Request bug report if fletch crashes

Fixes #87

R=johnniwinther@google.com

Review URL: https://codereview.chromium.org/1345213002 .

pkg/fletchc/lib/src/driver/driver_main.dart

@@ -80,6 +80,10 @@ import 'session_manager.dart' show
 import '../verbs/create_verb.dart' show
     CreateSessionTask;
 
+import '../please_report_crash.dart' show
+    crashReportRequested,
+    requestBugReportOnOtherCrashMessage;
+
 Function gracefulShutdown;
 
 class DriverCommandTransformerBuilder
@@ -235,6 +239,7 @@ Future<Null> handleVerb(
     List<String> arguments,
     ClientController client,
     IsolatePool pool) async {
+  crashReportRequested = false;
 
   Future<int> performVerb() async {
     client.parseArguments(arguments);
@@ -261,6 +266,10 @@ Future<Null> handleVerb(
       handleLateError: client.log.error)
       .catchError(client.reportErrorToClient, test: (e) => e is InputError)
       .catchError((error, StackTrace stackTrace) {
+        if (!crashReportRequested) {
+          client.printLineOnStderr(requestBugReportOnOtherCrashMessage);
+          crashReportRequested = true;
+        }
         client.printLineOnStderr('$error');
         if (stackTrace != null) {
           client.printLineOnStderr('$stackTrace');
@@ -416,6 +425,10 @@ class ClientController {
   }
 
   int reportErrorToClient(InputError error, StackTrace stackTrace) {
+    if (!crashReportRequested) {
+      printLineOnStderr(requestBugReportOnOtherCrashMessage);
+      crashReportRequested = true;
+    }
     printLineOnStderr(error.asDiagnostic().formatMessage());
     if (error.kind == DiagnosticKind.internalError) {
       printLineOnStderr('$stackTrace');
@@ -447,6 +460,8 @@ class IsolateController {
   /// Subscription for errors from [isolate].
   StreamSubscription errorSubscription;
 
+  bool crashReportRequested = false;
+
   IsolateController(this.isolate);
 
   /// Begin a session with the worker isolate.
@@ -474,9 +489,14 @@ class IsolateController {
   /// isolate sends DriverCommand.ClosePort, or if the isolate is killed due to
   /// DriverCommand.Signal arriving through client.commands.
   Future<Null> attachClient(ClientController client) async {
+    crashReportRequested = false;
     errorSubscription.onData((errorList) {
       String error = errorList[0];
       String stackTrace = errorList[1];
+      if (!crashReportRequested) {
+        client.printLineOnStderr(requestBugReportOnOtherCrashMessage);
+        crashReportRequested = true;
+      }
       client.printLineOnStderr(error);
       if (stackTrace != null) {
         client.printLineOnStderr(stackTrace);

pkg/fletchc/lib/src/fletch_compiler_implementation.dart

@@ -42,6 +42,10 @@ import 'package:compiler/src/util/util.dart' show
 import 'fletch_registry.dart' show
     FletchRegistry;
 
+import 'please_report_crash.dart' show
+    crashReportRequested,
+    requestBugReportOnCompilerCrashMessage;
+
 import 'fletch_function_builder.dart';
 import 'debug_info.dart';
 import 'find_position_visitor.dart';
@@ -275,6 +279,11 @@ class FletchCompilerImplementation extends apiimpl.Compiler {
     }
   }
 
+  void pleaseReportCrash() {
+    crashReportRequested = true;
+    print(requestBugReportOnCompilerCrashMessage);
+  }
+
   void reportError(
       Spannable node,
       MessageKind messageKind,

pkg/fletchc/lib/src/please_report_crash.dart

@@ -0,0 +1,40 @@
+// Copyright (c) 2015, the Fletch 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.md file.
+
+library fletchc.please_report_crash;
+
+bool crashReportRequested = false;
+
+// TODO(ahe): Include build ID.
+const String requestBugReportOnCompilerCrashMessage = """
+The Fletch compiler is broken.
+
+When compiling the above element, the compiler crashed. It is not
+possible to tell if this is caused by a problem in your program or
+not. Regardless, the compiler should not crash.
+
+The Fletch team would greatly appreciate if you would take a moment to
+report this problem at https://github.com/dart-lang/fletch/issues/new
+
+Please include the following information:
+
+* the name and version of your operating system
+
+* the entire message you see here (including the full stack trace
+  below as well as the source location above)
+""";
+
+// TODO(ahe): Include build ID.
+const String requestBugReportOnOtherCrashMessage = """
+The Fletch program is broken and has crashed.
+
+The Fletch team would greatly appreciate if you would take a moment to
+report this problem at https://github.com/dart-lang/fletch/issues/new
+
+Please include the following information:
+
+* the name and version of your operating system
+
+* the entire message you see here (including the full stack trace below)
+""";