fix(@angular/cli): print ng update errors stack to log file

packages/angular/cli/commands/update-impl.ts

@@ -18,6 +18,7 @@ import { Command } from '../models/command';
 import { Arguments } from '../models/interface';
 import { runTempPackageBin } from '../tasks/install-package';
 import { colors } from '../utilities/color';
+import { writeErrorToLogFile } from '../utilities/log-file';
 import { getPackageManager } from '../utilities/package-manager';
 import {
   PackageIdentifier,
@@ -141,9 +142,13 @@ export class UpdateCommand extends Command<UpdateCommandSchema> {
       return { success: !error, files };
     } catch (e) {
       if (e instanceof UnsuccessfulWorkflowExecution) {
-        this.logger.error('The update failed. See above.');
+        this.logger.error(`${colors.symbols.cross} Migration failed. See above for further details.\n`);
       } else {
-        this.logger.fatal(e.message);
+        const logPath = writeErrorToLogFile(e);
+        this.logger.fatal(
+          `${colors.symbols.cross} Migration failed: ${e.message}\n` +
+          `  See "${logPath}" for further details.\n`,
+        );
       }
 
       return { success: false, files };
@@ -223,8 +228,6 @@ export class UpdateCommand extends Command<UpdateCommandSchema> {
 
       const result = await this.executeSchematic(migration.collection.name, migration.name);
       if (!result.success) {
-        this.logger.error(`${colors.symbols.cross} Migration failed. See above for further details.\n`);
-
         return false;
       }
 

packages/angular/cli/lib/cli/index.ts

@@ -6,11 +6,11 @@
  * found in the LICENSE file at https://angular.io/license
  */
 import { createConsoleLogger } from '@angular-devkit/core/node';
-import { normalize } from 'path';
 import { format } from 'util';
 import { runCommand } from '../../models/command-runner';
 import { colors, supportsColor } from '../../utilities/color';
 import { getWorkspaceRaw } from '../../utilities/config';
+import { writeErrorToLogFile } from '../../utilities/log-file';
 import { getWorkspaceDetails } from '../../utilities/project';
 
 const debugEnv = process.env['NG_DEBUG'];
@@ -82,12 +82,7 @@ export default async function(options: { testing?: boolean; cliArgs: string[] })
   } catch (err) {
     if (err instanceof Error) {
       try {
-        const fs = await import('fs');
-        const os = await import('os');
-        const tempDirectory = fs.mkdtempSync(fs.realpathSync(os.tmpdir()) + '/' + 'ng-');
-        const logPath = normalize(tempDirectory + '/angular-errors.log');
-        fs.appendFileSync(logPath, '[error] ' + (err.stack || err));
-
+        const logPath = writeErrorToLogFile(err);
         logger.fatal(
           `An unhandled exception occurred: ${err.message}\n` +
             `See "${logPath}" for further details.`,

packages/angular/cli/utilities/log-file.ts

@@ -0,0 +1,29 @@
+/**
+ * @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 { appendFileSync, mkdtempSync, realpathSync } from 'fs';
+import { tmpdir } from 'os';
+import { normalize } from 'path';
+
+let logPath: string | undefined;
+
+/**
+ * Writes an Error to a temporary log file.
+ * If this method is called multiple times from the same process the same log file will be used.
+ * @returns The path of the generated log file.
+ */
+export function writeErrorToLogFile(error: Error): string {
+  if (!logPath) {
+    const tempDirectory = mkdtempSync(realpathSync(tmpdir()) + '/ng-');
+    logPath = normalize(tempDirectory + '/angular-errors.log');
+  }
+
+  appendFileSync(logPath, '[error] ' + (error.stack || error) + '\n\n');
+
+  return logPath;
+}