Reinsert (and test) handling of exceptions from user code.

tests/compiler/dart2js/user_crash_test.dart

+// Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'dart:async';
+import 'package:async_helper/async_helper.dart';
+import 'package:expect/expect.dart';
+import 'package:compiler/compiler_new.dart';
+import 'memory_compiler.dart';
+
+final EXCEPTION = 'Crash';
+
+main() {
+  asyncTest(() async {
+    test('Empty program', await run());
+    test('Crash diagnostics',
+         await run(diagnostics: new CrashingDiagnostics()),
+         expectedLines: [
+           'Uncaught exception in diagnostic handler: $EXCEPTION',
+           null /* Stack trace*/],
+         expectedExceptions: [EXCEPTION]);
+    test('Throw in package discovery',
+         await run(packagesDiscoveryProvider: (_) { throw EXCEPTION; }),
+         expectedLines: [
+           'Uncaught exception in package discovery: $EXCEPTION',
+           null /* Stack trace*/],
+         expectedExceptions: [EXCEPTION]);
+    test('new Future.error in package discovery',
+         await run(packagesDiscoveryProvider:
+             (_) => new Future.error(EXCEPTION)),
+         expectedExceptions: [EXCEPTION]);
+    test('Throw in input provider',
+         await run(memorySourceFiles: new CrashingMap()),
+         expectedLines: [
+           'Uncaught exception in input provider: $EXCEPTION',
+           null, // Stack trace
+           'memory:main.dart:\nError: $EXCEPTION' /* READ_SELF_ERROR */]);
+  });
+}
+
+void test(String title, RunResult result,
+          {List expectedLines: const [],
+           List expectedExceptions: const []}) {
+  print('--------------------------------------------------------------------');
+  print('Running $title');
+  print('--------------------------------------------------------------------');
+  print('lines:');
+  result.lines.forEach(print);
+  print('exceptions:');
+  result.exceptions.forEach(print);
+  Expect.equals(expectedLines.length, result.lines.length,
+      "Unexpected number of calls to print.");
+  Expect.equals(expectedExceptions.length, result.exceptions.length,
+      "Unexpected number of exceptions.");
+  for (int i = 0; i < expectedLines.length; i++) {
+    if (expectedLines[i] != null) {
+      Expect.equals(expectedLines[i], result.lines[i]);
+    }
+  }
+}
+
+Future<RunResult> run(
+    {Map<String, String> memorySourceFiles: const {'main.dart': 'main() {}'},
+     CompilerDiagnostics diagnostics,
+     PackagesDiscoveryProvider packagesDiscoveryProvider}) async {
+  RunResult result = new RunResult();
+  await runZoned(() async {
+    try {
+      await runCompiler(
+          entryPoint: Uri.parse('memory:main.dart'),
+          memorySourceFiles: memorySourceFiles,
+          diagnosticHandler: diagnostics,
+          packagesDiscoveryProvider: packagesDiscoveryProvider);
+    } catch (e) {
+      result.exceptions.add(e);
+    }
+
+  },
+  zoneSpecification: new ZoneSpecification(print:
+    (Zone self, ZoneDelegate parent, Zone zone, String line) {
+    result.lines.add(line);
+  }));
+  return result;
+}
+
+class RunResult {
+  List<String> lines = <String>[];
+  List exceptions = [];
+}
+
+class CrashingDiagnostics extends DiagnosticCollector {
+  @override
+  void report(code, Uri uri, int begin, int end, String text, Diagnostic kind) {
+    throw EXCEPTION;
+  }
+}
+
+class CrashingMap implements Map<String, String> {
+  operator [](_) => throw EXCEPTION;
+
+  noSuchMethod(_) => null;
+}