fix(@angular/cli): verify Angular/TS version combos

packages/@angular/cli/commands/build.ts

@@ -199,8 +199,9 @@ const BuildCommand = Command.extend({
   ]),
 
   run: function (commandOptions: BuildTaskOptions) {
-    // Check angular version.
+    // Check Angular and TypeScript versions.
     Version.assertAngularVersionIs2_3_1OrHigher(this.project.root);
+    Version.assertTypescriptVersion(this.project.root);
 
     // Default vendor chunk to false when build optimizer is on.
     if (commandOptions.vendorChunk === undefined) {

packages/@angular/cli/commands/serve.ts

@@ -126,7 +126,9 @@ const ServeCommand = Command.extend({
   run: function (commandOptions: ServeTaskOptions) {
     const ServeTask = require('../tasks/serve').default;
 
+    // Check Angular and TypeScript versions.
     Version.assertAngularVersionIs2_3_1OrHigher(this.project.root);
+    Version.assertTypescriptVersion(this.project.root);
 
     // Default vendor chunk to false when build optimizer is on.
     if (commandOptions.vendorChunk === undefined) {

packages/@angular/cli/lib/config/schema.json

@@ -586,6 +586,11 @@
           "description": "Show a warning when the global version is newer than the local one.",
           "type": "boolean",
           "default": true
+        },
+        "typescriptMismatch": {
+          "description": "Show a warning when the TypeScript version is incompatible",
+          "type": "boolean",
+          "default": true
         }
       }
     }

packages/@angular/cli/upgrade/version.ts

@@ -1,6 +1,6 @@
-import {SemVer} from 'semver';
+import {SemVer, satisfies} from 'semver';
 import {bold, red, yellow} from 'chalk';
-import {stripIndents} from 'common-tags';
+import {stripIndents, stripIndent} from 'common-tags';
 import {readFileSync, existsSync} from 'fs';
 import * as path from 'path';
 
@@ -143,6 +143,50 @@ export class Version {
     }
   }
 
+  static assertTypescriptVersion(projectRoot: string) {
+    if (!CliConfig.fromGlobal().get('warnings.typescriptMismatch')) {
+      return;
+    }
+    let compilerVersion: string, tsVersion: string;
+    try {
+      compilerVersion = requireProjectModule(projectRoot, '@angular/compiler-cli').VERSION.full;
+      tsVersion = requireProjectModule(projectRoot, 'typescript').version;
+    } catch (_) {
+      console.error(bold(red(stripIndents`
+        Versions of @angular/compiler-cli and typescript could not be determined.
+        The most common reason for this is a broken npm install.
+
+        Please make sure your package.json contains both @angular/compiler-cli and typescript in
+        devDependencies, then delete node_modules and package-lock.json (if you have one) and
+        run npm install again.
+      `)));
+      process.exit(2);
+    }
+
+    const versionCombos = [
+      { compiler: '>=2.3.1 <3.0.0', typescript: '>=2.0.2 <2.3.0' },
+      { compiler: '>=4.0.0 <5.0.0', typescript: '>=2.1.0 <2.4.0' },
+      { compiler: '>=5.0.0 <6.0.0', typescript: '>=2.4.0 <2.6.0' }
+    ];
+
+    const currentCombo = versionCombos.find((combo) => satisfies(compilerVersion, combo.compiler));
+
+    if (currentCombo && !satisfies(tsVersion, currentCombo.typescript)) {
+      // First line of warning looks weird being split in two, disable tslint for it.
+      console.log((yellow('\n' + stripIndent`
+        @angular/compiler-cli@${compilerVersion} requires typescript@'${
+          currentCombo.typescript}' but ${tsVersion} was found instead.
+        Using this version can result in undefined behaviour and difficult to debug problems.
+
+        Please run the following command to install a compatible version of TypeScript.
+
+            npm install typescript@'${currentCombo.typescript}'
+
+        To disable this warning run "ng set --global warnings.typescriptMismatch=false".
+      ` + '\n')));
+    }
+  }
+
   static isPreWebpack(): boolean {
     // CliConfig is a bit stricter with the schema, so we need to be a little looser with it.
     const version = Version.fromProject();

tests/e2e/tests/misc/typescript-warning.ts

@@ -0,0 +1,41 @@
+import { ng, npm } from '../../utils/process';
+import { getGlobalVariable } from '../../utils/env';
+
+
+export default function () {
+  // typescript@2.5 is not part of the officially supported range in latest stable.
+  // Update as needed.
+  let unsupportedTsVersion = '2.5';
+
+    // Skip this in Appveyor tests.
+  if (getGlobalVariable('argv').nightly) {
+    unsupportedTsVersion = '2.3';
+  }
+
+  return Promise.resolve()
+    .then(() => npm('uninstall', 'typescript', '--no-save'))
+    .then(() => ng('build'))
+    .catch((err) => {
+      if (!err.message.match('Versions of @angular/compiler-cli and typescript could not')) {
+        throw new Error('Expected to have missing dependency error in output.');
+      }
+    })
+    .then(() => npm('install', `typescript@${unsupportedTsVersion}`, '--no-save'))
+    .then(() => ng('build'))
+    .then((output) => {
+      if (!output.stdout.match('Using this version can result in undefined behaviour')) {
+        throw new Error('Expected to have typescript version mismatch warning in output.');
+      }
+    })
+    .then(() => ng('set', '--global', 'warnings.typescriptMismatch=false'))
+    .then(() => ng('build'))
+    .then((output) => {
+      if (output.stdout.match('Using this version can result in undefined behaviour')) {
+        throw new Error('Expected to not have typescript version mismatch warning in output.');
+      }
+    })
+    // Cleanup
+    .then(() => npm('install'))
+    .then(() => ng('set', '--global', 'warnings.typescriptMismatch=true'));
+}
+

tests/e2e/utils/process.ts

@@ -77,9 +77,9 @@ function _exec(options: ExecOptions, cmd: string, args: string[]): Promise<Proce
       _processes = _processes.filter(p => p !== childProcess);
 
       if (!error) {
-        resolve({ stdout });
+        resolve({ stdout, stderr });
       } else {
-        err.message += `${error}...\n\nSTDOUT:\n${stdout}\n`;
+        err.message += `${error}...\n\nSTDOUT:\n${stdout}\n\nSTDERR:\n${stderr}\n`;
         reject(err);
       }
     });