From d12d73263f5d1664a65a42f71f19158b7e07ef2c Mon Sep 17 00:00:00 2001
From: Armin Ronacher <armin.ronacher@active-4.com>
Date: Mon, 12 Jul 2010 18:04:10 +0200
Subject: [PATCH] Reverse order of execution of post-request handlers.  This
 fixes #82

---
 CHANGES              |  3 +++
 docs/upgrading.rst   | 11 +++++++++++
 flask/app.py         |  8 ++++++--
 tests/flask_tests.py | 24 ++++++++++++++++++++++++
 4 files changed, 44 insertions(+), 2 deletions(-)

diff --git a/CHANGES b/CHANGES
index 840d1a3d..c09b9e04 100644
--- a/CHANGES
+++ b/CHANGES
@@ -8,6 +8,9 @@ Version 0.6
 
 Release date to be announced, codename to be decided.
 
+- after request functions are now called in reverse order of
+  registration.
+
 Version 0.5.1
 -------------
 
diff --git a/docs/upgrading.rst b/docs/upgrading.rst
index 7ee35176..f3a7a27d 100644
--- a/docs/upgrading.rst
+++ b/docs/upgrading.rst
@@ -19,6 +19,17 @@ installation, make sure to pass it the ``-U`` parameter::
 
     $ easy_install -U Flask
 
+Version 0.6
+-----------
+
+Flask 0.6 comes with a backwards incompatible change which affects the
+order of after-request handlers.  Previously they were called in the order
+of the registration, now they are called in reverse order.  This change
+was made so that Flask behaves more like people expected it to work and
+how other systems handle request pre- and postprocessing.  If you
+dependend on the order of execution of post-request functions, be sure to
+change the order.
+
 Version 0.5
 -----------
 
diff --git a/flask/app.py b/flask/app.py
index d16613b7..49852e5e 100644
--- a/flask/app.py
+++ b/flask/app.py
@@ -707,6 +707,10 @@ class Flask(_PackageBoundObject):
         before it's sent to the WSGI server.  By default this will
         call all the :meth:`after_request` decorated functions.
 
+        .. versionchanged:: 0.5
+           As of Flask 0.5 the functions registered for after request
+           execution are called in reverse order of registration.
+
         :param response: a :attr:`response_class` object.
         :return: a new response object or the same, has to be an
                  instance of :attr:`response_class`.
@@ -717,9 +721,9 @@ class Flask(_PackageBoundObject):
             self.save_session(ctx.session, response)
         funcs = ()
         if mod and mod in self.after_request_funcs:
-            funcs = chain(funcs, self.after_request_funcs[mod])
+            funcs = reversed(self.after_request_funcs[mod])
         if None in self.after_request_funcs:
-            funcs = chain(funcs, self.after_request_funcs[None])
+            funcs = chain(funcs, reversed(self.after_request_funcs[None]))
         for handler in funcs:
             response = handler(response)
         return response
diff --git a/tests/flask_tests.py b/tests/flask_tests.py
index 5b4f34ef..380ecdad 100644
--- a/tests/flask_tests.py
+++ b/tests/flask_tests.py
@@ -318,6 +318,30 @@ class BasicFunctionalityTestCase(unittest.TestCase):
         assert 'Internal Server Error' in rv.data
         assert len(called) == 1
 
+    def test_before_after_request_order(self):
+        called = []
+        app = flask.Flask(__name__)
+        @app.before_request
+        def before1():
+            called.append(1)
+        @app.before_request
+        def before2():
+            called.append(2)
+        @app.after_request
+        def after1(response):
+            called.append(4)
+            return response
+        @app.after_request
+        def after1(response):
+            called.append(3)
+            return response
+        @app.route('/')
+        def index():
+            return '42'
+        rv = app.test_client().get('/')
+        assert rv.data == '42'
+        assert called == [1, 2, 3, 4]
+
     def test_error_handling(self):
         app = flask.Flask(__name__)
         @app.errorhandler(404)