added a new behaviour for responses that enable the tuple to be in the form of (response, headers) and continiue to support the (response, status, headers) format.

docs/quickstart.rst

@@ -676,9 +676,9 @@ converting return values into response objects is as follows:
     default parameters.
 3.  If a tuple is returned the items in the tuple can provide extra
     information.  Such tuples have to be in the form ``(response, status,
-    headers)`` where at least one item has to be in the tuple.  The
-    `status` value will override the status code and `headers` can be a
-    list or dictionary of additional header values.
+    headers)`` or ``(response, headers)`` where at least one item has
+    to be in the tuple.  The `status` value will override the status code
+    and `headers` can be a list or dictionary of additional header values.
 4.  If none of that works, Flask will assume the return value is a
     valid WSGI application and convert that into a response object.
 

flask/app.py

@@ -1544,7 +1544,8 @@ class Flask(_PackageBoundObject):
         a WSGI function         the function is called as WSGI application
                                 and buffered as response object
         :class:`tuple`          A tuple in the form ``(response, status,
-                                headers)`` where `response` is any of the
+                                headers)`` or ``(response, headers)``
+                                where `response` is any of the
                                 types defined here, `status` is a string
                                 or an integer and `headers` is a list or
                                 a dictionary with header values.
@@ -1556,34 +1557,38 @@ class Flask(_PackageBoundObject):
            Previously a tuple was interpreted as the arguments for the
            response object.
         """
-        status = headers = None
+        status_or_headers = headers = None
         if isinstance(rv, tuple):
-            rv, status, headers = rv + (None,) * (3 - len(rv))
+            rv, status_or_headers, headers = rv + (None,) * (3 - len(rv))
 
         if rv is None:
             raise ValueError('View function did not return a response')
 
+        if isinstance(status_or_headers, (dict, list)):
+            headers, status_or_headers = status_or_headers, None
+
         if not isinstance(rv, self.response_class):
             # When we create a response object directly, we let the constructor
             # set the headers and status.  We do this because there can be
             # some extra logic involved when creating these objects with
             # specific values (like default content type selection).
             if isinstance(rv, (text_type, bytes, bytearray)):
-                rv = self.response_class(rv, headers=headers, status=status)
-                headers = status = None
+                rv = self.response_class(rv, headers=headers, status=status_or_headers)
+                headers = status_or_headers = None
             else:
                 rv = self.response_class.force_type(rv, request.environ)
 
-        if status is not None:
-            if isinstance(status, string_types):
-                rv.status = status
+        if status_or_headers is not None:
+            if isinstance(status_or_headers, string_types):
+                rv.status = status_or_headers
             else:
-                rv.status_code = status
+                rv.status_code = status_or_headers
         if headers:
             rv.headers.extend(headers)
 
         return rv
 
+
     def create_url_adapter(self, request):
         """Creates a URL adapter for the given request.  The URL adapter
         is created at a point where the request context is not yet set up

flask/testsuite/basic.py

@@ -735,7 +735,17 @@ class BasicFunctionalityTestCase(FlaskTestCase):
             return 'Meh', 400, {
                 'X-Foo': 'Testing',
                 'Content-Type': 'text/plain; charset=utf-8'
+            } 
+        @app.route("/two_args")
+        def from_two_args_tuple():
+            return "Hello", {
+                'X-Foo': 'Test',
+                'Content-Type': 'text/plain; charset=utf-8'
             }
+        @app.route("/args_status")
+        def from_status_tuple():
+            return "Hi, status!", 400
+
         c = app.test_client()
         self.assert_equal(c.get('/unicode').data, u'Hällo Wörld'.encode('utf-8'))
         self.assert_equal(c.get('/string').data, u'Hällo Wörld'.encode('utf-8'))
@@ -745,6 +755,18 @@ class BasicFunctionalityTestCase(FlaskTestCase):
         self.assert_equal(rv.status_code, 400)
         self.assert_equal(rv.mimetype, 'text/plain')
 
+        rv2 = c.get("/two_args")
+        self.assert_equal(rv2.data, b'Hello')
+        self.assert_equal(rv2.headers['X-Foo'], 'Test')
+        self.assert_equal(rv2.status_code, 200)
+        self.assert_equal(rv2.mimetype, 'text/plain')
+
+        rv3 = c.get("/args_status")
+        self.assert_equal(rv3.data, b'Hi, status!')
+        self.assert_equal(rv3.status_code, 400)
+        self.assert_equal(rv3.mimetype, 'text/html')
+
+
     def test_make_response(self):
         app = flask.Flask(__name__)
         with app.test_request_context():