fix for request's errback, allows to get failed requests correctly

scrapy/core/engine.py

@@ -200,16 +200,12 @@ class ExecutionEngine(object):
                     response=response, request=request, spider=spider)
             return response
 
-        def _on_error(failure):
-            failure.request = request
-            return failure
-
         def _on_complete(_):
             slot.nextcall.schedule()
             return _
 
         dwld = self.downloader.fetch(request, spider)
-        dwld.addCallbacks(_on_success, _on_error)
+        dwld.addCallbacks(_on_success)
         dwld.addBoth(_on_complete)
         return dwld
 

scrapy/core/scraper.py

@@ -136,6 +136,7 @@ class Scraper(object):
                 request_result, request, spider)
 
     def call_spider(self, result, request, spider):
+        result.request = request
         dfd = defer_result(result)
         dfd.addCallbacks(request.callback or spider.parse, request.errback)
         return dfd.addCallback(iterate_spider_output)