From f4df2a3b2a9c37e31458e94cb09669ac17a70f11 Mon Sep 17 00:00:00 2001
From: Tim Schaub <tim.schaub@gmail.com>
Date: Fri, 21 Dec 2007 23:42:05 +0000
Subject: [PATCH] Changing prototype.js ajax stuff so exceptions aren't
 swallowed by default.  If you want this behavior, set
 request.options.onException to something that swallows, or use
 OpenLayers.Ajax.Responders.register for onException.  r=crschmidt (closes
 #1232)

git-svn-id: http://svn.openlayers.org/trunk/openlayers@5567 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf
---
 lib/OpenLayers/Ajax.js | 41 ++++++++++++++++++++++++++++++++++++++---
 1 file changed, 38 insertions(+), 3 deletions(-)

diff --git a/lib/OpenLayers/Ajax.js b/lib/OpenLayers/Ajax.js
index 28ff35c90e..df42d33544 100644
--- a/lib/OpenLayers/Ajax.js
+++ b/lib/OpenLayers/Ajax.js
@@ -493,14 +493,49 @@ OpenLayers.Ajax.Request = OpenLayers.Class(OpenLayers.Ajax.Base, {
 
     /**
      * Method: dispatchException
+     * If the optional onException function is set, execute it
+     * and then dispatch the call to any other listener registered
+     * for onException.
+     * 
+     * If no optional onException function is set, we suspect that
+     * the user may have also not used
+     * OpenLayers.Ajax.Responders.register to register a listener
+     * for the onException call.  To make sure that something
+     * gets done with this exception, only dispatch the call if there
+     * are listeners.
+     *
+     * If you explicitly want to swallow exceptions, set
+     * request.options.onException to an empty function (function(){})
+     * or register an empty function with <OpenLayers.Ajax.Responders>
+     * for onException.
      * 
      * Parameters:
      * exception - {?}
      */
     dispatchException: function(exception) {
-        (this.options.onException ||
-            OpenLayers.Ajax.emptyFunction)(this, exception);
-        OpenLayers.Ajax.Responders.dispatch('onException', this, exception);
+        var handler = this.options.onException;
+        if(handler) {
+            // call options.onException and alert any other listeners
+            handler(this, exception);
+            OpenLayers.Ajax.Responders.dispatch('onException', this, exception);
+        } else {
+            // check if there are any other listeners
+            var listener = false;
+            var responders = OpenLayers.Ajax.Responders.responders;
+            for (var i = 0; i < responders.length; i++) {
+                if(responders[i].onException) {
+                    listener = true;
+                    break;
+                }
+            }
+            if(listener) {
+                // call all listeners
+                OpenLayers.Ajax.Responders.dispatch('onException', this, exception);
+            } else {
+                // let the exception through
+                throw exception;
+            }
+        }
     }
 });