Trigger debug event on not yet caught exception in promises.

test/mjsunit/es6/debug-promises-uncaught.js

Index: test/mjsunit/es6/debug-promises-uncaught.js
diff --git a/test/mjsunit/es6/debug-promises-uncaught.js b/test/mjsunit/es6/debug-promises-uncaught.js
new file mode 100644
index 0000000000000000000000000000000000000000..0e85b354e699575d0f7d3a4795298f457d836fb2
--- /dev/null
+++ b/test/mjsunit/es6/debug-promises-uncaught.js
@@ -0,0 +1,57 @@
+// Copyright 2014 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --harmony-promises --expose-debug-as debug
+
+Debug = debug.Debug;
+
+var resolve_fun;
+var log = [];
+var step = 0;
+var exception = undefined;
+
+var p = new Promise(function(resolve, reject) {
+  log.push("resolve");
+  resolve();
+});
+
+var q = p.chain(
+  function() {
+    log.push("throw");
+    throw new Error("uncaught");
+  });
+
+function listener(event, exec_state, event_data, data) {
+  try {
+    // Ignore exceptions during startup in stress runs.
+    if (step > 1) return;
+    assertEquals(["resolve", "end main", "throw"], log);
+    if (event == Debug.DebugEvent.Exception) {

[yurys, 2014/04/24 08:49:50]

Would be nice to also test that this branch is not executed if
Debug.setBreakOnUncaughtException(); was called instead of
Debug.setBreakOnException(); at line 54. That would match "Pause on uncaught
exceptions only" in DevTools.

+      assertEquals(0, step);
+      exception = event_data.exception();
+      assertEquals(undefined, event_data.promise());
+    } else if (event == Debug.DebugEvent.PendingExceptionInPromise) {
+      assertEquals(1, step);
+      assertEquals(exception, event_data.exception());
+      assertEquals("uncaught", exception.message);
+      assertTrue(event_data.promise() instanceof Promise);
+      assertTrue(event_data.uncaught());
+    } else {
+      return;
+    }
+    step++;
+  } catch (e) {
+    // Signal a failure with exit code 1.  This is necessary since the
+    // debugger swallows exceptions and we expect the chained function
+    // and this listener to be executed after the main script is finished.
+    print("Unexpected exception:");

[rossberg, 2014/04/24 08:08:38]

Nit: don't need a newline after this

[Yang, 2014/04/24 10:42:04]

Done.

+    print(e + "\n" + e.stack);
+    quit(1);
+  }
+}
+
+Debug.setBreakOnException();
+Debug.setListener(listener);
+
+log.push("end main");