Handle duplicate urls in urlconf (#155)

Django resolves urls in order from top to bottom, and only uses the first matching URL found.

src/drf_yasg/generators.py

@@ -72,7 +72,7 @@ class EndpointEnumerator(_EndpointEnumerator):
 
         return path
 
-    def get_api_endpoints(self, patterns=None, prefix='', app_name=None, namespace=None):
+    def get_api_endpoints(self, patterns=None, prefix='', app_name=None, namespace=None, previously_seen_endpoints=None):
         """
         Return a list of all available API endpoints by inspecting the URL conf.
 
@@ -82,6 +82,8 @@ class EndpointEnumerator(_EndpointEnumerator):
             patterns = self.patterns
 
         api_endpoints = []
+        if previously_seen_endpoints is None:
+            previously_seen_endpoints = set()
 
         for pattern in patterns:
             path_regex = prefix + get_original_route(pattern)
@@ -92,6 +94,13 @@ class EndpointEnumerator(_EndpointEnumerator):
                     url_name = pattern.name
                     if self.should_include_endpoint(path, callback, app_name or '', namespace or '', url_name):
                         path = self.replace_version(path, callback)
+
+                        # avoid adding endpoints that have already been seen,
+                        # as Django resolves urls in top-down order
+                        if path in previously_seen_endpoints:
+                            continue
+                        previously_seen_endpoints.add(path)
+
                         for method in self.get_allowed_methods(callback):
                             endpoint = (path, method, callback)
                             api_endpoints.append(endpoint)
@@ -103,7 +112,8 @@ class EndpointEnumerator(_EndpointEnumerator):
                     patterns=pattern.url_patterns,
                     prefix=path_regex,
                     app_name="%s:%s" % (app_name, pattern.app_name) if app_name else pattern.app_name,
-                    namespace="%s:%s" % (namespace, pattern.namespace) if namespace else pattern.namespace
+                    namespace="%s:%s" % (namespace, pattern.namespace) if namespace else pattern.namespace,
+                    previously_seen_endpoints=previously_seen_endpoints
                 )
                 api_endpoints.extend(nested_endpoints)
             else: