Allow setting break-on-exceptions option over the service protocol.

runtime/observatory/lib/src/elements/debugger.dart

 // Copyright (c) 2014, 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.
 
 library debugger_page_element;
 
 import 'dart:async';
 import 'dart:html';
 import 'observatory_element.dart';
 import 'package:observatory/app.dart';
@@ skipping 348 matching lines @@
 
   String helpShort =
       'Continue running the isolate until the current function exits';
 
   String helpLong =
       'Continue running the isolate until the current function exits.\n'
       '\n'
       'Syntax: finish\n';
 }
 
+class BreakOnExceptionsCommand extends DebuggerCommand {
+  BreakOnExceptionsCommand(Debugger debugger)
+      : super(debugger, 'break-on-exceptions', []);

[rmacnak, 2015/06/11 17:31:17]

Don't really want to introduce the first hyphenated command...

[Cutch, 2015/06/11 21:20:12]

What about a 'set' command for configuring behaviour?

[rmacnak, 2015/06/12 00:09:38]

Somewhat better.

+
+  Future run(List<String> args) async {
+    if (args.length == 0) {
+      var result = await debugger.isolate.getExceptionPauseInfo();
+      debugger.console.print(result.toString());
+    } else if (args.length == 1) {
+      var result = await debugger.isolate.setExceptionPauseInfo(args[0]);
+      debugger.console.print(result.toString());
+    } else {
+      debugger.console.print("break-on-exceptions expects 0 or 1 argument");
+    }
+  }
+
+  String helpShort =
+      'Set the break-on-exceptions policy: all, none or unhandled';
+
+  String helpLong =
+      'Set the break-on-exceptions policy: all, none or unhandled'
+      '\n'
+      'Syntax: break-on-exceptions "all" | "none" | "unhandled"'
+      '- Set the policy\n'
+      '        break-on-exceptions                             '
+      '- Query the policy\n';
+}
+
 class BreakCommand extends DebuggerCommand {
   BreakCommand(Debugger debugger) : super(debugger, 'break', []);
 
   Future run(List<String> args) async {
     if (args.length > 1) {
       debugger.console.print('not implemented');
       return new Future.value(null);
     }
     var arg = (args.length == 0 ? '' : args[0]);
     var loc = await DebuggerLocation.parse(debugger, arg);
@@ skipping 470 matching lines @@
         new PrintCommand(this),
         new DownCommand(this),
         new UpCommand(this),
         new FrameCommand(this),
         new PauseCommand(this),
         new ContinueCommand(this),
         new NextCommand(this),
         new StepCommand(this),
         new FinishCommand(this),
         new BreakCommand(this),
+        new BreakOnExceptionsCommand(this),
         new ClearCommand(this),
         new DeleteCommand(this),
         new InfoCommand(this),
         new IsolateCommand(this),
         new RefreshCommand(this),
     ]);
   }
 
   VM get vm => page.app.vm;
 
@@ skipping 116 matching lines @@
       Frame frame = stack['frames'][0];
       var script = frame.location.script;
       script.load().then((_) {
         var line = script.tokenToLine(frame.location.tokenPos);
         var col = script.tokenToCol(frame.location.tokenPos);
         if (event.breakpoint != null) {
           var bpId = event.breakpoint.number;
           console.print('Paused at breakpoint ${bpId} at '
                         '${script.name}:${line}:${col}');
         } else if (event.exception != null) {
-          // TODO(turnidge): Test this.
-          console.print('Paused due to exception ${event.exception} at '
+          console.print('Paused due to exception at '
                         '${script.name}:${line}:${col}');
+          // This seems to be missing if we are paused-at-exception after
+          // paused-at-isolate-exit. Maybe we shutdown part of the debugger too
+          // soon?
+          console.printRef(event.exception);
         } else {
           console.print('Paused at ${script.name}:${line}:${col}');
         }
       });
     }
   }
 
   Future _reportBreakpointEvent(ServiceEvent event) {
     var bpt = event.breakpoint;
     var verb = null;
@@ skipping 655 matching lines @@
           default:
             busy = false;
             break;
         }
       });
   }
 
   DebuggerInputElement.created() : super.created();
 }