Fix repeated breadcrumbs when optional trailing slash is used

rest_framework/utils/breadcrumbs.py

@@ -6,7 +6,7 @@ def get_breadcrumbs(url):
 
     from rest_framework.views import APIView
 
-    def breadcrumbs_recursive(url, breadcrumbs_list, prefix):
+    def breadcrumbs_recursive(url, breadcrumbs_list, prefix, seen):
         """Add tuples of (name, url) to the breadcrumbs list, progressively chomping off parts of the url."""
 
         try:
@@ -16,7 +16,11 @@ def get_breadcrumbs(url):
         else:
             # Check if this is a REST framework view, and if so add it to the breadcrumbs
             if isinstance(getattr(view, 'cls_instance', None), APIView):
+                # Don't list the same view twice in a row.
+                # Probably an optional trailing slash.
+                if not seen or seen[-1] != view:
                     breadcrumbs_list.insert(0, (view.cls_instance.get_name(), prefix + url))
+                    seen.append(view)
 
         if url == '':
             # All done
@@ -24,11 +28,11 @@ def get_breadcrumbs(url):
 
         elif url.endswith('/'):
             # Drop trailing slash off the end and continue to try to resolve more breadcrumbs
-            return breadcrumbs_recursive(url.rstrip('/'), breadcrumbs_list, prefix)
+            return breadcrumbs_recursive(url.rstrip('/'), breadcrumbs_list, prefix, seen)
 
         # Drop trailing non-slash off the end and continue to try to resolve more breadcrumbs
-        return breadcrumbs_recursive(url[:url.rfind('/') + 1], breadcrumbs_list, prefix)
+        return breadcrumbs_recursive(url[:url.rfind('/') + 1], breadcrumbs_list, prefix, seen)
 
     prefix = get_script_prefix().rstrip('/')
     url = url[len(prefix):]
-    return breadcrumbs_recursive(url, [], prefix)
+    return breadcrumbs_recursive(url, [], prefix, [])