From 8c55f5eb159ae85d468a89b74ffaff3e824144ab Mon Sep 17 00:00:00 2001
From: Eugenio Lacuesta <eugenio.lacuesta@gmail.com>
Date: Fri, 3 Aug 2018 15:16:26 -0300
Subject: [PATCH] Simplify check for re-raised exception. Add tests.

---
 scrapy/core/spidermw.py                       |  4 ++--
 ...lid_values.py => test_spidermiddleware.py} | 20 +++++++++++++++++++
 2 files changed, 22 insertions(+), 2 deletions(-)
 rename tests/{test_spidermiddleware_invalid_values.py => test_spidermiddleware.py} (79%)

diff --git a/scrapy/core/spidermw.py b/scrapy/core/spidermw.py
index 1b67af130..4268c91d6 100644
--- a/scrapy/core/spidermw.py
+++ b/scrapy/core/spidermw.py
@@ -103,7 +103,7 @@ class SpiderMiddlewareManager(MiddlewareManager):
                         yield r
                 except Exception as ex:
                     exception_result = process_spider_exception(Failure(ex), index+1)
-                    if exception_result is None or isinstance(exception_result, Failure):
+                    if isinstance(exception_result, Failure):
                         raise
                     recovered.extend(exception_result)
 
@@ -115,7 +115,7 @@ class SpiderMiddlewareManager(MiddlewareManager):
                     result = method(response=response, result=result, spider=spider)
                 except Exception as ex:
                     exception_result = process_spider_exception(Failure(ex), method_index+1)
-                    if exception_result is None or isinstance(exception_result, Failure):
+                    if isinstance(exception_result, Failure):
                         raise
                     return exception_result
                 if _isiterable(result):
diff --git a/tests/test_spidermiddleware_invalid_values.py b/tests/test_spidermiddleware.py
similarity index 79%
rename from tests/test_spidermiddleware_invalid_values.py
rename to tests/test_spidermiddleware.py
index 0d9af8951..54756f2ff 100644
--- a/tests/test_spidermiddleware_invalid_values.py
+++ b/tests/test_spidermiddleware.py
@@ -80,3 +80,23 @@ class ProcessSpiderExceptionInvalidOutput(SpiderMiddlewareTestCase):
         result = self._scrape_response()
         self.assertIsInstance(result, Failure)
         self.assertIsInstance(result.value, _InvalidOutput)
+
+
+class ProcessSpiderExceptionReRaise(SpiderMiddlewareTestCase):
+    """Re raise the exception by returning None"""
+
+    def test_process_spider_exception_return_none(self):
+
+        class ProcessSpiderOutputExceptionReturnNoneMiddleware:
+            def process_spider_exception(self, response, exception, spider):
+                return None
+
+        class RaiseExceptionProcessSpiderOutputMiddleware:
+            def process_spider_output(self, response, result, spider):
+                1/0
+
+        self.mwman._add_middleware(ProcessSpiderOutputExceptionReturnNoneMiddleware())
+        self.mwman._add_middleware(RaiseExceptionProcessSpiderOutputMiddleware())
+        result = self._scrape_response()
+        self.assertIsInstance(result, Failure)
+        self.assertIsInstance(result.value, ZeroDivisionError)