Isolate.spawn{Uri} only reports errors asynchronously.

runtime/lib/isolate_patch.dart

Index: runtime/lib/isolate_patch.dart
diff --git a/runtime/lib/isolate_patch.dart b/runtime/lib/isolate_patch.dart
index 3792a5b4d2ddbdee1d72446d80c67cae5cd82062..7757cfa79dba30f1810f9574153bc876db0e1b21 100644
--- a/runtime/lib/isolate_patch.dart
+++ b/runtime/lib/isolate_patch.dart
@@ -241,8 +241,11 @@ patch class Isolate {
         completer.complete(new Isolate._fromControlPort(controlPort));
       };
     } catch(e, st) {
-      // TODO(14718): we want errors to go into the returned future.
-      rethrow;
+      // Don't complete immediately with an error, since the caller didn't
+      // yet have the time to install an error handler.

[Ivan Posva, 2013/12/12 12:11:49]

time -> opportunity

[floitsch, 2013/12/12 21:08:37]

Done.

+      scheduleMicrotask(() {
+        completer.completeError(e, st);
+      });
     };
     return completer.future;
   }
@@ -261,8 +264,11 @@ patch class Isolate {
         completer.complete(new Isolate._fromControlPort(controlPort));
       };
     } catch(e, st) {
-      // TODO(14718): we want errors to go into the returned future.
-      rethrow;
+      // Don't complete immediately with an error, since the caller didn't
+      // yet have the time to install an error handler.

[Ivan Posva, 2013/12/12 12:11:49]

ditto

[floitsch, 2013/12/12 21:08:37]

Done.

+      scheduleMicrotask(() {
+        completer.completeError(e, st);
+      });
     };
     return completer.future;
   }