-link-resolution-default', {}, tree)
+        .toPromise();
+  }
+});