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:

tests/test_schema_generator.py

@@ -2,7 +2,9 @@ import json
 from collections import OrderedDict
 
 import pytest
+from django.conf.urls import url
 from rest_framework import routers, serializers, viewsets
+from rest_framework.decorators import api_view
 from rest_framework.response import Response
 
 from drf_yasg import codecs, openapi
@@ -113,3 +115,35 @@ def test_replaced_serializer():
         responses = swagger['paths']['/details/{id}/']['get']['responses']
         assert '404' in responses
         assert responses['404']['schema']['$ref'] == "#/definitions/Detail"
+
+
+def test_url_order():
+    # this view with description override should show up in the schema ...
+    @swagger_auto_schema(method='get', operation_description="description override")
+    @api_view()
+    def test_override(request, pk=None):
+        return Response({"message": "Hello, world!"})
+
+    # ... instead of this view which appears later in the url patterns
+    @api_view()
+    def test_view(request, pk=None):
+        return Response({"message": "Hello, world!"})
+
+    patterns = [
+        url(r'^/test/$', test_override),
+        url(r'^/test/$', test_view),
+    ]
+
+    generator = OpenAPISchemaGenerator(
+        info=openapi.Info(title="Test generator", default_version="v1"),
+        version="v2",
+        url='',
+        patterns=patterns
+    )
+
+    # description override is successful
+    swagger = generator.get_schema(None, True)
+    assert swagger['paths']['/test/']['get']['description'] == 'description override'
+
+    # get_endpoints only includes one endpoint
+    assert len(generator.get_endpoints(None)['/test/'][1]) == 1