From ec8e7f27e7250b7fb93fbf3ee01e03b94643311b Mon Sep 17 00:00:00 2001
From: Tom Christie <tom@tomchristie.com>
Date: Tue, 19 May 2015 15:49:37 +0100
Subject: [PATCH] Fixes for format preservation

---
 rest_framework/renderers.py         |  2 +-
 rest_framework/reverse.py           | 27 +++++++++++++++++++++++----
 rest_framework/utils/breadcrumbs.py |  7 ++++---
 3 files changed, 28 insertions(+), 8 deletions(-)

diff --git a/rest_framework/renderers.py b/rest_framework/renderers.py
index 93400c0bb..bfc8bd5cb 100644
--- a/rest_framework/renderers.py
+++ b/rest_framework/renderers.py
@@ -586,7 +586,7 @@ class BrowsableAPIRenderer(BaseRenderer):
         return view.get_view_description(html=True)
 
     def get_breadcrumbs(self, request):
-        return get_breadcrumbs(request.path)
+        return get_breadcrumbs(request.path, request)
 
     def get_context(self, data, accepted_media_type, renderer_context):
         """
diff --git a/rest_framework/reverse.py b/rest_framework/reverse.py
index 7235ac5d4..7cb910274 100644
--- a/rest_framework/reverse.py
+++ b/rest_framework/reverse.py
@@ -10,6 +10,27 @@ from rest_framework.settings import api_settings
 from rest_framework.utils.urls import replace_query_param
 
 
+def preserve_builtin_query_params(url, request=None):
+    """
+    Given an incoming request, and an outgoing URL representation,
+    append the value of any built-in query parameters.
+    """
+    if request is None:
+        return url
+
+    overrides = [
+        api_settings.URL_FORMAT_OVERRIDE,
+        api_settings.URL_ACCEPT_OVERRIDE
+    ]
+
+    for param in overrides:
+        if param and (param in request.GET):
+            value = request.GET[param]
+            url = replace_query_param(url, param, value)
+
+    return url
+
+
 def reverse(viewname, args=None, kwargs=None, request=None, format=None, **extra):
     """
     If versioning is being used then we pass any `reverse` calls through
@@ -27,10 +48,8 @@ def reverse(viewname, args=None, kwargs=None, request=None, format=None, **extra
     else:
         url = _reverse(viewname, args, kwargs, request, format, **extra)
 
-    FORMAT_OVERRIDE = api_settings.URL_FORMAT_OVERRIDE
-    if FORMAT_OVERRIDE and (FORMAT_OVERRIDE in request.query_params):
-        return replace_query_param(url, FORMAT_OVERRIDE, request.query_params[FORMAT_OVERRIDE])
-    return url
+    return preserve_builtin_query_params(url, request)
+
 
 def _reverse(viewname, args=None, kwargs=None, request=None, format=None, **extra):
     """
diff --git a/rest_framework/utils/breadcrumbs.py b/rest_framework/utils/breadcrumbs.py
index e6690d170..b2a74376e 100644
--- a/rest_framework/utils/breadcrumbs.py
+++ b/rest_framework/utils/breadcrumbs.py
@@ -2,12 +2,12 @@ from __future__ import unicode_literals
 from django.core.urlresolvers import resolve, get_script_prefix
 
 
-def get_breadcrumbs(url):
+def get_breadcrumbs(url, request=None):
     """
     Given a url returns a list of breadcrumbs, which are each a
     tuple of (name, url).
     """
-
+    from rest_framework.reverse import preserve_builtin_query_params
     from rest_framework.settings import api_settings
     from rest_framework.views import APIView
 
@@ -33,7 +33,8 @@ def get_breadcrumbs(url):
                 if not seen or seen[-1] != view:
                     suffix = getattr(view, 'suffix', None)
                     name = view_name_func(cls, suffix)
-                    breadcrumbs_list.insert(0, (name, prefix + url))
+                    insert_url = preserve_builtin_query_params(prefix + url, request)
+                    breadcrumbs_list.insert(0, (name, insert_url))
                     seen.append(view)
 
         if url == '':